Clinical Radiology

Last updated on January 11, 2020 at 11:30

Radiopaedia

Radiopaedia.org is your golden bible for this subject – you’ll find almost everything you need there, especially images. If you search for a pathology you’ll get cases of that pathology. There are even annotated cases. You can filter by these by filtering study modality -> annotated image.

This helpful man in the radiology department has made playlists of radiology cases which you can check out.

Flashcards for radiopharmaceuticals

Frequently shown pictures on the exam

1. The fundamentals of X-ray imaging. X-ray equipments. Radiation protection.

  • Fundamentals of x-ray
    • X-rays (electromagnetic radiation with a wavelength of 0,01 – 10 nm
      • Hard x-rays
        • Higher energy
        • > 90 kV
        • Wavelength < 0,1 nm
        • Penetrate tissues better
        • The type mostly used in medicine
      • Soft x-rays
        • Lower energy
        • < 40 kV
        • Wavelength > 0,1 nm
        • Highlights differences between tissues with similar x-ray absorption
          • Used in mammography
    • Different tissues absorb different amount of radiation depending on the density and componsition
      • The radiation which is not absorbed will hit a detector behind the patient
      • Different tissues range from radiolucent (black on the screen) to radiopaque (white on the screen)
      • There are four basic tissue densities visible on x-ray
        • Air
          • Black/very dark
        • Fat
          • Dark gray
          • Darker than water
        • Water (blood, soft tissue)
          • Light gray
        • Bone/calcium/metal/contrast agents
          • Almost white
    • Regular x-rays account for 75% of imaging examinations
    • Distortion
      • = how anatomical structures are misrepresented on an x-ray
      • Due to
        • Superimposition (stuff over other stuff)
        • Forgetting (some of the information is lost due to x-ray scattering)
        • Magnification (stuff looks bigger than they are)
    • Contrast agents
      • Agents which are radiopaque
        • They fill a hollow or tublar organ
      • Can be given IV, orally, rectally, by catheter…
      • They work by the photoelectric effect
      • Contraindications
        • Pregnancy
        • Use of metformin
        • Previous reaction to contrast
        • Renal disease
        • Hyperthyroidism
      • Permits visuazilation of anatomical structures which are not normally seen
        • Blood vessels
      • Small risk for contrast reaction if given IV or intraarterially
        • Mild
          • Metallic taste
          • Feeling of warmth
        • Moderate
          • Reduced renal function
          • Vomiting
          • Hives
        • Severe
          • Vasovagal syncope
          • Laryngeal oedema
          • Severe hypotension
          • Anaphylaxis
        • Late reactions (after 1 hour)
          • Skin reactions
          • Contrast-induced nephropathy (renal failure)
      • Examples
        • Barium
        • Iodine
  • Components
    • X-ray tube – produces X-rays
      • Anode
        • Made of tungsten disc
          • Tungsten and wolfram are the same!
        • The positive terminal
        • It’s the target of electrons
      • Cathode
        • Made of tungsten filament
        • The negative terminal
        • It’s the source of electrons
    • Generator
      • Gives power to the x-ray tube
      • The energy of the x-ray depends on the tube voltage (accelerating voltage)
      • The amount of x-rays depends on the cathode current
    • Gantry
      • = Radiation source + detector
    • Table
      • Floating table, can be moved
    • Detector
      • Film/screen (old)
      • Computed radiography (modern)
        • Digital
        • X-rays hit a plate that absorbs the x-rays and stores the energy at a specific location
        • The plate is scanned by a laser, which detects the energies at the different locations
        • The location is detected and stored in a computer
      • Digital radiography (modern)
        • X-rays hit a detector and is converted into light or an electrical charge immediately -> stored in the computer
    • Control panel
      • To control the energy, etc
  • Production of x-rays
    • X-rays are produced in two ways
      • Both types occur in the same x-ray
      • Bremsstrahlung (breaking radiation)
        • A fast-moving electron is attracted to the positively charged nucleus
        • This will slow down the electron, causing it to lose some kinetic energy (speed)
        • This kinetic energy will be released as gamma radiation
        • Bremsstrahlung can have have a large range of energies
          • This causes a continous spectrum of energies
      • Characteristic radiation
        • A fast-moving electron collides with an electron in a shell of an atom in the anode, the electron in the shell is ejected
        • Another electron from an upper shell will take its place
        • This releases gamma radiation
        • This radiation only has characteristic amounts of energy, causing a line spectrum of energies
        • In a mammograpy there is more characteristic radiation than in other types of x-ray images
        • The characteristic elements depend on the material of the anode!
  • Types of regular x-rays
    • Chest radiographs
      • 120 kV tube voltage used 
      • Posteroanterior (PA)
        • Most common
        • Patient’s chest faces the detector
        • X-rays come from behind the patient (from posterior to anterior)
      • Anteroposterior (AP)
        • Rare
        • Less used because the heart appears larger than it really is
    • Abdominal radiographs
    • Bone radiographs
      • 50 – 100 kV
  • Fluoroscopy
    • = Real-time x-ray imaging
    • 30 frames/second generally
    • 120 frames/second for heart imaging
    • Often used with contrast
      • Fluoroscopy allows you to see with high temporal solution (many fps) the movement of contrast
    • Can be recorded as a movie, and single frames can be examined
    • Indications
      • Interventional cardiology
      • Peripheral angiography
      • GI
      • Barium swallow
  • Radiation
    • Absorbed radiation is measured by Gray (Gy)
      • It does not take into account the biological effect of radiation
    • Health effects of radiation is measured by Sievert (Sv)
      • It does take into account the biological effect of radiation
    • Types of radiation used for therapy
      • Gamma rays (?)
        • Used in stereotactic radiosurgery with gamma knife
      • Alpha radiation
        • Radium-223
        • For example for bone metastases or prostate cancer
      • Beta radiation
        • Iodine-131
        • For example for thyroid cancer
    • Types of radiation used in diagnostics
      • Positron
        • PET scan
      • Gamma
        • X-ray
        • CT
        • Many nuclear imaging studies
    • X-ray interactions with matter
      • Compton scattering
        • Makes x-rays scatter off the patient -> the patient becomes the source of scattered radiation
          • This scattered radiation can hit personell or equipment
          • Personell and equipment should be protected
        • Reduces image contrast
      • Photoelectric effect
        • It’s what makes contrast agents work
      • Coherent/Rayleigh scattering
      • Pair production does NOT occur
        • Only at energy levels much higher than medical x-ray
    • Biological effects of radiation
      • Deterministic effects (nonrandom)
        • Examples
          • Skin erythema
          • Hair loss (3 Gy)
          • Sterility
          • Death (3 – 5 Gy)
        • Occur when the radiation-induced cell damage exceeds the cell’s ability to repair the damage
      • Stochastic effects (random)
        • May occur at any level of exposure
        • Probability for occuring increases with increasing dose
        • Severity is independent of the dose
        • Due to DNA and free radical damage
        • May occur years after exposure
        • Examples
          • Cancer
            • 10 mSv increases risk for cancer (0,04 mSv per x-ray)
      • Most radiosensitive organs
        • Organs with rapidly dividing cells
        • Bone marrow
        • Colon
        • Lung
        • Breast
        • Stomach
    • Protection from radiation
      • Radiation protection involves 3 parts
        • ALARA
        • Justifiable exposure
        • Dose limits
      • ALARA principle – as low as reasonably achievable
        • High quality images should be obtained by using the lowest possible dose
        • Factors contributing to reducing radiation
          • Beam collimators
            • Decrease scattering
          • Lead apron
          • Careful indications
            • Asking yourself whether the benefits outweigh the risk, and whether a non-radiating modality could be used instead
          • Standing far away from the patient as possible
          • Accurately setting the field of examination
      • Three major safety practices
        • Time – limiting exposure duration
        • Distance
          • According to the inverse square law one can reduce their exposure to 25% by standing twice as far away from the source
        • Shielding
          • Using lead to limit the amount of radiation exposure
      • Yearly occupational limit – < 20 mSv
      • Personal monitoring = dosimetry
        • Every person can carry a dosimeter which measures the radiation dose received

2. The fundamentals of CT and MRI imaging, examination methods.

  • Fundamentals of Computed Tomography (CT)
    • Passing a rotating fan beam of x-rays through the patient
      • Basically many x-rays at different angles around the patient
    • Computer can generate many images from different angles from a single examination
      • Can even generate a 3D image
    • 10 – 100x more radiation than x-ray
    • The appearance of tissues on CT
      • Densities are generally the same as for x-rays
      • Bright on CT = high density
      • Dark on CT = low density
      • The actual radiodensity of a tissue can be measured
        • The radiodensity of a tissue is expressed in Hounsfield units (HU) or CT numbers
          • HU is the reduction coefficient of the tissue relative to water
        • The HU of air is -1000
        • The HU of fat is -80
        • The HU of water is 0
        • The HU of blood is +50
    • Higher sensitivity than x-ray
    • Types
      • High-resolution computed tomography (HRCT)
        • For lung and skull
      • Dual energy CT (DECT)
    • CT scans are presented as a series of slices of tissue
      • Slices are always viewed as if from below the patient
        • I.e. structures on the patient’s right side is on the left of the image
        • Also true for MRi
      • The slices can be thick or thin
        • Thin slices (high-resolution CT):
          • Slower scanning
          • Increased dose (more pictures are taken)
          • Higher image detail
        • Thick slices:
          • Faster scanning
          • Lower dose
          • Worse image detail
    • Contrast agents
      • Used in 75% of all CT studies (contrast CT)
    • Windowing
      • Windowing is a process where the CT image is manipulated by a computer (the “window” is adjusted)
        • Adjusting the “window width” adjusts the range of CT numbers which are visible (changes contrast)
          • Example: A wide window shows tissues with CT numbers between 400 and 2000
            • Good for differentiating tissues with different radiodensity
            • Like air and soft tissue
          • A narrow window shows tissues with CT numbers between 50 and 350
            • Good for differentiating tissues with similar radiodensity
            • Like different soft tissues
        • Adjusting the “window length” or “window center” changes the brightness of the CT image
      • This manipulation changes the appearence of the picture to highlight certain structures
  • Magnetic resonance imaging
    • Magnetic fields applied to the body align hydrogen atoms in the body
      • When the fields are released, radio waves are released
      • These radio waves are detected, and the frequency of the waves depend on the environment of the atoms (the tissues)
    • Especially used for CNS, joints, heart, angiography (visualization of vessels)
    • Can’t be used for people with old pacemakers
      • (Can be used with new pacemakers)
    • MRi contrast agents
      • Molecular basis of them (I don’t understand what these mean)
        • Water content
        • Restricted water movement
        • Macromolecular motion
        • Lipid content
        • Paramagnetic ions
    • Types
      • T1 weighted
        • Fat is white
        • Water is dark
        • Brain, muscle is gray
        • Bone itself is dark BUT bone marrow (fat) is white
          • This makes bone look white
        • Gadolinium (contrast material) is white
        • More effective at visualizing normal anatomy
      • T2 weighted
        • Fat is dark
        • Blood, oedema, CSF is white
        • Brain, muscle is gray
        • More effective at visualizing inflammation
      • Diffusion weighted (DWI)
        • Measures how easy it is for water molecules to move around in a tissue
        • Ischaemic tissue is white
      • Proton density weighted (PD)
      • Flow sensitive
        • Time of flight (TOF) 
        • Can measure flow of fluids without contrast
        • MR angiography
        • MR venography
        • CSF flow studies
      • Fat or water saturation
        • Fluid-attenuated inversion recovery (FLAIR)
      • Short tau inversion recovery (STIR)
      • Diffusion tensor (DTI)
      • Susceptibility-weighted (SWI)
    • Advantages
      • No radiation
    • Disadvantages
      • Motion causes artifacts
      • Expensive
      • Strong magnets

3. Fundamentals of ultrasound physics. Ultrasound methods. Patient preparation before examination.

  • Fundamentals of ultrasound
    • High-frequency sound waves produced by a transducer are used to make images
      • 2 – 20 MHz 
      • Higher frequency waves penetrate less deeply into the tissue but has increased resolution
        • High-frequency waves used for superficial structures
        • Low-frequency waves used for deep structures
    • Image is made by sending high-frequency sound into the patient and measuring the magnitude and time of returning echoes
      • The echoes depend on the density of tissue
    • Different tissues give different echoes
      • Cyst -> Hypoechoic/anechoic (because it’s mostly water)
      • Homogenous tissues (liver, spleen -> homogenous small echoes
      • Calcium, fat, air -> hyperechoic
    • Ultrasound interactions with tissues
      • Reflection
      • Refraction
      • Transmission
      • Attenuation
    • Acoustic shadowing
      • Some tissues reflect all sound waves back to the transducer
      • This means that tissues distal to these tissues are not exposed to sound waves and will therefore not be visible on ultrasound -> acoustic shadowing
      • Examples
        • Calcium (stones)
        • Air
    • Acoustic amplification
      • Some tissues refect very few sound waves back to the transducer
      • This means that the tissues distal to these tissue are exposed to more sound waves than normal and will be hyperechoic on ultrasound -> acoustic amplification
      • Examples
        • Cysts
        • Fluid
    • Advantages
      • Produce no ionizing radiation
        • Especially usefully in obstetrics
      • Quick
      • No long-term side effects
      • Portable
    • Real-time ultrasound
      • Allows images to be seen in sequential frames, just like a movie
      • Good for moving structures, like the heart
    • Patient preparation
      • Abstinence from food before abdominal studies
      • Only liquid is allowed
    • Types
      • A-mode (amplitude)
        • One-dimensional
        • Used in ophthalmology
      • B-mode (brightness)
        • Most often used
        • Produces a 2D image
      • M-mode (motion)
        • The motion of a structure is plotted along the x-axis
        • Used for movement of cardiac valves
      • Colour doppler
        • The machine analyses the frequency of the echoes -> blood can be coloured according to which direction it’s moving in
          • Blood flowing toward the transducer is red
          • Blood flowing away from the transducer is blue
        • Good to evaluate stenoses, direction of blood flow, valvular insufficiency
    • Indications
      • Examination of heart (echocardiography)
      • Examination of biliary system
      • Examination of urinary system
      • Asymptomatic, pulsatile abdominal masses
      • Female pelvic organs
      • Abdominal hernia
      • Appendicitis
      • Ascites

4. Imaging of pneumonias.

  • Pneumonia is a consolidation of the lung produced by exudate
  • Chest X-ray
  • Appearence
    • Appears denser (more opaque) than the surrounding lung
    • Indistinct margins
      • Except if they are next to the pleura of interlobar fissures, where the margins will be sharp
    • Appears “fluffy”
    • If pneumonia is central, hypodense bronchi can be seen (bronchograms)
  • Types of pneumonia
    • Lobar pneumonia
      • Typically S. pneumoniae
      • Spread by alveoli
      • Pneumonia in the whole or almost the whole lobe
      • Bronchobrams often present
    • Segmental pneumonia (bronchopneumonia)
      • Typically S. aureus, pseudomonas
      • Pneumonia in several segments
      • Bronchograms rarely present
    • Interstitial pneumonia (pneumonitis)
      • Mycoplasma or pneumocystis (PCP) in AIDS
      • Involves airway walls and alveolar septa
      • Perihilar reticular interstitial pneumonia
    • Round pneumonia
      • Spherical in shape
      • Usually posterior in lung, in lower lobes
      • Should be distinguished clinically from tumors
    • Cavitary pneumonia
      • Postprimary TB
  • Aspiration
    • Most commonly occurs in right lower lobe
  • White-out of a hemithorax
    • Complete opacification of one hemithorax
    • Differential diagnosis
      • Total pneumonectomy
      • Extended pleural effusion or hydropneumothorax
      • Large mass obstructing airways, causing atelectasis of the whole lung
  • Flattening of diaphragm
    • Due to increased pressure/hyperinflation of lungs
      • Tension pneumothorax
      • COPD
      • Emphysema

5. Thoracic masses. Imaging strategy, differential diagnosis.

  • Lung anatomy
    • Primary lung lobule
      • Not so important in radiology
    • Secondary lung lobule
      • Represent a cluster of up to 30 acini supplied by a common distal pulmonary artery and bronchiole
      • Have polyhedral shape
      • Bounded by intralobular septa
        • Are visible as Kerley B lines in pulmonary oedema
  • Lung mass < 3 cm = nodule
  • Lung mass > 3 cm = mass
  • Modalities
    • X-ray
    • CT
    • PET
  • Benign vs malignant
    • Characteristics of benign masses
      • Age < 40
      • Small (< 3 cm)
      • Round
      • Well-defined edges
      • Slow growth over time (years)
        • Comparison with older images is important!
      • Solid
      • Central, laminar or diffuse calcification
    • Characteristics of malignant masses
      • Age > 40 
      • Large (> 3 cm)
      • Irregular shape
      • Poorly defined edges
      • Obvious growth over time
      • Cavitated
      • Active accumulation of FDG on PET scan
  • Indirect signs of lung mass
    • Atelectasis
    • Postobstructive pneumonia
    • Pleural effusion
    • Hilar adenopathy
  • High risk
    • Smoker
    • > 40 years
    • Clinical symptoms suspicious of cancer
      • Haemoptysis
      • Weight loss
      • Hoarseness
    • Mass has malignant characteristics on imaging
  • If mass and/or patient is high risk -> investigation
    • CT
      • Also for small peripheral lung masses
    • PET
    • Biopsy
  • Differential diagnosis
    • Granuloma
      • TB
      • Histoplasmosis
    • Hamartoma
    • Primary lung cancer
      • Usually solitary nodule
      • Adenocarcinoma
        • Peripheral mass
      • Squamous cell carcinoma
        • Central mass
      • Small cell carcinoma
        • Hilar mass
    • Metastases
      • Usually multiple nodules
    • Round pneumonia
  • If tumor in apex of lung = Pancoast tumor
  • Multiple lung nodules must always be examined with CT
  • Mediastinum
    • First-line modality: X-ray
      • For differential diagnosis: MRi
    • 4 T’s of mediastinal masses
      • Thymoma
      • Teratoma
      • Thyroid neoplasm
      • “Terrible” lymphoma
    • Mediastinal lymph nodes
      • Chest CT
        • Essential for mediastinal lymph node examination 
      • Enlarged over 10 mm
        • Many lymph node groups can get enlarged at the same time
      • Can be calcified and therefore abnormal even if < 10 mm!

6. Pulmonary embolism. Diagnosis and diagnostic difficulties.

  • Good video
  • Clinical features
    • Dyspnoea
    • Tachypnoea
    • Pleuritic chest pain
    • Rales
    • Clinical features of DVT
      • Leg swelling
      • Pain on palpation of deep veins
  • CT pulmonary angiography – (CTPA)
    • Fast spiral CT scanner scans the patient in one breath hold
    • Patient is given a rapid bolus of IV injection of iodinated contrast
    • A technique called “bolus tracking” is used
      • The technician takes a picture before the bolus is injected
      • Draws a region of interest (ROI) on the pulmonary trunk
      • The machine will then continously take low resolution CT images through the pulmonary trunk
      • The contrast bolus is injected
      • When the Hounsfield unit of the ROI exceeds a certain threshold -> the contrast bolus has reached the pulmonary trunk -> the machine will start to take high resolution CT images of the whole lung
    • Highly specific and sensitive for PE
    • Pulmonary emboli are visible as partial or complete filling defects located within the contrast-enhanced lumens of the pulmonary arteries
  • Chest X-ray
    • Westermark sign
      • Collapsed vessels distal to the PE
      • Seen in only 2% of cases
  • Diagnosis
    • Modified Wells score – asseses the probability of PE
      • Points are awarded for certain criteria
      • If the sum is > 4 -> PE is likely
      • If Wells score is < 4 -> PE is unlikely
      • Points
        • Clinical symptoms of DVT – 3 points
        • PE is more likely than other diagnoses – 3
        • Previous PE/DVT – 1,5
        • Tachycardia – 1,5
        • Surgery or immobilization in the past 4 weeks – 1,5
        • Haemoptysis – 1
        • Malignancy – 1 point
    • If patient is haemodynamically stable
      • and Wells score > 4 (high probability)
        • CTPA
      • and Wells score < 4 (low probability)
        • Measure D-dimer
          • D-dimer positive -> CTPA
          • D-dimer negative -> PE unlikely
    • If patient is haemodynamically unstable and Wells score > 4
      • Bedside echocardiography
        • Echocardiography shows RV overload -> PE likely
      • Lower limb compression ultrasound
    • If patient is allergic to iodinated contrast and Wells score > 4
      • Nuclear V/Q scan (topic 39)

7. Pneumothorax and hydrothorax. Etiology, radiologic characteristics.

  • Pneumothorax (PTX)
    • The collection of air within the pleural space
    • Can lead to partial or complete lung collapse
    • Types
      • Spontaneous pneumothorax (without any trauma)
        • Primary if it occurs without clinically appearent underlying lung disease
        • Secondary if it occurs as a complication of underlying lung disease
      • Open pneumothorax
        • Air enters through a lesion in the chest wall during inspiration
        • Air leaves through the same lesion during expiration
      • Closed pneumothorax
        • Air enters through a lesion in the visceral pleura on the lung
        • Air leaves through the same lesion during expiration
      • Tension pneumothorax
        • Air enters through a lesion in the chest wall or a lesion in the visceral pleura during inspiration
        • Air cannot leave during the expiration
          • This is because the lesion formed a one-way valve
        • The result is that the pressure inside the pleural cavity increases with each inspiration
          • This compresses structures in the chest
        • Any type of pneumothorax (spontaneous, traumatic, iatrogenic) can progress into tension pneumothorax
        • Mediastinal structures are shifted away from the side of the pneumothorax
        • Tension PTX is an emergency – treatment should not be delayed by imaging if there is strong clinical suspicion
    • Etiology
      • Primary spontaneous pneumothorax
        • Rupture of subpleural apical blebs
        • Risk factors
          • Family history
          • Male
          • Slim, tall stature
          • Smoking
      • Secondary spontaneous pneumothorax
        • Emphysema
        • Cystic fibrosis
        • TB
      • Traumatic pneumothorax
        • Blunt trauma
        • Penetrating injury
      • Iatrogenic pneumothorax
        • Mechanical ventilation
        • Central venous catheter placement
        • Bronchoscopy
        • Pleural tap
    • Clinical features
      • Sudden, severe chest pain and dyspnoea
      • Reduced breath sounds
      • Hyperresonant percussion
      • Subcutaneous emphysema
      • Additional features in tension PTX
        • Acute respiratory distress
        • Tachycardia
        • Hypotension
        • Distended neck veins
    • Diagnosis
      • First-line: X-ray
        • Visceral pleural line
          • The visceral pleura of the collapsed lung becomes visible as a thin white line
          • Must be visible for diagnosis of PTX
        • The visceral pleural line should be convex
          • (it maintains the shape of the chest wall)
        • Deep sulcus sign
          • Dark and deep costophrenic angle on affected side
        • Additional signs of tension PTX
          • Midline shift towards contralateral side
          • Ipsilateral diaphragm is flattened or even inverted
      • Second-line: CT
        • If there is strong suspicion of PTX, but x-ray is normal
  • Pleural effusion
    • = Fluid in the pleural space
      • At least 100 mL if visible in upright chest x-ray
    • Types according to composition and cause
      • Transudates (hydrothorax/HTX)
        • Congestive heart failure
        • Hypoalbuminaemia
          • Cirrhosis
          • Nephrotic syndrome
      • Exudates
        • Malignancy
        • Pneumonia
        • Haemothorax
        • Chylothorax
    • Types according to laterality
      • Bilateral effusions
        • Congestive heart failure
      • Unilateral effusions
        • Pulmonary embolism
        • Trauma
        • TB
        • Pancreatitis (only left side)
    • Diagnosis
      • First-line: X-ray
        • Can’t detect very small effusions (< 300 mL)
        • Blunting of the costophrenic angle
        • Opacification of parts of or the whole lung
        • Midline shift towards contralateral side
      • Ultrasound
        • Can detect very small effusions
        • Hypoechoic/anechoic structures in costophrenic recess
      • Chest CT
        • Can detect very small effusion
        • Can measure fluid density and therefore distinguish fluid from blood, etc
      • MRi
    • If there is simultaneous pneumothorax (hydropneumothorax)
      • There will be a horizontal fluid level (air-fluid level)
        • Also called “niveau” 
    • Freimann-Dahl image
      • Chest x-ray in decubitus (side) position
      • Detects subpulmonic effusion (fluid at the base of the lung)

8. Interstitial pulmonary diseases. Pulmonary fibrosis. Silicosis. Emphysema.

  • Interstitial lung disease
    • Pathological types
      • Pulmonary fibrosis
      • Pneumoconiosis
      • Silicosis
      • Pneumonitis
      • Sarcoidosis
      • Interstitial oedema
    • Radiological types
      • Reticular interstitial disease – appears as a network of lines
      • Nodular interstitial disease – appears as many dots
      • Reticulonodular intestitial disease – combination
    • “Packets” of disease are separated by normal-appearing lung
      • The margins of the “packets” are sharp and discrete
  • Pulmonary interstitial oedema
    • Etiology
      • Congestive heart failure (pulmonary congestion)
      • Lymphangitis carinomatosa
    • Diagnosis
      • First line: X-ray
        • Fluid in lung fissures
        • Peribronchial cuffing – fluid in the walls of the bronchioles
        • Pleural effusion
        • Kerley B lines
          • Short parallel lines at the lung periphery, in contact with the pleura
  • Pulmonary fibrosis
    • Diagnosis
      • First line: X-ray
        • Reticular opacities
        • Ground-glass opacities
        • Honeycombing
          • Small cystic spaces with thickened walls
      • CT
        • Honeycombing
        • Thickening of interlobular septa
  • Silicosis
    • Occupational disease
    • Diagnosis
      • First line: X-ray
        • Eggshell calcification
          • Well-defined, sickle-shaped calficiation of the rims of hilar lymph nodes
        • Bilateral diffuse ground glass opacities
        • Uniformly distributed small nodules
  • Emphysema
    • Types
      • Centrilobular emphysema
        • Only affects respiratory bronchioles and central portions of the acinus
        • Associated with smoking
        • Affects upper lobes
      • Panlobular emphysema
        • Affects the entire alveolus
        • Affects lower lobes
        • Associated with alpha-1 antitrypsin deficiency
      • Paraseptal emphysema
        • Affects alveoli around the septae of the lung and the subpleural surfaces
    • Diagnosis
      • First line: X-ray
        • Barrel chest (hyperinflation)
          • Horizontal ribs
          • Widened intercostal spaces
          • Increased anterioposterior diameter
          • Diaphragm pushed down and flattened
          • Hyperlucency (increased radiotransparency)
      • CT
        • For planning surgeries

9. Diagnostic imaging of cardiac diseases. Methods, indications. Cardiomyopathies. Diseases of the pericardium.

  • Diagnostic methods of heart diseases
    • X-ray
    • Fluoroscopy
    • Coronary angiography
    • Echocardiography
      • Transthoracic echocardiography (TTE)
      • Transoesophageal echocardiography (TEE)
    • MRI
      • MRI angiography
      • Cardiac MRI
        • Shows myocardial viability and function
      • MRI can be “coupled” to an ECG so that it only takes pictures during the same part of the cardiac cycle
    • CT
      • Cardiac CT
      • CT coronary angiography
        • Very high negative predictive value for coronary artery disease
        • Coronary diameter 4 – 5 mm
      • “Triple rule out” CT angiography
      • CT can be “coupled” to an ECG so that it only takes pictures during the same part of the cardiac cycle
        • Thoracic aorta CT angiography, coronary CT and cardiac CT are ECG-coupled
        • Pulmonary CT angiography and superior vena cava venography are not ECG-coupled
    • Nuclear imaging
      • See topic 40
  • Enlarged cardiac shadow
    • Defined as a cardio-thoracic ratio > 50%
      • Meaning that the width of the heart is more than 50% the width of the chest wall on a standing PA x-ray
    • Causes
      • Pericardiac effusion
      • Cardiomegaly
  • Pulmonary venous congestion/pulmonary oedema/postcapillary pulmonary hypertension
    • X-ray
      • Fluffy, indistinct patchy densities
      • Kerley B lines
      • Apical vessels of the lung are more expanded than the basal veins
        • Due to redistribution of blood flow to the upper zone
        • Called apicobasal caliper discrepancy or upper lobe pulmonary venous diversion (cephalisation)
      • Frequently centrally located
        • Forms a “butterfly” wing pattern around the hilum
    • Pleural effusion often also present
  • Pulmonary arterial hypertension
    • X-ray
      • Prominent central pulmonary vessels
    • CT
      • Pulmonary artery larger than the ascending aorta
      • Central pulmonary vessels are larger than normal, especially when compared to peripheral pulmonary vessels
        • Also called centroperipheral caliber discrepancy  or “pruning” of the peripheral vessels
  • Cardiomyopathies
    • Dilatative cardiomyopathy
      • Echocardiography
        • Atrial and ventricular dilation
        • Reduced left ventricular ejection fraction
      • X-ray
        • Cardiomegaly
        • Pulmonary oedema
    • Hypertrophic cardiomyopathy
      • Echocardiography
        • Thickened left ventricular wall (> 15 mm)
    • Ischaemic cardiomyopathy
      • Delayed myocardial enhancement MRi
        • A post-infarct scar or an infarcted myocardium will show “delayed” or “late” enhancement
    • Myocardial perfusion imaging in rest
      • Nuclear imaging method
    • Multigated analysis (MUGA)/radionuclide ventriculography (RNVG)
      • Nuclear imaging method
    • See topic 40
  • Diseases of the pericardium
    • Pericardial effusion
      • Pericardial ultrasound
      • X-ray
        • Enlarged cardiac shadow
        • If very large effusion: water bottle sign
      • CT
    • Constrictive pericarditis
      • X-ray, CT, echocardiography
        • Pericardial thickening, calcification
  • Thrombotic disease (thrombi in heart)
    • Modality
      • Echocardiography
  • Congenital malformations
    • Total anomalous pulmonary venous return
      • Snowman sign on imaging
    • Partial anomalous pulmonary venous return
      • Scimitar sign/syndrome
    • Transposition of great vessels
      • Egg on a string sign on imaging
    • Ebstein’s anomaly
      • Box-shaped heart sign on imaging
    • Tetralogy of Fallot
      • Boot-shaped heart on imaging
      • Involves
        • Ventricular septal defect
        • Right ventricular outflow obstruction
        • Overriding aorta
        • Right ventricular hypertrophy
  • Enlarged left atrium
    • Causes the left main bronchus to be superiorly displaced

10. Imaging of ischemic heart diseases and cardiac valve diseases.

  • Ischaemic heart disease
    • First-line: Invasive coronary angiography
      • A catheter is inserted into femoral or radial artery or vein by Seldinger technique and directed to the coronary arteries
      • The cardiologist can use the catheter to eject contrast directly into the coronaries
      • While giving contrast the cardiologist activates the X-ray
      • Allows for clear visualization of plaques in coronaries
      • In the same procedure, percutaneous transluminal coronary angioplasty (PTCA) can be performed
        • Angioplasty involves opening a closed artery with a balloon and possibly inserting a stent afterwards
        • Also called percutaneous coronary intervention (PCI)
    • Echocardiography
      • Can detect myocardial wall motion abnormalities
    • Nuclear medicine myocardial perfusion studies
    • Cardiac CT
      • Used to rule out CAD in low-risk patients
      • Calcium scoring
        • Measures the amount of calcium in coronaries
        • Assesses the risk of coronary artery disease
    • Coronary CT angiography
    • Cardiac MRI
  • Triple rule out angiography
    • Single exam to rule out pulmonary embolism, acute aortic syndrome and acute coronary syndrome
    • It’s essentially an extended coronary CT angiogram
    • Indications
      • Atypical acute chest pain
      • Acute chest pain in patients with low risk for acute coronary syndrome, acute aortic syndrome and PE
  • Cardiac valve diseases
    • Aortic stenosis
      • Clinical features
        • Chest pain
        • Heart failure symptoms
        • Syncope
      • Diagnosis
        • Echocardiography
          • Narrowing of the aortic valve
          • Increased pressure gradient across aortic valve
        • X-ray
          • Enlarged left border of heart
          • Calcification of aortic valve
          • Dilation of ascending aorta
        • Left-heart catheterization
    • Aortic regurgitation
      • Phase contrast MRi
        • Can measure the flow velocity across the aortic valve
    • Mitral stenosis
      • X-ray
        • Enlarged left atrium
          • Straightened left cardiac border
        • Signs of pulmonary congestion
        • Posterior displacement of oesophagus
          • Visible on lateral X-ray with barium swallow
      • Echocardiography

11. Diseases of the aorta. Imaging methods, the role of CT and MRI.

  • Acute aortic syndrome
    • Involves three diseases with similar symptoms
      • Aortic dissection
        • Stanford A (proximal)
          • Affects ascending aorta
          • May also affect descending aorta
        • Stanford B (distal) = Debakey III
          • Affects descending aorta
        • Debakey I (ascending and descending)
          • Affects ascending and descending aorta
          • Most common
      • Intramural haematoma
        • Due to bleeding from vasa vasorum
      • Penetrating aortic ulcer (PAU)
    • Clinical features
      • Sudden severe chest or back pain
      • Syncope
    • Diagnosis
      • First line: CT angiography with contrast
        • Shows intimal flap which separates the true lumen from the false lumen
          • True lumen
            • Often the smaller lumen
            • Great arteries originate from it
          • False lumen
            • Often the larger lumen
        • Dilation of aorta
      • X-ray
        • Widened mediastinum
        • Irregular aortic contour

12. Imaging in acute abdomen.

  • Acute abdomen
    • = an emergency characterized by sudden onset of severe abdominal pain, tenderness and muscular rigidity
    • Can be lethal -> rapid diagnosis is important
    • Differential diagnosis
      • Acute cholecystitis
      • Splenic rupture
      • Appendicitis
      • Gastric or duodenal ulcer perforation
      • Acute pancreatitis
      • Acute coronary syndrome
      • Diverticulitis
      • Nephrolithiasis
      • Ileus
      • Mesenteric ischaemia
      • Abdominal aortic aneurysm
      • Pelvic inflammatory disease
      • Ectopic pregnancy
    • First we must make a clinical guess on what the relevant differential diagnoses are
      • Based on location of pain, lab tests, previous history, risk factors, etc
      • The modality to use depends on what we suspect the diagnosis might be
  • Imaging in acute abdomen
    • Suspicion of
      • Perforation
      • Ileus
      • -> Abdominal X-ray (if patient is not fit for CT) or abdominal CT (if patient is stable)
    • Suspicion of
      • Pancreatitis
      • Cholecystitis
      • Appendicitis
      • Diverticulitis
      • PID
      • Nephrolithiasis
      • Abdominal aortic aneurysm
      • Ectopic pregnancy
      • etc.
      • -> Abdominal ultrasound
      • -> later -> CT
    • Problems
      • Related to technical difficulties
        • Ultrasound can’t see a retrocoecal appendix
        • Bowel gas may interfere with US
        • Patient may be uncooperative
      • Related to management
        • There may be no previous history
          • No way to know the kidney function or allergic status of the patient (if they need contrast)
      • Related to radiation
        • Pregnant women
        • Children
        • Women with unknown pregnancies
      • Related to time
        • Imaging in pancreatitis may be negative in the first 72 hours
        • Abdominal aortic aneurysm – patient might not make it to a CT
        • eFAST might be negative too early after trauma
  • Imaging in trauma
    • FAST – focused assessment with sonography in trauma
      • A rapid beside ultrasound protocol for examining patient after trauma
      • Used to identify fluid (blood) in the peritoneum
      • eFAST – extended FAST
        • Also looks for pneumothorax, haemothorax, pleural effusion, etc.
        • Order of examination
          • Hepatorenal region -> Pericardium -> Perisplenic -> Suprapubic -> Right and left chest

13. Imaging of the esophagus, stomach and small bowels. Methods, indications, imaging strategy.

  • Upper and lower GI tract are separated by the ligament of Treitz
    • = the suspensory ligament of the duodenum
  • Imaging of whole upper GI tract
    • Upper GI series = upper GI study
      • Barium is swallowed and fluoroscopy of the oesophagus, stomach and small intestine is performed
      • Can diagnose both anatomic and functional abnormalities
      • Can also be double-contrast if both barium and air is swallowed
  • Imaging of oesophagus
    • Single-contrast oesophagogram = barium swallow
      • Barium is swallowed and fluoroscopy is performed to make a video of how barium moves down the oesophagus
      • Filling defect on barium swallow
        • Oesophageal stricture
        • Cancer
        • Foreign body
        • Polyp
        • Oesophageal varices
    • Double-contrast oesophagogram
      • Barium is swallowed first, then air is swallowed
      • Fluoroscopy -> video
    • Biphasic oesophagogram
      • Both single-contrast and double-contrast examinations are performed
      • Indications
        • Dysphagia
        • Before oesophageal surgery
        • Evaluate function of oesophageal stent
    • CT with contrast
      • Tumor staging of oesophageal tumors
    • Endoscopy = oesophagoscopy
      • Examination of mucosa
      • Perform biopsy of mucosa -> tumor/Barrett diagnosis
    • Endosonography = endoscopic ultrasound
      • Cancer diagnosis and surrounding metastasis
    • Hiatal hernia
      • Barium swallow or endoscopy
  • Imaging of stomach
    • Endoscopy = gastroscopy
      • Most important
    • Ultrasound
      • Visualization of gastric wall and pylorus
        • Pyloric stenosis in children!
    • Barium swallow
      • Evaluate stomach function
      • Visualization of shape and size of stomach
        • Hiatal hernia!
    • Double contrast barium swallow
      • Barium + CO2-releasing tablets
    • Barium follow-through
      • Evaluate stomach emptying
    • CT with contrast
      • Staging of gastric cancer
  • Imaging of the small bowels
    • Bowels must be opacified and distended to be visible
      • -> Oral contrast is often used
    • Patient preparation before small bowel imaging
      • Fasting minimum 6 hours before
      • Moderate laxatives (like lactulose)
    • During examination
      • Buscopan/glucagon – slow intestinal motility -> decrease motion artifacts
    • Modalities
      • Enterography (plain x-ray, no contrast)
        • Can see ileus and perforation
        • If diameter > 3 cm -> obstruction or paralytic ileus
      • Enteroclysis = small bowel enema
        • Oral contrast (barium) + methylcellulose
          • Must be delivered into the small intestine by nasoduodenal tube
          • Methylcellulose is not a contrast agent itself, but it increases the volume of the contrast material
          • Methylcellulose has low x-ray absorbance (it’s radiolucent)
      • CT enterography (CT small bowel)
        • Oral contrast
        • IV contrast may also be given
      • CT enteroclysis
        • Oral contrast
          • Must be delivered into the small intestine by nasoduodenal tube
        • Combination of fluoroscopy and CT enterography
        • Shows movement of contrast through small intestines
      • Small bowel follow through
        • Fluoroscopy as the oral contrast moves through the small bowels
        • Gastric emptying starts immediately, should be finished in 3 – 4 hours
        • Complete small bowel emptying should be finished in 6 – 8 hours
          • > 12 hours is pathological
      • MR enterography
      • MR enteroclysis
    • Finding on images
      • Thickened bowel wall (> 3 mm)
      • Submucosal oedema or haemorrhage
      • Extraluminal contrast or air
        • Indicates perforation
    • Intussiception/invagination of bowel in children
      • Most commonly due to Meckel diverticulum
      • Also due to polyp, tumor
    • Pneumatosis intestinalis = intramural bowel gas
      • Air in the bowel wall
      • (not a complication of respiratory therapy)
      • Caused by
        • Ischaemia
        • Necrotizing enterocolitis
    • Duodenal atresia
      • Double bubble sign on imaging
    • GI tract bleeding
      • CT angiography
  • Oral contrast agents
    • Barium is contraindicated in
      • Suspicion of perforation of GI tract
      • After GI surgery
      • High risk for aspiration
    • Gastrographin is used instead
      • A water-soluble, iodinated contrast agent
    • Barium leak can cause necrotizing peritonitis

14. Imaging of the colon. Inflammatory diseases of the colon. Diverticulosis. Colon tumors.

  • Imaging of colon
    • Patient preparation
      • Fasting minimum 6 hours before
      • Only clear fluids (water, thin drinks) the day before the examination
      • Strong laxatives
    • During examination
      • Buscopan/glucagon – slow intestinal motility -> decrease motion artifacts
    • Modalities
      • Optical colonoscopy/endoscopy
        • Biopsy can also be performed
      • Irrigoscopy
        • X-ray of large intestine
        • With oral contrast
        • To check for:
          • Postoperative complications
          • Anastomosis
          • Fistula
      • Barium enema
        • Not so common anymore
      • CT colonography
        • Computer can reconstruct the inside of the colon, thereby yielding “CT virtual colonoscopy”
          • Avoids the uncomfortable procedure of colonoscopy
          • CT virtual colonoscopy refers to using the data from a CT colonography to examine the colon from the inside
        • Structures outside the colon are also visible
        • Colon must be inflated by CO2
      • Colonic transit study
        • Used to evaluate constipation
        • Patient swallows capsules which contain many small markers
          • These markers are visible on x-ray
          • The patient swallows 2 capsules every day for 3 days
        • 5 days after the first capsule, the patient takes a plain abdominal x-ray
          • The position of the markers in the colon is useful information
      • MR colonography
        • Bright lumen MR colonography
        • Dark lumen MR colonography
      •  Defecography
        • Used to evaluate constipation
        • No preparation needed
        • Rectum is filled with barium paste
        • Patient 💩s on a special toilet under fluoroscopy
  • Colitis
    • CT colonography
    • Findings
      • Segmental thickening of bowel wall
      • Irregular narrowing of bowel lumen
  • Diverticulosis
    • CT virtual colonoscopy
    • Barium enema
    • Findings
      • Outpouchings on the colon
  • Colon tumours
    • CT virtual colonoscopy
    • Colonoscopy
    • Barium enema
    • Findings
      • Polypoid filling defect
      • Apple-core lesion
        • An annular constriction of the colonic lumen which looks like an apple-core
  • Abdominal abscess
    • CT with contrast
  • Rectal atresia
    • Wangensteen-Rice x-ray is used

15. Imaging of the liver and the hepatobiliary system. Imaging techniques, indications, information content.

  • Patient preparation
    • Patient must be fasting
    • (After any meal or drink the gallbladder contracts)
  • Modalities
    • Ultrasound (primary modality)
      • B-mode
      • Doppler
      • Contrast-enhanced ultrasound
    • Triple-phase CT scan
      • With IV contrast
      • Arterial phase
        • 30 seconds after contrast
        • Hypervascular tumors (who receive arterial blood) are enhanced and can be visualized
        • Normal liver parenchyme (which receives portal venous blood) is not yet enhanced
      • Portal venous phase
        • 70 seconds after contrast
        • The normal liver parenchyme is now enhanced
        • Hypovascular tumors are not enhanced and can be visualized
      • Equilibrium phase
        • 5 minutes after contrast injection
        • Tumors which lose their contrast slower or faster than the liver parenchyme will be visible
    • MRi
      • Especialy good for differentiation types of liver lesions
      • IV contrasts that can be used
        • Gadolinium
          • For T1-weighted MRi
          • Tumors become darker
        • Manganese
          • For T1-weighted MRi
          • Specific for hepatocytes in healthy tissue
            • Will not accumulate in haemangioma
          • It’s a positive contrast agent -> makes healthy tissue lighter
          • Lesions will remain dark
        • SPIO 
          • For T2-weighted MRi
          • Specific for reticuloendothelial cells in healthy parenchyme
          • It’s a negative contrast agent -> makes healthy tissue dark
        • Double contrast
          • SPIO + gadolinium
          • SPIO makes liver dark, gadolinium makes lesion light (?)
    • Magnetic resonance cholangiopangreatography (MRCP)
      • Non-invasive examination of biliary tree
      • Does not need contrast
      • Indications
        • Strictures
        • Gallstones
        • Stones in bile duct
    • Percutaneous transhepatic cholangiography (PTC)
      • Contrast is injected into biliary tree -> fluoroscopy is performed
      • Can be used therapeutically, i.e. insert stent and remove obstructions
    • Endoscopic retrograde cholangiopancreatography (ERCP)
  • Steatosis
    • Ultrasound of right upper quadrant
      • Liver will be more echogenic than the renal cortex
        • = the liver will be lighter on ultrasound than the renal cortex
        • Normally, the liver is isoechoic with the renal cortex
    • CT without contrast
      • Liver will be less dense than the spleen
        • = the liver will be darker on CT than the spleen
        • This is opposite to the normal
    • Focal steatosis can look like a mass
      • However, focal steatosis has no mass effect
      • Meaning that it doesn’t displace vessels or liver parenchyme like a mass would
  • Cirrhosis
    • Ultrasound of right upper quadrant
      • Right lobe smaller than the left
      • Liver parenchyme is no longer isoechoic
        • Some parts are hypoechoic, some are hyperechoic
    • CT
      • Right lobe smaller than left and caudate lobes
      • Lobulation of liver parenchyme
      • Nodules in liver
      • Inhomogenous appearence of liver parenchyme
    • Secondary signs
      • Splenomegaly
      • Ascites
        • Grey fluid on CT
        • Hypoechoic fluid on US
      • Portocaval collaterals
        • Dilated vessels around the stomach, spleen, oesophagus
  • Hepatocellular carcinoma
    • Ultrasound of right upper quadrant
    • CT
  • Metastasis
    • 40% from the colon
    • Most commonly multifocal
    • CT with contrast
    • MRi
  • Imaging of biliary tree and gallbladder
    • Modalities
      • Ultrasound of right upper quadrant
      • MRCP
      • ERCP
      • Endoscopic ultrasound
        • Ultrasound probe in duodenum
      • Nuclear medicine hepatobiliary scan
    • Cholecystitis
      • Ultrasound of RUQ
        • Thickened gallbladder wall
        • Gallbladder wall oedema
          • Gallbladder looks like it has a double wall
      • Nuclear medicine hepatobiliary scan
    • Cholelithiasis
      • Ultrasound of right upper quadrant
        • Gallstones will have posterior acoustic shadow
      • MRCP
      • ERCP
    • Choledocholithiasis
      • Ultrasound of RUQ
        • Dilated bile duct
        • Stone may be visible
      • MRCP
      • ERCP

16. Imaging of the pancreas and the spleen. Imaging techniques, indications, information content.

  • Pancreas
    • Modalities
      • CT
      • US
    • Acute pancreatitis
      • First line: Ultrasound
        • Oedematous echopoor pancreas
        • Peripancreatic fluid
        • Indistinct pancreatic margins
      • CT
        • With contrast
        • Indications
          • If in doubt if it’s actually acute pancreatitis
          • Test for complications
            • Necrotizing pancreatitis
            • Abscess
        • Enlargement of all parts
          • Oedematous swelling
        • Indistinct pancreatic margins
        • Peripancreatic fluid
        • CT severity index (CTSI)
          • Awards points for certain findings
          • Sum of points determine the extent of necrosis
        • Abscess
          • Circumscribed fluid collection
        • Necrosis
          • Low attenuation
      • MRCP
        • If we’re unsure if it’s caused by stone
      • ERCP
        • To remove stone
    • Chronic pancreatitis
      • CT or US
        • Calcifications in pancreas
        • Atrophic pancreas
        • Pseudocysts
    • Pancreatic cancer
      • Most commonly in the head
      • US
        • Echopoor lesion
      • CT
        • Hypodense lesion
  • Spleen
    • Modalities
      • US
        • Normal or contrast-enhanced (CEUS)
      • CT
    • Splenomegaly
    • Splenic infarct
    • Splenic rupture
      • CT
        • Hypodense haemorrhage

17. Imaging of the urinary system. Indications, diagnostic strategy. Renal inflammatory diseases, nephrolithiasis.

  • Kidney
    • Kidneys filter IV iodinated contrast agents
      • Will therefore be enhanced by these agents
    • Modalities
      • CT urogram
        • With IV contrast
        • Visualizes tumors, strictures in urinary tract
      • CT pelvis & abdomen
        • With or without contrast
      • Ultrasound
        • Visualizes tumors, cysts, kidney stones, hydronephrosis
      • CT cystography
        • Contrast is instilled into the patient bladder through catheter
      • Cystoscopy
        • Endoscope advanced retrogradely through urethra
      • Renal scintigraphy
        • Nuclear medicine technique
    • Inflammatory disease of the kidney
      • Glomerulonephritis, interstitial nephritis, pyelonephritis, etc.
      • Ultrasound
        • Enlarged kidney
        • Hyperechoic parenchyme
      • Contrast not used as the risk for kidney complications is increased
    • Nephrolithiasis & urolithiasis
      • First-line: CT abdomen & pelvis without contrast
        • Stone can be seen
        • Hydronephrosis or dilated ureters proximally
      • Ultrasound
        • If radiation is a problem
      • Kidney, ureter, bladder (KUB) x-ray
        • Only calcium stones are radiopaque
        • Other stones are not visible
        • Not much used
    • Renal failure
      • Acute
        • Enlarged kidney on US
      • Chronic
        • Smaller kidney on US
        • Renal scintigraphy to determine kidney function
  • Bladder
    • Bladder should always be filled with urine
    • Modalities
      • US
      • CT urography
      • MR urography
    • Ectopic ureterocele
      • Cystic structure projecting into bladder

18. Onco-uroradiology: Adrenal and renal masses. Masses of the urinary bladder, the prostate and the testis. Imaging techniques and strategy.

  • Masses of the adrenal gland
    • In childhood
      • US is primary modality
    • In adults
      • CT is primary modality
      • US
      • MRI with in phase – out phase
    • Haemorrhage
      • US
      • CT
    • Adenoma
      • Most are incidental findings (so-called incidentalomas)
      • CT
        • Small
        • Low density (dark)
          • < 10 HU – due to lots of fat
      • MRI with in phase – out phase
    • Adrenal cancer or metastases
      • CT
        • Bilateral (metastasis)
        • Not low density
        • Large
    • Adrenal washout
      • = The rate of contrast washout of the adrenal gland
      • Can be used to diagnose adrenal adenoma
      • > 60% absolute washout (AWO) = adrenal adenoma
      • > 40% relative washout (RWO) = adrenal adenoma
      • < 50% washout = adrenal metastasis
  • Masses of the kidney
    • Kidney cysts
      • US
        • Hypoechoic/anechoic cysts
    • Benign tumors
      • US
    • Renal cancer
      • Can be cystic or solid
      • Most common in adults – renal cell carcinoma = hypernephroma
        • CT
      • Most common in children – Wilms tumor = nephroblastoma
        • US
      • US
        • Hyperechoic or hypoechoic lesion
      • CT
        • Usually both with and without contrast
        • For staging
        • Tumor enhances with contrast
        • Renal vein invasion common
  • Masses of the bladder
    • Most common – transitional cell tumor
      • Often found simultaneously in many places in the urinary tract
    • CT urogram
      • Tumor produces filling defect
      • Thickened bladder wall
  • Masses of the prostate
    • Modality
      • Transrectal ultrasound
        • Also used to guide biopsy for definitive diagnosis
      • MRi
  • Diseases of the testicles
    • Testicular torsion
      • Doppler ultrasound
        • Reduced perfusion in affected testicle

19. Imaging of the arterial system and arterial diseases. Methods of angiography. Indications and complications.

  • Angiography
    • Visualizes the lumen of arteries, veins and the heart chambers
    • Can be performed by many different techniques
      • CT angiography with iodine contrast
      • MRi angiography with gadolinium contrast
      • MRi with time-of-flight sequence
        • No contrast needed
      • Invasive/interventional angiography
        • A catheter is inserted into a vessel (coronaries, cerebral arteries)
        • Contrast is ejected through the catheter
        • Fluoroscopy captures the movement of contrast through the vessel
        • Digital subtraction angiography (DSA)
          • A type of invasive angiography which is widely used
          • The computer uses magic to remove radioopaque structures like bone from the image, allowing the blood vessels to be better visualized
            • The structures are digitally subtracted from the picture, hence the name

20. Imaging of the venous and lymphatic system and their diseases. Deep vein thrombosis.

  • Deep vein thrombosis
    • First-line: Compression Doppler ultrasound
      • Visible thrombus
      • Abnormal flow proximal to the thrombus

21. Imaging of musculoskeletal trauma (bones and soft tissue). Radiologic signs of fracture healing. Terminology.

  • Imaging of musculoskeletal trauma
    • X-ray first
      • 2 directions are always needed!
        • Fractures are often visible in only one direction, so we need 2 x-rays from different perpendicular directions to evaluate 
      • Evaluation of x-ray
        • Anatomical shape, form and alignment
        • Cortex and medullary structure
          • Medulla should have trabecular pattern
        • Surface of joint
        • Surrounding soft tissues
        • In children
          • Epiphyseal plates
      • Fracture
        • -> one part of the bone is displaced compared to the rest of the bone
        • If the distal part of the bone is displaced dorsally compared to the proximal part due to a fracture, it’s a dorsal fracture
      • Fat blood interface sign (FBI sign)
        • Horizontal fluid level outside the bone that forms as blood and bone marrow fat escapes during a fracture
      • Rule of 2s
        • Get 2 x-rays with perpendicular directions
        • Image 2 joints (proximal and distal to the injury)
        • Get images at 2 occasions
        • Get images of 2 limbs – for comparison
    • Then US/CT/MRi
    • CT
      • For complex fractures/tumors
      • Interverterbral discs
    • MRi
      • Best for soft tissue
      • Bone does not give signal on MRi, but fatty bone marrow is visible
      • For inflammatory processes, tumors, sports injuries (often involve ligaments and not bones)
  • Sesamoid bones
    • Can be present as a variant of normal anatomy or as a response to strain
    • Often embedded in tendons
  • Meniscus tear
    • MRI
  • Polytrauma
    • CT
  • Weber fracture
    • Weber A – Fibula fracture under the syndesmosis with tibia
    • Weber B – Fibula fracture at the level of the syndesmosis with tibia
    • Weber C – Fibula fracture above the syndesmosis with tibia
  • Don Juan fracture
    • Fracture of calcaneus
  • Shoulder
    • Fracture often accompanies dislocation
      • Dislocation -> head of the humerus ends up behind the coracoid process
    • Fracture of surgical head of the humerus is the most common
    • AP front-facing position

22. Imaging of degenerative joint diseases.

  • Modalities
    • X-ray
  • Findings in degenerative arthritis
    • Joint space narrowing
    • Sclerosis
    • Osteophytes
      • Extra bony spurs

23. Imaging of inflammatory bone and joint diseases. Osteomyelitis, arthritis. Aseptic bone necrosis.

  • Osteomyelitis
    • Osteolysis in the acute phase
    • Osteosclerosis in the chronic phase
  • Osteonecrosis
    • Most commonly in femural head
    • MRI is used

24. Imaging of bone metastases. Radiologic and nuclear medicine techniques.

  • Modalities
    • X-ray
    • Bone scintigraphy
  • Two types of bone metastases
    • Osteolytic metastases
      • Most common
      • Lesions of reduced density
      • Etiology
        • Multiple myeloma
        • RCC
    • Osteosclerotic metastases
      • Lesions of increased density
      • Etiology
        • Prostate cc
        • Breast cc (often has mixed metastases)
  • Codman triangle
    • A sign on x-ray
    • Occurs due to there not being enough time for ossification of the periosteum
    • Seen in aggressive lesions like
      • Osteosarcoma and other malignant bone tumors
      • Osteomyelitis
      • Bone metastasis

25. Neuroradiology. Imaging techniques and indications.

  • Imaging
    • Modalities
      • DSA (digital subtraction angiography)
        • Best for visualizing intracranial arteries
      • MRi head
        • Best for white matter lesions
        • (T2)
      • Myelography
        • Examination of spinal subarachnoid space
        • Contrast is injected into the subarachnoid space
      • MRi spine
        • Best for spinal lesions
      • Nuclear medicine scans
        • Functional/metabolic studies
      • X-ray
        • For bone degeneration or trauma of the spine or skull
      • Ultrasound
        • For carotid disease
      • CT
        • See next topic
      • MR angiography
        • Time-of-flight (TOF) type – no need for contrast
  • CNS tumors
    • Oligodendroglioma
      • Most frequently calcified CNS tumor (90% of them)
    • Giant cell astrocytoma
      • Near foramen of Monroe -> indicates tuberous sclerosis
  • CNS abscess
    • First choice: MRI (T2 and DWI)
    • Abscess has oedema around it
  • CNS infections
    • Progressive multifocal leukencephalopathy (PML)
      • Deadly viral infection in AIDS patients
  • CNS malformations
    • Schizencephalia
      • Cerebellum not affected
    • Cavernoma
      • A CNS vascular malformation
  • Multiple sclerosis
    • MRI shows sclerotic plaques of the white matter
      • Most commonly the periventricular white matter
  • For 2 years after removal of herniated disc, IV contrast must be used
    • This is because scar tissue forms after the operation, and we need contrast to differentiate it from pathologies
  • Alzheimer
    • 18F-Forbetapir – binds to beta amyloid plaques

26. Neuroradiology. Imaging of acute intracranial vascular diseases. Stroke.

  • Ischaemic stroke
    • Gold standard: Multimodal CT evaluation
      • Non-contrast CT
      • CT angiography
      • CT perfusion
    • Diffusion weighted MRi
      • Shows ischaemia within minutes
      • Ischaemia causes decreased tissue water diffusion
    •  Phases
      • Acute phase
        • CT cannot reliably detect ischaemia this early (< 24 hours)
        • However, CT may detect the embolus itself (hyperdense artery, often middle cerebral a.)
      • Subacute phase (after 12-24  hours)
        • Ischaemic tissue is hypodense
        • Ischaemic tissue swells -> mass effect
      • Chronic phase (after days)
        • Ischaemic tissue becomes less hypodense (but is still hypodense)
  • Haemorrhagic stroke
    • Gold-standard: Multimodal CT evaluation
      • Non-contrast CT
      • CT angiography
      • CT perfusion
    • Phases
      • Acute phase (< 24 hours)
        • Hyperdense (blood)
      • Subacute phase (after 24 hours)
        • Isodense with brain
      • Chronic phase (after days)
        • Hypodense
  • Brain aneurysm
    • CT or MR angiography

27. Imaging in neurotrauma.

  • Modalities
    • Non-contrast CT head
      • Trauma
      • Suspected intracranial haemorrhage
        • For example “worst headache of my life”
      • (Not in tension headache)
    • MRI head
      • Pre-operative work up
  • Haemorrhage on non-contrast CT
    • Acute – hyperdense
    • Subacute – isodense with brain
    • Late/chronic – hypodense
  • Epidural haematoma
    • Arterial origin
      • Mostly middle meningeal arterty
    • Findings
      • Biconvex hyperdense lesion
      • Sharply demarcated
      • Doesn’t displacement meninges
      • Is limited by suture lines
      • Can cross falx and tentorium
      • Has mass effect
  • Subdural haemoatoma
    • Venous origin
      • Mostly bridging veins
    • Findings
      • Crescent shaped hyperdense lesion
      • Falx cerebri displaced
        • Bleeding can be parafalcine
      • Is between dura and arachnoid
      • Not limited by suture lines (can cross them)
      • Has mass effect (can cause midlift shift due to displacement)
    • The intensity of the lesion changes with time from hyperdense to isodense to hypodense
    • Clinical features
      • “Worst headache of my life”/thunderclap headache
      • Altered mental status
      • Photophobia
      • Nuchal rigidity
      • Vomiting

28. Imaging of the vertebral column and the spinal cord. Main diseases.

  • Disc hernia
    • MRI (T2)
  • Spinal trauma
    • X-ray

29. Imaging of the head and the neck. Imaging methods, indications and strategy.

  • Imaging
    • Modalities
      • CT
        • Inner ear
        • 120 kV
      • MRi
        • Retrocochlear lesions
        • Paresis
        • Schwannoma
        • Tumors
      • X-ray
        • Paranasal sinuses
        • Facial trauma
  • Cholesteatoma
    • Basically an epidermoid cyst in middle ear or mastoid process
    • CT or MRi
    • No contrast necessary (not enhanced by contrast)
  • Carotid space
    • A deep compartment of the head and neck
    • Contains
      • Common and internal carotid arteries
      • Internal jugular vein
      • Deep cervical lymph node chains (lymph node regions II – IV)
      • Vagus nerve
      • Sympathetic plexus
    • Pathologies
      • Aneurysm/dissection of carotid
      • Thrombophlebitis of int. jugular v.
      • Schwannoma
      • Paraganglioma
  • Salivary glands
    • Salivary stones
      • First-line: Ultrasound
    • Salivary gland tumors
      • Most common: Pleuomorphic adenoma
      • Most common malignant: Mucoepidermoid cc
      • First-line: Ultrasound
  • Thyroid gland
    • Ultrasound
    • Scintigraphy

30. Imaging of the orbit and the paranasal sinuses. Imaging methods, indications and strategy.

  • Nasopharyngeal angiofibroma
    • T2 MRi
      • Black dots on MRi are vessels
    • Treatment
      • Embolization of supplying vessels
  • Midline fractures
    • Le fort I – III
    • Blow-out fractures (of the orbit)
  • Spaces of the eye
    • Ocular space
      • Anterior chamber of the eye
      • Posterior chamber of the eye
    • Intraoconal space
      • The ocular muscles of the eye form a cone
      • Optic meningioma can be found here
    • Conal space
      • The conal space is formed by the ocular muscles and an envelope of fascia
      • Endocrine ophthalmopathy can be found here
    • Extraconal space
      • Abscess spread from the sinuses can be found here

31. Imaging of the breast. Mammography, clinical mammography, ultrasound.

  • Breast cancer screening
    • Modality
      • Main modality for examination of breast: Mammography
        • Uses low-energy, soft X-rays
          • 20 – 30/40 kV
          • Soft rays are better at differentiating soft tissues of the breast
        • Molybdenum anode (instead of tungsten)
          • Produces more characteristic x-rays
        • Standard views
          • Cranocaudal (CC)
          • Mediolateral oblique (MLO)
        • Breast prosthesis (silicone/saline) behind the pectoral muscle is the best for mammography
        • Breast is compressed
          • Reduces blurring from motion
          • Reduces scattered radiation
          • Reduces radiation dose
      • Complementary roles:
        • US
          • High-frequency (7 – 12 MHz)
          • Linear probe
          • Most used in women < 30 years
          • For dense breasts
          • Axilla must also be scanned
        • MRI
          • Dynamic MRi
          • Native + contrast-enhanced
    • In Hungary
      • Normal population
        • From 45 – 65 years
        • Every 2nd year
      • High-risk patients
        • From 30 years
        • Annually
  • Benign breast tumors
    • Circumscribed on imaging
    • Fibroadenoma
      • Most common in young women
  • Breast cancer
    • Most commonly in the outer upper quadrant
    • Star-shape (stellate) on imaging
    • Invasive ductal cc = most common cancer
    • Precancerous lesion:
      • Atypical ductal hyperplasia

32. Imaging strategy in gynecologic tumors (cervix, uterus, ovarium).

  • Modalities
    • Ultrasound
      • Transvaginal
        • Ovary
        • Uterus
        • Endometriosis
      • Transabdominal
        • Second choice
      • Transrectal
    • CT with contrast
      • Preferred for staging of ovarian cc
    • MRi pelvis
      • Preferred for staging of endometrial, cervical, vulvar cc
  • Most important modality for oncological staging of all pelvic cancers
    • MRI
  • Ovarian cancer
    • Modality
      • Ultrasound
        • Preferably transvaginal
        • Abdominal or rectal also possible
      • CT abdomen & pelvis
        • For TNM staging
      • MRi
        • Only local staging (T and N)
  • Endometriosis
    • Modality
      • Transvaginal ultrasound
        • Ovarian cysts (chocolate cysts)
      • Laparoscopy
      • MRi
  • Endometrial cancer
    • Modality
      • Pelvic MRI
        • For TNM staging
      • Curettage + histology
  • Cervical cancer
    • Modality
      • Pelvic MRI
        • For TNM staging

33. Intravascular radiologic interventions I. Methods of revascularization (PTA, stent implantation, selective thrombolysis, catheter thrombectomy/embolectomy).

  • Percutaneous transluminal angioplasty
    • Indications
      • Coronary artery disease
      • Peripheral artery disease
    • A deflated balloon attached to a catheter is passed into a narrowed vessel
    • -> the balloon is inflated -> opens the vessel
    • A stent can be placed where the vessel was narrowed to keep it open
    • Stent can be made of
      • Steel
      • Gold
      • Nickel-titanium
      • (NOT wolfram)
  • Selective thrombolysis/fibrinolysis
    • A catheter is directed close to a thrombus
    • Fibrinolytics are ejected through the catheter, lysing the thrombus
  • Catheter thrombectomy/embolectomy
    • A catheter is directed to a thrombus and removes it
  • Transjugular intrahepatic porto-systemic shunt (TIPS)
    • Treats portal hypertension
    • A shunt is made between a hepatic vein and portal vein, allowing some portal blood flow to bypass the liver
      • This decreases portal hypertension

34. Intravascular radiologic interventions II. Interventional radiologic treatment of bleeding, vasoocclusive techniques (embolization, sclerotisation).

  • Transcatheter embolization
    • Produces emboli which close vessels
      • Vessels supplying tumors
      • Arteriovenous malformations
      • GI tract bleeding
      • Aneurysm
    • A catheter is lead to the vessel -> particles, glue, etc are ejected -> cause embolization
  • Sclerotisation
    • Delivering hypertonic sodium chloride or ethanol by catheter into liver cyst

35. Image-guided biopsies. Cyst puncture, drainage (biliary, renal, bladder etc.)

  • Needle size
    • Measured in gauges (G)
    • More gauges -> thinner needle
    • 20G is thinner than 18G
  • Image-guided biopsies
    • Fine needle aspiration biopsy
      • Tissue loses organization
      • 20 – 22G needle
      • Indications
        • Breast biopsy
        • Thyroid biopsy
        • Lymph node biopsy
    • Core biopsy = trucut biopsy
      • Tissue maintains organization
      • Ultrasound or CT guided
      • Trucut needle is used
        • 18G needle 
        • Bigger than FNAB needle
  • Drainage and puncture
    • Drainage = Long-term tube placement/emptying of fluid
    • Puncture = one-time sample acquisition
    • Can be guided by US or CT
    • Indications
      • Abscess
      • Exudate
      • Transudate
      • Haematoma
    • Can be
      • Diagnostic (determine composition of pleural effusion)
      • Therapeutic (abscess)
    • Percutaneous transhepatic cholangiography (PTC)
      • To visualize anatomy of biliary tract
    • Percutaneous transhepatic biliary drainage (PTBD)
      • To relieve pressure in bile ducts due to blockage
      • Ultrasound-guided

36. Radiologic interventions in tumor treatment (Tumor ablation techniques. Selective cytostatic treatment, chemoembolization).

  • Transarterial chemoembolisation therapy (TACE)
    • Combination of transcatheter embolization and supplying chemotherapeutical drug-eluding beads directly to the tumor with a catheter
      • Tumor is both embolised and chemo’d
    • Used for liver cancer
  • Radiofrequency ablation (RFA)
    • US or CT guided
    • Generally used for small tumors
      • Liver
      • Lung
      • Pancreas
    • Procedure
      • A needle-like radiofrequency probe is placed inside the tumor
      • Radiofrequency waves passing through the probe increases the temperature in the tumor -> destruction
  • Microwave ablation (MWA)
    • 900 MHz – 300 GHz
    • US or CT guided
    • Procedure
      • A needle-like microwave probe is placed inside the tumor
      • Microwaves are created from the needle
      • Microwaves heat the tumor -> destruction

37. The fundamentals of nuclear medicine imaging. Types of radiation, applications.

  • Fundamentals of nuclear medicine
    • Nuclear medicine is functional not structural imaging
      • Measures the function of organ or tissue, not the structure
      • Can be combined with conventional imaging to produce functional + structural images
        • For example PET/CT
    • A patient is given a short-lived radioactive material
      • This is called a radioactive isotope, radiotracer or radionuclide
      • Half-life of minutes or hours
    • The radionuclide is attached to a carrier compound (a pharmaceutical) which concentrates in certain tissues
      • This combination is called a radiopharmaceutical
      • Examples of radiopharmaceuticals
        • F18-FDG = fluorine-18 + fluorodeoxyglucose (FDG)
          • Fluorine-18 is radioactive (emits positrons)
          • FDG concentrates in tumors
        • 99mTc-pertechnetate = technetium-99m + pertechnetate
          • Technetium-99m emits gamma rays
            • 99mTc is the most widely used radioisotope
          • Pertechnetate concentrates in thyroid, brain
        • Iodine-131
          • No carrier compound needed; the radioactive isotope I-131 concentrates in the thyroid
          • I-131 emits both gamma and beta rays
          • Can be used both for thyroid imaging and destruction of thyroid cancer
    • The radiation emitted by the radiopharmaceutical is detected by a so-called gamma camera
    • Most nuclear medicine scans have a resolution of about 1 cm
      • Meaning that they can’t detect lesions smaller than that
    • Most common types
      • Single photon emission computed tomography (SPECT)
        • Less expensive than PET but better contrast and resolution
        • Uses gamma-emitting radioisotopes
          • Technetium-99m
          • Iodine-123
        • Especially used in
          • Myocardial perfusion imaging
          • Bone imaging
          • Functional brain imaging
      • Positron emission tomography (PET)
        • More expensive than SPECT but better contrast and resolution
        • Metabolic changes in the heart, brain and tumours can be examined
        • Uses positron-emitting radioisotopes
          • 18F-FDG (most frequent)
          • Radioisotopes used in PET have ultrashort half-lives
            • They must therefore be made at the site of the examination
        • Indications
          • Diagnosis and follow-up of cancer
          • Locate hidden metastases
          • Detect recurrence of cancer
          • Measure brain activity
        • Physics
          • The patient is given an isotope which releases positrons
          • Inside the body these positrons will meet with electrons. They will annihilate each other
          • The annihilation produces gamma photons which are detected
      • Bone scan
      • Ventilation/perfusion scan
      • Cardiac scans
      • Thyroid scans
  • (Important) types of radiation
    • Beta particles
      • High-energy, high-speed electrons or positrons
      • Deliver high radiation dose to the patient
        • A disadvantage for imaging
        • An advantage for tissue destruction
    • Gamma waves
      • Lower energy
      • Good for imaging
      • Similar to x-rays

38. Advantages of hybrid techniques (SPECT/CT, PET/CT).

  • Hybrid techniques
    • Combine two imaging modalities
    • Indications
      • Tumor staging
      • Evaluation of a lesion where other modalities are inconclusive
      • Assess treatment response
      • Evaluation of recurrence or relapse
    • SPECT/CT
      • Anatomical information with CT
      • Functional information with SPECT
    • PET/CT
      • Anatomical information with CT
      • Metabolic information with PET

39. Radioisotope diagnostics of pulmonary embolism (perfusion and inhalation). Radioisotope methods in pulmonary malignancies.

  • Pulmonary ventilation/perfusion (V/Q) scan for PE
    • Not so much used anymore – CT pulmonary angiography is more used for diagnosing PE
    • V/Q scan used if CT-PA is not available or if there is contraindication to it
    • X-ray should be performed first to rule out other diseases of the lungs and heart
    • Perfusion and ventilation are studied separately
    • Perfusion study
      • Radiopharmaceutical used: 99mTc – macroaggregated albumin
        • Imaging begins immediately after IV injection
      • Uptake should be visible throughout the lungs
        • Less around the hila and heart
      • If perfusion study shows perfusion defects, a ventilation scan is performed
    • Ventilation study
      • Radiopharmaceutical used: aerosol labeled 99mTc -> patient inhales it
      • The radiotracer should wash into the lungs homogeneously
    • Pulmonary embolism
      • Ventilation will be normal but perfusion will be absent in an area
  • Radioisotope methods in pulmonary malignancies
    • Neuroendocrine (carcinoid) lung tumors express somatostatin receptors -> radiopharmaceuticals will bind to these receptors
      • Lung carcinoid and adenocarcinomas
      • Radiopharmaceuticals which bind to SST receptors
        • 111In-octreotide – indium-111-octreotide
        • 99mTc-depreotide
    • PET/CT
      • For lung cancer and metastases
      • 18F-FDG
        • Increased glucose metabolism in tumor

40. Radioisotope examination of myocardial perfusion (transient and permanent ischaemia, viability). Radioisotope examination of left ventricle pump function and wall motion problems.

  • Nuclear medicine studies of heart
    • Rest myocardial perfusion study
      • Can measure impairment of the myocardial perfusion
      • SPECT/CT
      • Indications
        • Myocardial infarction
        • Cardiomyopathy
    • Stress/rest myocardial perfusion study
      • Physical or pharmacological stress is applied
        • Dipyridamol or treadmill
      • SPECT/CT
      • Rest SPECT later the same day or the day after
      • If perfusion in stress > perfusion in rest -> reversible ischaemia
      • If perfusion in stress = perfusion in rest -> necrosis/scar
      • Indications
        • Angina pectoris
        • Coronary artery disease
    • Myocardial viability examination
      • Myocardium can be:
        • Stunned
          • Wall is dysfunctional but perfusion is normal
        • Ischaemic
          • There is decreased perfusion during stress but normal perfusion during rest
          • These patient will benefit from revascularization
        • Hibernating
          • There is decreased perfusion during stress and rest
          • But the myocytes are viable and will benefit from revascularization
        • Infarcted
          • There is no perfusion during stress or rest
          • Myocytes are not viable and will therefore not benefit from revascularization
      • These examinations determine the viability of the myocardium
        • I.e., the possibility for the myocardium to return to normal after revascularization
      • With PET
        • 18F-FDG
      • With SPECT
        • 201Tl-chloride (Thallium-201)
    • Radionuclide ventriculography (RNVG) = multigated analysis (MUGA)
      • Measures ventricular function
      • Coupled to ECG
        • -> Synchronizes image acquisition to R-waves
      • 99mTc-pyrophosphate-RBC
    • First-passage radionuclide angiography
      • 99mTc-DTPA
      • A dynamic series of images as the radiopharmaceutical flows from the right heart to the left heart and out
      • Allows measurement of
        • Wall motion of ventricles
        • Ventricular volumes
        • Ejection fraction
        • Cardiac output

41. Radioisotope diagnostics of thyroid diseases and parathyroid diseases.

  • Thyroid
    • Modalities
      • Thyroid scintigraphy (thyroid scan)
      • SPECT/CT
      • 18F-FDG PET
        • For thyroid carcinoma metastases which don’t take up iodine or 99mTc-pertechnetate
    • Thyroid scintigraphy
      • Radiopharmaceuticals used
        • 99mTc-pertechnetate
          • Most common
        • Iodine-123
        • Iodine-131
    • Findings
      • Hot nodule (increased isotope uptake compared to surrounding thyroid)
        • Multiple -> toxic goitre
        • Single
          • Thyroid carcinoma
          • Autonomous adenoma
      • Cold nodule (decreased isotope uptake compared to surrounding thyroid)
        • Adenoma
        • Colloid goitre
        • Cyst
      • Diffuse increased uptake -> Hyperthyroidism
      • Diffuse decreased uptake -> Hypothyroidism
  • Parathyroid scintigraphy
    • Used to localize hyperfunctioning parathyroid tissue in case of hyperthyroidism
    • There are no specific radiotracers for parathyroid tissue, so special modalies must be used
    • Modalities
      • Double-tracer parathyroid scintigraphy
        • 2 tracers (99mTc-MIBI and 99mTc-pertechnetate)
        • Digital subtraction is used to visualize the hyperfuncitoning parathyroid tissue
      • Dual-phase parathyroid scintigraphy
        • 1 tracer (99mTc-MIBI)
        • 2 phases
          • First – 10 minutes after injection
          • Second – 2 hours after injection
      • SPECT/CT

42. Nuclear medicine methods in childhood (kidney, bone, 123I-MIBG scintigraphy).

  • Radiation in children
    • Important to weigh risk against benefits when exposing children to radiation
    • Appropriate radiation doses for children are calculated by body weight
    • Sufficient hydration improves image quality and decreases radioactivity affecting the patient
  • Important nuclear medicine methods in children
    • Renal imaging
      • Renal scintigraphy
        • Static method
        • 99mTc-DMSA
        • Measures corticol loss
        • Indications
          • Congenital renal diseases
          • Pyelonephritis
          • Obstructive renal disease
      • Camera-renography
        • Dynamic method
        • Images before and after furosemide
          • If furosemide improves excretion the obstruction is anatomical
          • If it doesn’t then it’s a functional problem of the kidney
        • 99mTc-DTPA – for glomerular secretion
        • 99mTc-MAG3 – for tubular secretion
        • Creates a time-activity curve = renogram with 3 phases
          • Phase I – perfusion
          • Phase II – filtration or secretion function
          • Phase III – excretion function
        • Indications
          • Obstructive renal disease
          • Reflux disease
    • Bone scintigraphy
      • 99mTc-MDP (diphosphate)
      • Can be difficult to evaluate due to high activity of the epiphyses
      • Indications
        • Inflammations
        • Bone tumors
        • Osteonecrosis
        • Fractures
    • I123-MIBG scintigraphy
      • I123-MIBG binds to adrenergic receptors in neuroendocrine tumors
      • Indications
        • Neuroblastoma
        • Phaeochromocytoma
      • Thyroid must be protected from radiation
        • Iodine is given before examination

43. Radioisotope diagnostics in breast and gynecologic tumors. The significance of sentinel lymph node scintigraphy.

  • Scintimammography
    • 99mTc-MIBI
  • Sentinel lymph node scintigraphy
    • Radiopharmaceutical injected close to tumor
      • It will travel with the same lymph vessels as the tumor cells, thereby reaching sentinel lymph nodes
      • 99mTc-HSA (human serum albumin)
    • Advantage: Avoids unnecessary lymph node dissections
    • Indications
      • Early tumor stage

44. Brain perfusion examinations in nuclear medicine (indications, radiopharmaceuticals, imaging).

  • Modalities
    • Brain scintigraphy
      • 99mTc-DTPA
      • Used for confirmation of brain death
    • Brain perfusion scintigraphy
      • With SPECT
      • 99mTc-HM-PAO – accumulates in gray matter
      • Indications
        • Cerebrovascular disease
        • Dementia
    • CSF scintigraphy
      • 99mTc-DTPA intrathecally
      • Indications
        • Spinal tumor
        • Hydrocephalus
    • Brain receptor scintigraphy
      • 123I-ioflupane – Binds to dopamine transporter
      • 123I-IBZM (DaTscan) – Binds to D2 receptors
        • Both are used to differentiate Parkinson from other neurodegenerative diseases
    • Brain metabolism (PET investigation)
      • 18F-FDG or 11C-methionine
      • Examination of brain tumors

45. Nuclear medicine examinations in gastroenterology.

  • Liver scintigraphy
    • 99mTc-Fyton
      • Phagocytosed by Kuppfer cells
    • Focal defect shows the lesion
    • + SPECT/CT
    • Indications
      • Tumor
      • Metastasis
      • Haemangioma
      • Focal nodular hyperplasia
  • Liver blood-pool scintigraphy
    • 99mTc-pyrophosphate-labeled RBCs
      • Accumulates in blood-pools in haemangioma
    • + SPECT/CT
    • Haemangioma is shown by focal increased activity
  • Hepatobiliary scintigraphy/HIDA scan
    • 99mTc-HIDA
      • HIDA = Hepatic IDA
      • Is excreted by the liver into the bile duct
    • Examine liver excretion function and function of gallbladder
    • Indications
      • Bile excretion disorders
      • Gallbladder disorders
      • Bile tree disorders
  • PET/CT in GI tract
    • 18F-FDG
    • Indications
      • Oesophagus carcinoma
      • Colorectal cancer
      • Other GI cancers
  • Oesophagus scintigraphy
    • 99mTc-DTPA
      • Patient eats it with a meal
    • Indications
      • Motility failures of oesophagus or stomach, stenoses

46. Isotope renography (indications, radiopharmaceuticals, imaging).

  • Renal scintigraphy
    • Static method
    • 99mTc-DMSA
    • Measures corticol loss
    • Can measure relative ratio of renal function between the two kidneys
    • Indications
      • Pyelonephritis
      • Renal infarction
      • Acute renal failure
      • Hydronephrosis
  • Camera-renography
    • Dynamic method
    • Images before and after furosemide
      • If furosemide improves excretion the obstruction is anatomical
      • If it doesn’t then it’s a functional problem of the kidney
    • 99mTc-DTPA – for glomerular secretion
    • 99mTc-MAG3 – for tubular secretion
    • Creates a time-activity curve = renogram with 3 phases
      • Phase I – perfusion
      • Phase II – filtration or secretion function
      • Phase III – excretion function
    • Indications
      • Obstructive renal disease
      • Hypertension
      • Measuring GFR

47. Indications of bone scintigraphy. The significance and indications of 3-phase bone scintigraphy.

  • Bone scintigraphy/scan
    • Screening method of choice for
      • Detection of bone metastases
      • Diagnosing fractures which aren’t visible by conventional imaging
    • Advantages
      • Widely available
      • Inexpensive
      • Shows entire skeleton
    • Disadvantages
      • Poor spatial resolution
      • Poor contrast resolution
    • Tc99m-MDP is the most frequently used radiopharmaceutical
      • Injection -> Wait 2 – 4 hours -> Imaging
        • Normal bone scan only has this delayed “phase”
    • Indications
      • Metastasis of bone
      • Primary bone tumor
      • Osteomyelitis
      • Fractures
      • Metabolic bone diseases
        • Hyperparathyroidism
      • Osteonecrosis
  • Three-phase bone scintigraphy
    • A special type of bone scan
      • Produces dynamic images as well as static
    • 3 phases
      • Flow phase = perfusion phase
        • Imaging obtained for 60 seconds after injection
        • Demonstrates the perfusion of a particular area
      • Blood pool phase
        • Imaging obtained 5 minutes after injection
        • Demonstrates the pooling of blood in a particular area
          • Increased in inflammation
      • Delayed phase = bone phase
        • Imaging obtained 2 – 4 hours after injection
        • Demonstrates blood flow and rate of bone formation
    • Indications
      • Osteomyelitis
        • Especially to differentiate osteomyelitis from cellulitis
      • Bone pain
      • Skeletal metastases
      • Arthritis
    • Dual energy x-ray absorptiometry (DEXA)
      • = Bone densitometry
      • Measures bone density
      • Good for osteoporosis

48. Radioiodine therapy in the diseases of the thyroid gland.

  • Radiotherapy
    • Patients must follow rules to avoid radiation burden for other people
      • Like keeping distance from people, etc
  • Therapy of thyroid diseases
    • Iodine-131
      • Given orally, is taken up by thyroid cells, where it is trapped
      • Decays into
        • Beta radiation -> damages thyroid tissue
        • Gamma radiation -> can be detected with gamma camera
      • Indications
        • Post-thyroidectomy due to cancer
          • Especially when the whole thyroid hasn’t been removed to preserve the parathyroids
        • Metastatic thyroic cancer
        • Thyroid ablation in hyperthyroidism
  • Therapy of other cancers
    • Radium-223 – produces alpha radiation
      • Prostate cancer
      • Bone metastases

49. Radionuclide therapy of neuroendocrine and neuroectodermal tumors.

  • Neuroendocrine (carcinoid) tumors express somatostatin receptors -> radiopharmaceuticals will bind to these receptors
    • Indications
      • Lung neuroendocrine tumors
      • Adenocarcinomas of GI tract and pancreas
    • Radiopharmaceuticals which bind to SST receptors
      • 111In-octreotide – indium-111-octreotide
      • 99mTc-depreotide
  • I123-MIBG scintigraphy
    • I123-MIBG binds to adrenergic receptors in neuroendocrine tumors
    • Indications
      • Neuroblastoma
      • Phaeochromocytoma
    • Thyroid must be protected from radiation
      • Iodine is given before examination


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6 thoughts on “Clinical Radiology”

  1. Hi, great notes btw.

    On topic 27, should not epidural hematoma cause more mass effect than subdural?

    Thanks

    1. Actually both of them have mass effect, but I’m not sure epidural causes more mass effect than subdural. Why do you say that?

      1. Yes, we are in agreement then. Earlier today, i thought i saw the topic state that epidural hematomas did not cause mass effect. But, i must have read it wrong.

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