I85PREP
⌘ K
RANZCR AIT study materials
RANZCR AIT study resources

RANZCR AIT practice questions

One question at a time. Build your RANZCR AIT understanding.

First 50 of 199 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Clinical Radiology Phase 1

On a plain radiograph, which density appears most radiolucent?

  1. Air Correct answer.
  2. Bone
  3. Fat
  4. Soft tissue

Explanation

Radiographic density is graded by the degree to which tissue attenuates the x-ray beam. Air attenuates least and therefore appears blackest, while fat, soft tissue, and bone attenuate progressively more and appear increasingly white.

Question 2Clinical Radiology Phase 1

Which imaging modality is the first-line investigation for suspected acute ischaemic stroke in most centres?

  1. Skull radiograph
  2. MRI diffusion-weighted imaging
  3. Non-contrast CT brain Correct answer.
  4. Carotid Doppler ultrasound

Explanation

Non-contrast CT is rapid and widely available and reliably excludes haemorrhage, which is the key decision before thrombolysis. It is therefore the standard first-line study even though it is less sensitive than MRI for early infarction.

Question 3Clinical Radiology Phase 1

A patient with a suspected scaphoid fracture has a normal initial wrist radiograph. What is the most appropriate immediate management?

  1. Discharge without follow-up
  2. Immediate bone scan
  3. Immobilise the wrist and repeat imaging in 7 to 14 days Correct answer.
  4. Immediate CT of the wrist

Explanation

Scaphoid fractures are frequently occult on initial radiographs and carry a risk of non-union and avascular necrosis. Standard practice is immobilisation with repeat radiographs or early MRI, so immobilisation with follow-up is correct.

Question 4Clinical Radiology Phase 1

Which feature best distinguishes a simple hepatic cyst from a solid liver lesion on ultrasound?

  1. Anechoic content with posterior acoustic enhancement Correct answer.
  2. Heterogeneous echogenicity
  3. Internal vascularity on colour Doppler
  4. Irregular thickened wall

Explanation

A simple cyst contains fluid that produces no echoes and transmits sound better than surrounding tissue, giving posterior acoustic enhancement. Internal vascularity, heterogeneity, and irregular walls all suggest a solid or complex lesion instead.

Question 5Clinical Radiology Phase 1

Which of the following is the most appropriate initial imaging test for suspected acute appendicitis in a young adult?

  1. Barium enema
  2. Plain abdominal radiograph
  3. Intravenous urogram
  4. Ultrasound of the right iliac fossa Correct answer.

Explanation

Ultrasound is non-ionising, widely available, and highly specific for appendicitis in thinner patients, so it is a reasonable first-line test. CT is used when ultrasound is inconclusive or the patient is obese.

Question 6Clinical Radiology Phase 1

Which structure is located immediately anterior to the trachea in the lower neck?

  1. Recurrent laryngeal nerve
  2. Longus colli muscle
  3. Oesophagus
  4. Isthmus of the thyroid gland Correct answer.

Explanation

The thyroid isthmus crosses the midline anterior to the second to fourth tracheal rings. The oesophagus and longus colli lie posterior to the trachea, and the recurrent laryngeal nerve runs in the tracheo-oesophageal groove.

Question 7Clinical Radiology Phase 1

A chest radiograph shows an endotracheal tube whose tip lies below the carina. What is the main concern?

  1. Pneumothorax from tracheal perforation
  2. Oesophageal intubation
  3. Tube obstruction by the cuff
  4. Right main bronchus intubation with left lung collapse Correct answer.

Explanation

The right main bronchus arises at a shallower angle than the left, so an over-advanced tube preferentially enters it. This over-ventilates the right lung and leaves the left lung to collapse, and the tip should sit 3 to 5 cm above the carina.

Question 8Clinical Radiology Phase 1

Which imaging finding is characteristic of a complete rotator cuff tear on MRI?

  1. Full-thickness gap in the tendon with fluid signal extending through it Correct answer.
  2. Subacromial bursal fluid alone
  3. Greater tuberosity sclerosis
  4. Increased signal confined within the tendon on T2

Explanation

A complete tear shows a defect extending across the full thickness of the tendon, often filled with fluid-equivalent signal. Intrasubstance signal confined within the tendon indicates a partial tear rather than a complete one.

Question 9Clinical Radiology Phase 1

A 60-year-old smoker presents with haemoptysis. Chest radiograph shows a hilar mass. What is the most appropriate next imaging step to stage the disease?

  1. Contrast-enhanced CT of the chest including the adrenals Correct answer.
  2. Repeat chest radiograph in 6 weeks
  3. Abdominal ultrasound
  4. MRI of the cervical spine

Explanation

Contrast-enhanced CT of the chest is the standard staging study for suspected lung cancer and should include the liver and adrenals, common sites of metastasis. A tissue diagnosis then follows.

Question 10Clinical Radiology Phase 1

Which feature on MRI best indicates a benign simple breast cyst?

  1. Rim enhancement after contrast
  2. Spiculated margins
  3. Smooth margins with homogeneous high T2 signal and no enhancement Correct answer.
  4. Restricted diffusion with low ADC

Explanation

A simple cyst is well defined, uniformly bright on T2-weighted images, and shows no internal enhancement. Spiculation, rim enhancement, and restricted diffusion all raise concern for malignancy.

Question 11Clinical Radiology Phase 1

A patient has sudden severe headache with a normal non-contrast CT performed 12 hours after onset. What is the most appropriate next step?

  1. Discharge with analgesia
  2. Skull radiograph
  3. MRI of the brain without contrast
  4. Lumbar puncture for xanthochromia Correct answer.

Explanation

CT sensitivity for subarachnoid haemorrhage falls with time from onset, so a normal scan at 12 hours does not exclude it. Lumbar puncture for xanthochromia is indicated when CT is negative and clinical suspicion remains.

Question 12Clinical Radiology Phase 1

Which finding on an abdominal radiograph suggests a mechanical small bowel obstruction?

  1. Dilated peripheral loops with haustral markings
  2. Multiple dilated central loops with valvulae crossing the full width Correct answer.
  3. Gas in the biliary tree
  4. Free gas under the diaphragm

Explanation

Small bowel obstruction produces centrally placed dilated loops whose valvulae conniventes traverse the entire lumen. Large bowel loops are peripheral with incomplete haustral markings.

Question 13Clinical Radiology Phase 1

Which is the most sensitive sequence for detecting acute demyelinating lesions in the brain?

  1. T2-weighted fluid-attenuated inversion recovery Correct answer.
  2. Gradient echo imaging
  3. T1-weighted imaging
  4. Diffusion tensor imaging

Explanation

FLAIR suppresses CSF signal while retaining T2 weighting, making periventricular and juxtacortical demyelinating plaques conspicuous. T1 is relatively insensitive to these lesions.

Question 14Clinical Radiology Phase 1

A renal ultrasound shows a hyperechoic mass in the renal sinus with posterior acoustic shadowing. What is the most likely diagnosis?

  1. Renal calculus Correct answer.
  2. Simple renal cyst
  3. Hydronephrosis
  4. Renal cell carcinoma

Explanation

Stones are strongly reflective and attenuate sound, producing a bright focus with a clean posterior shadow. Solid tumours are echogenic but do not shadow in this way.

Question 15Clinical Radiology Phase 1

Which parameter most directly reflects radiation dose to tissue from a CT examination?

  1. Scan field of view
  2. Tube current in milliamperes
  3. Pitch
  4. Volume CT dose index Correct answer.

Explanation

Volume CT dose index estimates the average absorbed dose within the scanned volume and is reported on the dose sheet. Tube current and pitch influence dose but are technical settings rather than dose metrics.

Question 16Clinical Radiology Phase 1

A 70-year-old presents with a pulsatile abdominal mass. Which investigation is the definitive test for an abdominal aortic aneurysm?

  1. Plain abdominal radiograph
  2. CT angiography of the aorta Correct answer.
  3. Abdominal ultrasound
  4. MRI of the lumbar spine

Explanation

CT angiography accurately measures aneurysm diameter, defines extent, and assesses suitability for endovascular repair. Ultrasound is a good screening tool but does not provide the anatomical detail needed for treatment planning.

Question 17Clinical Radiology Phase 1

Which feature on high-resolution CT is most characteristic of usual interstitial pneumonia?

  1. Upper lobe centrilobular nodules
  2. Unilateral pleural effusion with nodular thickening
  3. Subpleural basal reticulation with honeycombing Correct answer.
  4. Bilateral ground-glass with sparing of the periphery

Explanation

Usual interstitial pneumonia shows a basal, subpleural predominance of reticulation, traction bronchiectasis, and honeycombing. Upper lobe nodules or diffuse ground-glass suggest alternative patterns such as hypersensitivity pneumonitis.

Question 18Clinical Radiology Phase 1

Which imaging modality is preferred for evaluating suspected acute spinal cord compression when MRI is contraindicated?

  1. Bone scan
  2. Ultrasound of the spine
  3. CT myelography Correct answer.
  4. Plain radiograph of the spine

Explanation

CT myelography outlines the thecal sac and cord after intrathecal contrast and can demonstrate compression when MRI cannot be performed. Plain radiographs show bone only and bone scan is insensitive to cord compression.

Question 19Clinical Radiology Phase 1

A thyroid ultrasound shows a solid hypoechoic nodule with microcalcifications and irregular margins. What is the most appropriate next step?

  1. Radioiodine therapy
  2. Repeat ultrasound in 12 months
  3. Thyroidectomy without cytology
  4. Ultrasound-guided fine needle aspiration Correct answer.

Explanation

The described features are highly suspicious for papillary carcinoma under the standard risk stratification systems. Cytological sampling by ultrasound-guided fine needle aspiration is the accepted next step.

Question 20Clinical Radiology Phase 1

A patient with acute flank pain has a non-contrast CT showing a 6 mm stone at the vesicoureteric junction with mild hydronephrosis. Which finding would most strongly indicate the need for urgent decompression?

  1. Presence of a ureteric stent from a previous episode
  2. A single functioning kidney with rising creatinine Correct answer.
  3. Stone size of 6 mm
  4. Mild ipsilateral hydronephrosis

Explanation

Obstruction in a solitary or poorly functioning kidney threatens overall renal function and warrants urgent decompression. Stone size, mild hydronephrosis, and a previously placed stent are not by themselves indications for emergency intervention.

Question 21Clinical Radiology Phase 1

Which sequence is most sensitive for detecting a small vestibular schwannoma?

  1. Thin-section T1 post-contrast imaging of the internal auditory canal Correct answer.
  2. T2-weighted imaging of the whole brain
  3. Non-contrast T1 imaging
  4. CT of the petrous temporal bone

Explanation

Small vestibular schwannomas enhance avidly and are best shown on thin-section post-contrast T1 imaging targeted to the internal auditory canal. CT may show bony widening but misses small intracanalicular tumours.

Question 22Clinical Radiology Phase 1

A renal mass shows macroscopic fat on CT. Which diagnosis is most likely?

  1. Angiomyolipoma Correct answer.
  2. Renal oncocytoma
  3. Transitional cell carcinoma
  4. Clear cell renal carcinoma

Explanation

Macroscopic fat within a renal mass is characteristic of an angiomyolipoma, which contains adipose tissue. Clear cell carcinoma may contain microscopic fat but rarely macroscopic fat.

Question 23Clinical Radiology Phase 1

In a patient with suspected acute mesenteric ischaemia and a normal plain radiograph, which investigation is most appropriate?

  1. Abdominal ultrasound with Doppler
  2. Barium follow-through
  3. Repeat plain radiograph in 24 hours
  4. CT angiography of the mesenteric vessels Correct answer.

Explanation

CT angiography directly demonstrates arterial or venous occlusion and assesses bowel viability, and plain films are often normal early. Delay in diagnosis carries high mortality.

Question 24Clinical Radiology Phase 1

A chest radiograph shows a widened mediastinum after blunt trauma. Which finding on CT most strongly indicates a traumatic aortic injury?

  1. Atherosclerotic calcification of the aortic arch
  2. Left ventricular hypertrophy
  3. Aortic diameter of 3 cm
  4. Irregular outpouching at the aortic isthmus with periaortic haematoma Correct answer.

Explanation

Blunt aortic injury most often occurs at the isthmus, appearing as an irregular contour change or pseudoaneurysm with surrounding haematoma. Atherosclerosis, mild dilatation, and ventricular hypertrophy are chronic findings unrelated to acute injury.

Question 25Clinical Radiology Phase 1

Which pattern of enhancement on MRI is most consistent with a haemangioma in the liver?

  1. Arterial hyperenhancement with washout
  2. Rim enhancement with central necrosis
  3. Peripheral nodular enhancement with progressive centripetal filling Correct answer.
  4. Uniform hypoenhancement in all phases

Explanation

Hepatic haemangiomas show discontinuous peripheral nodular enhancement that fills centripetally over time. Arterial hyperenhancement with washout is the hallmark of hepatocellular carcinoma.

Question 26Clinical Radiology Phase 1

Which imaging modality is the first-line investigation for a suspected deep vein thrombosis of the lower limb?

  1. Contrast venography of the leg
  2. Compression ultrasound of the leg veins Correct answer.
  3. CT pulmonary angiography
  4. MRI of the thigh

Explanation

Compression ultrasound is non-invasive, widely available and highly accurate for proximal deep vein thrombosis, so it is the accepted first-line test. It assesses vein compressibility and Doppler flow without ionising radiation or contrast.

Question 27Clinical Radiology Phase 1

On a plain abdominal radiograph, which finding most strongly suggests pneumoperitoneum?

  1. Free gas under the diaphragm on an erect film Correct answer.
  2. Multiple air-fluid levels in the central abdomen
  3. Dilated loops of colon with haustral markings
  4. A gasless abdomen with central opacity

Explanation

Free intraperitoneal gas rises to the highest point, so on an erect chest or abdominal film it appears as a crescent beneath the hemidiaphragm. This is the classic plain-film sign of a perforated viscus.

Question 28Clinical Radiology Phase 1

Which radiological sign on a barium swallow indicates achalasia of the oesophagus?

  1. Smooth tapering at the gastro-oesophageal junction with proximal dilatation Correct answer.
  2. Anterior indentation of the oesophagus by the aortic arch
  3. Diffuse mucosal ulceration with skip lesions
  4. Multiple strictures along the mid-oesophagus

Explanation

Achalasia results from failure of lower oesophageal sphincter relaxation, producing a smooth 'bird-beak' taper at the gastro-oesophageal junction with a dilated, fluid-filled oesophagus above it. The mucosa remains intact, distinguishing it from malignant strictures.

Question 29Clinical Radiology Phase 1

Which feature on ultrasound most reliably distinguishes a simple hepatic cyst from a solid liver lesion?

  1. Anechoic content with posterior acoustic enhancement Correct answer.
  2. Irregular margins with internal vascularity
  3. A hyperechoic rim with central shadowing
  4. Internal echoes with low-level echogenicity

Explanation

A simple cyst is fluid-filled, so it appears anechoic with a thin imperceptible wall and enhances sound transmission posteriorly. Solid lesions contain internal echoes and typically lack posterior enhancement.

Question 30Clinical Radiology Phase 1

Which projection best demonstrates a small pneumothorax on a chest radiograph?

  1. Lordotic apical view
  2. Lateral decubitus film of the unaffected side
  3. Erect posteroanterior film in full inspiration Correct answer.
  4. Supine anteroposterior film in expiration

Explanation

An erect film allows air to collect at the lung apex, where a small pneumothorax is most visible as a pleural line with no lung markings beyond it. Full inspiration increases the chance of detecting a subtle rim of air.

Question 31Clinical Radiology Phase 1

Which imaging finding is characteristic of a simple bone cyst in a child?

  1. Multiple lytic lesions with endosteal scalloping
  2. Stippled calcification within the epiphysis
  3. A destructive lesion with periosteal reaction and soft tissue mass
  4. A well-defined lucent lesion in the metaphysis with a thin sclerotic margin Correct answer.

Explanation

A simple (unicameral) bone cyst typically appears as a well-defined central lucency in the metaphysis of a long bone, often with a thin sclerotic rim and no aggressive features. It is common in children and may fracture after minor trauma.

Question 32Clinical Radiology Phase 1

On MRI of the knee, which structure is assessed by the McMurray-style meniscal signal grading system?

  1. The anterior cruciate ligament, graded by fibre continuity
  2. The patellar cartilage, graded by thickness loss
  3. The medial collateral ligament, graded by oedema
  4. The menisci, graded by internal signal and surface contact Correct answer.

Explanation

Meniscal signal is graded from internal linear high signal not reaching a surface to signal contacting an articular surface, which indicates a tear. Surface contact on at least two slices is the key criterion for a definite meniscal tear.

Question 33Clinical Radiology Phase 1

Which feature is typical of a benign thyroid nodule on ultrasound?

  1. A spongiform appearance with multiple small cystic spaces Correct answer.
  2. Taller-than-wide shape in the transverse plane
  3. Punctate microcalcifications throughout a solid nodule
  4. Irregular infiltrative margins with extrathyroidal extension

Explanation

A spongiform nodule composed mostly of small cystic spaces is highly specific for a benign colloid nodule. This pattern carries a very low risk of malignancy and usually requires no biopsy.

Question 34Clinical Radiology Phase 1

A patient has a suspected scaphoid fracture after a fall but initial radiographs are normal. What is the most appropriate next step?

  1. Immediate open reduction and internal fixation
  2. Ultrasound of the wrist to exclude fracture
  3. Discharge with analgesia and no follow-up
  4. Immobilise and repeat radiographs in 10 to 14 days, or perform early MRI Correct answer.

Explanation

Scaphoid fractures may be occult on initial films, and missed fractures risk non-union and avascular necrosis. Immobilisation with repeat imaging, or early MRI which is highly sensitive, is the accepted approach.

Question 35Clinical Radiology Phase 1

A 45-year-old woman has a solid renal mass that enhances avidly on corticomedullary phase and shows washout on delayed imaging. Which diagnosis is most likely?

  1. Clear cell renal cell carcinoma Correct answer.
  2. Renal abscess
  3. Simple cortical cyst
  4. Angiomyolipoma

Explanation

Clear cell renal cell carcinoma is typically hypervascular, enhancing strongly in the corticomedullary phase and washing out on delayed phases. This enhancement pattern reflects its rich capillary network.

Question 36Clinical Radiology Phase 1

Which imaging test is most appropriate to confirm a suspected acute pulmonary embolism in a haemodynamically stable patient with normal renal function?

  1. Lower limb compression ultrasound
  2. Chest radiograph
  3. CT pulmonary angiography Correct answer.
  4. Ventilation-perfusion scintigraphy

Explanation

CT pulmonary angiography directly visualises thrombus in the pulmonary arteries and is the first-line test in stable patients with adequate renal function. It is rapid, widely available and highly accurate.

Question 37Clinical Radiology Phase 1

A patient with known cirrhosis presents with fever and abdominal pain. Ascitic fluid ultrasound shows internal septations and echogenic debris. Which complication is most likely?

  1. Portal vein thrombosis
  2. Simple transudative ascites
  3. Budd-Chiari syndrome
  4. Spontaneous bacterial peritonitis Correct answer.

Explanation

In a cirrhotic patient, fever with complex ascites containing septations and debris suggests infected ascites, and spontaneous bacterial peritonitis is the leading concern. Diagnostic paracentesis with cell count and culture is required.

Question 38Clinical Radiology Phase 1

On CT of the chest, which feature most suggests a malignant solitary pulmonary nodule?

  1. Stable size over 5 years
  2. Smooth well-defined margins with diffuse calcification
  3. Fat attenuation within the nodule
  4. Spiculated margins with a doubling time of 3 months Correct answer.

Explanation

Spiculated or lobulated margins and rapid growth are features associated with malignancy. A doubling time of roughly 1 to 6 months is typical for lung cancer, whereas stability for years and benign calcification favour a benign cause.

Question 39Clinical Radiology Phase 1

A young adult has an MRI showing a well-defined lesion in the conus medullaris with high T2 signal and a syrinx. Which diagnosis should be considered first?

  1. Epidural abscess
  2. Meningioma
  3. Ependymoma of the spinal cord Correct answer.
  4. Schwannoma

Explanation

Ependymomas are the most common intramedullary tumours in adults and often occur in the conus or filum, frequently with a syrinx and haemorrhage (haemosiderin cap). They are centrally located and expand the cord.

Question 40Clinical Radiology Phase 1

A patient with acute pancreatitis has a CT showing a fluid collection in the lesser sac that has developed a defined wall after 5 weeks. What is this collection called?

  1. Walled-off necrosis
  2. Pancreatic pseudocyst Correct answer.
  3. Pancreatic abscess
  4. Acute peripancreatic fluid collection

Explanation

A pseudocyst is a fluid collection with a defined wall that develops more than 4 weeks after acute pancreatitis, usually without solid necrotic debris. Earlier, unencapsulated collections are termed acute peripancreatic fluid collections.

Question 41Clinical Radiology Phase 1

Which imaging feature on CT best distinguishes a haemangioma from other liver lesions?

  1. Peripheral rim enhancement with central non-enhancement
  2. Peripheral nodular enhancement with centripetal fill-in Correct answer.
  3. Arterial hyperenhancement with portal venous washout
  4. Diffuse homogeneous enhancement on all phases

Explanation

Hepatic haemangiomas show discontinuous peripheral nodular enhancement that progressively fills toward the centre over successive phases. This centripetal pattern reflects slow blood pooling within vascular spaces.

Question 42Clinical Radiology Phase 1

A patient with a suspected acute abdominal aortic aneurysm rupture is unstable. What is the most appropriate initial imaging strategy?

  1. Plain abdominal radiograph
  2. CT angiography after stabilisation
  3. MRI of the abdomen
  4. Bedside ultrasound in the emergency department Correct answer.

Explanation

In an unstable patient, bedside ultrasound can rapidly confirm the presence of an aneurysm and free fluid without leaving the resuscitation area. CT is preferred in stable patients for operative planning.

Question 43Clinical Radiology Phase 1

On a chest radiograph, which feature suggests left atrial enlargement?

  1. Bilateral hilar enlargement with eggshell calcification
  2. Double right heart border and splaying of the carina Correct answer.
  3. Elevation of the hemidiaphragms
  4. Increased retrosternal airspace

Explanation

Left atrial enlargement produces a double right heart border from the overlapping right atrium and left atrium, and widens the carinal angle. These signs reflect posterior and superior enlargement of the left atrium.

Question 44Clinical Radiology Phase 1

A 30-year-old has sudden onset of severe flank pain and a non-contrast CT shows a wedge-shaped renal area of reduced enhancement. Which diagnosis is most likely?

  1. Renal cell carcinoma
  2. Renal cyst rupture
  3. Renal infarction Correct answer.
  4. Acute pyelonephritis

Explanation

A wedge-shaped, non-enhancing cortical defect in a patient with acute flank pain is characteristic of renal infarction, often due to thromboembolism. The defect respects segmental arterial territories and may show a cortical rim sign.

Question 45Clinical Radiology Phase 1

Which MRI sequence is most appropriate for evaluating suspected acute osteomyelitis of the vertebral body?

  1. Gradient echo imaging of the whole spine
  2. Diffusion-weighted imaging without anatomical sequences
  3. T1-weighted with fat suppression after gadolinium, alongside STIR Correct answer.
  4. Non-contrast T1-weighted imaging alone

Explanation

Acute vertebral osteomyelitis is best assessed with fat-suppressed fluid-sensitive sequences to show marrow oedema and post-gadolinium T1-weighted fat-suppressed images to show enhancement and abscess formation. These combined sequences provide high sensitivity and specificity.

Question 46Clinical Radiology Phase 1

A patient has a suspected ureteric stone and a non-contrast CT is planned. Which feature most reliably indicates obstruction on CT?

  1. Hydroureteronephrosis proximal to the stone with perinephric stranding Correct answer.
  2. Mild dilatation of the renal pelvis only
  3. A stone measuring less than 5 mm
  4. Presence of a calcific density along the ureter

Explanation

Obstruction is suggested by dilatation of the collecting system and ureter proximal to the stone, together with perinephric oedema or stranding. Stone size alone does not confirm obstruction.

Question 47Clinical Radiology Phase 1

Which imaging finding is most characteristic of a hydatidiform mole on pelvic ultrasound?

  1. An adnexal mass with a fetal pole separate from the uterus
  2. A heterogeneous intrauterine mass with multiple cystic spaces ('snowstorm') Correct answer.
  3. A simple anechoic gestational sac with a yolk sac
  4. A thickened endometrium with a pseudogestational sac

Explanation

A complete hydatidiform mole produces a distended uterus filled with a heterogeneous mass of small cystic spaces, classically described as a snowstorm appearance. Colour Doppler shows increased vascularity and beta-hCG is markedly elevated.

Question 48Clinical Radiology Phase 1

A patient with a suspected cerebrospinal fluid leak has a skull base defect on high-resolution CT. Which additional test best confirms the leak?

  1. MRI of the pituitary fossa
  2. Plain skull radiograph
  3. Beta-2 transferrin assay of the fluid Correct answer.
  4. Serum sodium measurement

Explanation

Beta-2 transferrin is a protein found almost exclusively in cerebrospinal fluid, so its detection in nasal or ear fluid confirms a CSF leak. This biochemical test complements imaging rather than replacing it.

Question 49Clinical Radiology Phase 1

A patient has a suspected acute aortic dissection. Which feature on CT angiography most reliably identifies a false lumen?

  1. A flap separating two lumens, with the false lumen often larger and less enhanced Correct answer.
  2. Circumferential calcification of the aortic wall without a flap
  3. Complete occlusion of the aorta at the level of the diaphragm
  4. Atherosclerotic plaque at the aortic bifurcation

Explanation

An intimal flap dividing the aorta into true and false lumens is the diagnostic feature of dissection. The false lumen tends to be larger, may show delayed enhancement and may contain thrombus, while the true lumen is often compressed.

Question 50Clinical Radiology Phase 1

Which finding on MRI best distinguishes a pituitary macroadenoma from a craniopharyngioma?

  1. Enlargement of the sella with a mass arising from the gland and displacing the chiasm Correct answer.
  2. A suprasellar cystic mass with calcification and rim enhancement
  3. Bilateral enlargement of the optic nerves
  4. A homogeneous mass centred in the pineal region

Explanation

Pituitary macroadenomas arise within the sella, enlarge it and extend upward to compress the optic chiasm, often with a snowman shape. Craniopharyngiomas are typically suprasellar, cystic and calcified, particularly in children.