Free Diagnostic Radiology mock test

Diagnostic Radiology sample questions with answers

10 more original exam-style Diagnostic Radiology questions, worked in full. They are not real or recalled exam questions, and none of them is in the mock above or on the bank page, so sit the mock first if you have not.

1. Question 1 · Neuro Imaging (Brain, Spine, Head Trauma and Neurovascular)

   A 66-year-old woman was last known well 14 hours ago. NIHSS is 18. CT angiography shows a left internal carotid artery terminus occlusion and CT perfusion demonstrates an infarct core of 12 mL with a large hypoperfused volume. Which management decision is best supported by current evidence?

   1. AAdminister intravenous thrombolysis alone, as thrombectomy is not indicated beyond 6 hours
   2. BProceed to mechanical thrombectomy on the basis of clinical-core mismatch in the extended window
   3. CGive antiplatelet therapy only and repeat CT at 24 hours
   4. DDefer any reperfusion therapy because perfusion imaging is unreliable beyond 6 hours
   Show answer and explanation

   Correct answer: B. Proceed to mechanical thrombectomy on the basis of clinical-core mismatch in the extended window

   The DAWN and DEFUSE 3 trials established benefit of mechanical thrombectomy for anterior circulation large vessel occlusion selected by perfusion or clinical-core mismatch out to 16-24 hours, and this patient (severe deficit with a small core) meets those criteria. Intravenous thrombolysis is outside its licensed window at 14 hours and cannot substitute for thrombectomy. Withholding reperfusion or waiting for a repeat CT would deny a therapy with a large absolute benefit; extended-window perfusion selection is precisely what the trials validated.

   Reference: Nogueira RG et al., DAWN trial, NEJM 2018; Albers GW et al., DEFUSE 3, NEJM 2018; AHA/ASA Acute Ischemic Stroke Guidelines, 2019

2. Question 2 · Chest Imaging (Thoracic Radiology)

   Twelve days after a right pneumonectomy, a patient becomes febrile and coughs up copious watery fluid. The chest radiograph, compared with one taken three days earlier, shows a marked drop in the air-fluid level within the postpneumonectomy space and shift of the mediastinum away from the operated side. What is the most likely complication?

   1. AExpected postoperative course with gradual fluid accumulation
   2. BBronchopleural fistula, probably with associated empyema
   3. CChylothorax
   4. DRecurrent tumour at the bronchial stump
   Show answer and explanation

   Correct answer: B. Bronchopleural fistula, probably with associated empyema

   After pneumonectomy the space normally fills progressively with fluid and the mediastinum shifts towards the operated side; a new or enlarging air space with a falling fluid level, together with fever and expectoration of fluid, indicates a bronchopleural fistula, and contralateral mediastinal shift signals a tension effect from the infected, pressurised space. This is a surgical emergency because of the risk of aspiration into the remaining lung. Chylothorax produces increasing fluid rather than air, and recurrent tumour presents later with soft-tissue mass rather than an acute change in fluid level.

   Reference: RadioGraphics review of imaging of the postpneumonectomy chest and its complications (2015); Grainger & Allison's Diagnostic Radiology, 7th edition (2021)

3. Question 3 · Contrast Media, Imaging Physics and Radiation Safety

   A departmental audit finds that the median CTDIvol for routine adult head CT is above the published national diagnostic reference level (DRL). What is the correct interpretation and response?

   1. AEvery patient scanned has received an unacceptable dose and each case must be reported to the regulator as an incident
   2. BA DRL is a limit for individual patients and exceeding it in any single patient constitutes a breach of regulation
   3. CDRLs apply to the median dose of a representative sample of standard-sized patients; exceeding the DRL is a trigger for local investigation and protocol optimisation, not an automatic regulatory breach
   4. DDRLs apply only to paediatric imaging and can be ignored in adult practice
   Show answer and explanation

   Correct answer: C. DRLs apply to the median dose of a representative sample of standard-sized patients; exceeding the DRL is a trigger for local investigation and protocol optimisation, not an automatic regulatory breach

   A diagnostic reference level is an optimisation tool applied to the median or typical dose from a representative sample of standard-sized patients for a defined examination; exceeding it should prompt a local review of protocol, technique and equipment rather than being treated as a dose limit or an automatic notifiable event. Individual patient doses may legitimately exceed the DRL when clinically justified, DRLs are not patient dose limits, and they are established for adult as well as paediatric examinations.

   Reference: ICRP Publication 135, Diagnostic Reference Levels in Medical Imaging, 2017

4. Question 4 · Cardiovascular Imaging

   A 59-year-old man with previous tuberculous pericarditis has raised jugular venous pressure, ascites and preserved ejection fraction. Which combination of findings on CT and cardiac MRI would best support constrictive pericarditis rather than restrictive cardiomyopathy?

   1. ABiatrial enlargement out of proportion to ventricular size with diffusely elevated myocardial extracellular volume
   2. BPericardial thickening of 5 mm with calcification, tubular deformity of the ventricles, dilated inferior vena cava and respirophasic septal shift on real-time cine imaging
   3. CMarked left ventricular hypertrophy with difficulty nulling the myocardium on the inversion-time scout
   4. DA large circumferential pericardial effusion with right atrial free wall inversion
   Show answer and explanation

   Correct answer: B. Pericardial thickening of 5 mm with calcification, tubular deformity of the ventricles, dilated inferior vena cava and respirophasic septal shift on real-time cine imaging

   Constriction is a mechanical problem of a rigid pericardium: thickening above 3-4 mm, calcification, conical or tubular ventricular deformity, systemic venous congestion and, most specifically, exaggerated ventricular interdependence seen as respirophasic septal shift or bounce on real-time free-breathing cine imaging. Restrictive cardiomyopathy is a myocardial disease with marked biatrial dilatation and abnormal myocardial tissue characteristics such as elevated ECV or amyloid-type nulling and a normal pericardium. Right atrial inversion with a large effusion describes tamponade, a different physiology.

   Reference: ESC Guidelines for the Diagnosis and Management of Pericardial Diseases (European Heart Journal, 2015); ASE/SCMR multimodality imaging of pericardial disease

5. Question 5 · Patient Safety and Quality in Radiology

   A prolonged, technically difficult fluoroscopically guided embolisation for recurrent pelvic haemorrhage records a cumulative reference-point air kerma of 6.5 Gy. What is the most appropriate post-procedure action?

   1. ARecord the dose in the medical record, inform the patient and referring team of possible skin effects, give written instructions to report any skin change, and arrange clinical skin follow-up at approximately 30 days
   2. BPrescribe prophylactic topical corticosteroid to the entry site and discharge without follow-up
   3. CImmediately obtain a skin biopsy of the beam entry site to establish a baseline
   4. DNo specific action is required because reference-point air kerma overestimates skin dose
   Show answer and explanation

   Correct answer: A. Record the dose in the medical record, inform the patient and referring team of possible skin effects, give written instructions to report any skin change, and arrange clinical skin follow-up at approximately 30 days

   A cumulative reference-point air kerma of 5 Gy is a widely used substantial radiation dose level that triggers documentation, patient notification and planned clinical follow-up, because deterministic skin injury may not become apparent for two to four weeks or longer. Doing nothing removes the safety net even though reference-point air kerma is only a surrogate for peak skin dose. Prophylactic steroid without follow-up and baseline skin biopsy are not evidence-based and biopsy risks injuring already irradiated skin.

   Reference: NCRP Report No. 168, Radiation Dose Management for Fluoroscopically Guided Interventional Medical Procedures, 2010; SIR/ACR Joint Guideline for Patient Radiation Dose Management for Fluoroscopically Guided Interventional Procedures, JVIR 2009

6. Question 6 · Interventional and Vascular Radiology (procedural competence)

   During planning of a radiofrequency ablation for an exophytic renal tumour, CT shows a loop of colon lying 4 mm from the intended ablation zone. Which of the following is the most appropriate protective measure?

   1. AInstil 5 per cent dextrose in water into the space to displace the colon (hydrodissection)
   2. BInstil normal saline into the space to displace the colon
   3. CIncrease generator power to shorten the ablation time so the colon is exposed for less time
   4. DAbandon percutaneous treatment and refer directly for radical nephrectomy
   Show answer and explanation

   Correct answer: A. Instil 5 per cent dextrose in water into the space to displace the colon (hydrodissection)

   Hydrodissection displaces adjacent bowel from the ablation zone, and for radiofrequency ablation the fluid must be non-ionic - 5 per cent dextrose in water - because it does not conduct current. Normal saline is electrically conductive and can propagate current towards the bowel, increasing rather than reducing thermal injury risk (it is acceptable for microwave or cryoablation). Increasing power does not reduce collateral heating, and referral for nephrectomy is unnecessary when a well-established protective technique such as hydro- or pneumodissection is available.

   Reference: Garnon J et al., Adjunctive Thermoprotection During Percutaneous Thermal Ablation, Cardiovascular and Interventional Radiology, 2019; CIRSE Standards of Practice on Thermal Ablation

7. Question 7 · Body Imaging (Gastrointestinal, Hepatobiliary, Genitourinary and Abdominopelvic)

   A pancreatic protocol CT in a 66-year-old man shows a 3 cm hypoenhancing mass in the pancreatic head. The tumour contacts the superior mesenteric artery over 100 degrees of its circumference, with no contour deformity of the vessel; there is no distant metastatic disease and the coeliac axis is free. Using current NCCN vascular criteria, how should this tumour be classified?

   1. AResectable
   2. BBorderline resectable
   3. CLocally advanced (unresectable)
   4. DMetastatic disease
   Show answer and explanation

   Correct answer: C. Locally advanced (unresectable)

   Solid tumour contact with the superior mesenteric artery exceeding 180 degrees defines locally advanced, unresectable disease in the NCCN pancreatic adenocarcinoma criteria; contact of 180 degrees or less would be borderline resectable. Resectable disease requires no arterial contact and no more than 180 degrees of venous contact without contour irregularity. There is no evidence of distant spread here, so metastatic classification is not applicable. Note that vein contour deformity or thrombosis with a suitable segment for reconstruction would keep a tumour borderline rather than making it locally advanced.

   Reference: NCCN Clinical Practice Guidelines in Oncology: Pancreatic Adenocarcinoma, 2023; Al-Hawary MM et al., 'Pancreatic Ductal Adenocarcinoma Radiology Reporting Template', Radiology (RSNA), 2014

8. Question 8 · Musculoskeletal Imaging

   A 32-year-old man falls on an outstretched hand. The PA wrist radiograph shows a 5 mm gap between the scaphoid and lunate with a cortical ring projected over the distal scaphoid. The lateral view shows a scapholunate angle of 80 degrees with the lunate tilted dorsally. What is the diagnosis?

   1. AVolar intercalated segment instability (VISI)
   2. BDorsal intercalated segment instability (DISI) due to scapholunate dissociation
   3. CLunotriquetral dissociation
   4. DPerilunate dislocation
   Show answer and explanation

   Correct answer: B. Dorsal intercalated segment instability (DISI) due to scapholunate dissociation

   Scapholunate widening greater than 3 mm (the Terry Thomas sign) with a scaphoid ring sign from abnormal scaphoid flexion, together with a scapholunate angle above 60-70 degrees and dorsal tilt of the lunate, defines DISI secondary to scapholunate ligament disruption. VISI shows volar lunate tilt and a reduced scapholunate angle and typically follows lunotriquetral injury. In perilunate dislocation the lunate remains aligned with the radius while the capitate dislocates dorsally, which is not described here.

   Reference: Helms CA. Fundamentals of Skeletal Radiology, 5th ed (2019); Resnick D, Diagnosis of Bone and Joint Disorders

9. Question 9 · Paediatric Imaging

   A six-month-old with macrocephaly and developmental delay has MRI showing an enlarged posterior fossa, a hypoplastic vermis that is rotated upward and counterclockwise, a cystic fourth ventricle filling the posterior fossa, and elevation of the torcular above the lambdoid suture. Which is the correct diagnosis?

   1. ADandy-Walker malformation
   2. BBlake pouch cyst
   3. CMega cisterna magna
   4. DRetrocerebellar arachnoid cyst
   Show answer and explanation

   Correct answer: A. Dandy-Walker malformation

   Vermian hypoplasia with upward and counterclockwise rotation, cystic dilatation of the fourth ventricle, an enlarged posterior fossa and torcular-lambdoid inversion define the Dandy-Walker malformation. A Blake pouch cyst shows an intact, normally formed (though upwardly displaced) vermis with a normal-sized posterior fossa; mega cisterna magna has a normal vermis and fourth ventricle; an arachnoid cyst displaces and compresses the cerebellum rather than communicating with a dilated fourth ventricle and does not cause vermian hypoplasia.

   Reference: Barkovich AJ, Raybaud C, Pediatric Neuroimaging, 6th ed., Wolters Kluwer (2019); Robinson AJ, Pediatr Radiol posterior fossa malformation review

10. Question 10 · Women's Imaging (Breast, Obstetric and Gynaecologic)

    A 57-year-old postmenopausal woman has a 6 cm multilocular adnexal cyst containing four papillary projections with internal colour Doppler flow. Using the O-RADS ultrasound risk stratification system, which category applies and what is the recommended management?

    1. AO-RADS 3 (low risk, 1-10%); ultrasound follow-up in 6 months
    2. BO-RADS 4 (intermediate risk, 10-50%); referral to a gynaecologist
    3. CO-RADS 5 (high risk, 50% or greater); referral to a gynaecologic oncologist
    4. DO-RADS 2 (almost certainly benign, under 1%); no further imaging
    Show answer and explanation

    Correct answer: C. O-RADS 5 (high risk, 50% or greater); referral to a gynaecologic oncologist

    In O-RADS ultrasound, a multilocular cystic lesion with solid components, or any lesion with four or more papillary projections, is classified as O-RADS 5, carrying a malignancy risk of 50% or greater and warranting referral to a gynaecologic oncologist. Lesions with one to three papillary projections fall into O-RADS 4, an anechoic unilocular cyst without solid components would be O-RADS 2, and O-RADS 3 covers unilocular cysts 10 cm or larger with smooth walls or a smooth multilocular cyst under 10 cm without solid tissue.

    Reference: Andreotti RF et al., Radiology - O-RADS US Risk Stratification and Management System, ACR consensus (2020)