Here is your complete high-yield MCQ Master Summary for Gastrointestinal Tract, Liver & Biliary, and Urinary Tract Radiology - same format as your previous sheet.
Radiology MCQ Master Summary
GI Tract | Liver & Biliary | Urinary Tract Anomalies
SECTION 1: GASTROINTESTINAL TRACT
Question 1
A barium swallow shows a dilated oesophagus with smooth, tapered narrowing at the gastro-oesophageal junction. What is the diagnosis?
Answer: ✅ Achalasia
Why?
- The classic sign is the "bird's beak" appearance - the lower oesophageal sphincter fails to relax, creating a smooth, symmetric taper at the cardia
- Confirmed in Bailey & Love's Surgery, Scott-Brown's, and S. Das Manual on Clinical Surgery
- The proximal oesophagus is dilated and non-peristaltic
Key distinction: Bird's beak in achalasia = smooth taper (benign). Bird's beak in sigmoid volvulus = at the point of twist. Don't confuse the two!
Question 2
Which condition gives the "bird's beak" sign on barium enema?
Answer: ✅ Sigmoid volvulus (at the site of torsion)
| Sign | Diagnosis |
|---|
| Bird's beak - barium swallow | Achalasia |
| Bird's beak - barium enema | Sigmoid volvulus |
| Bird's beak - upper GI with obstruction | Gastric volvulus |
Question 3
Which imaging finding is MOST specific for intussusception?
Answer: ✅ Coiled spring sign (on barium enema) / Target sign (on ultrasound)
- Barium/contrast enema: Coiled spring sign - trapped contrast outlines the mucosa of the intussusceptum
- Ultrasound: Target sign (bull's-eye) - concentric rings on transverse view
- Barium enema is also therapeutic in intussusception (hydrostatic reduction)
Question 4
A patient has a string sign on barium meal. What is the likely diagnosis?
Answer: ✅ Crohn's disease (terminal ileum) OR Hypertrophic pyloric stenosis (in infants)
| String sign location | Diagnosis |
|---|
| Terminal ileum (adult) | Crohn's disease |
| Pylorus (infant, projectile vomiting) | Hypertrophic pyloric stenosis |
| Longitudinal narrow lumen | Severe stricture |
Exam pearl: In a vomiting infant + string sign at pylorus = Pyloric stenosis. Best confirmatory imaging = Ultrasound (pyloric muscle thickness > 4 mm, pyloric channel length > 16 mm).
Question 5
The best initial imaging for suspected appendicitis in an adult is:
Options:
- Plain X-ray abdomen
- Barium enema
- Ultrasound
- CT abdomen with contrast ✅
Answer: ✅ CT abdomen with contrast
Why?
- CT is the gold standard for diagnosing appendicitis in adults (sensitivity ~94-98%)
- Ultrasound is preferred in children and pregnant women (no radiation)
- Plain X-ray may show appendicolith in ~10% but is not diagnostic
Question 6
Which radiology sign is associated with Hirschsprung's disease?
Answer: ✅ Transition zone on barium enema
- Narrow aganglionic segment → abrupt transition to dilated proximal colon
- The transition zone is at the recto-sigmoid junction in most cases
- Gold standard diagnosis: Rectal biopsy (absence of ganglion cells)
- Best imaging: Barium enema (shows transition zone, delayed evacuation at 24h)
Question 7
A 6-month-old child presents with episodic abdominal pain and currant jelly stools. The best investigation is:
Answer: ✅ Ultrasound abdomen
- Diagnosis: Intussusception
- Ultrasound shows the target/bull's-eye sign
- If confirmed, air or water-soluble contrast enema is used for reduction
- Age peak: 6 months - 2 years
Question 8
A Meckel's diverticulum is best detected by which nuclear medicine scan?
Answer: ✅ Technetium-99m pertechnetate scan (Meckel scan)
Why?
- Meckel's diverticulum contains ectopic gastric mucosa in ~50% of symptomatic cases
- Tc-99m pertechnetate is taken up by gastric mucosa
- The scan shows a hot spot in the right lower quadrant
- Rule of 2's: 2% of population, within 2 feet of ileocecal valve, 2 inches long, presents before age 2
Question 9
On barium enema, "thumbprinting" of the colon wall is most characteristic of:
Answer: ✅ Ischaemic colitis
| Thumbprinting | Think |
|---|
| Colon wall | Ischaemic colitis |
| Also seen in | Crohn's disease, amoebiasis |
| Mechanism | Submucosal oedema/haemorrhage |
Question 10
Which part of the GI tract is most commonly affected in Crohn's disease on imaging?
Answer: ✅ Terminal ileum
- Small bowel follow-through / CT enterography shows: skip lesions, cobblestone mucosa, string sign, fistulae, rose thorn ulcers
- Best imaging modality for Crohn's = MRI enterography (no radiation, superior soft tissue detail)
SECTION 2: LIVER & BILIARY TRACT
Question 11
Best investigation for gallstones (cholelithiasis)?
Answer: ✅ Ultrasound abdomen
Why?
- Sensitivity ~95-98% for gallstones
- Shows: echogenic foci with posterior acoustic shadowing
- Gallstones are mobile (move with position)
- Only ~10-15% of gallstones are radio-opaque on plain X-ray (so X-ray is a poor test)
Question 12
A patient with known cirrhosis has a liver lesion that shows arterial enhancement and rapid washout on CT. The most likely diagnosis is:
Answer: ✅ Hepatocellular carcinoma (HCC)
Why?
- HCC is hypervascular - fed by hepatic artery
- Classic CT/MRI pattern: arterial phase enhancement → rapid washout in portal venous phase ("washout sign")
- Confirmed by Grainger & Allison's Diagnostic Radiology and Goldman-Cecil Medicine
- Serum AFP is elevated in most cases
Exam pearl: Arterial enhancement + washout in cirrhotic liver = HCC until proven otherwise. No biopsy needed if imaging criteria are met.
Question 13
Which of the following is the BEST imaging for suspected bile duct stones (choledocholithiasis)?
Options:
- Oral cholecystography
- Ultrasound
- MRCP ✅
- Plain X-ray
Answer: ✅ MRCP (Magnetic Resonance Cholangiopancreatography)
| Investigation | Use |
|---|
| Ultrasound | First-line, gallstones (not bile duct stones well) |
| MRCP | Best non-invasive for CBD stones, strictures |
| ERCP | Diagnostic + therapeutic (stone removal) |
| CT | Bile duct dilatation, complications |
Question 14
A hydatid cyst of the liver shows which classic sign on imaging?
Answer: ✅ "Water lily sign" (floating membranes) / "Daughter cysts" on ultrasound
| Hydatid cyst features | Finding |
|---|
| Ultrasound/CT | Daughter cysts within a mother cyst |
| Detached endocyst | Water lily sign |
| Calcification | Eggshell calcification of the wall |
| Causative organism | Echinococcus granulosus |
Question 15
Caroli disease is a congenital abnormality of which structure?
Answer: ✅ Intrahepatic bile ducts (segmental saccular dilatation)
- Imaging shows saccular or fusiform dilatation of intrahepatic bile ducts
- "Central dot sign" on CT: portal vein radicle within the dilated duct
- Associated with medullary sponge kidney and congenital hepatic fibrosis
SECTION 3: URINARY TRACT
Question 16
The BEST imaging for renal colic and ureteric stones is:
Answer: ✅ Non-contrast CT KUB (CT urogram)
Why?
- Sensitivity ~97%, detects all stone types including uric acid stones (invisible on plain X-ray)
- Plain X-ray (KUB): Only detects radio-opaque stones (~90% of renal calculi are calcium-containing)
- Uric acid stones are radiolucent on X-ray but visible on CT
- Ultrasound: good for hydronephrosis, but misses small ureteric stones
Question 17
Which kidney anomaly is associated with UPJ (ureteropelvic junction) obstruction as a common complication?
Answer: ✅ Horseshoe kidney
Why?
- In horseshoe kidney, the ureters cross anteriorly over the isthmus → kinking → UPJ obstruction
- Also predisposed to: urolithiasis (21-60%), vesicoureteral reflux, Wilms tumor
- Confirmed by Campbell-Walsh Urology and Hinman's Atlas of Urologic Surgery
Question 18
An abdominal mass in a child under 5 years - what is the MOST likely diagnosis and best initial imaging?
Answer: ✅ Wilms Tumor (Nephroblastoma) - Ultrasound first
| Feature | Detail |
|---|
| Most common renal tumor in children | Peak age 3-4 years |
| Origin | Intrarenal, displaces structures |
| Best initial imaging | Ultrasound abdomen |
| Best staging | CT chest and abdomen |
| Key distinction | Wilms = intrarenal. Neuroblastoma = crosses midline, calcifications |
Exam pearl: Wilms tumor displaces bowel. Neuroblastoma encases vessels and crosses midline. On imaging, these two are the most tested abdominal masses in children.
Question 19
Which finding on IVU/CT urogram is typical of renal tuberculosis?
Answer: ✅ "Moth-eaten" calyces / Putty kidney (end-stage)
| Stage of renal TB | Imaging finding |
|---|
| Early | Papillary necrosis, moth-eaten calyces |
| Intermediate | Strictures, infundibular stenosis |
| Late (end-stage) | Autonephrectomy - "putty kidney" (dystrophic calcification of entire kidney) |
| Bladder | Thimble bladder (contracted, calcified) |
Question 20
What is the most common cause of a non-visualised kidney on IVU (intravenous urography)?
Answer: ✅ Hydronephrosis OR Non-functioning kidney (obstructed/destroyed)
- A non-visualising kidney on IVU means the kidney is either absent, non-functioning, or severely obstructed
- Follow-up with DMSA nuclear scan (static renal scan) to assess differential renal function
- DTPA/MAG3 scan (dynamic) to assess drainage and obstruction
HIGH-YIELD RADIOLOGY SIGNS TABLE
| Sign | Diagnosis |
|---|
| Bird's beak - oesophagus | Achalasia |
| Bird's beak - barium enema | Sigmoid volvulus |
| Coiled spring sign | Intussusception |
| Target / Bull's-eye sign (US) | Intussusception |
| String sign - pylorus (infant) | Hypertrophic pyloric stenosis |
| String sign - terminal ileum | Crohn's disease |
| Thumbprinting - colon | Ischaemic colitis |
| Transition zone - barium enema | Hirschsprung's disease |
| Apple-core lesion | Colorectal carcinoma |
| Water lily sign | Hydatid cyst |
| Daughter cysts | Echinococcus (hydatid) |
| Eggshell calcification - liver | Hydatid cyst |
| Central dot sign (CT liver) | Caroli disease |
| Arterial enhancement + washout | Hepatocellular carcinoma |
| Posterior acoustic shadowing (US) | Gallstones |
| Moth-eaten calyces | Renal TB (early) |
| Putty kidney | Renal TB (end-stage) |
| Thimble bladder | TB cystitis |
| Eggshell calcification - bladder | Schistosomiasis |
HIGH-YIELD IMAGING CHOICES
| Clinical Scenario | Best Investigation |
|---|
| Gallstones | Ultrasound |
| CBD stones / bile duct | MRCP |
| Therapeutic bile duct stone removal | ERCP |
| HCC surveillance in cirrhosis | Ultrasound + AFP every 6 months |
| Renal colic / ureteric stones | Non-contrast CT KUB |
| Abdominal mass in child | Ultrasound → CT for staging |
| Meckel's diverticulum | Tc-99m pertechnetate scan |
| Hirschsprung's disease | Barium enema (transition zone) |
| Intussusception (diagnosis) | Ultrasound |
| Intussusception (treatment) | Air / water-soluble contrast enema |
| Crohn's disease (small bowel) | MRI enterography |
| Acute appendicitis (adult) | CT abdomen with contrast |
| Acute appendicitis (child/pregnant) | Ultrasound |
| Renal TB staging | IVU / CT urogram + DMSA scan |
| Pyloric stenosis (infant) | Ultrasound (pyloric thickness > 4mm) |
ONE-LINE EXAM PEARLS
- Achalasia → Bird's beak on barium swallow + dilated oesophagus above
- Intussusception → Target sign on USS, coiled spring on barium, currant jelly stools
- Gallstones → Ultrasound is best (95-98% sensitivity, posterior acoustic shadowing)
- HCC in cirrhosis → Arterial enhancement + washout on CT/MRI = diagnostic
- MRCP = best non-invasive test for CBD stones and biliary strictures
- Meckel's diverticulum → Tc-99m scan (ectopic gastric mucosa)
- Renal stones → Non-contrast CT KUB is gold standard (catches uric acid stones too)
- Horseshoe kidney → Predisposed to UPJ obstruction, stones, Wilms tumor
- Wilms tumor → Intrarenal, age <5. Neuroblastoma → crosses midline, calcifies
- Renal TB end-stage → Putty kidney (whole kidney calcified = autonephrectomy)
- Hirschsprung's → Transition zone on barium enema, confirm by rectal biopsy
- String sign at pylorus in vomiting infant → Pyloric stenosis → confirm by USS
- Crohn's → Skip lesions, cobblestone, string sign, rose-thorn ulcers, terminal ileum
- Ischaemic colitis → Thumbprinting on plain film or barium enema
- Hydatid cyst → Daughter cysts + water lily sign + eggshell calcification
Sources: Grainger & Allison's Diagnostic Radiology, Bailey & Love's Short Practice of Surgery (28th ed.), S. Das Manual on Clinical Surgery (13th ed.), Goldman-Cecil Medicine, Rosen's Emergency Medicine, Campbell-Walsh Urology, Rockwood & Green's Fractures in Adults (10th ed.), Hinman's Atlas of Urologic Surgery, Smith & Tanagho's General Urology (19th ed.), Yamada's Textbook of Gastroenterology (7th ed.)
