Abdominal and Pelvic Radiology Practice Questions

Q: A 30-year-old patient presents with acute abdominal pain and obstipation. An X-ray is provided. What is the most likely diagnosis?

Small bowel obstruction. ***Small bowel obstruction*** - Classic X-ray findings include **central dilated small bowel loops** with **valvulae conniventes** (complete mucosal folds) and **stepladder air-fluid levels**. - **Paucity of colonic gas** distally is characteristic, as obstruction prevents bowel contents from reaching the colon. *Large bowel obstruction* - X-ray shows **peripheral dilated colonic loops** with **haustrations** (incomplete mucosal folds), not central small bowel dilation. - **Cecal dilation** is often prominent, and small bowel may appear normal or minimally dilated. *Gastric outlet obstruction* - X-ray typically shows **marked gastric distension** with a **dilated stomach** containing air-fluid levels. - **Minimal small bowel gas** is present, as obstruction occurs at the **pylorus** or **duodenum**. *Duodenal atresia* - Characteristic **double-bubble sign** on X-ray showing dilated **stomach** and **proximal duodenum**. - This condition occurs in **neonates**, not 30-year-old patients, and presents shortly after birth.

Q: Gas in the biliary tree on plain abdominal X-ray is suggestive of which of the following conditions?

Biliary enteric fistula. **Explanation:** The presence of gas in the biliary tree on a plain abdominal X-ray is known as **pneumobilia**. This occurs when there is an abnormal communication between the gastrointestinal tract and the biliary system, allowing enteric gas to reflux upwards. **1. Why Biliary Enteric Fistula is Correct:** The most common cause of pneumobilia is a **biliary-enteric fistula**, typically a cholecystoduodenal fistula. This often results from a large gallstone eroding through the gallbladder wall into the duodenum. On X-ray, this appears as linear, branching radiolucencies in the right upper quadrant, typically located centrally (near the hilum) due to the direction of bile flow. This is a key component of **Rigler’s Triad** (pneumobilia, small bowel obstruction, and ectopic gallstone) seen in gallstone ileus. **2. Why Other Options are Incorrect:** * **Empyema of the gallbladder:** This refers to pus in the gallbladder. While it indicates severe infection, it does not typically produce gas unless complicated by gas-forming organisms (Emphysematous cholecystitis), where gas would be seen in the **gallbladder wall/lumen**, not the biliary tree. * **Mirizzi Syndrome:** This is extrinsic compression of the common hepatic duct by a stone impacted in the cystic duct. It causes obstructive jaundice but does not create a passage for gas. * **Porcelain Gallbladder:** This is intramural calcification of the gallbladder wall. It appears as a radio-opaque (white) rim on X-ray, not radiolucent gas. **Clinical Pearls for NEET-PG:** * **Pneumobilia vs. Portal Venous Gas:** Pneumobilia is **central** (near the hilum), whereas portal venous gas is **peripheral** (carried by centrifugal blood flow). * **Common Causes:** Iatrogenic (post-ERCP/sphincterotomy) is the #1 cause overall; Biliary-enteric fistula is the most common spontaneous cause. * **Rigler’s Triad:** Diagnostic for Gallstone Ileus.

Q: A 24-year-old man presents to the emergency department with a 12-hour history of intermittent, crampy abdominal pain and five episodes of vomiting. He denies any rectal bleeding. On examination, his abdomen is distended with absent bowel sounds. Per-rectal examination is normal. An abdominal X-ray reveals findings suggestive of a specific condition. Based on the X-ray findings, which of the following statements are true?

Haustra are not visible.. ***Haustra are not visible*** - In **small bowel obstruction**, haustra are absent because haustra are characteristic features of the **large bowel** (colon), not the small bowel. - The absence of haustra on X-ray helps differentiate **small bowel** from **large bowel obstruction**, making this a key diagnostic feature. *Distribution of intestinal loops is mainly in the center* - While small bowel loops are typically **centrally located**, this distribution can vary and is not as definitive as other radiological features. - **Large bowel** can also occupy central areas, making this feature less reliable for distinguishing small bowel obstruction. *No visible plicae circulares* - **Plicae circulares** (valvulae conniventes) are actually **visible** in small bowel obstruction and are a characteristic feature of the small bowel. - These **mucosal folds** extend across the full width of the small bowel lumen and help identify small bowel on X-ray. *String of beads sign is present* - The **string of beads sign** represents alternating **gas and fluid levels** and can be seen in small bowel obstruction, but it's not consistently present. - This sign is more suggestive than diagnostic and may not be visible in all cases of **small bowel obstruction**.

Q: Which of the following is a specific diagnostic criterion for Budd-Chiari syndrome?

Intrahepatic collaterals. ### Explanation **Budd-Chiari Syndrome (BCS)** is characterized by the obstruction of hepatic venous outflow, occurring at any level from the small hepatic veins to the junction of the inferior vena cava (IVC) and the right atrium. **Why Option A is Correct:** **Intrahepatic collaterals** are considered a **specific** radiologic sign of BCS. When the primary hepatic veins are thrombosed or stenosed, the liver attempts to decompress itself by forming new vascular pathways. These typically appear as "comma-shaped" or "tortuous" vessels connecting the obstructed hepatic veins to systemic circulation or patent accessory veins. Their presence is highly suggestive of chronic BCS. **Analysis of Incorrect Options:** * **B. Dilated paraumbilical vein:** This is a sign of **portal hypertension**, not specifically BCS. While BCS can lead to portal hypertension, a dilated paraumbilical vein (part of the *Caput Medusae* complex) is more commonly associated with cirrhosis of any etiology. * **C. Post-acoustic shadowing:** This is an ultrasound artifact seen behind highly attenuating structures like gallstones or calcifications. It has no diagnostic relevance to venous outflow obstruction. **Clinical Pearls for NEET-PG:** * **Classic Triad:** Abdominal pain, ascites, and hepatomegaly. * **Caudate Lobe Hypertrophy:** The most common imaging finding. The caudate lobe often enlarges because its venous drainage (directly into the IVC) is usually spared. * **"Spider-web" Appearance:** Seen on hepatic venography when small collateral vessels form around an occluded main hepatic vein. * **Contrast Enhancement:** On CT, the liver may show a "nutmeg" appearance (mottled enhancement) due to venous congestion. * **US Doppler:** The gold standard initial screening tool, showing absent or reversed flow in hepatic veins.

Q: What is the diagnosis suggested by the intravenous urogram (IVU) study?

Congenital megaureter. ***Congenital megaureter*** - **Markedly dilated distal ureter** (>7mm diameter) with **hydroureter** extending to the ureterovesical junction, classic IVU finding in congenital megaureter. - IVU shows **normal renal pelvis** without **pelviureteric junction obstruction**, distinguishing it from other obstructive uropathies. *Vesicoureteral reflux (VUR)* - **Cannot be diagnosed on IVU** as it requires **voiding cystourethrogram (VCUG)** to demonstrate retrograde flow of urine from bladder to ureter. - IVU may show **secondary changes** like calyceal blunting or scarring but cannot directly visualize the reflux mechanism. *Duplication of a renal pelvis* - IVU would show **two separate renal pelves** and **collecting systems** within the same kidney, creating a distinctive "double outline" appearance. - Often associated with **duplex ureter** which may be complete or incomplete, clearly different from isolated ureteral dilatation. *Post-caval ureter* - IVU demonstrates characteristic **medial deviation** of the ureter at **L3-L4 vertebral level** as it courses behind the inferior vena cava. - Creates a distinctive **"fishhook" or "J-shaped" appearance** of the ureter on IVU, not generalized ureteral dilatation.

Q: Early arterial phase enhancement on CECT scan of the liver indicates which of the following?

Hepatocellular carcinoma (HCC). ### Explanation **Correct Answer: B. Hepatocellular carcinoma (HCC)** **The Underlying Concept:** The liver has a dual blood supply: the **portal vein (75%)** and the **hepatic artery (25%)**. Normal liver parenchyma derives most of its blood from the portal vein. However, **Hepatocellular Carcinoma (HCC)** is a highly vascular tumor that derives its blood supply almost exclusively (90-100%) from the **hepatic artery**. On a Triple-Phase Contrast-Enhanced CT (CECT), HCC exhibits a classic enhancement pattern: 1. **Early Arterial Phase:** Intense, "bright" enhancement (Hypervascularity) as the contrast enters via the hepatic artery. 2. **Portal Venous/Delayed Phase:** Rapid "washout," appearing hypodense compared to the surrounding liver which is now enhancing via the portal vein. **Why the other options are incorrect:** * **A. Hydatid Cyst:** Typically appears as a well-defined fluid-density lesion with a "cyst-within-a-cyst" appearance (daughter cysts) and peripheral wall calcification. It does not show internal arterial enhancement. * **C. Hepatic Abscess:** Usually presents as a low-attenuation collection with **peripheral rim enhancement** (target sign), not diffuse early arterial enhancement. * **D. Simple Hepatic Cyst:** These are benign, fluid-filled structures that show **no enhancement** in any phase (0-10 HU). **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad for HCC on CT:** Arterial enhancement + Portal venous washout + Pseudocapsule. * **Tumor Marker:** Elevated **Alpha-fetoprotein (AFP)** is highly suggestive of HCC. * **Hemangioma:** Shows peripheral globular enhancement with "centripetal fill-in" (contrast moves from periphery to center). * **Focal Nodular Hyperplasia (FNH):** Shows intense arterial enhancement with a characteristic **central stellate scar**.

Q: What is the location of the stricture in the given RGU?

Bulbar urethra. ***Bulbar urethra*** - The **bulbar urethra** is the most common site of urethral strictures, particularly following **trauma** or **infection**. - On **retrograde urethrography (RGU)**, bulbar strictures appear as **smooth narrowing** in the **posterior penile/perineal region**, which is the typical location seen in most imaging studies. *Membranous urethra* - The **membranous urethra** is located within the **urogenital diaphragm** and is less commonly affected by strictures. - **RGU** may not adequately visualize this segment due to its **short length** and **deep pelvic location**. *Penile urethra* - The **penile urethra** extends from the **penoscrotal junction** to the **external meatus** and is less frequently involved in stricture formation. - **Penile strictures** typically result from **hypospadias repair** or **lichen sclerosus**, which are less common causes. *Prostatic urethra* - The **prostatic urethra** is rarely affected by **inflammatory strictures** and is better evaluated by **voiding cystourethrography (VCUG)**. - **RGU** has limited ability to visualize the **prostatic segment** due to **contrast flow limitations** in retrograde studies.

Q: An X-ray shows findings suggestive of:

Pseudopneumoperitoneum. ***Pseudopneumoperitoneum*** - Shows **bowel haustrations** beneath the right hemidiaphragm, indicating **Chilaiditi sign** (bowel interposition between liver and diaphragm). - This is a **benign condition** where the colon mimics free air but contains characteristic **colonic markings**. *Pseudopneumomediastinum* - Would show **mediastinal air-like appearance** caused by **bowel gas** in the mediastinum, not subdiaphragmatic location. - Typically involves **esophageal** or **gastric** structures creating false mediastinal air impression. *Pneumoperitoneum* - Shows **true free air** in the peritoneal cavity without **bowel wall markings** or haustrations. - Usually indicates **bowel perforation** requiring urgent surgical intervention, unlike the benign Chilaiditi sign. *Pneumomediastinum* - Presents as **actual air** in the mediastinal space, often outlining cardiac borders and great vessels. - Commonly caused by **alveolar rupture**, **esophageal perforation**, or **chest trauma** with air tracking into mediastinum.

Question 1

A 30-year-old patient presents with acute abdominal pain and obstipation. An X-ray is provided. What is the most likely diagnosis?

Accepted Answer

Small bowel obstruction

Answer

Large bowel obstruction

Answer

Gastric outlet obstruction

Answer

Duodenal atresia

Question 2

Gas in the biliary tree on plain abdominal X-ray is suggestive of which of the following conditions?

Accepted Answer

Biliary enteric fistula

Answer

Empyema of the gallbladder

Answer

Mirizzi syndrome

Answer

Porcelain gallbladder

Question 3

A 24-year-old man presents to the emergency department with a 12-hour history of intermittent, crampy abdominal pain and five episodes of vomiting. He denies any rectal bleeding. On examination, his abdomen is distended with absent bowel sounds. Per-rectal examination is normal. An abdominal X-ray reveals findings suggestive of a specific condition. Based on the X-ray findings, which of the following statements are true?

Accepted Answer

Haustra are not visible.

Answer

Distribution of intestinal loops is mainly in the center.

Answer

No visible plicae circulares.

Answer

String of beads sign is present.

Question 4

Semen analysis of a young man presenting with primary infertility revealed low volume, fructose-negative ejaculate with azoospermia. Which of the following is the most useful imaging modality to evaluate the cause of his infertility?

Accepted Answer

Transrectal ultrasonography

Answer

Colour duplex ultrasonography of the scrotum

Answer

Retrograde urethrography

Answer

Spermatic venography

Question 5

Which of the following is a specific diagnostic criterion for Budd-Chiari syndrome?

Accepted Answer

Intrahepatic collaterals

Answer

Dilated paraumbilical vein

Answer

Post-acoustic shadowing

Answer

None of the above

Question 6

Which imaging modality is BEST used to detect distant metastasis in pancreatic cancer?

Accepted Answer

Positron-emission tomography with fluorodeoxyglucose (PET-FDG)

Answer

Magnetic Resonance Cholangiopancreatography (MRCP)

Answer

Dual phase, contrast-enhanced spiral CT

Answer

Endoscopic Ultrasound (EUS)

Question 7

What is the diagnosis suggested by the intravenous urogram (IVU) study?

Accepted Answer

Congenital megaureter

Answer

Vesicoureteral reflux (VUR)

Answer

Duplication of a renal pelvis

Answer

Post-caval ureter

Question 8

Early arterial phase enhancement on CECT scan of the liver indicates which of the following?

Accepted Answer

Hepatocellular carcinoma (HCC)

Answer

Hydatid cyst

Answer

Hepatic abscess

Answer

Simple hepatic cyst

Question 9

What is the location of the stricture in the given RGU?

Accepted Answer

Bulbar urethra

Answer

Membranous urethra

Answer

Penile urethra

Answer

Prostatic urethra

Question 10

An X-ray shows findings suggestive of:

Accepted Answer

Pseudopneumoperitoneum

Answer

Pseudopneumomediastinum

Answer

Pneumoperitoneum

Answer

Pneumomediastinum

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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