Abdominal and Pelvic Radiology Practice Questions

Q: What is the first radiologic sign of Crohn's disease in the terminal ileum?

Aphthoid ulceration. **Explanation:** **1. Why Aphthoid Ulceration is Correct:** Aphthoid ulcers are the **earliest radiologic manifestation** of Crohn’s disease. Pathologically, these represent small, superficial erosions occurring over lymphoid follicles (Peyer's patches). On a double-contrast barium study, they appear as tiny "punched-out" collections of barium surrounded by a radiolucent halo of edema (the "target" or "bull’s eye" sign). Because Crohn’s is a transmural process that begins in the mucosa, these superficial lesions precede deeper ulceration and structural changes. **2. Analysis of Incorrect Options:** * **B. Pseudosacculation:** This is a **late/chronic sign**. It occurs due to asymmetrical involvement where one side of the bowel wall is scarred and fibrotic (shortened), while the opposite uninvolved border bulges out. * **C. Cobblestone pattern:** This represents a **more advanced stage**. It is caused by deep longitudinal and transverse ulcers intersecting, leaving islands of edematous, intact mucosa between them. * **D. Thickening of the bowel wall:** While common in Crohn’s due to transmural inflammation, it is a non-specific finding often seen on CT/USG and usually develops after the initial mucosal insults (aphthoid ulcers) have occurred. **3. NEET-PG High-Yield Pearls:** * **String Sign of Kantor:** Seen in the terminal ileum due to severe narrowing (spasm or fibrosis). * **Proud Flesh:** Inflammatory polyps/regeneration between ulcers. * **Creeping Fat:** Mesenteric fat wrapping around the bowel (classic surgical/CT finding). * **Skip Lesions:** Discontinuous involvement (unlike the continuous involvement in Ulcerative Colitis). * **Comb Sign:** Hypervascularity of the mesentery on CT, indicating active inflammation.

Q: What is this appearance, seen in early pregnancy, known as?

Double bleb sign. ***Double bleb sign*** - Seen on **transvaginal ultrasound** at approximately **5-6 weeks gestation**, representing the **amnion** and **yolk sac** as two distinct fluid-filled structures within the gestational sac. - This sign confirms **early intrauterine pregnancy** and indicates normal embryonic development with proper formation of extraembryonic structures. *Yolk sac sign* - Refers to the **single yolk sac** visualization within the gestational sac, typically seen around **5-5.5 weeks**. - Does not involve the characteristic **two separate blebs** (amnion + yolk sac) that define the double bleb sign. *Double decidual sac sign* - An earlier ultrasound finding seen around **4-5 weeks** showing **two concentric rings** of decidual tissue around the gestational sac. - Represents the **decidua capsularis** and **decidua parietalis**, not the amnion and yolk sac structures. *Twin peak sign* - A finding in **dichorionic diamniotic twin pregnancies** showing a **triangular projection** of placental tissue at the membrane insertion site. - Used to differentiate **chorionicity** in multiple pregnancies, not relevant to single early pregnancy appearances.

Q: What is the initial investigation for suspected gallbladder stones?

Ultrasound (USG). **Explanation:** **Ultrasound (USG)** is the **initial and gold standard investigation** for suspected gallbladder stones (cholelithiasis). It has a high sensitivity and specificity (>95%) for detecting stones. The underlying medical concept relies on the fact that gallstones are dense structures that reflect sound waves, appearing as **hyperechoic foci** with characteristic **posterior acoustic shadowing**. Additionally, USG is non-invasive, cost-effective, lacks radiation, and can simultaneously assess for signs of inflammation (e.g., gallbladder wall thickening or pericholecystic fluid). **Analysis of Incorrect Options:** * **Fasting Respiratory Correlate Pulmonary (FRCP):** This is a distractor term and not a standard radiological investigation for biliary disease. (Note: Do not confuse with ERCP, which is an invasive therapeutic procedure). * **MRCP:** While highly sensitive for detecting stones in the *bile ducts* (choledocholithiasis), it is expensive and time-consuming. It is reserved as a second-line investigation when USG is inconclusive or ductal stones are suspected. * **CT Scan:** CT is inferior to USG for gallstones because many stones are "iso-attenuating" (radiolucent) to bile, making them invisible on a standard CT. CT is, however, the best modality for detecting complications like gallbladder perforation or emphysematous cholecystitis. **High-Yield Clinical Pearls for NEET-PG:** * **WES Triad:** (Wall-Echo-Shadow) is a classic USG sign seen when the gallbladder is completely filled with stones. * **HIDA Scan:** The most sensitive/accurate test for **Acute Cholecystitis** (shows non-visualization of the gallbladder). * **Oral Cholecystography:** Historically used but now obsolete; it relied on the functional ability of the gallbladder to concentrate dye.

Q: Which pattern is seen in the jejunum on an X-ray?

Valvulae connivantes. **Explanation:** The correct answer is **A. Valvulae connivantes**. **1. Why Valvulae connivantes is correct:** Valvulae connivantes (also known as Plicae circulares or Kerckring folds) are the mucosal folds of the small intestine. They are most prominent in the **jejunum**. On an abdominal X-ray, especially in cases of small bowel obstruction, these folds appear as thin, closely spaced lines that **span the entire width of the bowel lumen**. This "stack of coins" appearance is a classic radiologic hallmark used to distinguish the jejunum from the ileum (which has fewer folds and appears smoother) and the large intestine. **2. Why the other options are incorrect:** * **B. Taenia coli:** These are three longitudinal bands of smooth muscle found in the **large intestine**. On X-ray, the contraction of these bands creates **haustrations**. Unlike valvulae connivantes, haustral folds are thicker, further apart, and **do not span the entire diameter** of the bowel. * **C. Reverse 3 sign:** This is a specific radiologic sign seen on a barium swallow or during an ERCP, typically associated with **Carcinoma of the Head of the Pancreas** or periampullary tumors (Frostberg’s sign), where the duodenal loop is indented. It is not a normal pattern of the jejunum. **High-Yield Clinical Pearls for NEET-PG:** * **Jejunum vs. Ileum:** Jejunum is in the LUQ (Left Upper Quadrant) with prominent folds; Ileum is in the RLQ (Right Lower Quadrant) with a featureless/smooth appearance. * **Small Bowel Obstruction (SBO):** Characterized by dilated loops (>3 cm), valvulae connivantes, and multiple air-fluid levels on erect films. * **Large Bowel Obstruction (LBO):** Characterized by peripheral distribution and haustrations that do not cross the entire lumen.

Q: A 30-year-old female presents with right hypochondrial pain. CT scan reveals floating membranes in the liver. What is the most likely diagnosis?

Hydatid cyst. ### Explanation **Correct Answer: B. Hydatid Cyst** The presence of **"floating membranes"** within a hepatic cystic lesion is a pathognomonic radiological sign for **Hydatid disease** (Cystic Echinococcosis), caused by *Echinococcus granulosus*. This is known as the **Water-Lily Sign**. It occurs when the endocyst (the inner germinal layer) ruptures and detaches from the pericyst (the host-derived outer layer), causing the collapsed membranes to float within the cyst fluid. **Why other options are incorrect:** * **Amoebiasis (Amoebic Liver Abscess):** Typically presents as a "anchovy sauce" appearance on aspiration. On CT, it appears as a well-defined, low-attenuation lesion with a peripheral enhancing rim, but it lacks internal membranes or daughter cysts. * **Tuberculosis:** Hepatic TB usually presents as hepatomegaly with multiple small "miliary" granulomas or a large "tuberculoma" which may show central necrosis or calcification, but not floating membranes. * **Hepatocellular Carcinoma (HCC):** This is a solid, hypervascular tumor showing "wash-in" (arterial phase enhancement) and "wash-out" (venous/delayed phase) on contrast CT. It is not primarily a cystic lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Gharbi Classification:** Used to stage Hydatid cysts (Type I: Pure fluid; Type II: Floating membranes; Type III: Daughter cysts/honeycomb; Type IV: Solid/Heterogeneous; Type V: Calcified wall). * **Other Signs:** **"Honeycomb sign"** (multiple daughter cysts) and **"Eggshell calcification"** of the cyst wall. * **Treatment:** PAIR (Puncture, Aspiration, Injection of scolicidal agent, Re-aspiration) or surgical resection, always covered with **Albendazole**. * **Risk:** Avoid simple aspiration if Hydatid is suspected due to the risk of **anaphylactic shock** from spillage of cyst contents.

Q: Radiographic findings of cardiac achalasia include all except?

Diffuse esophageal spasm. **Explanation:** **Achalasia Cardia** is a primary esophageal motility disorder characterized by the failure of the Lower Esophageal Sphincter (LES) to relax and the absence of progressive peristalsis. **Why Option D is correct:** **Diffuse Esophageal Spasm (DES)** is a distinct clinical entity and a differential diagnosis for achalasia, not a radiographic finding of it. In DES, the esophagus shows uncoordinated, simultaneous contractions, leading to a characteristic **"Corkscrew" or "Rosary bead" appearance** on a barium swallow. In contrast, Achalasia is defined by aperistalsis. **Why the other options are incorrect:** * **Esophageal Dilatation (A):** Chronic obstruction at the LES leads to proximal pooling of food and saliva, causing the esophagus to dilate (Megaesophagus). On a chest X-ray, this may appear as a widened mediastinum with an absent gastric air shadow. * **Rat-tail appearance (B):** Also known as the **"Bird’s beak" appearance**, this represents the smooth, symmetric, conical narrowing of the distal esophagus at the level of the gastroesophageal junction. * **Failure of LES to relax (C):** This is the hallmark pathophysiologic and manometric finding of Achalasia. On fluoroscopy, the "beak" only opens intermittently and incompletely, often requiring the hydrostatic pressure of a large column of barium to force it open. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Esophageal Manometry (shows incomplete LES relaxation and aperistalsis). * **Heller’s Myotomy:** The surgical treatment of choice. * **Chagas Disease:** Can cause secondary achalasia (Pseudoachalasia) due to destruction of the myenteric (Auerbach’s) plexus by *Trypanosoma cruzi*. * **Sigmoid Esophagus:** The term used for the advanced, tortuous stage of esophageal dilatation in achalasia.

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.

Question 1

What is the first radiologic sign of Crohn's disease in the terminal ileum?

Accepted Answer

Aphthoid ulceration

Answer

Pseudosacculation

Answer

Cobblestone pattern

Answer

Thickening of the bowel wall

Question 2

A 61-year-old man undergoes a CT scan study of the abdomen for unexplained abdominal distension. Low attenuation intraperitoneal collections with enhancing septae are demonstrated. There is scalloping of the liver border and omental thickening. Which one of the following is most likely to be the underlying cause?

Accepted Answer

Cystadenocarcinoma of the appendix

Answer

Carcinoid tumor of the appendix

Answer

Perforated duodenal ulcer

Answer

Spontaneous bacterial peritonitis

Question 3

What is this appearance, seen in early pregnancy, known as?

Accepted Answer

Double bleb sign

Answer

Yolk sac sign

Answer

Double decidual sac sign

Answer

Twin peak sign

Question 4

What is the initial investigation for suspected gallbladder stones?

Accepted Answer

Ultrasound (USG)

Answer

Fasting Respiratory Correlate Pulmonary (FRCP)

Answer

Magnetic Resonance Cholangiopancreatography (MRCP)

Answer

CT scan

Question 5

Which investigation is most sensitive for detecting minimal intraperitoneal free air?

Accepted Answer

Chest x-ray

Answer

Standing x-ray of the abdomen

Answer

Right lateral decubitus x-ray of the abdomen

Answer

Left lateral decubitus x-ray of the abdomen

Question 6

Which pattern is seen in the jejunum on an X-ray?

Accepted Answer

Valvulae connivantes

Answer

Taenia coli

Answer

Reverse 3 sign

Answer

None of the above

Question 7

A 30-year-old female presents with right hypochondrial pain. CT scan reveals floating membranes in the liver. What is the most likely diagnosis?

Accepted Answer

Hydatid cyst

Answer

Amoebiasis

Answer

Tuberculosis

Answer

Hepatocellular carcinoma

Question 8

Radiographic findings of cardiac achalasia include all except?

Accepted Answer

Diffuse esophageal spasm

Answer

Esophageal dilatation

Answer

Rat-tail appearance

Answer

Failure of lower esophageal sphincter to relax

Question 9

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 10

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

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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