Abdominal and Pelvic Radiology Practice Questions

Q: A sentinel loop is seen on an X-ray. What is the most likely diagnosis?

Acute pancreatitis. ### **Explanation** **1. Why Acute Pancreatitis is the Correct Answer:** A **sentinel loop** refers to a localized segment of paralyzed, dilated small bowel (paralytic ileus) occurring adjacent to an inflamed organ. In the context of **acute pancreatitis**, the intense inflammatory process in the retroperitoneum spreads to the nearby jejunal loops. This irritation causes local aperistalsis and subsequent gas accumulation. On an abdominal X-ray, this typically appears as a single or double dilated loop of small bowel in the **left upper quadrant** or epigastrium. **2. Analysis of Incorrect Options:** * **Meckel's Diverticulum:** Usually asymptomatic or presents with painless lower GI bleeding or intestinal obstruction (intussusception/volvulus). It does not typically cause a localized sentinel loop on X-ray. * **Acute Cholecystitis:** While inflammation of the gallbladder can occasionally cause a sentinel loop in the **right upper quadrant**, it is far less common than in pancreatitis. The classic X-ray finding for cholecystitis (if any) is gallstones or rarely "emphysematous cholecystitis" (gas in the gallbladder wall). * **Acute Mesenteric Adenitis:** This mimics appendicitis and involves inflammation of mesenteric lymph nodes. It does not typically result in localized ileus or the sentinel loop sign. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Colon Cut-off Sign:** Another classic X-ray sign of acute pancreatitis; it refers to abrupt collapse of the colon at the splenic flexure due to inflammation spreading along the phrenicocolic ligament. * **Gold Standard Imaging:** While X-ray shows these supportive signs, **Contrast-Enhanced CT (CECT)** is the investigation of choice for diagnosing complications and assessing the severity (Balthazar score) of acute pancreatitis. * **Sentinel Loop Locations:** * LUQ: Pancreatitis * RUQ: Cholecystitis * RLQ: Appendicitis

Q: Which of the following is NOT a feature of Ulcerative Colitis?

String sign of Kantor. ### Explanation The correct answer is **C. String sign of Kantor**, which is a classic radiological feature of **Crohn’s Disease**, not Ulcerative Colitis (UC). #### Why String Sign of Kantor is the Correct Answer: The "String sign of Kantor" refers to the terminal ileum becoming severely narrowed due to transmural inflammation, edema, and spasm. On a barium study, this appears as a thin, string-like opacification. Since UC is a mucosal disease that primarily affects the colon and involves the terminal ileum only via "backwash ileitis" (which results in a dilated, patulous ileum), the string sign is characteristic of Crohn’s. #### Analysis of Incorrect Options: * **A. Fine mucosal granularity:** This is the **earliest** radiological sign of UC. It represents mucosal edema and hyperemia, giving the bowel wall a "sandpaper" appearance on double-contrast barium enema. * **B. Pseudopolyps:** These are islands of normal or regenerating mucosa surrounded by areas of extensive ulceration. They are a hallmark of chronic UC. * **C. Lead pipe appearance:** This occurs in the chronic stage of UC. Due to repeated cycles of inflammation and healing, the colon loses its haustrations, shortens, and becomes rigid, resembling a lead pipe. #### NEET-PG High-Yield Pearls: * **Distribution:** UC is continuous and starts from the rectum (rectum is always involved). Crohn’s has "skip lesions" and is transmural. * **Thumbprinting:** Seen in acute phases of UC or ischemic colitis due to severe mucosal edema. * **Collar Button Ulcers:** Deep, undermining ulcers seen in UC when the ulceration penetrates the lamina propria. * **Stovepipe Colon:** Another name for the "Lead pipe" appearance. * **Cobblestone Appearance:** Characteristic of Crohn’s Disease (due to longitudinal and transverse ulcers).

Q: Which ultrasonographic finding is characteristic of a hydatidiform mole?

Snowstorm pattern. **Explanation:** **Hydatidiform mole** (a type of Gestational Trophoblastic Disease) is characterized by the proliferation of trophoblastic tissue and hydropic degeneration of chorionic villi. On ultrasonography, these multiple small, hydropic vesicles (cysts) create a classic **"Snowstorm pattern."** This appearance is due to the presence of numerous echogenic areas interspersed with small sonolucent (cystic) spaces, representing the swollen villi and intrauterine hemorrhage, without a viable fetus in a complete mole. **Analysis of Incorrect Options:** * **B. Snow-driven pattern:** This is a distractor term not used in standard radiological nomenclature for molar pregnancy. * **C. Cotton wool appearance:** This is a classic radiological description for **Paget’s disease of the bone** (specifically the skull), representing thickened calvarium with disorganized sclerotic and lytic patches. * **D. Polka dot sign:** This is the characteristic CT/MRI appearance of a **Vertebral Hemangioma**, caused by thickened vertical trabeculae seen in cross-section. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Ultrasonography is the primary modality for diagnosis. * **Biochemical Marker:** Markedly elevated **serum β-hCG** levels (often >100,000 mIU/mL) are characteristic. * **Theca Lutein Cysts:** Large, multiloculated ovarian cysts are frequently seen bilaterally due to high hCG stimulation. * **Management:** The treatment of choice is **Suction and Evacuation**. * **The "Bunch of Grapes" appearance:** This refers to the macroscopic/gross pathological appearance of the vesicles.

Q: The 'pencil tip' deformity is typically observed in which of the following conditions?

Achalasia Cardia. **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 peristalsis in the distal esophagus. On a **Barium Swallow**, this results in a classic appearance where the distal esophagus shows smooth, symmetrical, conical narrowing at the level of the gastroesophageal junction. This appearance is famously described as the **'Pencil tip'**, **'Bird’s beak'**, or **'Rat-tail'** deformity. The proximal esophagus often shows compensatory dilatation (megaesophagus). **Analysis of Options:** * **Carcinoma of the Esophagus:** Typically presents with an **'Irregular, eccentric narrowing'** or a **'Shouldering effect'** (Apple-core appearance) due to the malignant mass. The narrowing is usually abrupt and irregular, unlike the smooth tapering seen in Achalasia. * **Barrett's Esophagus:** This is a premalignant condition (metaplasia). Radiologically, it may show signs of gastroesophageal reflux, such as ulcerations or a mid-esophageal stricture, but it does not produce the characteristic pencil-tip tapering. **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:** A secondary cause of Achalasia (caused by *Trypanosoma cruzi*). * **Chest X-ray:** May show an absent gastric air bubble and a widened mediastinum with an air-fluid level.

Q: Multiphasic hepatic imaging includes all except?

Capillary phase. **Explanation:** Multiphasic CT/MRI of the liver is the gold standard for evaluating hypervascular lesions like Hepatocellular Carcinoma (HCC). It relies on the dual blood supply of the liver: the **portal vein (75%)** and the **hepatic artery (25%)**. **Why "Capillary Phase" is the correct answer:** In hepatic imaging, there is no distinct "capillary phase" used for diagnostic protocols. While capillary exchange occurs physiologically, it is not a defined temporal window in multiphasic imaging. Instead, the transition between arterial and venous phases is captured through specific parenchymal enhancements. **Analysis of Incorrect Options:** * **Early Arterial Phase (15–25 sec):** Used primarily for CT angiography. It visualizes arterial anatomy and identifies active bleeding or pseudoaneurysms. * **Hepatic Parenchymal Phase (Late Arterial Phase, 35–45 sec):** This is the **most critical phase** for detecting hypervascular tumors (e.g., HCC, FNH, Adenoma). These lesions derive their blood supply from the hepatic artery and "light up" (enhance) against the yet-to-enhance liver parenchyma. * **Portal Venous Inflow Phase (60–80 sec):** The liver parenchyma reaches maximal enhancement as blood returns via the portal vein. This phase is best for detecting hypovascular metastases (e.g., from colon cancer) which appear dark against the bright liver. **High-Yield Clinical Pearls for NEET-PG:** * **HCC Classic Pattern:** Arterial phase enhancement (wash-in) followed by portal venous/delayed phase "wash-out" and a pseudocapsule. * **Hemangioma Pattern:** Peripheral globular enhancement with centripetal fill-in (progressive filling toward the center). * **Delayed Phase (3–5 mins):** Useful for identifying "wash-out" in HCC and "pooling" in hemangiomas.

Q: What is a potential limitation of Contrast-Enhanced Computed Tomography (CECT) in the evaluation of acute pancreatitis?

Inability to clearly diagnose gallstone pancreatitis. **Explanation:** **Why Option C is Correct:** While CECT is the gold standard for assessing the complications and severity of acute pancreatitis, it has a significant limitation in identifying the etiology, specifically **gallstones**. Most gallstones are **isodense** to bile on CT, making them difficult to visualize within the gallbladder or common bile duct. Therefore, **Transabdominal Ultrasonography (USG)** remains the initial investigation of choice for diagnosing gallstone-induced pancreatitis, as it has a much higher sensitivity for detecting cholelithiasis. **Analysis of Incorrect Options:** * **Option A & B:** CECT is excellent for assessing both severity and prognosis. Using the **Modified CT Severity Index (MCTSI)** or Balthazar score, radiologists can quantify pancreatic necrosis and inflammation, which directly correlates with patient outcomes and organ failure risk. * **Option D:** CECT is highly sensitive in detecting and characterizing **peripancreatic fluid collections (APFC)**, as well as distinguishing them from walled-off necrosis (WON) or pseudocysts in later stages. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** CECT should ideally be performed **72–96 hours** after the onset of symptoms. Scanning too early may underestimate the extent of pancreatic necrosis. * **Gold Standard:** CECT is the investigation of choice for diagnosing **pancreatic necrosis**. * **MRCP:** This is the most sensitive non-invasive modality for detecting **choledocholithiasis** (stones in the CBD) if USG is inconclusive. * **Sentinel Loop Sign:** A high-yield X-ray finding in acute pancreatitis representing localized ileus of a jejunal loop.

Q: A middle-aged female presents with chronic right-sided abdominal pain and intermittent fever. Clinical examination reveals mild hepatomegaly. A contrast-enhanced CT abdomen was performed. Based on the imaging characteristics of the focal lesion, what is the most likely diagnosis?

Hydatid cyst. ***Hydatid cyst*** - CT shows characteristic **daughter cysts** within the main cyst and **water lily sign** (floating membrane), pathognomonic of **Echinococcus granulosus** infection. - Often presents with **peripheral calcification** in chronic cases and occurs in endemic regions with sheep-rearing activities. *Liver abscess* - CT typically shows **rim enhancement** with central hypodense collection and **gas bubbles** in bacterial abscesses. - Lacks the characteristic **daughter cysts** and **water lily sign** seen in hydatid disease. *Pseudocyst of pancreas* - Usually located in the **pancreatic bed** or **lesser sac**, not within the liver parenchyma. - Associated with **acute pancreatitis** history and lacks the **multilayered cystic appearance** of hydatid cysts. *Hepatocellular carcinoma* - Shows **arterial enhancement** with **washout** in portal venous phase on contrast CT. - Appears as a **solid mass** rather than a cystic lesion with **septations** and **daughter cysts**.

Q: The liver lesion pointed out with the arrow (CT - arterial and portal venous phase) is most likely to be?

Hemangioma. ***Hemangioma*** - Shows characteristic **peripheral nodular enhancement** in arterial phase with **progressive centripetal fill-in** during portal venous phase, creating a classic "iris" pattern. - Most common **benign liver tumor**, typically asymptomatic and does not require treatment unless symptomatic or very large. *Adenoma* - Demonstrates **homogeneous enhancement** in arterial phase that **washes out** in portal venous phase, unlike the progressive fill-in of hemangioma. - Associated with **oral contraceptive use** and has risk of **hemorrhage** and **malignant transformation**. *Hepatocellular carcinoma* - Shows **intense arterial enhancement** followed by **rapid washout** in portal venous phase, creating a "washout" pattern rather than progressive fill-in. - Typically occurs in patients with **cirrhosis** and elevated **alpha-fetoprotein** levels. *Focal nodular hyperplasia* - Exhibits **intense homogeneous enhancement** in arterial phase with **isointense** appearance in portal venous phase. - Characterized by a **central stellate scar** and spoke-wheel vascular pattern on imaging.

Q: The X-ray demonstrates which of the following conditions?

Small bowel obstruction. ***Small bowel obstruction*** - Classic X-ray findings include **dilated central loops** with **valvulae conniventes** (complete mucosal folds crossing the bowel) and a **step-ladder pattern**. - Typically shows **absent or minimal large bowel gas** distal to the obstruction point. *Sigmoid volvulus* - Characterized by the pathognomonic **coffee-bean sign** - a massively dilated sigmoid loop resembling a coffee bean shape. - Shows **loss of haustral markings** in the twisted sigmoid segment with a characteristic bent appearance. *Large bowel obstruction* - Demonstrates **dilated peripheral loops** with **haustral markings** (incomplete mucosal folds that don't cross the entire bowel width). - Shows **distended colon** with haustra creating a scalloped appearance, typically sparing the small bowel. *Perforation* - Key finding is **free air under the diaphragm** (pneumoperitoneum) on upright chest X-ray or **Rigler's sign** on supine films. - May show **air outlining both sides** of the bowel wall or air in abnormal locations like the liver edge.

Question 1

A sentinel loop is seen on an X-ray. What is the most likely diagnosis?

Accepted Answer

Acute pancreatitis

Answer

Meckel's diverticulum

Answer

Acute cholecystitis

Answer

Acute mesenteric adenitis

Question 2

Which of the following is NOT a feature of Ulcerative Colitis?

Accepted Answer

String sign of Kantor

Answer

Fine mucosal granularity

Answer

Pseudopolyps

Answer

Lead pipe appearance

Question 3

Which ultrasonographic finding is characteristic of a hydatidiform mole?

Accepted Answer

Snowstorm pattern

Answer

Snow-driven pattern

Answer

Cotton wool appearance

Answer

Polka dot sign

Question 4

The 'pencil tip' deformity is typically observed in which of the following conditions?

Accepted Answer

Achalasia Cardia

Answer

Carcinoma of the esophagus

Answer

Barrett's esophagus

Answer

None of the above

Question 5

Which of the following is NOT a feature of chronic pancreatitis associated with pancreatic cancer?

Accepted Answer

Duct/gland width ratio <0.5

Answer

Calcification

Answer

Duct penetrating sign

Answer

Dilation of bile and pancreatic duct

Question 6

Multiphasic hepatic imaging includes all except?

Accepted Answer

Capillary phase

Answer

Early arterial phase

Answer

Hepatic parenchymal phase

Answer

Portal venous inflow phase

Question 7

What is a potential limitation of Contrast-Enhanced Computed Tomography (CECT) in the evaluation of acute pancreatitis?

Accepted Answer

Inability to clearly diagnose gallstone pancreatitis

Answer

Inability to assess severity

Answer

Limited usefulness in assessing prognosis

Answer

Inability to diagnose peripancreatic fluid collection

Question 8

A middle-aged female presents with chronic right-sided abdominal pain and intermittent fever. Clinical examination reveals mild hepatomegaly. A contrast-enhanced CT abdomen was performed. Based on the imaging characteristics of the focal lesion, what is the most likely diagnosis?

Accepted Answer

Hydatid cyst

Answer

Liver abscess

Answer

Pseudocyst of pancreas

Answer

Hepatocellular carcinoma

Question 9

The liver lesion pointed out with the arrow (CT - arterial and portal venous phase) is most likely to be?

Accepted Answer

Hemangioma

Answer

Adenoma

Answer

Hepatocellular carcinoma

Answer

Focal nodular hyperplasia

Question 10

The X-ray demonstrates which of the following conditions?

Accepted Answer

Small bowel obstruction

Answer

Sigmoid volvulus

Answer

Large bowel obstruction

Answer

Perforation

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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