Abdominal and Pelvic Radiology Practice Questions

Q: The 'Mercedes Benz' sign is seen in which of the following conditions?

Gall stone. **Explanation:** The **'Mercedes Benz' sign** is a classic radiological finding associated with **cholelithiasis (gallstones)**. It refers to the presence of star-shaped, radiolucent gas fissures within a gallstone. These fissures occur due to the shrinkage of cholesterol crystals or the entrapment of gas (nitrogen, oxygen, and carbon dioxide) within the stone's core. On an X-ray or CT scan, these gas-filled clefts resemble the three-pointed star logo of the Mercedes-Benz brand. **Analysis of Options:** * **Volvulus:** Sigmoid volvulus typically presents with the **'Coffee Bean' sign** or 'Omega' sign, representing a massively dilated loop of bowel. * **Struvite calculus:** These are staghorn calculi found in the renal pelvis, often associated with Proteus infections. They appear as large, radiopaque branching structures on a KUB (Kidney-Ureter-Bladder) film. * **Intussusception:** This condition is characterized by the **'Target' sign** or 'Doughnut' sign on ultrasound/CT, representing the telescoping of one bowel segment into another. **High-Yield Clinical Pearls for NEET-PG:** * **Gas in Gallstones:** The Mercedes Benz sign is seen in approximately 50% of gallstones on CT but is less common on plain X-rays. * **Limy Bile:** This refers to excessive calcium carbonate in the gallbladder, making the entire gallbladder appear radiopaque. * **Porcelain Gallbladder:** Intramural calcification of the gallbladder wall, often associated with chronic cholecystitis and an increased risk of gallbladder carcinoma. * **Rigler’s Triad:** (Seen in Gallstone Ileus) 1. Pneumobilia, 2. Small bowel obstruction, 3. Ectopic gallstone in the iliac fossa.

Q: A plain X-ray abdomen is performed in a case of small bowel obstruction. Small bowel is considered dilated if its diameter is more than:

3 cm. In abdominal radiology, the **"3-6-9 Rule"** is the standard clinical guideline used to identify abnormal bowel dilatation on a plain X-ray. According to this rule, the upper limits of normal diameter for the bowel segments are: * **Small Bowel:** < 3 cm * **Large Bowel (Colon):** < 6 cm * **Cecum:** < 9 cm **Why 3 cm is correct:** A small bowel loop is considered pathologically dilated if its diameter measures **3 cm or more**. In the context of intestinal obstruction, this dilatation occurs due to the accumulation of gas and fluid proximal to the site of the block. On X-ray, this is often accompanied by the "valvulae conniventes" (plicae circulares) crossing the entire width of the lumen, giving a "stacked coin" appearance. **Analysis of incorrect options:** * **2 cm (Option A):** This is within the normal physiological range for small bowel loops. * **4 cm (Option C):** While 4 cm is definitely dilated, it is not the threshold value. The diagnostic cutoff starts at 3 cm. * **5 cm (Option D):** This represents significant dilatation but is closer to the threshold for the large bowel (6 cm). **High-Yield Clinical Pearls for NEET-PG:** * **Step-ladder pattern:** Characteristic of small bowel obstruction due to multiple fluid levels. * **String of beads sign:** Small bubbles of gas trapped between valvulae conniventes in a fluid-filled small bowel. * **Coffee bean sign:** Classic for sigmoid volvulus (large bowel). * **Rigler’s sign:** Seeing both sides of the bowel wall, indicating pneumoperitoneum.

Q: Which of the following is NOT true regarding a renal pseudotumor?

Frequently requires surgical intervention. ### Explanation **Renal pseudotumors** are anatomical variants of normal renal parenchyma that mimic a neoplasm on imaging. Understanding these is crucial to avoid unnecessary invasive procedures. **1. Why Option A is the correct answer:** Renal pseudotumors are **benign anatomical variants**, not true pathologies. They consist of normal, healthy renal tissue (cortex and glomeruli). Therefore, they **do not require surgical intervention** or biopsy. Management is purely conservative, usually involving confirmation via Doppler US, CT, or nuclear medicine (DMSA scan) to rule out a true malignancy. **2. Analysis of Incorrect Options:** * **Option B (Hypertrophied Column of Bertin):** This is the most common type of pseudotumor. It occurs when cortical tissue indents the renal sinus, often appearing as a "mass" between the upper and middle poles. * **Option C (Dromedary Hump):** This is a focal bulge on the lateral border of the left kidney caused by the splenic impression during development. It is a classic example of a pseudotumor. * **Option D (No clinical significance):** Since these are normal variants, they do not cause symptoms, hematuria, or functional impairment. Their only "significance" is the potential for being misdiagnosed as a renal cell carcinoma (RCC). **Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** A **Technetium-99m DMSA scan** is the most definitive way to differentiate a pseudotumor from a tumor. A pseudotumor will show **normal or increased uptake** (as it contains functioning nephrons), whereas a true tumor will appear as a "cold" spot. * **Imaging Clue:** On CT, a pseudotumor shows the **same enhancement pattern** as the rest of the renal cortex in all phases. * **Common Sites:** Columns of Bertin are typically found at the junction of the upper and middle thirds of the kidney.

Q: In Intravenous Pyelography (IVP), the "Adder head" appearance is seen in which of the following conditions?

Ureterocele. **Explanation:** The **"Adder head"** (or Cobra head) appearance is a classic radiological sign of a **Ureterocele**. **1. Why Ureterocele is correct:** A ureterocele is a congenital cystic dilatation of the distal-most intramural portion of the ureter. On an Intravenous Pyelogram (IVP), the dilated terminal ureter appears as a radiopaque bulbous area surrounded by a thin radiolucent halo (representing the ureterocele wall). This combination resembles the head of a cobra or an adder snake. This sign is typically seen in **orthotopic (simple) ureteroceles** in adults. **2. Why other options are incorrect:** * **Polycystic Kidney Disease (ADPKD):** Characterized by the **"Swiss Cheese"** appearance due to multiple radiolucent cysts stretching and distorting the pelvicalyceal system. * **Horseshoe Kidney:** Characterized by the **"Flower vase"** appearance. The lower poles are fused, causing the axes of the kidneys to be reversed (lower poles more medial than upper poles). * **Hydronephrosis:** Presents as dilatation of the renal pelvis and calyces. If severe, it may show the **"Clubbing of calyces"** or the **"Rim sign"** on delayed films, but not an adder head. **Clinical Pearls for NEET-PG:** * **Cobra head sign:** If the radiolucent halo (the "wall") is thick or irregular, suspect a **pseudoureterocele** (often secondary to a bladder tumor or impacted stone). * **Drooping Lily Sign:** Seen in a duplicated collecting system where an obstructed upper pole ureterocele displaces the lower pole moiety downwards and outwards. * **Weigert-Meyer Law:** In duplication, the upper pole ureter inserts ectopically (inferomedial to the normal orifice) and is prone to obstruction/ureterocele.

Q: 'Thumb print' appearance on Barium enema is found in:

Bowel ischemia. **Explanation:** The **'Thumbprint' appearance** (or thumbprinting) is a classic radiologic sign seen on a Barium enema or plain abdominal X-ray. It represents **focal submucosal edema and hemorrhage** caused by an acute insult to the bowel wall, most commonly **Ischemic Colitis**. When the bowel wall becomes congested, the thickened folds protrude into the air or contrast-filled lumen, creating indentations that resemble the impression of a thumb. **Analysis of Options:** * **Bowel Ischemia (Correct):** This is the most common cause. The submucosal hemorrhage creates the characteristic scalloped appearance of the colonic wall. It is typically seen in the "watershed" areas like the splenic flexure (Griffith’s point). * **Volvulus:** Characterized by a **'Coffee bean' sign** (sigmoid volvulus) or a **'Bird’s beak' appearance** on a barium enema at the site of the twist. * **Gastric Ulcer:** Typically evaluated via endoscopy or upper GI series. Signs include an **ulcer crater** or **Hampton’s line**, but not thumbprinting, which is a colonic sign. * **Intussusception:** Classically presents with a **'Coiled spring' appearance** or **'Cup-shaped' defect** on a barium enema as the contrast trickles between the intussusceptum and intussuscipiens. **High-Yield Clinical Pearls for NEET-PG:** * **Other causes of thumbprinting:** Ulcerative Colitis (acute flare), Crohn’s disease, and submucosal lymphoma. * **Ischemic Colitis vs. Mesenteric Ischemia:** Thumbprinting is more specific to Ischemic Colitis (mucosal/submucosal injury) rather than acute mesenteric ischemia (which often shows a normal X-ray initially). * **Lead pipe appearance:** Seen in chronic Ulcerative Colitis due to loss of haustrations.

Q: Scalloping of the edge of the sigmoid colon on barium enema is typically seen in which of the following conditions?

Ulcerative colitis. **Explanation:** **Ulcerative Colitis (UC)** is the correct answer. The "scalloping" or "serrated" appearance of the colonic edge on a barium enema is a classic early radiological sign of UC. This occurs due to multiple small, superficial **mucosal ulcerations** and inflammatory changes. As the disease progresses, these ulcers may deepen (forming "collar-stud" ulcers) or lead to the formation of inflammatory pseudopolyps. In chronic stages, the loss of haustration and bowel shortening leads to the characteristic "lead-pipe" appearance. **Analysis of Incorrect Options:** * **Pseudomembranous Colitis:** Typically shows significant mucosal thickening and "thumbprinting" due to severe edema. On contrast studies, it may show the **"Accordion sign"** (trapped contrast between thickened haustral folds). * **Intussusception:** Characterized by the **"Coiled-spring appearance"** or "Cupola sign," where the barium outlines the intussusceptum within the intussuscipiens. * **Ischemic Colitis:** Classically presents with **"Thumbprinting"** (indentations on the barium column) caused by submucosal hemorrhage and edema, usually at the splenic flexure (Griffith’s point). **High-Yield Pearls for NEET-PG:** * **Lead-pipe Colon:** Feature of chronic Ulcerative Colitis (loss of haustra). * **String Sign of Kantor:** Seen in Crohn’s Disease (terminal ileal narrowing). * **Cobblestone Appearance:** Characteristic of Crohn’s Disease (deep longitudinal and transverse ulcers). * **Double-Duct Sign:** Seen in Periampullary Carcinoma/Carcinoma Head of Pancreas. * **Apple-core Lesion:** Classic for Colorectal Carcinoma.

Q: What is the initial imaging modality of choice for suspected pyonephrosis?

Ultrasound (USG). **Explanation:** **Pyonephrosis** is a surgical emergency characterized by the presence of infected, purulent material (pus) within an obstructed collecting system. Prompt diagnosis is critical to prevent urosepsis and permanent renal damage. **Why Ultrasound (USG) is the correct answer:** Ultrasound is the **initial imaging modality of choice** because it is rapid, non-invasive, bedside-compatible, and highly sensitive (up to 90%) for detecting both hydronephrosis and the presence of debris. The classic sonographic hallmark of pyonephrosis is the presence of **low-level internal echoes (layering debris)** within a dilated collecting system. It also allows for immediate therapeutic intervention via ultrasound-guided percutaneous nephrostomy (PCN). **Why other options are incorrect:** * **Contrast-enhanced CT (CECT):** While CT is more sensitive for identifying the *cause* of obstruction (e.g., stones) and assessing the renal parenchyma, it is generally considered the second-line or confirmatory investigation. The use of IV contrast may also be risky in patients with potential renal impairment due to obstruction. * **Intravenous Pyelogram (IVP):** This is largely obsolete in acute settings. In pyonephrosis, the affected kidney often shows "delayed or absent excretion," providing little diagnostic information regarding the nature of the fluid. * **MRI:** Though sensitive, MRI is time-consuming, expensive, and not practical for an emergency diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of Pyonephrosis:** Fever, flank pain, and hydronephrosis. * **Gold Standard for Diagnosis:** Aspiration of pus from the collecting system (usually during PCN). * **Key USG Finding:** Persistent low-level echoes in the dependent portion of the dilated calyces (fluid-debris level). * **Management:** Emergency drainage (PCN or retrograde stenting) is mandatory; antibiotics alone are insufficient.

Q: What is the primary imaging technique used in a case of suspected acute pancreatitis?

CECT abdomen with pancreatic protocol. **Explanation:** **Contrast-Enhanced Computed Tomography (CECT) of the abdomen with pancreatic protocol** is the gold standard and primary imaging modality for evaluating suspected acute pancreatitis and its complications. The "pancreatic protocol" involves thin-section imaging during the late arterial (pancreatic) phase and portal venous phase. This allows for the precise assessment of pancreatic parenchymal enhancement to identify **necrosis** (non-enhancing areas), peripancreatic fluid collections, and vascular complications like pseudoaneurysms. **Analysis of Options:** * **MRI Abdomen:** While highly sensitive for detecting early pancreatitis and choledocholithiasis (via MRCP), it is not the primary choice due to higher costs, longer scan times, and limited availability in emergency settings. * **USG Abdomen:** This is usually the **initial** screening tool to look for gallstones (the most common etiology), but it is poor at visualizing the pancreas itself due to overlying bowel gas and cannot reliably quantify necrosis. * **MR Enterography:** This is specifically used for evaluating small bowel pathology, such as Crohn’s disease, and has no role in the acute management of pancreatitis. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** CECT is most accurate when performed **72–96 hours** after symptom onset. Imaging done too early (<48 hours) may underestimate the extent of pancreatic necrosis. * **Balthazar Score:** A CT-based grading system used to assess the severity of acute pancreatitis. * **CT Severity Index (CTSI):** Combines the Balthazar grade with the percentage of pancreatic necrosis to predict patient prognosis and mortality. * **Sentinel Loop Sign:** A dilated loop of proximal jejunum seen on X-ray, indicating localized ileus due to nearby inflammation.

Question 1

Which of the following is not a feature of renovascular hypertension on IVU?

Accepted Answer

Filling defect in calyces

Answer

Delayed wash out of contrast

Answer

Ureteral kinking

Answer

Normal or small sized kidney

Question 2

The 'Mercedes Benz' sign is seen in which of the following conditions?

Accepted Answer

Gall stone

Answer

Volvulus

Answer

Struvite calculus

Answer

Intussusception

Question 3

A plain X-ray abdomen is performed in a case of small bowel obstruction. Small bowel is considered dilated if its diameter is more than:

Accepted Answer

3 cm

Answer

2 cm

Answer

4 cm

Answer

5 cm

Question 4

Which of the following is NOT true regarding a renal pseudotumor?

Accepted Answer

Frequently requires surgical intervention

Answer

Represents hypertrophied column of Bertin

Answer

Can be visualized as a dromedary hump

Answer

Has no clinical significance

Question 5

In Intravenous Pyelography (IVP), the "Adder head" appearance is seen in which of the following conditions?

Accepted Answer

Ureterocele

Answer

Polycystic kidney

Answer

Horseshoe kidney

Answer

Hydronephrosis

Question 6

'Thumb print' appearance on Barium enema is found in:

Accepted Answer

Bowel ischemia

Answer

Volvulus

Answer

Gastric ulcer

Answer

Intussusception

Question 7

Scalloping of the edge of the sigmoid colon on barium enema is typically seen in which of the following conditions?

Accepted Answer

Ulcerative colitis

Answer

Pseudomembranous colitis

Answer

Intussusception

Answer

Ischemic colitis

Question 8

What is the initial imaging modality of choice for suspected pyonephrosis?

Accepted Answer

Ultrasound (USG)

Answer

Contrast-enhanced CT (CECT)

Answer

Intravenous pyelogram (IVP)

Answer

Magnetic Resonance Imaging (MRI)

Question 9

Which of the following is NOT a cause of pneumoperitoneum?

Accepted Answer

Laparoscopy

Answer

Subdiaphragmatic fat

Answer

Chilaiditi syndrome

Answer

Subphrenic abscess

Question 10

What is the primary imaging technique used in a case of suspected acute pancreatitis?

Accepted Answer

CECT abdomen with pancreatic protocol

Answer

MRI abdomen

Answer

USG abdomen

Answer

MR enterography

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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