Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology Indian Medical PG Practice Questions and MCQs

Question 481: What is the investigation of choice for detecting renal scarring defects?

A. DMSA scan (Correct Answer)
B. DTPA scan
C. Dexa scan
D. MCU

Explanation: **Explanation:** The investigation of choice for detecting renal scarring is the **DMSA (Dimercaptosuccinic Acid) scan**. **1. Why DMSA is the Correct Answer:** DMSA is a **static renal scintigraphy** agent. It is taken up by the proximal convoluted tubules of the renal cortex and remains fixed there for several hours. This allows for high-resolution imaging of the renal parenchyma. Areas of scarring appear as "cold spots" (photopenic areas) with associated contour loss or thinning. It is the gold standard for diagnosing acute pyelonephritis and permanent cortical scarring, especially in pediatric patients with Vesicoureteral Reflux (VUR). **2. Why Other Options are Incorrect:** * **DTPA (Diethylenetriaminepentaacetic acid) scan:** This is a **dynamic scan** primarily used to assess the Glomerular Filtration Rate (GFR) and renal perfusion. It is the investigation of choice for evaluating obstructive uropathy (e.g., PUJ obstruction). * **DEXA scan:** This is used to measure Bone Mineral Density (BMD) for diagnosing osteoporosis; it has no role in renal imaging. * **MCU (Micturating Cystourethrogram):** This is the gold standard for diagnosing **Vesicoureteral Reflux (VUR)** and Posterior Urethral Valves (PUV). While VUR causes scarring, the MCU identifies the *cause*, whereas the DMSA identifies the *scar* itself. **High-Yield Clinical Pearls for NEET-PG:** * **Best time for DMSA:** To confirm permanent scarring, the scan should be performed **4–6 months** after an acute Urinary Tract Infection (UTI). * **MAG-3 Scan:** The most accurate dynamic scan for renal function in neonates/infants due to better secretion by immature kidneys. * **Investigation of choice for Renovascular Hypertension:** DTPA scan with Captopril challenge.

Question 482: The "beer - claw" appearance on CECT abdomen is most suggestive of which of the following conditions?

A. Hepatic laceration (Correct Answer)
B. Pancreatic laceration
C. Hepatocellular carcinoma
D. Renal cell carcinoma

Explanation: ### Explanation The **"bear-claw" appearance** (often referred to as the "bear-paw" or "claw" sign in trauma) is a classic radiological finding on Contrast-Enhanced Computed Tomography (CECT) of the abdomen, signifying **hepatic laceration**. **Why Hepatic Laceration is Correct:** In the setting of blunt abdominal trauma, a hepatic laceration appears as a linear or branching **hypodense (non-enhancing) area** within the vascularized liver parenchyma. When multiple stellate or parallel lacerations occur, they resemble the marks left by a bear's claws. This appearance indicates a disruption of the liver tissue and is used to grade the severity of the injury according to the American Association for the Surgery of Trauma (AAST) scale. **Analysis of Incorrect Options:** * **Pancreatic laceration:** While CECT is the gold standard for diagnosis, pancreatic trauma typically presents as a linear lucency across the body of the pancreas or associated peripancreatic fluid/hematoma, rather than a "bear-claw" pattern. * **Hepatocellular carcinoma (HCC):** HCC typically shows a "wash-in and wash-out" pattern (intense arterial enhancement with rapid venous clearing) and may show a pseudocapsule, but not the linear branching pattern of trauma. * **Renal cell carcinoma (RCC):** RCC presents as an enhancing renal mass. Note: The "Bear-paw sign" (specifically the **Bear-paw steatopyelonephritis**) is associated with **Xanthogranulomatous Pyelonephritis (XGP)**, not RCC. **Clinical Pearls for NEET-PG:** * **Liver:** The liver is the second most commonly injured organ in blunt trauma (Spleen is #1). * **Sentinel Clot Sign:** A high-attenuation clot seen near the site of organ injury, helping localize the source of bleeding. * **Grading:** Hepatic injuries are graded I-VI; Grade VI is total hepatic avulsion. * **Distinction:** Do not confuse the "Bear-claw" of liver trauma with the "Bear-paw" appearance of XGP (cross-section of dilated calyces resembling a paw).

Question 483: Which of the following is the best view for visualizing minimal pneumoperitoneum?

A. X-ray abdomen-erect view
B. X-ray abdomen-supine view
C. Left lateral decubitus with horizontal beam (Correct Answer)
D. Left lateral view with vertical beam

Explanation: **Explanation:** The detection of **pneumoperitoneum** (free intraperitoneal air) depends on the principle that air rises to the highest point within the peritoneal cavity. **Why Option C is Correct:** The **Left lateral decubitus view with a horizontal beam** is the most sensitive radiographic projection for detecting minimal pneumoperitoneum (capable of detecting as little as **1–2 ml** of air). In this position, the patient lies on their left side for approximately 10–20 minutes. This allows free air to rise and collect between the **lateral margin of the liver and the right abdominal wall**. This area is preferred because there is no gastric bubble or colonic gas on the right side to mimic or obscure the free air. **Analysis of Incorrect Options:** * **Option A (Erect Abdomen):** While commonly used to see air under the diaphragm, it requires the patient to stand. It is less sensitive than the left lateral decubitus for *minimal* air and may miss small amounts if the patient hasn't stood long enough. * **Option B (Supine Abdomen):** This is the least sensitive view. Air spreads out over the anterior surface of the viscera, making it difficult to see unless a large amount is present (producing signs like the **Rigler sign** or **Falciform ligament sign**). * **Option D (Left lateral with vertical beam):** A vertical beam would not allow the air to be tangential to the film, making it impossible to distinguish free air from intraluminal gas. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** **Non-contrast CT** is the most sensitive imaging modality overall for pneumoperitoneum. * **Chest X-ray:** An **Erect PA Chest X-ray** is actually more sensitive than an erect abdominal X-ray because the thin diaphragm is better visualized. * **Rigler Sign:** Seeing both sides of the bowel wall (intraluminal and extraluminal air); seen on supine films in large-volume pneumoperitoneum. * **Cupola Sign:** Air trapped under the central tendon of the diaphragm on a supine film.

Question 484: On barium swallow, what characteristic appearance is shown by a leiomyoma?

A. Rat tail appearance
B. Corkscrew appearance
C. Oval mass lined by barium (Correct Answer)
D. String sign

Explanation: **Explanation:** **Leiomyoma** is the most common benign mesenchymal tumor of the esophagus. It typically arises from the smooth muscle of the muscularis propria. On a barium swallow, it presents as a **smooth, oval, or crescent-shaped intramural filling defect**. Because the tumor is located within the wall but outside the mucosa, the overlying mucosa remains intact. This results in the characteristic appearance of an **oval mass lined by barium**, often forming sharp, right-angled, or slightly obtuse borders with the esophageal wall (the "abrupt shelf" sign). **Analysis of Incorrect Options:** * **A. Rat tail appearance (Bird-beak):** This is the classic sign of **Achalasia Cardia**, caused by the failure of the Lower Esophageal Sphincter (LES) to relax. It can also be seen in esophageal carcinoma (pseudoachalasia). * **B. Corkscrew appearance:** This indicates **Diffuse Esophageal Spasm (DES)**, resulting from tertiary, non-peristaltic contractions. * **D. String sign:** This is characteristic of **Hypertrophic Pyloric Stenosis** (in infants) or **Crohn’s disease** (terminal ileum), representing a severely narrowed luminal segment. **Clinical Pearls for NEET-PG:** * **Location:** Leiomyomas are most commonly found in the distal two-thirds of the esophagus. * **Management:** They are usually asymptomatic unless they exceed 5 cm. Surgical enucleation is the treatment of choice; biopsy is generally avoided during endoscopy to prevent scarring, which makes future enucleation difficult. * **Key Sign:** Look for the **"Splitting Sign"** on CT—the tumor splits the esophageal wall layers.

Question 485: The "Renal Rim Sign" is seen in which of the following conditions?

A. Hydronephrosis (Correct Answer)
B. Absent kidney
C. Wilm's tumor
D. Renal cell carcinoma

Explanation: ### Explanation **Correct Answer: A. Hydronephrosis** The **Renal Rim Sign** (also known as the "Crescent Sign") is a classic radiological finding seen on Contrast-Enhanced CT (CECT) or intravenous urography in cases of **severe, chronic hydronephrosis**. * **Pathophysiology:** In chronic obstructive uropathy, the collecting system becomes massively dilated. This pressure causes the overlying renal parenchyma to become markedly thinned and compressed. * **Radiological Appearance:** When contrast is administered, the thinned rim of functional parenchyma enhances and becomes opacified, while the dilated, fluid-filled calyces remain lucent. This creates a thin, hyperdense "rim" or "crescent" of enhancement around the periphery of the dilated collecting system. **Why other options are incorrect:** * **B. Absent kidney:** In renal agenesis or ectopia, there is no renal tissue present in the flank to enhance or form a rim. * **C. Wilm’s Tumor:** This typically presents as a large, heterogeneous solid mass that "claws" the normal parenchyma (the **Claw Sign**), rather than causing a uniform peripheral rim of enhancement. * **D. Renal Cell Carcinoma:** RCC usually presents as an enhancing solid mass that distorts the renal contour. While it may have a pseudocapsule, it does not produce the characteristic circumferential thinning seen in hydronephrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Renal Rim Sign vs. Nephrogram:** A delayed or "vicarious" nephrogram is often seen in acute obstruction, whereas the Rim Sign indicates a more chronic, advanced stage. * **The "Claw Sign":** Used to differentiate a tumor arising *from* the kidney (e.g., Wilm’s) versus a tumor *compressing* the kidney (e.g., Neuroblastoma). * **The "Bear Paw Appearance":** Characteristic of Xanthogranulomatous Pyelonephritis (XGP) on CT. * **The "Maiden Waist" Deformity:** Seen in retroperitoneal fibrosis affecting the ureters.

Question 486: A 40-year-old male presents with colicky abdominal pain, multiple episodes of bilious vomiting, and absence of bowel movements and flatus. An X-ray of the abdomen was performed. Based on the findings, what is the most likely diagnosis?

A. Duodenal obstruction
B. Jejunal obstruction (Correct Answer)
C. Ileal obstruction
D. Colonic obstruction

Explanation: ***Jejunal obstruction*** - **Colicky abdominal pain**, **bilious vomiting**, and **absence of bowel movements** with **valvulae conniventes** (stack of coins pattern) on X-ray are characteristic of jejunal obstruction. - The **valvulae conniventes** are complete mucosal folds that cross the entire bowel width, creating a distinctive radiographic appearance in the **proximal small bowel**. *Duodenal obstruction* - Typically presents with **non-bilious vomiting** initially, progressing to bilious if obstruction is distal to the **ampulla of Vater**. - X-ray shows the classic **"double bubble" sign** with gastric and duodenal dilatation, not multiple dilated loops. *Ileal obstruction* - Shows **fewer dilated loops** on X-ray with **incomplete mucosal markings** (**plicae circulares**) that don't cross the entire bowel width. - Often associated with **less prominent vomiting** and more **abdominal distension** compared to jejunal obstruction. *Colonic obstruction* - Presents with **progressive abdominal distension**, **constipation**, and **late-onset vomiting** that is typically **feculent**. - X-ray shows **haustra** (incomplete septa) and **peripheral distribution** of dilated bowel loops, not the central small bowel pattern.

Question 487: The keyhole sign is seen in which of the following conditions?

A. Hydronephrosis
B. Posterior urethral valve (Correct Answer)
C. Ectopic ureter
D. Polycystic kidney disease (PCKD)

Explanation: ### Explanation **Correct Answer: B. Posterior urethral valve (PUV)** The **"Keyhole Sign"** is a classic sonographic finding in male fetuses or neonates with **Posterior Urethral Valves (PUV)**. It is caused by the combination of a **thick-walled, dilated urinary bladder** (the "head" of the keyhole) and a **dilated posterior urethra** (the "slot" of the keyhole) proximal to the obstructing valve. PUV is the most common cause of bladder outlet obstruction in male infants, resulting from abnormal mucosal folds in the distal prostatic urethra. **Analysis of Incorrect Options:** * **A. Hydronephrosis:** While PUV *causes* bilateral hydronephrosis due to back-pressure, the term "keyhole sign" specifically refers to the bladder and urethral morphology, not the dilated renal pelvis itself. * **C. Ectopic ureter:** This typically presents with a duplex collecting system and may cause hydroureteronephrosis, but it does not cause the characteristic proximal urethral dilatation seen in the keyhole sign. * **D. Polycystic kidney disease (PCKD):** Autosomal Recessive PCKD (ARPKD) presents with bilaterally enlarged, echogenic kidneys and loss of corticomedullary differentiation, but lacks the obstructive bladder findings. **Clinical Pearls for NEET-PG:** * **Most common cause** of obstructive uropathy in male children: PUV. * **Associated findings:** Oligohydramnios (in utero), bilateral hydroureteronephrosis, and "bladder wall thickening." * **Gold standard investigation:** Voiding Cystourethrogram (VCUG), which demonstrates the dilated posterior urethra and the actual valve. * **Complication:** Renal dysplasia due to high-pressure reflux in utero.

Question 488: The 'flower vase' pattern of the renal pelvis in an intravenous urogram is typically seen in which of the following conditions?

A. Polycystic kidney
B. Renal carcinoma
C. Horseshoe kidney (Correct Answer)
D. Ectopic kidney

Explanation: **Explanation:** The **'flower vase' appearance** (also known as the 'handshake' or 'inverted flower vase' appearance) is a classic radiological sign of a **Horseshoe Kidney** on an Intravenous Urogram (IVU). **1. Why Horseshoe Kidney is correct:** In a horseshoe kidney, the lower poles are fused across the midline by an isthmus. This fusion prevents the normal internal rotation of the kidneys during development. Consequently, the kidneys remain low-seated, and the **long axes of the kidneys are reversed**: the upper poles are tilted laterally while the lower poles are tilted medially. This orientation, combined with anteriorly displaced ureters that must "drape" over the isthmus, creates the characteristic appearance of a flower vase. **2. Why other options are incorrect:** * **Polycystic Kidney:** Shows bilateral enlargement with "spider leg" deformity (stretching and elongation of calyces) due to multiple cysts. * **Renal Carcinoma:** Typically presents as a focal contour abnormality or "space-occupying lesion" that distorts or amputates the collecting system. * **Ectopic Kidney:** Refers to a kidney in an abnormal location (e.g., pelvic kidney). While it may show malrotation, it does not form the specific symmetric 'flower vase' axis seen in fused kidneys. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of fusion:** Lower poles (90%). * **Level of arrest:** The isthmus gets trapped under the **Inferior Mesenteric Artery (IMA)** at L3-L4. * **Complications:** Increased risk of nephrolithiasis (due to stasis), hydronephrosis (UPJ obstruction), and **Wilms tumor** (in children) or **Renal Cell Carcinoma**. * **Associated Sign:** The **'Dirk-the-Dagger' sign** (ureters curving medially then laterally over the isthmus).

Question 489: Which of the following is a radiological finding of a benign gastric ulcer?

A. Hampton line
B. Collar at the neck of the ulcer
C. Projection from the lumen of the stomach
D. All of the above (Correct Answer)

Explanation: In radiology, distinguishing between benign and malignant gastric ulcers is a high-yield topic for NEET-PG. The correct answer is **All of the above** because these features collectively indicate a non-neoplastic, inflammatory process. ### **Explanation of Radiological Findings:** 1. **Hampton Line (Option A):** This is a thin (1–2 mm), sharp lucent line across the neck of the ulcer crater. It represents the undermined but intact gastric mucosa at the ulcer edge. It is a hallmark of a benign ulcer. 2. **Ulcer Collar (Option B):** This is a thicker, translucent band at the neck of the ulcer caused by edema of the submucosa. Unlike the Hampton line, it is more prominent but still indicates a benign inflammatory response. 3. **Projection from the Lumen (Option C):** Benign ulcers typically represent a "hole" in the wall; therefore, when viewed in profile, the ulcer crater **projects beyond the normal predicted gastric contour**. In contrast, malignant ulcers (Carman Meniscus Sign) appear as excavations *within* a mass, staying within the gastric lumen. ### **Why other options are part of the correct set:** Since A, B, and C are all classic signs of benignity on a double-contrast barium swallow, "All of the above" is the most accurate choice. ### **High-Yield Clinical Pearls for NEET-PG:** * **Benign Ulcer:** Smooth margins, radiating mucosal folds that reach the very edge of the crater, and projection beyond the lumen. * **Malignant Ulcer:** Irregular base, nodular/heaped-up margins, and mucosal folds that stop short or are clubbed/fused before reaching the crater. * **Carman Meniscus Sign:** A semi-lunate (crescent) shaped ulcer with the convexity directed toward the gastric wall, pathognomonic for a large **malignant** gastric ulcer. * **Location:** Benign ulcers are most commonly found on the **lesser curvature** or posterior wall.

Question 490: Yoyo reflux is most commonly associated with which of the following conditions?

A. Duplication of ureter (Correct Answer)
B. Polycystic kidney disease
C. Medullary sponge kidney
D. Pseudo kidney

Explanation: **Explanation:** **Yoyo reflux** (also known as uretero-ureteral reflux) is a classic radiological and physiological phenomenon seen in cases of **incomplete duplication of the ureter** (bifid ureter). 1. **Why Option A is correct:** In a bifid ureter, two ureters drain a single kidney but join together before entering the bladder. During peristalsis, urine travels down one limb; however, when it reaches the point of bifurcation, some urine may be diverted retrograde (backwards) up the other limb instead of continuing into the common ureter. This "to-and-fro" movement of urine between the two ureteral limbs is termed "Yoyo reflux." It can lead to stasis, recurrent urinary tract infections (UTIs), and ureteral dilatation. 2. **Why other options are incorrect:** * **Polycystic Kidney Disease (ADPKD):** Characterized by multiple bilateral renal cysts; it does not involve ureteral duplication or this specific reflux pattern. * **Medullary Sponge Kidney:** Involves cystic dilatation of the collecting ducts (ectasia) presenting with a "paintbrush" appearance on IVP; it is not a structural ureteral anomaly. * **Pseudo kidney:** This is an ultrasound sign (concentric rings) typically associated with **intussusception** or bowel tumors, not a urological reflux pattern. **High-Yield Clinical Pearls for NEET-PG:** * **Weigert-Meyer Law:** Applies to **complete** duplication. The ureter from the **upper pole** inserts **ectopically** (inferior and medial) and is prone to **obstruction/ureterocele**. The **lower pole** ureter inserts normally but is prone to **vesicoureteral reflux (VUR)**. * **Yoyo reflux** is specific to **incomplete (bifid)** ureters, whereas **VUR** is more common in **complete** duplication. * **Investigation of choice:** Voiding Cystourethrogram (VCUG) for VUR; IVP or MRU for visualizing duplication anatomy.

Practice by Chapter

Imaging of Liver

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Biliary Tract Imaging

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Pancreatic Imaging

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Spleen and Lymphatic System

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Gastrointestinal Tract Imaging

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Renal and Urinary Tract Imaging

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Adrenal Imaging

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Female Pelvic Imaging

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Male Pelvic Imaging

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Abdominal Trauma Imaging

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Acute Abdomen Imaging

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Imaging of Peritoneal Cavity and Retroperitoneum

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