Abdominal and Pelvic Radiology Practice Questions

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.

Q: Which of the following is NOT radioopaque?

Uric acid. In radiology, the visibility of a urinary stone on a plain X-ray (KUB) depends on its **effective atomic number** and density compared to surrounding tissues. **Correct Answer: B. Uric acid** Uric acid stones are composed of organic compounds with low atomic numbers (Carbon, Nitrogen, Oxygen). Because they do not significantly attenuate X-ray beams, they are **radiolucent** on plain films. However, they are visible on Non-Contrast CT (NCCT), where they typically show low Hounsfield Units (400–600 HU). **Explanation of Incorrect Options:** * **A. Oxalate:** Calcium oxalate (monohydrate and dihydrate) is the most common type of urinary stone. Due to the high atomic number of Calcium, these stones are **highly radioopaque** and easily seen on X-ray. * **C. Cystine:** These stones contain sulfur atoms. While they are less dense than calcium stones, they are considered **faintly radioopaque** (often described as having a "ground-glass" appearance). They are NOT radiolucent. * **D. Mixed:** Most mixed stones contain a calcium component (e.g., calcium phosphate or oxalate), which renders the entire stone **radioopaque** on imaging. **NEET-PG High-Yield Pearls:** 1. **Mnemonic for Radiolucent Stones:** **"U S"** – **U**ric acid and **S**anthine (Xanthine). (Note: Indinavir stones are also radiolucent). 2. **Order of Opacity (Highest to Lowest):** Calcium Phosphate > Calcium Oxalate > Magnesium Ammonium Phosphate (Struvite) > Cystine > Uric Acid/Xanthine. 3. **Gold Standard Investigation:** NCCT (Non-Contrast Computed Tomography) is the investigation of choice for urolithiasis as it detects all stones except Indinavir stones. 4. **Struvite Stones:** Associated with Proteus infections and often form "Staghorn" calculi.

Q: The triad of vomiting, abdominal distension, and a "string of beads" sign on abdominal X-ray is typically suggestive of what condition?

Small bowel obstruction. **Explanation:** The clinical triad of vomiting, abdominal distension, and constipation/obstipation is the hallmark of **Small Bowel Obstruction (SBO)**. Radiologically, the **"string of beads" (or "string of pearls") sign** is highly specific for SBO. It occurs when the bowel loops are almost entirely filled with fluid, leaving only small bubbles of gas trapped between the valvulae conniventes (circular folds). On a horizontal beam or upright X-ray, these small gas bubbles appear as a row of translucent beads. **Analysis of Options:** * **Duodenal Atresia:** Characterized by the **"double bubble" sign** (gas in the stomach and proximal duodenum) and typically presents in neonates with bilious vomiting, not a string of beads. * **Large Bowel Obstruction:** Presents with peripheral bowel dilatation and the presence of haustrations (which do not cross the entire width of the bowel). It typically lacks the string of beads sign, which is specific to the valvulae conniventes of the small intestine. * **Gastric Volvulus:** Usually presents with **Borchardt’s triad** (epigastric pain, unproductive retching, and inability to pass a nasogastric tube). X-ray shows a single, massively dilated retrocardiac or epigastric air-fluid level. **High-Yield NEET-PG Pearls:** * **Step-ladder pattern:** Another classic sign of SBO, representing multiple air-fluid levels at different heights in dilated loops. * **Valvulae Conniventes (Plicae circulares):** These folds cross the **entire width** of the small bowel, helping differentiate it from the large bowel (haustra). * **Most common cause of SBO:** Post-operative adhesions (overall) and incarcerated hernias (worldwide in some regions).

Q: A 40-year-old woman presents with abdominal pain. Two films from an ERCP are shown. What is the MOST likely diagnosis?

Pancreas divisum. ***Pancreas divisum*** - **Non-communicating ventral and dorsal pancreatic ducts** are the hallmark ERCP finding, with the **short ventral duct** draining through the **major papilla** and the **dominant dorsal duct** draining through the **minor papilla**. - This **congenital anomaly** occurs due to failure of fusion between the ventral and dorsal pancreatic ducts during embryological development, making it the most common pancreatic ductal variant. *Ductal adenocarcinoma* - Would show **stricture or abrupt cut-off** of the pancreatic duct on ERCP, often associated with **upstream ductal dilatation**. - Commonly presents with **painless jaundice**, **weight loss**, and may demonstrate the **double-duct sign** (simultaneous dilatation of both pancreatic and bile ducts). *Double-duct sign* - This is a **radiological finding**, not a primary diagnosis, characterized by **simultaneous dilatation** of both the **pancreatic duct** and **common bile duct**. - Typically indicates **pancreatic head malignancy** or other obstructing lesions, but is a descriptive sign rather than a specific disease entity. *Annular pancreas* - ERCP would show **pancreatic tissue encircling the duodenum** with ductal anatomy that maintains communication between ventral and dorsal systems. - Typically presents with **duodenal obstruction** symptoms and shows a characteristic **ring-like configuration** around the second part of the duodenum on imaging.

Q: What is the investigation of choice for evaluating a renal mass?

CT scan. **Explanation:** The investigation of choice for evaluating a renal mass is a **Contrast-Enhanced Computed Tomography (CECT)** scan. CT is the gold standard because it provides superior anatomical detail, allowing for the characterization of the mass (solid vs. cystic), assessment of enhancement patterns (crucial for diagnosing Renal Cell Carcinoma), and staging (evaluation of local extension, lymphadenopathy, and venous involvement like renal vein or IVC thrombus). **Analysis of Options:** * **CT Scan (Correct):** It is highly sensitive and specific. A mass showing enhancement of >15–20 Hounsfield Units (HU) post-contrast is highly suggestive of malignancy (RCC). * **Plain X-ray (Incorrect):** It has very low sensitivity. It may only show indirect signs like an altered renal contour or incidental calcifications, but cannot characterize a mass. * **Intravenous Pyelogram (IVP) (Incorrect):** Historically used to visualize the collecting system, IVP is poor at evaluating parenchymal masses and has been largely replaced by CT Urography. * **Renal Scintigraphy (Incorrect):** Nuclear medicine (e.g., DMSA, DTPA) is used to assess renal function and scarring, not for the primary morphological evaluation of a suspected tumor. **High-Yield Clinical Pearls for NEET-PG:** * **Bosniak Classification:** Used on CT to categorize renal cysts (I and II are benign; III and IV require surgery). * **MRI:** Reserved for patients with contrast allergies, renal failure, or when evaluating the cephalad extent of an IVC thrombus. * **USG:** Usually the *initial* investigation (screening), but CT is the *investigation of choice* for definitive evaluation. * **Triphasic CT:** The protocol includes non-contrast, corticomedullary, and nephrographic phases for optimal lesion detection.

Q: A hysterosalpingogram showing a congenital mullerian anomaly is depicted. What is the most likely diagnosis?

Unicornuate uterus. ***Unicornuate uterus*** - HSG shows a **single banana-shaped uterine cavity** with **lateral deviation** to one side, distinguishing it from other anomalies. - Only **one fallopian tube** is visualized on HSG, as this represents incomplete development of one **Müllerian duct**. *Septate uterus* - HSG would show a **triangular-shaped fundal contour** with two separate cavities that converge at the cervix. - Both **fallopian tubes** are present and visible, unlike the single tube seen in unicornuate uterus. *Bicornuate uterus* - HSG demonstrates a **heart-shaped** or **Y-shaped** uterine cavity with an **obtuse angle** between the horns. - Both **uterine horns** and **fallopian tubes** are visualized, contrasting with the single cavity in unicornuate uterus. *Uterine didelphys* - HSG shows **two completely separate uterine cavities** with **two cervices** and often two vaginal canals. - Each cavity has its own **fallopian tube**, resulting in complete duplication rather than the single cavity of unicornuate uterus.

Q: Which of the following is NOT a feature of papillary necrosis?

Hyperdense nephrogram. **Explanation:** Renal Papillary Necrosis (RPN) is a condition characterized by ischemic necrosis of the renal papillae, most commonly associated with Diabetes Mellitus, Analgesic abuse, Sickle cell disease, and Pyelonephritis (Mnemonic: **POSTCARD**). **Why "Hyperdense Nephrogram" is the correct answer:** A hyperdense (or persistent) nephrogram is typically seen in conditions of acute tubular obstruction or stasis, such as **Acute Ureteral Obstruction** (e.g., stone), **Acute Tubular Necrosis (ATN)**, or **Contrast-induced Nephropathy**. It is not a feature of RPN. In RPN, the pathology involves the sloughing of papillae into the collecting system, leading to filling defects rather than a generalized increase in parenchymal density. **Analysis of Incorrect Options:** * **Egg in cup appearance:** This occurs in the "medullary" type of RPN where the central part of the papilla is necrotic, creating a cavity that fills with contrast, resembling an egg sitting in a cup-shaped calyx. * **Calyceal horns:** This refers to the extension of contrast into the tracks of the necrotic papilla, appearing as sharp, horn-like projections from the calyx. * **Ring shadows:** This is a classic sign seen on Intravenous Urography (IVU) when a sloughed papilla becomes detached and is surrounded by contrast medium in the calyx. **NEET-PG High-Yield Pearls:** * **Lobster Claw Sign:** Another name for the appearance of contrast tracking around a partially sloughed papilla. * **Ball-on-tee appearance:** Seen in the papillary type of RPN. * **Most common cause:** Diabetes Mellitus is the most frequent clinical association. * **Differential for Ring Shadows:** Sloughed papilla, non-opaque calculi, and blood clots.

Q: Which of the following signs is seen in Crohn's disease?

String sign of Kantor. **Explanation:** **String Sign of Kantor (Correct Answer):** This is a classic radiological sign seen on a Barium meal follow-through (BMFT) in patients with **Crohn’s disease**. It represents severe narrowing of the terminal ileum due to transmural inflammation, persistent spasm, and eventually, cicatricial fibrosis. The lumen becomes so constricted that it resembles a thin "string" of barium. It is most commonly associated with the stenotic phase of Crohn’s. **Analysis of Incorrect Options:** * **Strout’s Sign:** This refers to the thickening and straightening of the mucosal folds of the small bowel, often seen in **Malabsorption syndromes** (like Celiac disease) or Giardiasis. * **Pincer Sign (Claw Sign):** This is the characteristic appearance of **Intussusception** on a Barium enema. It occurs when the contrast outlines the leading edge of the intussusceptum (the prolapsed segment). * **Inverted 3 Sign (Frostberg’s Sign):** This is seen on a barium study of the duodenum in cases of **Carcinoma of the Head of the Pancreas** or chronic pancreatitis. The "3" shape is formed by the pressure of the enlarged pancreas on the medial wall of the duodenum. **High-Yield Clinical Pearls for NEET-PG:** * **Crohn’s Disease:** Other key signs include **Cobblestoning** (longitudinal/transverse ulcers), **Proud Flesh** (polypoid regeneration), and **Skip Lesions**. * **Ulcerative Colitis:** Look for the **Lead Pipe appearance** (loss of haustrations) and **Thumbprinting** (due to mucosal edema). * **Comb Sign:** On CT, this refers to prominent vasa recta in the mesentery, indicating active Crohn’s disease.

Question 1

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 2

Which of the following is NOT a cause of pneumoperitoneum?

Accepted Answer

Laparoscopy

Answer

Subdiaphragmatic fat

Answer

Chilaiditi syndrome

Answer

Subphrenic abscess

Question 3

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

Question 4

Which of the following is NOT radioopaque?

Accepted Answer

Uric acid

Answer

Oxalate

Answer

Cystine

Answer

Mixed

Question 5

The triad of vomiting, abdominal distension, and a "string of beads" sign on abdominal X-ray is typically suggestive of what condition?

Accepted Answer

Small bowel obstruction

Answer

Duodenal atresia

Answer

Large bowel obstruction

Answer

Gastric volvulus

Question 6

A 40-year-old woman presents with abdominal pain. Two films from an ERCP are shown. What is the MOST likely diagnosis?

Accepted Answer

Pancreas divisum

Answer

Ductal adenocarcinoma

Answer

Double-duct sign

Answer

Annular pancreas

Question 7

What is the investigation of choice for evaluating a renal mass?

Accepted Answer

CT scan

Answer

Plain X-ray

Answer

IVP

Answer

Renal scintigraphy

Question 8

A hysterosalpingogram showing a congenital mullerian anomaly is depicted. What is the most likely diagnosis?

Accepted Answer

Unicornuate uterus

Answer

Septate uterus

Answer

Bicornuate uterus

Answer

Uterine didelphys

Question 9

Which of the following is NOT a feature of papillary necrosis?

Accepted Answer

Hyperdense nephrogram

Answer

Egg in cup appearance

Answer

Calyceal horns

Answer

"Ring shadows"

Question 10

Which of the following signs is seen in Crohn's disease?

Accepted Answer

String sign of Kantor

Answer

Strout's sign

Answer

Pincer sign

Answer

Inverted 3 sign

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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