Abdominal and Pelvic Radiology Practice Questions

Q: Minimal ascites can be best detected by which imaging modality?

Ultrasound (USG). **Explanation:** **1. Why Ultrasound (USG) is the Correct Answer:** Ultrasound is the most sensitive and preferred initial modality for detecting minimal ascites. It can detect as little as **5–10 mL** of fluid in the peritoneal cavity. Its high sensitivity is due to the fact that fluid is anechoic (black), providing a sharp contrast against the echogenic (bright) surfaces of the liver and pelvic organs. The best site to detect minimal fluid in a supine patient is **Morison’s pouch** (hepatorenal recess) or the **Pouch of Douglas** in the pelvis. **2. Why Other Options are Incorrect:** * **Plain X-ray Abdomen:** This is the least sensitive modality. Ascites only becomes visible on X-ray when the volume exceeds **500–1000 mL**. Signs like "ground-glass appearance" or "Dog’s ear sign" (fluid in the paravesical fossae) indicate massive, not minimal, ascites. * **CT Scan:** While CT is highly accurate and can detect small amounts of fluid (approx. 30 mL), it is not the "best" first-line choice due to ionizing radiation, higher cost, and the fact that USG is more sensitive for trace amounts of free fluid. * **MRI:** Although sensitive, MRI is never the primary modality for detecting ascites due to its high cost, lack of portability, and long scan times. **3. High-Yield Clinical Pearls for NEET-PG:** * **Minimum fluid for clinical detection:** 500–1500 mL (via shifting dullness). * **Puddle Sign:** A physical exam maneuver used to detect small amounts of fluid (approx. 120 mL), though USG remains superior. * **FAST Scan (Focused Assessment with Sonography for Trauma):** Uses USG to quickly identify hemoperitoneum (blood) in the perihepatic, perisplenic, pelvic, and pericardial spaces. * **Order of sensitivity for fluid detection:** USG > CT > Clinical Exam > X-ray.

Q: Balthazar grading is used for acute pancreatitis based on findings on which imaging modality?

Computed Tomography (CT). **Explanation:** The **Balthazar score** is a radiological grading system used to assess the severity of **acute pancreatitis** specifically based on **Contrast-Enhanced Computed Tomography (CECT)** findings. It evaluates the presence of pancreatic inflammation and peripancreatic fluid collections to predict prognosis and the risk of complications. **Why CT is the correct answer:** CECT is the gold standard for diagnosing complications of acute pancreatitis. The Balthazar grading (Grades A to E) assesses the size, shape, and contour of the pancreas along with the number of fluid collections. When combined with the degree of pancreatic necrosis, it forms the **CT Severity Index (CTSI)**, which correlates strongly with patient morbidity and mortality. **Why other options are incorrect:** * **Ultrasound (USG):** While often the first-line investigation to look for gallstones (etiology), USG is limited by overlying bowel gas and cannot accurately grade the severity or necrosis of the pancreas. * **MRI:** Though MRI (MRCP) is excellent for visualizing the biliary tree and detecting "walled-off necrosis," the Balthazar score was historically developed and validated specifically for CT. * **ERCP:** This is an invasive therapeutic procedure used to remove ductal stones or place stents; it is not a diagnostic grading tool for parenchymal inflammation. **High-Yield Clinical Pearls for NEET-PG:** * **Balthazar Grades:** A (Normal), B (Enlargement), C (Inflammation/Peripancreatic fat stranding), D (Single fluid collection), E (Two or more collections or gas). * **CT Severity Index (CTSI):** Balthazar Score (0–4 points) + Necrosis Score (0–6 points). A score of 7–10 indicates severe disease. * **Timing:** CECT is most accurate for assessing necrosis **48–72 hours** after the onset of symptoms. * **Modified CTSI:** A newer version that includes extrapancreatic complications (e.g., pleural effusion, ascites).

Q: Which investigation is used for assessing the proper functioning of the biliary system?

All of the above. **Explanation:** The assessment of the biliary system requires a multi-modal approach to evaluate both **anatomy** (structure) and **physiology** (function). 1. **Ultrasound (USG):** This is the **initial investigation of choice** for the biliary system. It is highly sensitive for detecting anatomical abnormalities such as gallstones (cholelithiasis), gallbladder wall thickening (cholecystitis), and biliary ductal dilatation. By observing gallbladder contraction after a fatty meal, it also provides a basic assessment of function. 2. **CT Scan:** While less sensitive than USG for gallstones, CT is superior for evaluating the distal common bile duct, detecting peri-ampullary tumors, and identifying complications like perforation or abscess formation. It assesses the patency and flow within the biliary tree. 3. **HIDA Scan (Hepatobiliary Iminodiacetic Acid Scan):** This is a nuclear medicine study and is the **gold standard for assessing biliary function**. It tracks the production and flow of bile from the liver into the gallbladder and small intestine. It is specifically used to diagnose **Acute Cholecystitis** (demonstrated by non-visualization of the gallbladder) and **Biliary Atresia** in neonates. Since all three modalities contribute essential information regarding the structural integrity and functional patency of the biliary tract, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **IOC (Investigation of Choice) for Gallstones:** Ultrasound. * **Most Sensitive/Gold Standard for Acute Cholecystitis:** HIDA Scan. * **Best for Biliary Atresia:** HIDA Scan (after 5 days of Phenobarbitone priming). * **Best for Choledocholithiasis (Non-invasive):** MRCP (Magnetic Resonance Cholangiopancreatography).

Q: The nephrogram phase of an intravenous pyelogram (IVP) is due to dye in which part of the kidney?

Proximal convoluted tubules. **Explanation:** The **Nephrogram Phase** is the initial stage of an Intravenous Pyelogram (IVP), occurring within 1–3 minutes after the injection of contrast medium. **Why Proximal Convoluted Tubules (PCT) is correct:** The contrast used in IVP (water-soluble iodinated contrast) is filtered by the glomerulus. Once filtered, it enters the renal tubules. The "blush" or opacification of the renal parenchyma seen during the nephrogram phase is primarily due to the high concentration of contrast medium within the **proximal convoluted tubules**. Because the PCTs make up the bulk of the renal cortex, their opacification creates the characteristic dense appearance of the kidney before the dye moves into the drainage system. **Analysis of Incorrect Options:** * **Renal Pelvis:** Opacification of the renal pelvis occurs during the **Pyelogram Phase** (usually after 5–10 minutes), representing the excretory stage where contrast collects in the calyces and pelvis. * **Nephron:** While the PCT is part of the nephron, "Nephron" is too broad a term. The nephrogram specifically highlights the tubular concentration, particularly in the cortex (PCT). * **Collecting Tubules:** These are located deeper in the medulla and lead to the renal papillae. Contrast reaches these later than the PCT; their opacification contributes more to the late nephrogram and early pyelogram phase. **High-Yield Clinical Pearls for NEET-PG:** * **Immediate/Early Nephrogram:** Seen in acute ureteric obstruction (e.g., calculus). * **Persistent/Increasingly Dense Nephrogram:** Classic sign of **Acute Tubular Necrosis (ATN)** or severe hypotension. * **Rim Nephrogram:** Characteristic of **Hydronephrosis** (contrast outlines the compressed parenchyma). * **Striated Nephrogram:** Often seen in **Acute Pyelonephritis** or renal vein thrombosis.

Q: The 'Adderhead' appearance is seen in which of the following conditions?

Ureterocele. **Explanation:** The **'Adderhead' appearance** (also known as the **Cobra-head sign**) is a classic radiological finding seen on an Intravenous Pyelogram (IVP) or contrast-enhanced CT. It represents a **simple ureterocele**, which is a congenital cystic dilatation of the distal-most intramural portion of the ureter. **Why it occurs:** The appearance is created by the contrast-filled, dilated distal ureter (the "head" of the cobra/adder) surrounded by a thin, radiolucent halo. This halo represents the combined thickness of the ureteral wall and the bladder mucosa, protruding into the bladder lumen. **Analysis of Incorrect Options:** * **Vesical diverticula:** These appear as contrast-filled outpouchings extending *outside* the bladder wall, often described as "ears" in children (bladder ears). * **Carcinoma of the urinary bladder:** Typically presents as an irregular, fixed filling defect within the bladder lumen, lacking the characteristic symmetrical halo of a ureterocele. * **Urethral stricture:** This is an obstructive lesion of the urethra, best visualized on a Retrograde Urethrogram (RGU) as a segment of narrowing, not as a bladder filling defect. **High-Yield Clinical Pearls for NEET-PG:** * **Cobra-head sign:** Pathognomonic for **simple (adult-type)** ureteroceles. * **Ectopic ureteroceles:** More common in children and often associated with a **duplicated collecting system** (Weigert-Meyer Law: the upper pole ureter inserts ectopically and prone to ureterocele). * **Reverse Cobra-head sign:** Can be seen in cases of bladder tumors or stones mimicking the appearance, but the lucent halo is usually thicker or irregular. * **Management:** Asymptomatic cases require no treatment; symptomatic cases (UTI, stones) are managed via endoscopic transurethral incision.

Q: A gas shadow in the heart and great vessels appears in which condition?

Intrauterine device (IUD). **Explanation:** The presence of gas shadows within the fetal heart and great vessels on an X-ray or ultrasound is known as **Robert’s Sign**. This is a classic radiological indicator of **Intrauterine Fetal Death (IUFD)**. 1. **Why Option A is Correct:** In the context of this question, "Intrauterine device" (IUD) is often used interchangeably with **Intrauterine Death** in older or specific exam terminologies (though "IUFD" is the standard clinical term). When a fetus dies in utero, anaerobic autolysis of fetal blood occurs, leading to the release of gas (primarily nitrogen) into the circulatory system. Robert’s Sign is one of the earliest radiological signs of fetal death, appearing as early as 12 hours after the event. 2. **Why Other Options are Incorrect:** * **Abortion:** While fetal death occurs in a missed abortion, the term "abortion" refers to the termination of pregnancy before viability. Robert’s Sign is specifically associated with the radiological evaluation of a more advanced fetus (IUFD). * **Stillbirth:** This is a clinical outcome (a baby born dead after 24 weeks). While a stillborn fetus may have shown Robert’s Sign in utero, the sign itself is a diagnostic tool used to confirm death *before* delivery. **High-Yield Clinical Pearls for NEET-PG:** * **Robert’s Sign:** Gas in fetal heart/vessels (earliest sign, ~12 hours). * **Spalding’s Sign:** Overlapping of fetal skull bones due to loss of liquor and brain liquefaction (appears after 2–7 days). * **Deuel’s Halo Sign:** Edema of fetal scalp causing elevation of the subcutaneous fat layer (indicates fetal distress/death). * **Ball’s Sign:** Abnormal acute angulation of the fetal spine.

Q: Whirlpool sign is a characteristic feature of which of the following conditions?

Midgut volvulus. **Explanation:** The **Whirlpool Sign** is a classic radiological finding most commonly associated with **Midgut Volvulus**. It occurs when the bowel loops and the mesenteric vessels (specifically the Superior Mesenteric Vein and its tributaries) wrap around the narrow stalk of the Superior Mesenteric Artery (SMA). On Ultrasound or CT, this creates a swirling, clockwise pattern of soft tissue and vessel shadows. **Why the correct answer is right:** * **Midgut Volvulus:** In cases of intestinal malrotation, the mesentery has a narrow base, making it prone to twisting. The "whirlpool" represents the torsion of the mesentery and the SMV around the fixed SMA. This is a surgical emergency often presenting in neonates with bilious vomiting. **Why the other options are wrong:** * **Sigmoid Volvulus:** Characterized by the **"Coffee Bean Sign"** or **"Omega Sign"** on X-ray. While a "whirl" can sometimes be seen on CT, the "Whirlpool Sign" is the hallmark description for Midgut Volvulus in medical exams. * **Intussusception:** Classically presents with the **"Target Sign"** or **"Donut Sign"** on transverse USG/CT and the **"Pseudokidney Sign"** on longitudinal views. * **Diverticulosis:** Typically presents with small, out-pouchings of the colonic wall (saw-tooth appearance) and does not involve mesenteric torsion. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation:** Upper GI Contrast Study (Barium Swallow/Meal) showing a **"Corkscrew appearance"** of the duodenum. * **Ladd’s Procedure:** The definitive surgical treatment for malrotation/volvulus. * **Vessel Orientation:** On Ultrasound, a reversal of the normal relationship between the SMA and SMV (SMV located to the left of SMA) is highly suggestive of malrotation.

Q: What is the investigation of choice for detecting small para-aortic lymph nodes?

CT scan. **Explanation:** **CT scan** is the investigation of choice for detecting small para-aortic lymph nodes because of its superior spatial resolution and ability to visualize the retroperitoneum without interference from overlying bowel gas. It allows for precise measurement of the short-axis diameter of nodes (typically considered pathological if >10 mm) and can detect changes in nodal density or morphology. Contrast-enhanced CT (CECT) further helps in differentiating lymph nodes from adjacent vascular structures. **Why other options are incorrect:** * **Ultrasound scan:** While useful for screening, it is highly operator-dependent. It often fails to visualize the para-aortic region adequately due to interference from overlying bowel gas or patient habitus (obesity). * **Lymphangiography:** Historically, this was the gold standard for evaluating nodal internal architecture. However, it is an invasive, technically difficult procedure involving the injection of oil-based contrast into lymphatic vessels. It has been almost entirely replaced by non-invasive cross-sectional imaging (CT/MRI). * **Arteriography:** This is used to visualize the lumen of arteries. While it may show displacement of vessels by massive nodal bulk, it cannot visualize the lymph nodes themselves. **Clinical Pearls for NEET-PG:** * **Gold Standard for Nodal Staging:** While CT is the "investigation of choice" for size and location, **PET-CT** is superior for detecting metastasis in normal-sized nodes (functional imaging). * **MRI:** Preferred over CT in patients with contrast allergies or for specific pelvic malignancies (e.g., Rectal or Cervical cancer) due to better soft-tissue contrast. * **Nodal Size Cut-off:** In the abdomen, a short-axis diameter **>10 mm** is generally the threshold for considering a lymph node suspicious for malignancy or infection.

Q: Spoked wheel appearance is seen in which of the following conditions?

Oncocytoma. **Explanation:** The **Spoked Wheel Appearance** is a classic radiological and pathological descriptor for **Renal Oncocytoma**, a benign epithelial tumor of the kidney. **1. Why Oncocytoma is correct:** The "spoke-wheel" pattern refers to the specific vascular arrangement seen on angiography or contrast-enhanced CT. It is caused by the presence of a **central stellate scar** with vessels radiating peripherally toward the tumor capsule. While highly characteristic, it is not pathognomonic, as it can occasionally be seen in Renal Cell Carcinoma (RCC), making pre-operative differentiation challenging. **2. Why the other options are incorrect:** * **Wilm’s Tumor (Nephroblastoma):** Typically presents as a large, heterogeneous mass in children. Its classic radiological sign is the **"Claw Sign"** (normal kidney parenchyma wrapping around the tumor). * **Hydronephrosis:** Characterized by the dilatation of the renal pelvis and calyces. On imaging, it appears as a fluid-filled branching structure, often described as a **"Bear Paw Appearance"** in severe cases (specifically Xanthogranulomatous Pyelonephritis). * **Polycystic Kidney Disease (ADPKD):** Presents as bilateral, massively enlarged kidneys replaced by multiple cysts of varying sizes. It does not exhibit a radial vascular pattern. **Clinical Pearls for NEET-PG:** * **Oncocytoma:** Originates from **intercalated cells** of collecting ducts. On Gross pathology, it shows a mahogany brown color due to excessive mitochondria. * **Angiography:** The "Spoke-wheel" sign is best visualized during the arterial phase of a renal angiogram. * **Differential Diagnosis:** The most important mimic is **Chromophobe RCC**; both share similar histological features (eosinophilic cytoplasm).

Q: Non-contrast spiral CT is the investigation of choice for which of the following conditions?

Acute ureteric colic. **Explanation:** **Non-contrast Computed Tomography (NCCT)** of the abdomen and pelvis, specifically using a spiral (helical) technique, is the gold standard and investigation of choice for **acute ureteric colic**. 1. **Why Option A is Correct:** NCCT has a sensitivity and specificity of over 95% for detecting urolithiasis. It can identify almost all types of stones (including radiolucent stones like uric acid stones, which are missed on X-ray KUB) as they appear hyperdense. The spiral technique allows for rapid imaging without respiratory gaps, enabling the detection of even tiny calculi and secondary signs of obstruction like hydroureter, hydronephrosis, or "stranding" of perinephric fat. 2. **Why Other Options are Incorrect:** * **Acute Pulmonary Embolism:** The investigation of choice is **CT Pulmonary Angiography (CTPA)**, which requires intravenous (IV) iodinated contrast to opacify the pulmonary arteries. * **Acute Mesenteric Ischemia:** The gold standard is **CT Angiography** (with IV contrast) to visualize arterial occlusions, venous thrombosis, and bowel wall enhancement patterns. * **Acute Prolapsed Intervertebral Disc (PIVD):** **MRI** is the investigation of choice due to its superior soft-tissue contrast, allowing for better visualization of the nerve roots, thecal sac, and the disc material itself. **High-Yield Clinical Pearls for NEET-PG:** * **Only stone not seen on NCCT:** Indinavir stones (protease inhibitor-induced) are the only urinary stones that are typically isodense to urine and may not be seen on CT. * **Phleboliths vs. Calculi:** On NCCT, a "comet tail sign" suggests a phlebolith (pelvic vein calcification), while a "rim sign" (edema around the stone) confirms a ureteric calculus. * **Radiation Safety:** For follow-up or in pregnant/pediatric patients, Ultrasound is the initial screening tool, though NCCT remains the most definitive.

Question 1

Minimal ascites can be best detected by which imaging modality?

Accepted Answer

Ultrasound (USG)

Answer

Plain X-ray abdomen

Answer

Magnetic Resonance Imaging (MRI)

Answer

Computed Tomography (CT) Scan

Question 2

Balthazar grading is used for acute pancreatitis based on findings on which imaging modality?

Accepted Answer

Computed Tomography (CT)

Answer

Ultrasound (USG)

Answer

Magnetic Resonance Imaging (MRI)

Answer

Endoscopic Retrograde Cholangiopancreatography (ERCP)

Question 3

Which investigation is used for assessing the proper functioning of the biliary system?

Accepted Answer

All of the above

Answer

Ultrasound (USG)

Answer

CT scan

Answer

HIDA scan

Question 4

The nephrogram phase of an intravenous pyelogram (IVP) is due to dye in which part of the kidney?

Accepted Answer

Proximal convoluted tubules

Answer

Renal pelvis

Answer

Nephron

Answer

Collecting tubules

Question 5

The 'Adderhead' appearance is seen in which of the following conditions?

Accepted Answer

Ureterocele

Answer

Vesical diverticula

Answer

Carcinoma of the urinary bladder

Answer

Urethral stricture

Question 6

A gas shadow in the heart and great vessels appears in which condition?

Accepted Answer

Intrauterine device (IUD)

Answer

Abortion

Answer

Stillbirth

Answer

None of the above

Question 7

Whirlpool sign is a characteristic feature of which of the following conditions?

Accepted Answer

Midgut volvulus

Answer

Sigmoid volvulus

Answer

Intussusception

Answer

Diverticulosis

Question 8

What is the investigation of choice for detecting small para-aortic lymph nodes?

Accepted Answer

CT scan

Answer

Ultrasound scan

Answer

Lymphangiography

Answer

Arteriography

Question 9

Spoked wheel appearance is seen in which of the following conditions?

Accepted Answer

Oncocytoma

Answer

Wilm's tumor

Answer

Hydronephrosis

Answer

Polycystic kidney disease

Question 10

Non-contrast spiral CT is the investigation of choice for which of the following conditions?

Accepted Answer

Acute ureteric colic

Answer

Acute pulmonary embolism

Answer

Acute mesenteric ischemia

Answer

Acute prolapsed intervertebral disc

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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