Abdominal and Pelvic Radiology Practice Questions

Q: What is the investigation of choice to detect a 4 mm nodule in the pancreas?

Endoscopic USG. **Explanation:** The correct answer is **Endoscopic Ultrasound (EUS)**. **Why EUS is the Investigation of Choice:** The pancreas is a retroperitoneal organ, making it difficult to visualize small lesions via transabdominal ultrasound due to overlying bowel gas. EUS involves placing a high-frequency transducer in the stomach or duodenum, directly adjacent to the pancreas. This proximity allows for the use of high-frequency sound waves, providing **superior spatial resolution**. EUS is currently the most sensitive modality for detecting small pancreatic lesions (<2 cm), with a sensitivity exceeding 90-95%, whereas CT and MRI often miss nodules smaller than 1 cm. **Analysis of Incorrect Options:** * **PET Scan:** While useful for detecting metabolic activity and distant metastasis, PET has poor spatial resolution and is not indicated for the primary detection of tiny anatomical nodules. * **CECT (Contrast-Enhanced CT):** This is the "gold standard" for staging and assessing resectability of pancreatic cancer, but its sensitivity drops significantly for lesions smaller than 10 mm. * **MRI/MRCP:** Excellent for characterizing ductal anatomy and cystic lesions, but it remains less sensitive than EUS for detecting solid nodules in the 4–5 mm range. **High-Yield Clinical Pearls for NEET-PG:** * **EUS-FNA:** EUS not only detects the nodule but also allows for **Fine Needle Aspiration (FNA)** for cytological confirmation, making it the most accurate diagnostic tool. * **Insulinomas:** For small, occult neuroendocrine tumors (like insulinomas) not seen on CT, EUS is the investigation of choice. * **Double Duct Sign:** On imaging, the simultaneous dilatation of the common bile duct and pancreatic duct suggests a lesion in the head of the pancreas or ampulla.

Q: Which of the following conditions is characterized by a trifoliate appearance?

Peptic ulcer. **Explanation:** The **trifoliate appearance** (also known as the **clover-leaf deformity**) is a classic radiological sign seen on a Barium meal study in patients with **chronic duodenal ulcers**. This appearance occurs due to the healing and cicatrization of a chronic ulcer in the duodenal bulb. The "leaves" of the clover are formed by the central ulcer crater (niche) surrounded by three components: the pre-stenotic outpouching, the post-stenotic outpouching, and the contraction of the bulb itself. **Analysis of Options:** * **A. CHPS (Congenital Hypertrophic Pyloric Stenosis):** Characterized by the **"String sign"** (narrowed pyloric canal), **"Beak sign,"** and **"Mushroom sign"** on Barium studies. * **B. Achalasia Cardia:** Classically presents with a **"Bird’s beak"** or **"Rat-tail"** appearance of the distal esophagus due to failure of the lower esophageal sphincter to relax. * **D. Pneumoperitoneum:** Characterized by the **"Gas under the diaphragm"** sign on an erect X-ray or the **"Rigler sign"** (gas on both sides of the bowel wall) on a supine film. **High-Yield Clinical Pearls for NEET-PG:** * **Duodenal Ulcer:** Most common site is the first part of the duodenum (duodenal bulb). * **Giant Duodenal Ulcer:** Defined as an ulcer >2 cm; it can mimic the entire duodenal bulb on imaging. * **Zollinger-Ellison Syndrome:** Suspect if ulcers are multiple, distal to the duodenal bulb, or refractory to treatment. * **Barium Meal Contraindication:** Never perform a Barium study if perforation is suspected (use water-soluble contrast like Gastrografin instead).

Q: A 72-year-old man presents with increasing dyspepsia and weight loss. His physical examination is unremarkable. A barium meal is performed. The oesophagus is normal, but a 'bull's eye' lesion is noted in the gastric mucosa. Which one of the following is not a recognised cause of this appearance?

Magenstrasse. ### Explanation The **'bull’s eye' lesion** (also known as a **target lesion**) on a barium meal refers to a central collection of barium (representing an ulcer or umbilication) surrounded by a radiolucent halo (representing a mass or elevated mucosal rim). #### Why Magenstrasse is the Correct Answer **Magenstrasse** (German for "stomach road") is a normal anatomical variant. It refers to the longitudinal mucosal folds along the **lesser curvature** of the stomach that form a physiological channel for the passage of liquids. It is a normal finding and does **not** produce a target or bull's eye appearance. #### Analysis of Incorrect Options (Causes of Bull's Eye Lesion) * **Gastrointestinal Stromal Tumour (GIST):** These are intramural mesenchymal tumours that often undergo central necrosis or pressure necrosis of the overlying mucosa, leading to a central ulceration on a subepithelial mass. * **Melanoma Metastases:** Melanoma is the most common source of hematogenous metastases to the GI tract. These typically present as multiple submucosal nodules with central ulceration, creating the classic "target" appearance. * **Gastric Carcinoma:** While less common than GIST or metastases, a necrotic polypoid adenocarcinoma or a primary gastric lymphoma can present with central ulceration mimicking a bull's eye. #### NEET-PG High-Yield Pearls * **Differential Diagnosis for Bull’s Eye Lesion:** 1. **Metastases:** Melanoma (most common), Breast, Lung. 2. **Subepithelial Tumours:** GIST, Leiomyoma, Neurofibroma. 3. **Inflammatory:** Eosinophilic granuloma, Kaposi sarcoma (in HIV patients). * **Magenstrasse** is significant because it is the site where most gastric ulcers occur, but it is not a "lesion" itself. * **Barium Meal Tip:** A "double-contoured" appearance or "target sign" always suggests a central ulceration within a mass.

Q: A 5-year-old child presents with gas under the diaphragm. What is the most likely diagnosis?

All of the above. **Explanation:** The presence of **gas under the diaphragm** on an erect X-ray is the hallmark sign of **pneumoperitoneum** (free intraperitoneal air). In a pediatric patient, this finding can result from various pathological, anatomical, or procedural causes. 1. **Enteric Fever (Typhoid):** This is a common cause of secondary peritonitis in children in developing countries. *Salmonella typhi* causes hyperplasia and subsequent necrosis of Peyer's patches in the terminal ileum, leading to **intestinal perforation**, typically in the second or third week of illness. 2. **Chilaiditi’s Syndrome:** This is a "pseudopneumoperitoneum." It occurs when a loop of colon (usually the hepatic flexure) is transposed between the liver and the right hemidiaphragm. On X-ray, it mimics gas under the diaphragm, but can be distinguished by the presence of **haustral markings** within the gas shadow. 3. **Iatrogenic Pneumoperitoneum:** This refers to air introduced during medical interventions, such as recent abdominal surgery, laparoscopy, or even aggressive mechanical ventilation (leading to air tracking from the thorax). **Why "All of the above" is correct:** All three conditions can present with the radiographic appearance of air (or apparent air) beneath the diaphragm. In a clinical exam setting, unless specific symptoms (like fever or recent surgery) are provided, all these etiologies remain differential diagnoses. **Clinical Pearls for NEET-PG:** * **Most sensitive view for pneumoperitoneum:** Left lateral decubitus (can detect as little as 1-2 ml of air). * **Rigler’s Sign:** Seeing both sides of the bowel wall due to free intraperitoneal air. * **Football Sign:** A large collection of air outlining the entire peritoneal cavity (common in neonatal bowel perforation). * **Cupola Sign:** Air trapped under the central tendon of the diaphragm.

Q: A 13-year-old boy presents with pain in the lower right tooth region with no remarkable medical history. On intraoral examination, tooth 85 was found to be carious and did not respond to EPT. Radiographs show changes in the apical region. What is the most probable diagnosis?

Radicular cyst. ### Explanation **Correct Answer: B. Radicular cyst** The clinical presentation describes a non-vital tooth (negative EPT response) with caries and periapical changes. A **Radicular cyst** (also known as a Periapical cyst) is the most common odontogenic cyst. It arises from the **epithelial rests of Malassez** in the periodontal ligament as a result of inflammation following pulp necrosis (due to caries or trauma). **Why it is the correct answer:** * **Pathogenesis:** Caries → Pulpitis → Pulp Necrosis (Non-vital tooth) → Periapical Periodontitis → Radicular Cyst. * **Radiology:** It typically appears as a well-defined, unilocular radiolucency at the apex of a non-vital tooth. * **Clinical Clue:** The negative Electric Pulp Test (EPT) is the definitive sign of a non-vital tooth, which is a prerequisite for a radicular cyst. **Why other options are incorrect:** * **Apical Granuloma:** While also associated with non-vital teeth, granulomas are usually smaller (<1.5 cm) and lack the distinct epithelial lining and cortical expansion often seen in larger cysts. Differentiation often requires histopathology. * **Odontogenic Keratocyst (OKC):** These typically arise from the dental lamina, are often associated with impacted teeth (especially third molars), and the involved teeth are usually **vital**. * **Lateral Periodontal Cyst:** These occur on the lateral aspect of the root and are associated with **vital** teeth. They arise from the remnants of the dental lamina. **High-Yield NEET-PG Pearls:** * **Most common odontogenic cyst:** Radicular Cyst. * **Origin:** Epithelial rests of Malassez. * **Key Diagnostic Feature:** Must be associated with a **non-vital tooth**. * **Histology:** Characterized by Rushton bodies (eosinophilic linear/curved inclusions). * **Treatment:** Root canal treatment (RCT) or extraction with cyst enucleation.

Q: Omental caking on CT scan suggests a high possibility of which of the following conditions?

Ovarian tumor. **Explanation:** **Omental Caking** is a classic radiological sign characterized by the infiltration of the greater omentum by solid soft-tissue masses, replacing the normal low-attenuation omental fat. On a CT scan, this appears as a thickened, nodular, or pancake-like soft tissue layer between the anterior abdominal wall and the bowel loops. **Why Ovarian Tumor is the Correct Answer:** The most common cause of omental caking is **peritoneal carcinomatosis**. Among all malignancies, **epithelial ovarian cancer** (especially serous cystadenocarcinoma) is the most frequent cause. This occurs because ovarian cancer cells shed directly into the peritoneal cavity and follow the natural flow of peritoneal fluid, eventually seeding and proliferating on the omentum. **Analysis of Incorrect Options:** * **A, B, and C (Colon, Pancreas, and Stomach Carcinoma):** While these gastrointestinal malignancies can lead to peritoneal seeding and omental involvement, they are statistically less common causes of a classic "omental cake" compared to ovarian cancer. These tumors more frequently present with localized nodal spread or hematogenous metastasis (e.g., to the liver) before extensive peritoneal thickening occurs. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis:** Apart from ovarian cancer, omental caking can also be seen in **Tuberculous Peritonitis** (look for high-adenosine deaminase levels and "wet" vs. "dry" patterns) and **Lymphoma**. * **Imaging Feature:** On CT, look for the "Smudged Fat" sign, which is an early precursor to a full omental cake. * **Management:** In the context of ovarian cancer, the presence of omental caking often necessitates an **omentectomy** as part of cytoreductive surgery. * **Psammoma Bodies:** If the primary is a serous ovarian tumor, the omental cake may show fine, sand-like calcifications on CT.

Q: The CT severity index in acute pancreatitis is described by which scoring system?

Balthazar. **Explanation:** The **Balthazar Score** (CT Severity Index - CTSI) is the gold standard for assessing the severity of acute pancreatitis using contrast-enhanced CT. It combines two parameters to predict morbidity and mortality: 1. **Balthazar Grade (0–4 points):** Evaluates peripancreatic inflammation and fluid collections (Grades A to E). 2. **Pancreatic Necrosis (0–6 points):** Quantifies the percentage of non-enhancing pancreatic parenchyma. A total score of 7–10 indicates severe disease with a high risk of complications and mortality. **Analysis of Incorrect Options:** * **B. Mengini:** Refers to the **Menghini technique**, which is a "one-second" needle biopsy method used primarily for liver biopsies. * **C. Chapman:** There is no standard "Chapman" scoring system in radiology; however, Chapman’s points are used in osteopathic medicine to denote viscerosomatic reflexes. * **D. Napelon:** This is a distractor and does not correspond to any recognized medical classification or scoring system. **High-Yield Facts for NEET-PG:** * **Modified CTSI (Mortele et al.):** An updated version that includes extrapancreatic complications (e.g., pleural effusion, ascites, vascular complications) and simplifies necrosis assessment. * **Timing:** CT is most accurate for assessing necrosis **72–96 hours** after the onset of symptoms. * **Balthazar Grade E:** Defined by the presence of two or more fluid collections or gas within the pancreas/retroperitoneum. * **Clinical Correlation:** While CTSI assesses local complications, the **Ranson Criteria** or **APACHE II** scores are used for clinical/systemic severity.

Q: What is the investigation of choice (IOC) for polycystic kidney disease?

Ultrasound (USG). **Explanation:** **1. Why Ultrasound (USG) is the Correct Choice:** Ultrasound is the **Investigation of Choice (IOC)** and the primary screening tool for Polycystic Kidney Disease (PKD), particularly Autosomal Dominant PKD (ADPKD). It is preferred because it is non-invasive, cost-effective, widely available, and involves **no ionizing radiation**—which is crucial since patients require lifelong monitoring. The diagnosis is based on the **Ravine Criteria** (modified as Pei-Levy criteria), which uses the number of cysts relative to the patient's age to confirm the diagnosis. **2. Why Other Options are Incorrect:** * **MRI:** While MRI is the most *sensitive* modality for detecting very small cysts (<2mm) and is the gold standard for measuring **Total Kidney Volume (TKV)** to predict disease progression, it is not the initial IOC due to high cost and limited accessibility. * **CECT:** CECT provides excellent anatomical detail but is not preferred for routine diagnosis due to radiation exposure and the risk of **Contrast-Induced Nephropathy (CIN)** in patients who may already have declining renal function. * **IVU:** This is an outdated modality. While it may show a "Swiss Cheese" appearance or "Spider Leg" deformity of the calyces, it has been entirely replaced by cross-sectional imaging. **3. High-Yield Clinical Pearls for NEET-PG:** * **ADPKD:** Associated with **PKD1** (Chr 16 - more severe) and **PKD2** (Chr 4) mutations. * **Extra-renal manifestations:** Most common is **Liver cysts**; most serious is **Berry Aneurysm** (Circle of Willis). * **ARPKD:** Presents in infancy with bilateral enlarged echogenic kidneys and is associated with **Congenital Hepatic Fibrosis**. * **Imaging Sign:** On USG, ADPKD shows large kidneys with multiple bilateral cysts of varying sizes. On IVU, it shows the **"Swiss Cheese" appearance**.

Q: A 44-year-old man with a history of quadriplegia presented to the emergency department with symptoms of a urinary tract infection. What is the diagnosis?

Neurogenic megacolon. ***Neurogenic megacolon*** - **Quadriplegia** results in **neurogenic bowel dysfunction** due to loss of autonomic control, leading to **massive colonic dilatation** and impaired motility. - The **spinal cord injury** disrupts the **parasympathetic** and **sympathetic** innervation of the colon, causing functional obstruction and toxic megacolon-like appearance. *Bladder perforation* - Would present with **acute abdominal pain**, **peritonitis**, and **free fluid** on imaging, not colonic dilatation. - Associated with **contrast extravasation** on CT urography or cystography, which is not consistent with this presentation. *Chronic constipation* - Typically shows **fecal impaction** with **moderate colonic dilatation** but not the **massive dilatation** seen in neurogenic megacolon. - Usually involves the **rectosigmoid region** primarily, whereas neurogenic megacolon affects the **entire colon** uniformly. *Gastric distention* - Would show **enlarged stomach** with **air-fluid levels**, not colonic involvement as seen in this case. - Associated with **gastroparesis** or **bowel obstruction**, but does not explain the **colonic changes** typical of spinal cord injury complications.

Q: Which structure is outlined with contrast on a CT scan using intraperitoneal contrast material?

Ovary. **Explanation:** The core concept tested here is the anatomical distinction between **intraperitoneal** and **extraperitoneal (retroperitoneal/subperitoneal)** structures. **Why Ovary is Correct:** The **ovaries** are unique because they are the only organs in the human body that are truly "intraperitoneal" but not covered by visceral peritoneum (they are covered by germinal epithelium). They are suspended within the peritoneal cavity by the mesovarium. When contrast material is injected into the peritoneal cavity (intraperitoneal contrast), it surrounds and outlines all structures located within that space. Therefore, the ovary will be clearly outlined by the contrast. **Why the other options are incorrect:** * **Prostate:** This is a **subperitoneal** (extraperitoneal) organ located below the pelvic floor. It is separated from the peritoneal cavity by the rectovesical pouch in males. * **Rectum:** The middle and lower thirds of the rectum are extraperitoneal. While the upper third is covered by peritoneum anteriorly and laterally, the rectum as a whole is considered a retroperitoneal/subperitoneal structure. * **Seminal Vesicles:** These are located extraperitoneally, situated between the base of the bladder and the rectum. **High-Yield Clinical Pearls for NEET-PG:** * **Intraperitoneal Organs:** Stomach, Spleen, Liver, First part of Duodenum, Jejunum, Ileum, Transverse Colon, Sigmoid Colon, and Ovaries. * **Retroperitoneal Organs (Mnemonic: SAD PUCKER):** **S**uprarenal glands, **A**orta/IVC, **D**uodenum (2nd/3rd parts), **P**ancreas (except tail), **U**reters, **C**olon (Ascending/Descending), **K**idneys, **E**sophagus, **R**ectum. * **Imaging Note:** Intraperitoneal contrast (CT Peritoneography) is often used to evaluate peritoneal dialysis complications or to detect occult hernias.

Question 1

What is the investigation of choice to detect a 4 mm nodule in the pancreas?

Accepted Answer

Endoscopic USG

Answer

PET scan

Answer

CECT

Answer

MRI

Question 2

Which of the following conditions is characterized by a trifoliate appearance?

Accepted Answer

Peptic ulcer

Answer

CHPS

Answer

Achalasia

Answer

Pneumoperitoneum

Question 3

A 72-year-old man presents with increasing dyspepsia and weight loss. His physical examination is unremarkable. A barium meal is performed. The oesophagus is normal, but a 'bull's eye' lesion is noted in the gastric mucosa. Which one of the following is not a recognised cause of this appearance?

Accepted Answer

Magenstrasse

Answer

Gastric carcinoma

Answer

Gastrointestinal stromal tumour (GIST)

Answer

Melanoma metastases

Question 4

A 5-year-old child presents with gas under the diaphragm. What is the most likely diagnosis?

Accepted Answer

All of the above

Answer

Enteric fever with intestinal perforation

Answer

Chilaiditi's syndrome

Answer

Iatrogenic pneumoperitoneum

Question 5

A 13-year-old boy presents with pain in the lower right tooth region with no remarkable medical history. On intraoral examination, tooth 85 was found to be carious and did not respond to EPT. Radiographs show changes in the apical region. What is the most probable diagnosis?

Accepted Answer

Radicular cyst

Answer

Apical granuloma

Answer

Odontogenic keratocyst

Answer

Lateral periodontal cyst

Question 6

Omental caking on CT scan suggests a high possibility of which of the following conditions?

Accepted Answer

Ovarian tumor

Answer

Carcinoma of the colon

Answer

Carcinoma of the pancreas

Answer

Carcinoma of the stomach

Question 7

The CT severity index in acute pancreatitis is described by which scoring system?

Accepted Answer

Balthazar

Answer

Mengini

Answer

Chapman

Answer

Napelon

Question 8

What is the investigation of choice (IOC) for polycystic kidney disease?

Accepted Answer

Ultrasound (USG)

Answer

Magnetic Resonance Imaging (MRI)

Answer

Intravenous Urography (IVU)

Answer

Contrast-Enhanced Computed Tomography (CECT)

Question 9

A 44-year-old man with a history of quadriplegia presented to the emergency department with symptoms of a urinary tract infection. What is the diagnosis?

Accepted Answer

Neurogenic megacolon

Answer

Bladder perforation

Answer

Chronic constipation

Answer

Gastric distention

Question 10

Which structure is outlined with contrast on a CT scan using intraperitoneal contrast material?

Accepted Answer

Ovary

Answer

Prostate

Answer

Rectum

Answer

Seminal Vesicles

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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