Popcorn calcification is seen in:
"Sunray appearance" on X-rays is suggestive of:
HU is a measure of
Which of the following appears the same on both T1 and T2 weighted MRI sequences?
Which of the following features is used to identify the colon on an X-ray?
Investigation of choice for studying Renal Cortical mass
Which of the following is not typically seen on a chest X-ray in pulmonary artery hypertension?
A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?
Step ladder pattern of gas shadow is seen in
Which of the following statements about hepatic adenoma is true?
NEET-PG 2012 - Radiology NEET-PG Practice Questions and MCQs
Question 11: Popcorn calcification is seen in:
- A. Pulmonary hamartoma (Correct Answer)
- B. Bronchogenic carcinoma
- C. Tuberculosis
- D. Pulmonary metastases
Explanation: ***Pulmonary hamartoma*** - **Popcorn calcification** is a pathognomonic radiographic finding highly suggestive of **pulmonary hamartoma**, a **benign tumor** composed of cartilage, fat, and connective tissue - This characteristic calcification pattern is due to the presence of **chondroid (cartilaginous) tissue** within the lesion - Appears as coarse, irregular calcifications resembling popcorn on chest X-ray or CT scan *Bronchogenic carcinoma* - Malignant lung lesions typically show **irregular, spiculated, or ill-defined margins** and tend to grow rapidly - While calcification can occur in some lung malignancies, it usually appears as **eccentric, stippled, or amorphous** rather than the distinctive popcorn pattern - Popcorn calcification is not a feature of primary lung cancers *Tuberculosis* - **Granulomatous infections** such as tuberculosis often lead to calcification, but it usually presents as **laminated, clustered, or target-like patterns** in lymph nodes or within granulomas (Ghon lesion, Ranke complex) - **Popcorn calcification** is not a typical feature of active or healed tuberculous lesions *Pulmonary metastases* - **Metastatic lesions** are generally not calcified, although a few primary tumors (e.g., mucinous adenocarcinoma, osteosarcoma, chondrosarcoma) can metastasize as calcified nodules - When calcification is present in metastases, it is rarely in the specific **popcorn pattern** and is usually diffuse, punctate, or amorphous
Question 12: "Sunray appearance" on X-rays is suggestive of:
- A. A metastatic tumour in the bone
- B. An Osteogenic sarcoma (Correct Answer)
- C. An Ewing's sarcoma
- D. A type of bone cancer that can show various radiographic appearances
Explanation: ***An Osteogenic sarcoma*** - The **"sunray appearance" (or sunburst)** on X-rays is a classic radiographic finding pathognomonic for **osteosarcoma**, especially in adults and adolescents. - This appearance is due to the **periosteal new bone formation** that grows perpendicular to the bone surface, creating a radiating spicule pattern. *A type of bone cancer that can show various radiographic appearances* - While true that bone cancers can show various appearances, the "sunray appearance" is specific enough to strongly point to a particular type, rather than just a general category. - This option is too broad and does not provide the most precise diagnosis indicated by the specific radiographic sign. *A metastatic tumour in the bone* - Metastatic bone lesions typically present with **lytic (bone destruction)** or **blastic (bone formation)** patterns, or a mixed pattern, but rarely produce the periosteal "sunray" appearance. - The characteristic radiographic finding for metastasis would often involve multiple lesions and different periosteal reactions, such as an **onion skin appearance** in some aggressive cases, but not typically sunray. *An Ewing's sarcoma* - Ewing's sarcoma commonly presents with an **"onion skin" periosteal reaction** due to multiple layers of new bone formation. - While both are primary bone tumors, the radiographic findings are distinctly different, allowing for differentiation.
Question 13: HU is a measure of
- A. CT (Correct Answer)
- B. MRI
- C. PET
- D. USG
Explanation: ***Correct Answer: CT*** - HU stands for **Hounsfield Units**, a standardized quantitative scale used exclusively in **computed tomography (CT)** to describe the **radiodensity** of tissues based on **X-ray attenuation**. - On this scale, **water is assigned 0 HU**, air is -1000 HU, and dense bone can be +1000 HU or more. - This allows objective measurement and comparison of tissue densities across different CT scanners and examinations. *Incorrect: MRI* - **Magnetic Resonance Imaging (MRI)** does not use Hounsfield Units. - MRI signal intensity is based on the **magnetic properties of tissues** and local hydrogen proton density, not X-ray attenuation. *Incorrect: PET* - **Positron Emission Tomography (PET)** measures the metabolic activity of cells using **radioactive tracers**. - Its output is typically quantified in **Standardized Uptake Value (SUV)**, not Hounsfield Units. *Incorrect: USG* - **Ultrasound (USG)** imaging uses sound waves to create images of internal body structures. - It measures the **acoustic impedance** of tissues and displays findings in terms of echogenicity, not Hounsfield Units.
Question 14: Which of the following appears the same on both T1 and T2 weighted MRI sequences?
- A. Gall bladder
- B. Fat (Correct Answer)
- C. Kidney
- D. CSF
Explanation: ***Fat*** - On both T1 and T2 weighted MRI sequences, fat appears **bright** (high signal intensity). - This consistent bright signal makes fat a useful internal reference point for signal interpretation. *Gall bladder* - The gall bladder is filled with **bile**, which appears bright on T2-weighted images due to its high water content, but can be variable on T1. - Bile does not maintain consistently the **same signal intensity** as fat on both sequences. *Kidney* - The renal parenchyma typically has **intermediate signal intensity** on both T1 and T2, but its signal characteristics are different from the consistently bright signal of fat. - The signal can vary depending on the specific sequence parameters and hydration status, unlike fat. *CSF* - **Cerebrospinal fluid (CSF)** appears dark (low signal) on T1-weighted images and bright (high signal) on T2-weighted images due to its high water content. - This distinct signal intensity difference between T1 and T2 is contrary to the shared bright appearance of fat on both sequences.
Question 15: Which of the following features is used to identify the colon on an X-ray?
- A. Haustra (Correct Answer)
- B. Valvulae conniventes
- C. String of beads sign
- D. More number of loops
Explanation: ***Haustra (Correct Answer)*** - **Haustra** are sacculations or pouches of the colon created by the uneven contraction of the **taeniae coli** - They are THE characteristic feature that helps distinguish the large bowel from the small bowel on an X-ray - These indentations typically do **not cross the entire width** of the bowel lumen, unlike the valvulae conniventes of the small intestine - Haustra appear as incomplete septations on plain radiographs *Valvulae conniventes (Incorrect)* - **Valvulae conniventes** (also known as plicae circulares) are large, circular folds of the **small intestine** mucosa that project into the lumen - They extend **completely across the lumen** of the small bowel, making them easily distinguishable from haustra which only partially traverse the colon - This is a feature of small bowel, not colon *String of beads sign (Incorrect)* - The "**string of beads sign**" is a **pathological radiographic finding** associated with small bowel obstruction - It refers to multiple small, gas-filled loops of small bowel stacked on top of each other, often with small pockets of fluid or air trapped between the folds, resembling beads on a string - This is not a normal anatomical feature used to identify the colon *More number of loops (Incorrect)* - The number of loops is **not a primary distinguishing feature** between the large and small bowel on an X-ray - While the small intestine generally has more convolutions or loops than the colon, this is a **less reliable and specific sign** compared to the presence of haustra - Haustra remain the gold standard feature for colon identification
Question 16: Investigation of choice for studying Renal Cortical mass
- A. 99mTc DTPA
- B. 53Cr Study
- C. 99mTc DMSA (Correct Answer)
- D. 99mTc Pyrophosphate
Explanation: ***99mTc DMSA*** - **99mTc DMSA** (Technetium-99m dimercaptosuccinic acid) is the radiopharmaceutical of choice for imaging the **renal cortex** and assessing **renal cortical mass** and scarring. - It binds preferentially to the cells of the **renal tubules**, allowing for excellent visualization of cortical tissue. *99mTc DTPA* - **99mTc DTPA** (Technetium-99m Diethylenetriaminepentaacetic acid) is primarily used to assess **glomerular filtration rate (GFR)** and renal blood flow. - It is filtered by the **glomeruli** but not reabsorbed or secreted by the tubules, making it suitable for functional studies rather than morphological assessment of cortical mass. *53Cr Study* - **53Cr** (Chromium-51) is used in studies to measure **red blood cell mass**, survival, or gastrointestinal protein loss. - It has no role in the direct assessment of **renal cortical mass** or function. *99mTc Pyrophosphate* - **99mTc Pyrophosphate** is primarily used to evaluate **myocardial infarction** (hot spots) or detect bone lesions. - It is not indicated for, nor does it provide useful information about, **renal cortical mass**.
Question 17: Which of the following is not typically seen on a chest X-ray in pulmonary artery hypertension?
- A. Enlargement of central arteries
- B. Peripheral pruning
- C. Narrowing of central arteries (Correct Answer)
- D. None of the options
Explanation: ***Narrowing of central arteries*** - **Pulmonary artery hypertension** is characterized by the **enlargement of the central pulmonary arteries** due to increased pressure. - **Narrowing of central arteries** would contradict the hemodynamic changes seen in pulmonary hypertension. - This is the finding that is **NOT typically seen**, making this the correct answer. *Enlargement of central arteries* - This is a **hallmark radiographic finding** in pulmonary hypertension, reflecting the **dilatation of the main and proximal pulmonary arteries** due to increased pressure. - The **pulmonary artery segment becomes prominent**, often appearing convex on the left heart border. *Peripheral pruning* - This refers to the **abrupt tapering and loss of peripheral pulmonary vascular markings**, indicating reduced blood flow to the distal lung parenchyma. - It is a **common finding in advanced pulmonary hypertension**, as the distal vessels constrict and become obliterated. *None of the options* - This is incorrect since **narrowing of central arteries** is clearly not a typical finding in pulmonary hypertension.
Question 18: A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?
- A. EDH
- B. SDH (Correct Answer)
- C. Contusion
- D. Diffuse axonal injury
Explanation: ***SDH*** - The image shows a **crescent-shaped collection** of hemorrhage with a concave inner margin, consistent with a **subdural hematoma** (SDH). - SDHs result from the tearing of **bridging veins** and typically conform to the brain's surface, crossing suture lines but not limited by bony sutures. *EDH* - An **epidural hematoma (EDH)** characteristically appears as a **lenticular** or **biconvex** shape on CT, not crescent-shaped. - EDHs are typically caused by arterial bleeding, often from the **middle meningeal artery**, and are limited by cranial sutures. *Contusion* - A **contusion** is brain tissue bruising that appears as **heterogeneous areas** of hemorrhage and edema within the brain parenchyma itself. - It would not manifest as a distinct extra-axial collection with a smooth, concave margin. *Diffuse axonal injury* - **Diffuse axonal injury (DAI)** involves widespread microscopic damage to axons, often at the gray-white matter junction. - It may appear as *punctate hemorrhages* or **small lesions** at these junctions on CT, but often the CT can be normal, and it would not present as a large extra-axial collection.
Question 19: Step ladder pattern of gas shadow is seen in
- A. Intestinal obstruction (Correct Answer)
- B. Gastric outlet obstruction
- C. Duodenal obstruction
- D. Sigmoid volvulus
Explanation: ***Intestinal obstruction*** - A **step-ladder pattern** of gas shadows is a classic radiological sign seen in **small bowel obstruction** due to dilated, fluid-filled loops of small bowel stacked on top of each other. - This pattern results from the accumulation of gas and fluid proximal to the obstruction, causing dilated bowel loops to arrange horizontally. *Gastric outlet obstruction* - This condition primarily results in a **dilated stomach** with fluid and gas, not typically a step-ladder pattern in the small bowel. - Vomiting is usually a prominent symptom, and imaging would show a large fluid-filled stomach. *Duodenal obstruction* - Causes dilatation of the stomach and duodenum, leading to a "**double-bubble sign**" (dilated stomach and proximal duodenum). - It does not typically produce the extensive, stacked small bowel loops seen in a step-ladder pattern. *Sigmoid volvulus* - Characterized by a distinctive large, dilated loop of sigmoid colon, often described as a "**coffee bean sign**" or an **inverted U-shape**. - This is a large bowel obstruction and does not typically present with a step-ladder pattern of small bowel gas.
Question 20: Which of the following statements about hepatic adenoma is true?
- A. Associated with OCP use
- B. Common in young females (Correct Answer)
- C. Cold on isotope scan
- D. Typically malignant tumor
Explanation: ***Older females*** - Hepatic adenomas are primarily seen in **younger females** of childbearing age, often linked to **oral contraceptive pill (OCP)** usage [1]. - This statement is **incorrect** as hepatic adenomas are not typically associated with older females. *OCP use* - Hepatic adenomas are **strongly associated** with the **use of oral contraceptive pills**, especially in young women [1]. - They may regress or resolve after discontinuation of OCPs, indicating a clear relationship [1]. *Cold on isotope scan* - Hepatic adenomas generally appear as **hot lesions** on imaging, meaning they take up more radioisotope than surrounding liver tissue. - A "cold" appearance would be atypical and may suggest malignancy or other liver lesions. *Benign lesion* - Hepatic adenomas are classified as **benign tumors** [2][3], although they have risks of complications like **hemorrhage** or malignant transformation [3]. - Even though they are benign, they require careful monitoring depending on size and symptoms. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, p. 874. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 398-399. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 874-875.