NEET-PG 2015 - Radiology PYQs Practice Questions

Q: What is the cardiothoracic ratio in children?

50-55%. ***50-55%*** - The normal **cardiothoracic ratio** in children is generally considered to be **50-55%** on a **posterior-anterior (PA) chest X-ray**. - In **infants and young children (under 2 years)**, the ratio can be **up to 55-60%** due to relatively larger cardiac size and more horizontal positioning of the heart. - In **older children (over 2 years)**, the normal ratio approaches adult values of **less than 50%**. - A ratio consistently greater than 55% could indicate **cardiomegaly**, which warrants further investigation. *30-35%* - This range is typically too low and would suggest an **unusually small heart** for the chest cavity, which is not a normal finding in children. - A very low ratio like this is not characteristic of the pediatric population and may indicate technical issues with the radiograph. *40-45%* - While this range approaches normal values for **older children and adults**, it is generally on the lower side for the average **pediatric cardiothoracic ratio**. - This percentage alone is not the best answer when considering the entire pediatric age spectrum, including infants and younger children. *60-65%* - A cardiothoracic ratio in this range would typically be considered **abnormal** and indicative of **cardiomegaly** in children beyond infancy. - Such an elevated ratio would suggest an enlarged heart, prompting further cardiac evaluation including **echocardiography** to assess for structural heart disease. [Practice more Radiology PYQs on OnCourse]

Q: Which of the following imaging modalities is most appropriate for initial evaluation of suspected acute appendicitis in a young adult patient?

Ultrasound. ***Ultrasound*** - **First-line imaging modality** for suspected acute appendicitis in young adults, especially in children, pregnant women, and young females - **Advantages:** No ionizing radiation, readily available, cost-effective, can be performed at bedside - **High specificity** (>90%) when positive findings are present - **Graded compression technique** helps visualize the appendix and assess for periappendiceal inflammation - **Limitations:** Operator-dependent, may be difficult in obese patients or with overlying bowel gas *CT scan (Contrast-enhanced)* - **Most sensitive imaging modality** (sensitivity >95%) for acute appendicitis - Considered when ultrasound is inconclusive or technically difficult - **Gold standard** in adults, especially in obese patients - Provides excellent visualization of the appendix and complications (perforation, abscess) - However, involves **ionizing radiation**, making it less ideal as first-line in young patients *MRI* - **Preferred in pregnant women** when ultrasound is inconclusive - No ionizing radiation exposure - High accuracy but **limited availability**, longer scan time, and higher cost - Not typically used as first-line imaging in non-pregnant young adults *Plain radiography (X-ray)* - **Limited role** in diagnosing acute appendicitis - Non-specific findings; may show fecalith, loss of psoas shadow, or signs of perforation - Cannot reliably visualize the appendix - **Not recommended** as initial imaging for suspected appendicitis [Practice more Radiology PYQs on OnCourse]

Q: Rigler's sign is suggestive of?

Pneumoperitoneum. ***Correct: Pneumoperitoneum*** - **Rigler's sign** (double wall sign) is the visualization of both the **inner (mucosal) and outer (serosal) surfaces** of the bowel wall on an abdominal X-ray. - This occurs when **free intraperitoneal air** outlines both sides of the bowel wall, making it a **pathognomonic sign of pneumoperitoneum**. - Commonly seen in **bowel perforation** from causes like peptic ulcer, trauma, or iatrogenic injury. *Incorrect: Pneumothorax* - Refers to air in the **pleural space** (thoracic cavity), not the peritoneal cavity. - Diagnosed on chest X-ray by the **visceral pleural line** with absent lung markings peripherally. - Completely different anatomical compartment from where Rigler's sign is observed. *Incorrect: Peritonitis* - Represents **inflammation of the peritoneum**, which is a clinical and pathological diagnosis. - While pneumoperitoneum from perforation can **lead to peritonitis**, Rigler's sign specifically indicates the **presence of free air**, not inflammation itself. - Peritonitis has no specific pathognomonic radiological sign like Rigler's. *Incorrect: Hemothorax* - Refers to **blood in the pleural cavity** (thoracic, not abdominal). - Appears as a **pleural effusion** with meniscus sign on chest X-ray. - Unrelated to abdominal radiological findings or free air. [Practice more Radiology PYQs on OnCourse]

Q: In which of the following cancers is intraoperative radiotherapy (IORT) applicable?

All of the options. ***All of the options*** - **Intraoperative radiotherapy (IORT)** is applicable to all three cancers listed: gastric cancer, colon carcinoma, and pancreatic carcinoma. - IORT is a technique where a **single, high dose of radiation** is delivered to the tumor bed during surgery to improve local control and reduce late toxicity to surrounding healthy tissues. - All three cancers benefit from IORT due to their **high risk of local recurrence** and the ability to directly target the tumor bed while sparing adjacent critical organs. **Gastric cancer:** - IORT addresses **high rates of local recurrence** after conventional surgery, especially in locally advanced stages - Allows direct radiation of potentially involved regional lymph nodes or margins difficult to eradicate surgically - Particularly useful when complete surgical clearance carries excessive morbidity risk **Colon carcinoma:** - IORT considered in **locally advanced or recurrent disease**, particularly when tumors invade adjacent structures - Beneficial after resections with positive or close margins - Delivers high dose to microscopic residual disease in the tumor bed, avoiding damage to vital organs from external beam radiotherapy **Pancreatic carcinoma:** - High propensity for **local invasion and recurrence** makes IORT particularly relevant - Delivers high dose directly to tumor bed following resection when microscopic residual disease is suspected - Overcomes limitations of external beam radiation due to proximity of critical organs (duodenum, stomach, kidneys) [Practice more Radiology PYQs on OnCourse]

Q: Which of the following is not considered a contraindication for undergoing an MRI?

Ryle's tube. ***Ryle's tube*** - A **Ryle's tube** is a form of nasogastric tube made of radiopaque plastic, which is entirely **MRI-safe** and does not interact with magnetic fields. - It is made from inert materials that are **non-ferromagnetic**, posing no risk during an MRI scan. *Cardiac pacemaker* - **Cardiac pacemakers** contain metallic components that can malfunction, demagnetize, or migrate due to the strong magnetic fields and radiofrequency pulses of an MRI. - This can lead to **arrhythmias**, **pacemaker failure**, or **heating of leads**, posing a significant risk to the patient. *Cochlear implant* - **Cochlear implants** contain strong magnets and electronic components that can be damaged or displaced by the MRI's magnetic field. - This can cause **pain**, **implant damage**, or **hearing loss** for the patient. *Metallic splinter in eye* - A **metallic splinter in the eye** is a severe contraindication because the strong magnetic field can cause the metal fragment to move. - This movement can lead to **tissue damage**, **hemorrhage**, or **blindness** if it dislodges in the delicate structures of the eye. [Practice more Radiology PYQs on OnCourse]

Question 1

What is the cardiothoracic ratio in children?

Accepted Answer

50-55%

Answer

30-35%

Answer

40-45%

Answer

60-65%

Question 2

Which of the following imaging modalities is most appropriate for initial evaluation of suspected acute appendicitis in a young adult patient?

Accepted Answer

Ultrasound

Answer

CT scan (Contrast-enhanced)

Answer

Plain radiography (X-ray)

Answer

MRI

Question 3

Rigler's sign is suggestive of?

Accepted Answer

Pneumoperitoneum

Answer

Pneumothorax

Answer

Peritonitis

Answer

Hemothorax

Question 4

In which of the following cancers is intraoperative radiotherapy (IORT) applicable?

Accepted Answer

All of the options

Answer

Gastric cancer

Answer

Colon carcinoma

Answer

Pancreatic carcinoma

Question 5

Which of the following is not considered a contraindication for undergoing an MRI?

Accepted Answer

Ryle's tube

Answer

Cardiac pacemaker

Answer

Cochlear implant

Answer

Metallic splinter in eye

Question 6

Substance used for PET scan is

Accepted Answer

18F-FDG

Answer

Gadolinium

Answer

Gastrografin

Answer

Iodine

Question 7

What is the best investigation for diagnosis and staging of renal cell carcinoma with thrombus extending into the IVC?

Accepted Answer

CT scan

Answer

Angiography

Answer

Colour doppler imaging

Answer

IVP

Question 8

Which condition is characterized by a specific appearance on CT scans that resembles small centrilobular nodules with branching linear structures?

Accepted Answer

Pulmonary tuberculosis

Answer

Silicosis

Answer

Pulmonary hydatid cyst

Answer

Small cell carcinoma

Question 9

Precisely directed high dose radiation is used in which of the following therapies?

Accepted Answer

Stereotactic radiosurgery

Answer

EBRT

Answer

IMRT

Answer

Brachytherapy

Question 10

All are done to minimize radiation exposure to the patient under fluoroscopy, except which of the following?

Accepted Answer

Increasing fluoroscopic time

Answer

Decreasing fluoroscopic time

Answer

Using low dose of radiation

Answer

Decrease in field of view

NEET-PG 2015 — Radiology