NEET-PG 2015 - Radiology Practice Questions

Q: Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?

Cysts larger than 2 cm. **Cysts larger than 2 cm** - **ARPKD** is characterized by numerous tiny cysts (typically 1-2 mm, rarely up to 1 cm) that are microscopically dilated collecting ducts, leading to diffuse renal enlargement. - Cysts larger than 2 cm are much more typical of **autosomal dominant polycystic kidney disease (ADPKD)**, which involves macroscopic cysts of various sizes. *Enlarged kidneys* - The proliferation of dilated collecting ducts and associated interstitial fibrosis in **ARPKD** leads to significantly enlarged kidneys, which is a hallmark ultrasound finding. - This enlargement is often bilateral and can be detected prenatally or in neonates. *Increased echogenicity* - The presence of numerous tiny cysts and dense fibrous tissue throughout the renal parenchyma in **ARPKD** causes increased diffuse echogenicity on ultrasound. - This is a common and important diagnostic feature, often described as "bright" or "hyperechoic" kidneys. *Corticomedullary differentiation is lost* - In **ARPKD**, the normal distinct differentiation between the renal cortex and medulla is obliterated due to the widespread involvement of the collecting ducts and the diffuse nature of the disease. - This loss of corticomedullary differentiation is a typical finding on ultrasound for severe renal parenchymal disease, including ARPKD.

Q: In a patient with a tender and rigid abdomen, what is the expected finding on X-ray?

Air under the diaphragm. ***Air under the diaphragm*** - The presence of **free air** (pneumoperitoneum) beneath the diaphragm on an upright abdominal X-ray is a classic sign of **visceral perforation**. - A **tender and rigid abdomen** (peritoneal signs) indicates irritation of the peritoneum, most commonly due to a ruptured hollow viscus. *Blood under the diaphragm* - While blood can accumulate under the diaphragm (e.g., from **trauma** or a ruptured ectopic pregnancy), it typically manifests as a **hemoperitoneum** on imaging. - Blood is **fluid** and would appear as a fluid collection, not free air, on X-ray. *Hazy lung fields* - **Hazy lung fields** suggest conditions like **pulmonary edema**, pneumonia, or acute respiratory distress syndrome (ARDS). - These findings are primarily associated with pulmonary pathology and are not directly indicative of an acute abdominal emergency like perforation. *Prominent vascular markings* - **Prominent vascular markings** often indicate increased blood flow to the lungs or **pulmonary hypertension**. - This finding is unrelated to acute abdominal pain or peritoneal irritation.

Q: On CT scan, gastric volvulus typically shows which of the following findings?

Enlarged twisted stomach. ***Enlarged twisted stomach*** - In gastric volvulus, the stomach **twists on its mesentery**, leading to outflow obstruction and subsequent **gastric distension** or enlargement. - CT scans typically show a **dilated stomach** that appears abnormally oriented or twisted, often with a characteristic **"whirl sign"** of the gastric outlet. *Normal twisted stomach* - A normal-sized stomach that is twisted is unlikely to cause the significant obstruction and symptoms associated with gastric volvulus. - The definition of volvulus implies a degree of internal organ torsion that would typically lead to **obstruction** and changes in organ size. *Shortened twisted stomach* - Gastric volvulus does not cause the stomach to shorten; rather, it leads to **distension** due to obstruction of gastric emptying. - Shortening of the stomach is not a characteristic feature of gastric volvulus. *None of the options* - This option is incorrect because the finding of an **enlarged twisted stomach** is a hallmark of gastric volvulus on imaging. - CT scans play a crucial role in identifying the **degree of distension** and the characteristic twisting pattern in this condition.

Q: In which of the following conditions is Stereotactic Radiosurgery primarily indicated?

Arteriovenous malformation of the brain. ***Arteriovenous malformation of the brain*** - **Stereotactic Radiosurgery (SRS)** is a highly effective treatment for brain AVMs, particularly those that are **small to medium-sized** and located in eloquent brain regions. - SRS delivers a **highly focused dose of radiation** directly to the AVM, causing the abnormal blood vessels to gradually close off over time, reducing the risk of hemorrhage. *Medulloblastoma of the spinal cord* - Medulloblastoma is a **highly aggressive malignant brain tumor** that often metastasizes to the spinal cord via cerebrospinal fluid. - Treatment for spinal medulloblastoma typically involves **cranio-spinal irradiation with chemotherapy**, and SRS is generally not the primary treatment modality for diffuse spinal disease. *Ependymoma* - Ependymomas are tumors arising from the **ependymal cells** lining the ventricles and spinal cord. - While surgery is the primary treatment, radiotherapy, including **conventional fractionated external beam radiation**, is often used as adjuvant therapy, but SRS is less commonly the sole primary indication. *Glioblastoma multiforme* - Glioblastoma multiforme (GBM) is the **most aggressive primary brain tumor** and is typically treated with **maximal surgical resection followed by concurrent chemoradiotherapy**. - While SRS may be used in carefully selected cases for **recurrent GBM** or as a boost in primary treatment, it is not the primary solitary indication for initial management.

Q: Which common tracer in PET is usually administered in the form of a glucose sugar?

Fluorine 18. ***Fluorine 18*** - **18F-FDG** (Fluorodeoxyglucose) is the most common PET tracer, utilizing **Fluorine-18** as its radioactive component. - FDG is a glucose analog, meaning it mimics glucose and is taken up by metabolically active cells, allowing for imaging of **glucose metabolism**. *Aluminum - 12* - **Aluminum-12** is not a common radionuclide used in PET imaging. - The most common tracers in PET are **positron emitters** like Fluorine-18, Carbon-11, Nitrogen-13, and Oxygen-15. *Carbon 11* - **Carbon-11** can be used in PET tracers (e.g., 11C-methionine), but it is **less common** than 18F-FDG due to its shorter half-life. - Its short half-life (20 minutes) requires an **on-site cyclotron** for production, limiting its widespread use. *Oxygen 15* - **Oxygen-15** is employed in PET tracers (e.g., 15O-water for cerebral blood flow), but it has an **even shorter half-life** (2 minutes) than Carbon-11. - Its extremely short half-life makes it **impractical** for routine clinical use in the form of a glucose sugar.

Question 1

Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?

Accepted Answer

Cysts larger than 2 cm

Answer

Increased echogenicity

Answer

Enlarged kidneys

Answer

Corticomedullary differentiation is lost

Question 2

In a patient with a tender and rigid abdomen, what is the expected finding on X-ray?

Accepted Answer

Air under the diaphragm

Answer

Blood under the diaphragm

Answer

Hazy lung fields

Answer

Prominent vascular markings

Question 3

On CT scan, gastric volvulus typically shows which of the following findings?

Accepted Answer

Enlarged twisted stomach

Answer

Normal twisted stomach

Answer

Shortened twisted stomach

Answer

None of the options

Question 4

In which of the following conditions is Stereotactic Radiosurgery primarily indicated?

Accepted Answer

Arteriovenous malformation of the brain

Answer

Ependymoma

Answer

Medulloblastoma of the spinal cord

Answer

Glioblastoma multiforme

Question 5

Which common tracer in PET is usually administered in the form of a glucose sugar?

Accepted Answer

Fluorine 18

Answer

Aluminum - 12

Answer

Carbon 11

Answer

Oxygen 15

NEET-PG 2015 — Radiology