INI-CET 2025 - Radiology PYQs Practice Questions

Q: Which of the following is the investigation of choice for spinal TB?

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice, as it provides excellent visualization of soft tissues, including the **spinal cord**, nerve roots, and early features like **bone marrow edema** and **paraspinal abscesses**. - It can clearly define the extent of the disease, including disc involvement, **epidural space compression**, and neural compromise, which is crucial for surgical planning. *Ultrasound* - **Ultrasound** is primarily used for assessing soft tissue masses and guiding aspirations but has limited ability to image deep structures like the **vertebral column** and spinal canal. - It cannot adequately assess the extent of **bone destruction**, vertebral body involvement, or **intradural pathology** associated with spinal TB. *CT scan* - **CT scan** is superior to conventional radiography for demonstrating **lytic bone destruction**, calcification, and fine bony detail associated with TB. - However, it is less effective than MRI in visualizing **soft tissue involvement**, **early marrow changes**, or the degree of **cord compression**. *CBNAAT* - **CBNAAT (Cartridge-Based Nucleic Acid Amplification Test)** is a **microbiological test** used for the rapid diagnosis of TB and detection of rifampicin resistance. - It requires a **tissue or fluid sample** (e.g., from aspiration or biopsy) and is used for **pathological confirmation**, not as the primary radiological investigation of choice. [Practice more Radiology PYQs on OnCourse]

Q: Based on the provided X-ray image, identify the type of thyroid malignancy.

Follicular carcinoma. ***Follicular carcinoma*** - This is the **correct answer** based on the X-ray showing bone metastases. - Follicular carcinoma characteristically spreads via **hematogenous (bloodstream) route** to distant sites, particularly **bones and lungs**. - Bone metastases from thyroid cancer are **most commonly** due to follicular carcinoma, presenting as **lytic lesions** on X-ray. - Follicular carcinoma accounts for 10-15% of thyroid cancers but is responsible for the majority of thyroid cancer bone metastases. *Incorrect: Papillary carcinoma* - Although papillary carcinoma is the **most common thyroid malignancy** (80% of cases), it predominantly spreads via **lymphatic route** to regional lymph nodes. - Distant hematogenous metastases to bone are **uncommon** in papillary carcinoma. - When papillary carcinoma does metastasize distantly, lungs are more commonly affected than bones. *Incorrect: Hurthle cell carcinoma* - This is an **aggressive variant of follicular carcinoma** (Hürthle cell or oncocytic variant). - While it can spread hematogenously, it is significantly **rarer** than conventional follicular carcinoma. - It represents only 3-5% of differentiated thyroid cancers. *Incorrect: Thyroid lymphoma* - Primary thyroid lymphoma is a **rare malignancy** typically presenting as a rapidly enlarging neck mass. - Usually occurs in elderly patients with a history of **Hashimoto's thyroiditis**. - Distant bone metastases are **not characteristic** of primary thyroid lymphoma. [Practice more Radiology PYQs on OnCourse]

Q: Eye of the tiger appearance on MRI is associated with:

Pantothenate kinase-associated degeneration. ***Pantothenate kinase-associated degeneration*** - The "eye of the tiger" sign is pathognomonic for **Pantothenate kinase-associated neurodegeneration (PKAN)**, a form of Neurodegeneration with Brain Iron Accumulation (NBIA). - It appears as a central area of high signal intensity (oedema/gliosis) surrounded by a rim of low signal intensity (iron deposition) in the **globus pallidus** on T2-weighted MRI. ***Wilson disease*** - Characterized by **copper deposition** in the liver, brain (e.g., basal ganglia, thalamus), and cornea (**Kayser-Fleischer rings**). - MRI findings typically show increased T2 signal intensity in the putamen, midbrain, and basal ganglia, but do not produce the classic "eye of the tiger" sign. ***Krabbe disease*** - This is a lysosomal storage disease (leukodystrophy) caused by a deficiency of the enzyme **galactocerebrosidase**. - MRI typically shows extensive white matter abnormalities and atrophy, but it is not associated with the **globus pallidus** changes seen in the "eye of the tiger" sign. ***Huntington chorea*** - A progressive brain disorder characterized by prominent atrophy of the **caudate nucleus** and putamen (striatum). - MRI primarily demonstrates severe **caudate atrophy** and is not associated with the characteristic PKAN finding in the globus pallidus. [Practice more Radiology PYQs on OnCourse]

Q: Honda or H sign on STIR MRI is characteristic of which condition?

Sacral insufficiency fracture. ***Sacral insufficiency fracture*** - The **Honda sign** (also known as the H sign or butterfly sign) is a characteristic finding on **STIR MRI** of the sacrum, particularly suggestive of a **sacral insufficiency fracture** caused by chronic microtrauma in osteoporotic bone. - It represents bilateral vertical fracture lines through the sacral alae connected by a horizontal fracture line through the body of S3 (or S2/S4), showing **medullary edema**/fracture line hyperintensity on STIR sequences. ***Multiple myeloma*** - Myeloma typically presents on MRI as multiple **focal lesions** (plasmacytomas) or diffuse marrow infiltration, often showing low signal intensity on T1 and variable T2/STIR signals. - While sacral involvement is possible, the classic H sign or Honda sign is not a typical presentation; rather, it often shows **lytic lesions** on plain films/CT. ***Acute osteomyelitis*** - Acute osteomyelitis of the sacrum would show localized **marrow edema** with corresponding T1 hypointensity and contrast-enhancing soft tissue/periosteal reaction. - It is usually unilateral and focal, lacking the characteristic H pattern of stress or insufficiency fractures. ***Bone marrow edema*** - Bone marrow edema is a generalized finding on STIR, indicating pathology such as trauma, infection, tumor infiltration, or avascular necrosis (AVN). - While the H sign is a type of bone marrow edema pattern, the sign itself is specific to a **sacral insufficiency fracture**, not a general edema observation. [Practice more Radiology PYQs on OnCourse]

Question 1

Which investigation is contraindicated in pregnancy?

Accepted Answer

CT scan

Answer

MRI

Answer

Ultrasound

Answer

Doppler

Question 2

Which of the following is the investigation of choice for spinal TB?

Accepted Answer

MRI

Answer

Ultrasound

Answer

CT scan

Answer

CBNAAT

Question 3

Based on the provided X-ray image, identify the type of thyroid malignancy.

Accepted Answer

Follicular carcinoma

Answer

Papillary carcinoma

Answer

Hurthle cell carcinoma

Answer

Thyroid lymphoma

Question 4

Eye of the tiger appearance on MRI is associated with:

Accepted Answer

Pantothenate kinase-associated degeneration

Answer

Wilson disease

Answer

Krabbe disease

Answer

Huntington chorea

Question 5

Honda or H sign on STIR MRI is characteristic of which condition?

Accepted Answer

Sacral insufficiency fracture

Answer

Multiple myeloma

Answer

Acute osteomyelitis

Answer

Bone marrow edema

Question 6

Identify the investigation modality shown in the image.

Accepted Answer

X-ray defecogram

Answer

Barium swallow

Answer

MR defecogram

Answer

X-ray barium enema

Question 7

What is the most useful investigation for localization of a parathyroid adenoma?

Accepted Answer

Sestamibi scan

Answer

USG

Answer

FDG PET

Answer

SPECT

Question 8

A child presents with seizures. Contrast-enhanced CT reveals a cystic lesion with a dot sign. What is the most likely diagnosis?

Accepted Answer

Neurocysticercosis

Answer

Tuberculoma

Answer

Brain abscess

Answer

Cerebral metastasis

INI-CET 2025 — Radiology