FRCR FRCR Neuroradiology 2 — Questions and Answers
Question 1: What is the imaging modality of choice for evaluating a suspected pituitary adenoma?
- Non-contrast CT of the head
- MRI of the pituitary with gadolinium (Correct answer)
- Plain skull X-ray (lateral view)
- 18F-FDG PET scan
Correct answer: MRI of the pituitary with gadolinium
Gadolinium-enhanced MRI provides superior soft tissue resolution of the pituitary gland and its relationship to the optic chiasm and cavernous sinuses.
Question 2: Which finding on MRI best differentiates a posterior fossa epidermoid cyst from an arachnoid cyst?
- T1 hyperintensity on pre-contrast imaging
- Restricted diffusion on diffusion-weighted imaging (Correct answer)
- Rim enhancement following gadolinium administration
- Calcification visible on CT
Correct answer: Restricted diffusion on diffusion-weighted imaging
Epidermoid cysts show characteristic restricted diffusion due to their densely packed lamellar keratin content, whereas arachnoid cysts follow CSF signal on all sequences including DWI.
Question 3: What is the most common location of cavernous malformations (cavernomas) in the brain?
- Cerebellum
- Basal ganglia
- Cerebral hemispheres (supratentorial) (Correct answer)
- Brainstem
Correct answer: Cerebral hemispheres (supratentorial)
Approximately 75–80% of cavernomas are supratentorial, reflecting the larger volume of cerebral hemispheric tissue.
Question 4: Which MRI finding is pathognomonic of a cerebral cavernous malformation (cavernoma)?
- Homogeneous ring enhancement with gadolinium
- Mixed-signal 'popcorn' lesion with complete hemosiderin rim on T2* GRE or SWI (Correct answer)
- T1 hyperintensity with surrounding edema
- Marked restricted diffusion on DWI
Correct answer: Mixed-signal 'popcorn' lesion with complete hemosiderin rim on T2* GRE or SWI
The 'popcorn' appearance with a complete low-signal hemosiderin rim on T2*-weighted sequences reflects blood products of varying ages within the malformation.
Question 5: In which condition are T1 hypointense 'black holes' on MRI a recognized finding that correlates with permanent neurological disability?
- Alzheimer's disease
- Multiple sclerosis (Correct answer)
- Cerebral amyloid angiopathy
- Neurosarcoidosis
Correct answer: Multiple sclerosis
Chronic T1 'black holes' in MS represent areas of severe, irreversible axonal loss and correlate with the degree of permanent disability.
Question 6: What is the most common intracranial tumor in adults overall?
- Meningioma
- Glioblastoma (GBM)
- Brain metastasis (Correct answer)
- Pituitary adenoma
Correct answer: Brain metastasis
Brain metastases outnumber primary brain tumors in adults, with lung, breast, melanoma, renal, and colon cancers being the most common primaries.
Question 7: Which MRI finding is most characteristic of herpes simplex encephalitis (HSE)?
- Bilateral symmetric thalamic T2 hyperintensity
- Unilateral or bilateral temporal lobe T2 hyperintensity with cortical restricted diffusion (Correct answer)
- Periventricular gadolinium enhancement
- Basal ganglia calcification on CT
Correct answer: Unilateral or bilateral temporal lobe T2 hyperintensity with cortical restricted diffusion
HSV-1 encephalitis classically involves the medial temporal lobes, insular cortex, and cingulate gyri with T2/FLAIR signal change and restricted diffusion.
FRCR FRCR Neuroradiology 2
What is the imaging modality of choice for evaluating a suspected pituitary adenoma?