Q-1. In spondylolisthesis which of the following investigation is least useful?
a) CT
b) MR
c) X-Ray spine AP
d) X-Ray spine Lateral
Answer: X-Ray spine AP
Explanation:
Investigations In spondylolisthesis:
Blood test: looking for infection, myeloma, hyper-calcemia/hypo-calcemia
Lateral spinal X-rays
Oblique spinal X-rays
CT scan of the spine: Gold standard imaging
MRI of the spine: commonly performed preoperatively to provide information regarding nerve compression and soft tissue.
Spondylolisthesis is a condition in which vertebral bone in back (vertebra) slides forward over the bone below it. It most often occurs in the lower spine (lumbo-sacral area). So X-ray AP is least useful.
Q-2. A patient was diagnosed with intracranial cavernous angioma on the MR scan. MR finding characteristic of the lesion is
a) Well defined nidus
b) Definite arterial feeders
c) Phlebectasis
d) Pop corn like lesion
Answer: Pop corn like lesion
Explanation:
Intracranial cavernous angioma:
Cerebral cavernous hemangioma is a common cerebral vascular malformation.
Cerebral cavernomas tend to be supra-tentorial (About 80% cases) but can be found anywhere including the brainstem.
They are usually solitary; although up to 1/3rd of patients with sporadic lesions have more than one.
MRI is the modality of choice, demonstrating a characteristic “popcorn” or “berry” appearance with a rim of signal loss due to hemosiderin, which demonstrates prominent blooming on susceptibility weighted sequences.
Cavernous malformations are angiographically occult and do not demonstrate arteriovenous shunting.
Q-3. Investigation of choice for lepto-meningeal carcinomatosis
a) PET
b) SPECT
c) Gd enhanced MRI
d) CT scan
Answer: Gd enhanced MRI
Explanation:
Lepto-meningeal metastasis refers to the spread of malignant cells through the CSF space.
These cells can originate both in primary CNS tumors, as well as from distant tumors that have metastasized.
Primary intra-cerebral malignancies:
Glioblastoma multiforme (GBM) and Anaplastic Astrocytoma
Medulloblastoma
s-PNET
Ependymoma
Germinoma
Choroid plexus carcinoma
Distant tumors (more common):
Breast cancer – most common
Lung cancer – most common
Melanoma
Lymphoma and leukemia
The first step in the diagnostic workup should be gadolinium-enhanced MRI, followed by a lumbar puncture (LP).
It is important to note that even with extensive disease; CSF cytology may be negative.
Gd enhanced MRI: Lepto-meningeal enhancement is the primary mode of diagnosis.
Q-4. Which of the following is used to differentiate between the epidermal cyst and arachnoid cyst?
a) Contrast enhancement
b) T1 MR Sequence
c) DW1 MR Sequence
d) Smooth margin
Answer: DW1 MR Sequence
Explanation:
On CT scans, epidermoid lesions with decreased attenuation are most often extra-dural.
They usually have the same attenuation as that of cerebrospinal fluid (CSF); this characteristic makes their differentiation from arachnoid cysts difficult on CT scans, but they are easily differentiated by Proton density-weighted, fluid-attenuated inversion recovery (FLAIR) images and DW1 MR Sequence.
Proton density-weighted and then fluid-attenuated inversion recovery (FLAIR) images are first used to differentiate epidermoids from arachnoid cysts.
DW1 MR Sequence is useful for differentiation from arachnoid cysts from epidermal cyst due to increased signal which is not seen with arachnoid cysts.
Q-5. A newborn presents with congestive heart failure, on examination has bulging anterior fontanellae with a bruit on auscultation. Trans-fontanellar USG shows a hypoechoic midline mass with dilated lateral ventricles. Most likely diagnosis is –
a) Medulloblastoma
b) Encephalocele
c) Vein of Galen malformation
d) Arachnoid cyst
Answer: Vein of Galen malformation
Explanation:
Vein of Galen malformation: Rare arteriovenous malformation of the central nervous system characterized by a high venous flow.
Increasingly the diagnosis is being made ante-natally with third trimester antenatal ultrasound.
Presentation is often with high-output cardiac failure in the neonatal period, although low-flow aneurysms may remain undetected into adulthood.
Ultrasound diagnosis:
A cystic or tubular mass on the midline of brain or in the pineal region with a turbulent venous and/or arterial flow with Doppler signal is typical of the diagnosis. However, when a clot has formed, it may be iso – or even hyper-echoic.
Q-6. A middle aged female presents with slowly progressive weakness of lower limb, spasticity and recent onset of micturition. On neurological examination there is evidence of dorsal myelopathy. MRI scan of spine reveals mid-dorsal intra-dural contrast enhancing mass lesion. Diagnosis is
a) Intra-dural lipoma
b) Dermoid cyst
c) Meningioma
d) Epidermoid cyst
Answer: Meningioma
Explanation:
On MRI and CT, meningiomas exhibit the same enhancement appearance after the injection of contrast medium.
Intense enhancement is seen in 85% of tumors. A ring appearance may represent a capsule.
Meningiomas have a collar of thickened, enhancing tissue that surrounds their dural attachment; this is also known as a dural tail.
This sign represents thickened dura, which may be either reactive or neoplastic.
Although this radiographic feature is not specific for meningiomas, it is highly suggestive of the diagnosis.
Meningioma is the dural based lesion as it arises from the meninges and shows post contrast enhancement.
Meningioma, schwannoma and pituitary adenoma are extra-axial tumors.