RADIOLOGY MCQ----IMAGING of CNS INFECTION

Q.All are true regarding imaging of CNS infection except

a. CE T1W MR  is the most sensitive MR sequence for meningitis

b. Diffusion-weighted imaging characteristically shows  restricted diffusion

c. HSV-1 is the causative agent in 95% of herpetic encephalitis

d. HSV-1 is the most common cause of fatal sporadic encephalitis

e. HSV-2  account for 80% to 90% of neonatal herpes virus infections 

ANS---a

FLAIR is the most sensitive MR sequence for meningitis

MCQ FRCR -----BRAINSTEM GLIOMA

Q.All are true regarding brainstem glioma except

a. pontine glioma occurs most often between 5 and 6 years of age

b.pontine glioma  is diffusely infiltrating and tends to run a malignant course

c. In general, midbrain tumours have a tendency to be indolent and of low-grade astrocytic nature

d. Contrast enhancement of a medullary tumor does not necessarily mean an aggressive tumor

e. Hydrocephalus is relatively infrequent in midbrain tumour tumors

337.----e

Hydrocephalus is relatively infrequent in pontine tumors .In contrast to pontine and medullary tumors, hydrocephalus is the common presenting finding in patients with midbrain tumors.

On a nonenhanced CT, one third of the pontine tumors are hypodense, one third are isodense, and one fourth are mixed density, both decreased and isodense. Only 5% of tumors are of increased density, with the increased density representing either calcification or blood, and the hemorrhagic focus usually indicating a malignant zone within the tumor 

Masses that are predominately hyperdense in pons, with or without surrounding focal edema, should be considered as possible cavernomas . The mass that shows a rim of hemosiderin hypointensity on T2 or T2* should be thought of as a cavernoma of the brainstem and followed with imaging.

Radiology mcq ---astrocytoma

Q.All are true regarding pilocystic astrocytoma except

a. cystic with mural nodules in 50%

b. Calcification is uncommon

c. the high incidence of contrast enhancement on both CT and MRI

d. Twenty-five-year survival rate  -- on the order of 90%

e. decreased apparent diffusion coefficient (ADC) values

Q.----e

Diffusion studies show increased motion of water within both the cystic and the solid portions of the tumor, with increased apparent diffusion coefficient (ADC) values –a point of difference from the solid component of cystic PNET

Cerebellar astrocytomas are hypointense on T1 and hyperintense on T2, proton density, and FLAIR . The solid portion of the tumor is typically more hyperintense than the solid component of otherwise similarly appearing cystic PNET

The cystic portions of the tumor often show only elevated lactate and a lack of other metabolites. The presence of lactate in the cystic portion of the tumor has nothing to do with the tumor being aggressive, as in the case of malignant glioma, where it reflects anaerobic metabolism. Lactate in the cyst fluid of low-grade astrocytoma reflects the byproducts of metabolism that seep into the cysts. There is a low incidence of blood products in the wall of the cyst

Cerebellar astrocytomas do not present acutely as hemorrhagic masses, a finding that, when present, suggests a more aggressive tumor such as a PNET, atypical teratoid rhabdoid tumor (ATRT), or a tumor with a tendency to hemorrhage such as an ependymoma