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