Frcr and Board review ---mcq ---CJD

Q. A 60 yrs old patient presents with rapidly progressive dementia, myoclonic jerks, and periodic sharp-wave EEG tracing.CJD is suspected.MR of brain was advised as  MR is highly sensitive and specific for the detection of CJD abnormalities.All are true regarding CJD except

a. Lesions do not enhance and do not demonstrate mass effect

b. DWIs is superior to over any T2-weighted images in the assessment of CJD

c. DWI changes have been observed as early as 1 month after the onset of symptoms

d. hyperintensity on DWI found in the cortex and basal ganglia

e. primary sensorimotor cortex is almost always involved

ANS.----e

CJD patient shows symmetric increased signal in T2-weighted images in the caudate nuclei , putamen, thalamus and cortex , basal ganglia , periventricular white matter , and occipital lobes .In CJD.primary sensorimotor cortex is almost always spared, even when extensive abnormalities are found in the frontal and parietal cortex.

The mechanism of hyperintensity on DWI found in the cortex and basal ganglia is poorly understood, although it correlates with deposition of abnormal prion protein, vacuolation, neuronal loss, and gliosis. 

DWI changes have been observed as early as 1 month after the onset of symptoms and may show modifications 6 months prior to T2-weighted images and 4 months prior to FLAIR images