1Q.All are true regarding diffusion imaging in stroke except
a. DWI changes have been observed at less than 1 hour after the onset of ischemia
b. the ADC map shows hyperintensity beyond 10 days of stroke
c.Infarcts with greater percentages of low ADC values have higher rates of hemorrhagic transformation
d. Enhancement and restricted diffusion often coexist in arterial infarction.
e. DWI of lesion volumes enlarge over time after the acute stroke.
ANS---d
Enhancement and restricted diffusion are not generally found
coexisting in arterial infarction.
ADC values is seen low within hours after the stroke and continue
to decline for the next few days. They remain reduced through the
first 4 to 5 days after stroke and then undergo pseudonormalization
between 4 and 10 days . After this the ADC subsequently has been
found to rise in the lesion (i.e., the ADC map shows
hyperintensity) beyond 10 days.
DWI has been shown to improve lesion localization and detect the age of the infarction more accurately, DWI has also been shown more accurately to detect and size ischemic lesions.
2Q.Which MR imaging is used to detect longitudinal changes due to Wallerian degeneration?
a.Spin –echo imaging
b.Gradient-echo imaging
c.Diffuion-tensor imaging
d.FLAIR
e.Inversion recovery imaging
ANS----C
3Q. Who were jointly awarded the Nobel Prize in Physiology or Medicine (2003) “for their discoveries concerning magnetic resonance imaging”
a. Lauterbur and Sir Peter Mansfield
b. Bloch and Purcell
c. Ernst and Anderson
d. Jackson and Damadian
e. Aberdeen and Nottingham
ANS -----a--Lauterbur and Sir Peter Mansfield
