Axial Flair, DWI/ADC images show multiple FLAIR signal abnormalities in right
centrum semiovale with corresponding restricted diffusion.
CE MRA shows loss of signal in the right carotid artery proximal to the internal
carotid artery. CTA show dense calcium at the right carotid bifurcation with
patent external and internal carotid arteries. 3DTOF of the COW show luminal
irregularity of the right MCA artery as well as loss of signal of the terminal
M3 branches. The left side and posterior circulation appear preserved.
Perfusion maps show increased time-to-peak and mean transit time with corresponding
decrease in cerebral blow flow over a large segment of right MCA distribution.
The cerebral blood volume is mildly increased in the same region. The area of
decreased perfusion is more than 75% larger than the DWI abnormality.
Dynamic contrast-enhanced CT perfusion was performed, with generation of CBF
(cerebral blood flow), CBV (cerebral blood volume), and MTT (mean transit time)
color maps. Axial CT perfusion maps confirm significantly prolonged MTT,
decreased CBF, and slightly increased CBV in the right MCA distribution.
Quantitative measures from the CT perfusion further demonstrate increased MTT
and decreased CBF in the MCA distribution . The CBV is however increased due to
vasomotor autoregulation with vasodilatation and collateral circulation.
Key words: mri pwi ct perfusion vascular dwi mra cta
Cerebral ischemia & infarction
with diffusion-perfusion mismatch