Measurement of time-to-peak parameter by use of a new standardization method in patients with stenotic or occlusive disease of the carotid artery.
OBJECTIVE
A quantitative, easily obtained measure of cerebral hemodynamics would be valuable in planning surgical or interventional therapy for patients with stenotic or occlusive disease of the carotid artery. We evaluated the recently introduced standardized time-to-peak variable (stdTTP), obtained with dynamic susceptibility contrast-enhanced MR (DSC-MR) imaging, in different states of stenotic/occlusive carotid artery disease.


METHODS
We examined 24 patients with unilateral, high-grade stenosis (85%-95%) of one internal carotid artery (ICA) and 10 patients with stenosis (85%-95%) of one ICA and occlusion of the contralateral ICA. Mean stdTTP was evaluated in the central vascular territories of the anterior, middle, and posterior cerebral arteries and the anterior and posterior border zones and compared with the mean stdTTP values from 36 cerebral hemispheres without hemodynamic impairment.


RESULTS
Patients showed no significant prolongation of stdTTP in the central vascular territories compared with the reference group, whereas significant prolongations of stdTTP were measured in the anterior and posterior border zones in patients with ICA disease (ANOVA, P <.05) and were most prominent in higher grades of carotid disease. Hemispheres with hemodynamic impairment always showed a stdTTP > 3.5 s in the border zones.


CONCLUSIONS
The StdTTP quantitatively describes the hemodynamic impairment in cerebral hemispheres supplied by a stenosed or occluded ICA. An stdTTP value of > 3.5 s, as has been postulated, seems to point out hemodynamic impairment.
Nasel
C
C
Division of Neuroradiology, Department of Radiology, University of Vienna, Austria.
Azizi
A
A
Wilfort
A
A
Mallek
R
R
Schindler
E
E
D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply; D002343:Carotid Artery, Internal / Q000473:pathology / Q000503:physiopathology; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D003287:Contrast Media; D017352:Echo-Planar Imaging; D005260:Female; D019786:Gadolinium DTPA; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012039:Regional Blood Flow / Q000502:physiology; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA