Short-Term Changes in Cerebral Microhemodynamics after Carotid Stenting
Iain D. Wilkinsona,
Paul D. Griffithsa,
Nigel Hoggarda,
Trevor J. Clevelandb,
Peter A. Gainesb,
Sumaira Macdonaldb,
Fiona McKevittb and
Graham S. Venablesb
a Academic Unit of Radiology, University of Sheffield, England
b Sheffield Vascular Institute, Sheffield Teaching Hospitals, England
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FIG 1. Signal intensity versus time.
A, Mean signal intensity as a function of time from an ROI placed within the proximal intracranial branch of the MCA. The start-stop interval is used to define the mean baseline signal intensity, while the stop-last interval represents the first pass of the contrast bolus. Note that subsequent decreases in signal intensity occur as the contrast material is recirculated.
B, Gamma-variate fit (solid line) to the baseline subtracted and inverted data (dashed line). The two variables used to quantify the curve are the first moment of the gamma-variate fit, termed the first-moment transit time (TTFM), and the area under the fitted curve (relative cerebral blood volume [rCBV]).
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FIG 2. Placement of the ROIs.
A, PCAT.
B, MCAT1.
C, MCAT2.
D, ACAT.
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FIG 3. Perfusion data obtained at the level of the lateral ventricles in a patient with a symptomatic 95% stenosis in the left ICA and a 50% stenosis of the contralateral ICA.
A, Preintervention rCBV map.
B, Preintervention TTFM map.
C, Gamma-variate fits corresponding to the depicted regions show a longer TTFM and a smaller rCBV in the symptomatic hemisphere.
D, Postintervention rCBV map.
E, Postintervention TTFM map.
F, Corresponding gamma-variate fits. Note the resolution of interhemispheric asymmetry in TTFM.
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AJNR - American Journal of Neuroradiology