Perfusion CT compared to H(2) (15)O/O (15)O PET in patients with chronic cervical carotid artery occlusion.
BACKGROUND
The purpose of this study was to compare the results of perfusion computed tomography (PCT) with those of (15)O(2)/H(2) (15)O positron emission tomography (PET) in a subset of Carotid Occlusion Surgery Study (COSS) patients.


METHODS
Six patients enrolled in the COSS underwent a standard-of-care PCT in addition to the (15)O(2)/H(2) (15)O PET study used for selection for extracranial-intracranial bypass surgery. PCT and PET studies were coregistered and then processed separately by different radiologists. Relative measurement of cerebral blood flow (CBF) and oxygen extraction fraction (OEF) were calculated from PET. PCT datasets were processed using different arterial input functions (AIF). Relative PCT and PET CBF values from matching regions of interest were compared using linear regression model to determine the most appropriate arterial input function for PCT. Also, PCT measurements using the most accurate AIF were evaluated for linear regression with respect to relative PET OEF values.


RESULTS
The most accurate PCT relative CBF maps with respect to the gold standard PET CBF were obtained when CBF values for each arterial territory are calculated using a dedicated AIF for each territory (R (2) = 0.796, p < 0.001). PCT mean transit time (MTT) is the parameter that showed the best correlation with the count-based PET OEF ratios (R (2) = 0.590, p < 0.001).


CONCLUSIONS
PCT relative CBF compares favorably to PET relative CBF in patients with chronic carotid occlusion when processed using a dedicated AIF for each territory. The PCT MTT parameter correlated best with PET relative OEF.
Department of Radiology, Neuroradiology Section, University of California, San Francisco, San Francisco, CA 94143-0628, USA.
Amita
A
Kamath
Wade S
WS
Smith
William J
WJ
Powers
Alessandro
A
Cianfoni
Jeffrey D
JD
Chien
Tom
T
Videen
Michael T
MT
Lawton
Bruce
B
Finley
William P
WP
Dillon
Max
M
Wintermark
D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D002340:Carotid Artery Diseases / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D002343:Carotid Artery, Internal; D002560:Cerebrovascular Circulation / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*