Cerebral Perfusion Computed Tomography with a New Scanning Protocol and Reduced Scanning Time: Retrospective Review

• Published in: Hong Kong journal of radiology : HKJR = Xianggang fang she ke yi xue za zhi Vol. 16; no. 3; pp. 203 - 208
• Main Authors: Chan, KC, Abrigo, JM, Cheung, TCY, Cheung, SW, Siu, DYW
• Format: Journal Article
• Language: English
• Published: Hong Kong Hong Kong Academy of Medicine 01.09.2013
• Subjects: Blood; Datasets; Radiation; Tomography
• ISSN: 2223-6619; 2307-4620
• DOI: 10.12809/hkjr1312154

Objective: To retrospectively analyse the quantitative change in cerebral blood flow, cerebral blood volume, and mean transit time after adopting a new protocol for perfusion computed tomography (PCT) where the delay time for scanning was changed from 5 to 8 seconds and acquisition time decreased from 50 to 42 seconds. Methods: All elective cerebral PCTs performed from June to October 2009 were retrieved. The original dataset and extracted dataset (excluding the first 3 seconds and last 5 seconds of the original dataset which corresponded to the new protocol) were pair-wise processed in the same workstation. This entailed using the same arterial input and venous output functions; 12 identical regions of interest were applied. Perfusion parameter values were compared using the Wilcoxon rank signed test. Significance was declared at an α ≤ 0.05. Results: A total of 45 PCTs with and without acetazolamide challenge were included, yielding 540 regions of interest. The mean percentage differences of cerebral blood flow, cerebral blood volume, and mean transit time between the two datasets were significant (p < 0.001) but small (5.9%, 5.0% and 4.2%, respectively). In the extracted datasets, the absolute values remained within a 15.0% difference in 97.0% of the cerebral blood flows, 99.8% of the cerebral blood volumes, and 99.6% of the mean transit times. With the new protocol, on average a 15.9% reduction in radiation dosage was achieved. Conclusion: By adopting our new scanning protocol for cerebral PCT, a significant reduction in radiation dosage was achieved, while the changes in cerebral blood flow, cerebral blood volume, and mean transit time values were considered acceptable.