Abstract
Aim: To analyze variability of intracranial circulation and to design optimization of protocol for patients with acute ischemic stroke and to verify feasibility of new protocol. Method: The test group of 46 patients with suspected acute ischemic stroke, which underwent perfusion CT of the brain and CT angiography, was retrospectively assessed.
CT angiography did not prove significant stenosis or occlusion of arteries. By these patients, time of intracranial circulation in arteries and veins was analyzed.
Based on this analysis, adjustment of length and timing of perfusion CT of the brain was established with the help of test bolus technique of contrast agent. Two groups of patients were examined according to optimized protocols (20 repeated scans, one scan within 1.5 seconds, whole brain was cov-ered) with different voltage on X-ray tube (80 kV and 70 kV).
Volume CT dose index (CTDIvol ) and dose length product (DLP) were assessed as standard indicators of dose. Results: All examinations were evaluated as adequate from the point of view of diagnostic quality of examination.
Only one examination in the optimized protocol with 70 kV was not evaluable. CT dose index and dose length product were reduced in both optimized perfusion CT protocols.
Mean value of CTDIvol and DLP was 130.37 mGy and 2068.17 mGy . cm in the test group. Mean value of CTDIvol and DLP was 85.64 mGy and 1326.44 mGy . cm in the optimized protocol and 50.57 mGy and 783.42 mGy . cm in the optimized protocol with voltage reduced to 70 kV.
Conclusion: Optimization of start and reduction of length of perfusion CT of the brain is possible based on test bolus technique of contrast agent. It is possible to significantly reduce dose with the help of low voltage protocol. (C) 2019, Galen spol. s.r.o.
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