Radiation exposure during computerized tomography-based neuroimaging for acute ischemic stroke: a case-control study

Abstract

Patients and clinicians often raise concerns about radiation exposure to various organs during computerized tomography-based imaging. We evaluated radiation exposure during standard and low-dose imaging protocols for non-contrast computerized tomography, computerized tomography angiography and computerized tomography perfusion of the head. Whether reducing the radiation dose affected the image quality was also evaluated. Radiation data were retrieved for computerized tomography-based imaging studies performed for acute ischemic stroke patients during 2015. The volume-weighted computerized tomography dose index, dose-length product, scan length, effective dose and whole-body integral dose for brain, skin, eye, thyroid and red bone marrow were extracted from dose-tracking software. Dose metrics for low-dose protocols data were compared with standard protocols. The calculated effective doses for non-contrast computerized tomography, computerized tomography angiography and computerized tomography perfusion were 2.56 ± 0.67 mSv, 4.45 ± 2.5 mSv, and 4.47 ± 0.85 mSv, respectively for 391 acute ischemic stroke patients. Corresponding radiation exposures for low-dose protocol (n = 31) were non-contrast computerized tomography (2.36 ± 0.65 mSv), computerized tomography angiography (1.57 ± 0.74 mSv) and computerized tomography perfusion (2.20 ± 0.55 mSv). Overall, the effective dose for one complete stroke imaging protocol (non-contrast computerized tomography + computerized tomography angiography + computerized tomography perfusion) for the standard-dose protocol was 11.48 mSv, which was reduced to 6.13 mSv (46.6% reduction) using a low-dose protocol (p < 0.001). Reduced radiation exposure was noted for other radiosensitive organs. Radiation exposures of sensitive organs are within acceptable limits with standard neuroimaging protocols for acute ischemic stroke. Lower-dose computerized tomography imaging protocols reduced the radiation doses without appreciable deterioration in image quality.

Keywords: Acute ischemic stroke; Computerized tomography; Neuroimaging; Radiation; Radiation dose.