[Quality assessment in single-slice spiral brain CT examinations of patients with cerebrovascular accident]

Our objective was to apply quality criteria proposed by the European Commission (EC) Guidelines to the brain CT examinations for cerebrovascular accident (CVA) diagnosis at single-slice spiral CT scanners from five different hospitals in the Madrid area.

A sample of 100 brain CT examinations was collected and independently reviewed by five radiologists, to determine the degree of fulfilment of image quality criteria. Dose measurements were performed to estimate the values of the CT dose indexes (CTDIw, CTDIair), the dose length product (DLP), and the effective dose (E).

Once the McNemar test was applied to the sample, the number of observers' readings was reduced to three. The quality criteria were, in general, fulfilled, since mean values of image quality score between 80% and 92% were deduced, with variation coefficients per centre in the range of 0.07-0.1. However, both visualization criteria 1.1.2 and 1.1.3 exhibited similar ranges of fulfilment (38% - 94%). The good compliance with critical reproduction criteria in the study reflected the capability of these CT scanners to create images of adequate quality, although optimisation should be achieved in some of the centres. Concerning radiation exposure, the mean values per centre of the dose quantities were in the range of 42-64 mGy for the weighted CTDI (CTDIw), 423-744 mGy x cm for DLP, and 1.1-1.9 mSv for E.

The mean values at three centres were close to but above the reference value proposed by the EC Guidelines for CTDIw (60 mGy), and lower than the corresponding reference level for DLP (1050 mGy x cm). Dose optimisation techniques focused on the adjustment of the CTDIw-related examination parameters were proposed.