Interobserver agreement in the assessment of cerebral atrophy on CT using bicaudate and sylvian-fissure ratios.

To assess the interobserver variability of cerebral-atrophy measures on CT, three investigators measured the bicaudate ratio (BCR) and the sylvian-fissure ratio (SFR) on 20 CT studies of patients with ischaemic stroke. The intraclass correlation coefficient of BCR measurements was 0.82 [95% confidence interval (CI) 0.75-0.94], and that of SFR measurements 0.69 (95% CI 0.57-0.89). The range of pairwise-calculated Pearson correlation coefficients was smaller for measurement of the BCR (0.89-0.92) than for the SFR measurements (0.66-0.84).