Segmentation of progressive multifocal leukoencephalopathy lesions in fluid-attenuated inversion recovery magnetic

Background and Purpose. The authors compared the reproducibility of a manua l and a semiautomated technique for the quantitation of white-matter lesion s in magnetic resonance imaging (MRI). Methods. Volumes of white-matter les ions were determined using fluid-attenuated inversion recovery MRI in 23 AI DS patients with progressive multifocal leukoencephalopathy. Manual outlini ng was compared to an automated method based on region growing and adaptive thresholding. Results. Lesion volumes from the 2 methods correlated well ( 61 lesions, r = 0.99, P < 10(-4)), although the volumes differed substantia lly (12.8% +/- 13.7%). Interscan, intrasubject reproducibility was better f or the automated than the manual method (2.9% +/- 3.2% vs 12.4% +/- 16.2% v olume difference, P = .02). Conclusion. The automated algorithm appeared mo re reproducible, which renders it superior to the manual method for longitu dinal studies.