Has your patient's multiple sclerosis lesion burden or brain atrophy actually changed?

• Published in: Multiple sclerosis Vol. 10; no. 4; pp. 402 - 406
• Main Authors: Wei, Xingchang, Guttmann, Charles RG, Warfield, Simon K, Eliasziw, Michael, Mitchell, J Ross
• Format: Journal Article
• Language: English
• Published: Thousand Oaks, CA SAGE Publications 01.08.2004; Arnold; Sage Publications Ltd
• Subjects: Algorithms; Atrophy; Biological and medical sciences; Brain - pathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Diagnosis, Computer-Assisted; Differential Threshold; Humans; Immunomodulators; Magnetic Resonance Imaging; Medical sciences; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Multiple Sclerosis, Chronic Progressive - diagnosis; Multiple Sclerosis, Relapsing-Remitting - diagnosis; Neurology; Pharmacology. Drug treatments; image processing; magnetic resonance imaging; brain atrophy; multiple sclerosis; computer-assisted; Human; brain atrophy; computer-assisted; image processing; Multiple sclerosis; Nervous system diseases; Image processing; Central nervous system; magnetic resonance imaging; multiple sclerosis; Nuclear magnetic resonance imaging; Inflammatory disease; Encephalon; Atrophy; Central nervous system disease; Computer; Medical imagery; Degenerative disease
• ISSN: 1352-4585; 1477-0970
• DOI: 10.1191/1352458504ms1061oa

Changes in mean magnetic resonance imaging (MRI)-derived measurements between patient groups are often used to determine outcomes in therapeutic trials and other longitudinal studies of multiple sclerosis (MS). However, in day-to-day clinical practice the changes withinindividual patients may also be of interest. In this paper, we estimated the measurement error of an automated brain tissue quantification algorithm and determined the thresholds for statistically significant change of MRI-derived T2 lesion volume and brain atrophy in individual patients. Twenty patients with MS were scanned twice within 30 min. Brain tissue volumes were measured using the computer algorithm. Brain atrophy was estimated by calculation of brain parenchymal fraction. The threshold of change between repeated scans that represented statistically significant change beyond measurement error with 95% certainty was 0.65 mL for T2 lesion burden and 0.0056 for brain parenchymal fraction. Changes in lesion burden and brain atrophy below these thresholds can be safely (with 95% certainty) explained by measurement variability alone. These values provide clinical neurologists with a useful reference to interpret MRI-derived measures in individual patients.