Sensitivity and reproducibility of volume change measurements of differentbrain portions on magnetic resonance imaging in patients with multiple sclerosis

The course of multiple sclerosis (MS) can be monitored by measuring changes in brain volume, but consensus is still lacking on the best strategy to be adopted. We compared the reproducibility and sensitivity of volume measure ments from different brain portions for detecting changes on magnetic reson ance imaging (MRI) in patients with MS. T1-weighted MRI of the brain was pe rformed in 50 patients with relapsing-remitting MS at study entry and after an average follow-up of 18.4 months. Using a semiautomated technique for b rain parenchyma segmentation, the volumes of the following brain portions w ere measured: (a) the whole brain (whole-brain volume, WBV), (b) the seven slices rostral to the velum interpositum (seven-slice volume, SSV), (c) the central slice of the image set (central-slice volume, CSV) and (d) the inf ratentorial regions (infratentorial-brain volume, IBV). All these measureme nts were carried out by a single observer and were repeated twice on ten ra ndomly selected scans to test the intra-observer reproducibility using the four strategies. At follow-up there was a significant decrease in all the m easures of brain volume (P ranged from 0.002 to < 0.001). The univariate co rrelations between changes in WBV, SSV, CSV and IBV were all statistically significant, with the exception of that between changes in CSV and IBV; r v alues ranged from 0.34 (for the WBV/IBV correlation) to 0.80 (for the WBV/S SV correlation). The mean intra-observer coefficient of variations were 1.9 % for WBV, 1.5 % for SSV, 2.9 % for CSV and 2.2 % for IBV measurements. Th e measurement of volume on a portion of brain selectively including the reg ions in which MS pathology is more diffuse is as reliable and sensitive to disease-related changes as that on the whole brain, with significant time s aving for processing.