Automated T2 quantitation in neuropsychiatric lupus erythematosus: a marker of active disease.

Abstract

Active neuropsychiatric systemic lupus erythematosus (NPSLE) is characterized by brain edema as measured by manual quantitative magnetic resonance (MR) relaxometry. An automated image processing method was developed to segment gray matter (GM), while minimizing the effects of confounding factors, specifically cerebral atrophy and volume averaging artifacts. Twenty patients with SLE (10 major, 10 minor), matched for atrophy, were studied. We compared T2 calculated for GM segmented by manual and automated methods. Both methods demonstrated a marked increase in GM T2 in patients with major NPSLE (P < 0.001), confirming the presence of cerebral edema. The results from each method were highly correlated, (r = 0.64, P = 0.002). The automated method effectively identifies GM, minimizes volume averaging artifacts, and produces results similar to the manual method. This method markedly decreases analysis time and will make quantitative relaxometry a valuable contribution to the clinical management of NPSLE.