SENSITIVITIES OF NONINVASIVE TESTS FOR CENTRAL-NERVOUS-SYSTEM VASCULITIS - A COMPARISON OF LUMBAR PUNCTURE, COMPUTED-TOMOGRAPHY, AND MAGNETIC-RESONANCE-IMAGING

Objective. To determine the sensitivities of lumbar puncture (LP), com puted tomography (CT), and magnetic resonance imaging (MRI) for centra l nervous system (CNS) vasculitis. Methods. We reviewed the charts and radiologic studies of 20 patients with angiogram positive CNS vasculi tis. Results. The patients ranged in age from 7-72 years, with a mean of 43.7 +/- 15.5 years. Twelve patients (60%) were women; 8 (40%) were men. Seven had primary angiitis of the CNS (PACNS), 8 had rheumatolog ical illnesses (4 had systemic lupus erythematosus), and 5 had vasculi tis due to other diverse etiologies, including 2 who had CNS infection s. LP was positive in 8/15 angiographically proven cases, for a sensit ivity of 53% [95% confidence interval (CI): 27-79]. The sensitivity of CT was 65% (11/17) (95% CI: 38-86), and that of MRI 75% (12/16) (CI: 48-93). The use of LP plus either CT or MRI was more sensitive than LP alone: for LP and CT, the sensitivity was 92% (11/12) (CI: 62-100), a nd for LP and MRI, 100% (12/12) (CI: 74-100). The combination of CT an d MRI was not more sensitive than either test alone. Conclusion. The s ensitivities of LP, CT, and MRI for angiogram positive vasculitis are only modest. CT and MRI may be completely normal in cases of CNS vascu litis when the angiogram is positive. LP and either CT or MRI are of a dditive benefit in the diagnosis of CNS vasculitis, and should be done before angiography; and, in a patient with both a normal LP and a nor mal CT or MRI, a CNS angiogram is unlikely to be positive for vasculit is.