Subclinical cerebral involvement in Behcet's disease: a SPECT study.

Neurologic involvement has been reported in Behcet's disease (BD) with prevalence rates of 4-49%. Involvement of the central nervous system (CNS) usually follows systemic manifestations of BD by months to years, but as the initial future in only 5% of cases. The variance of the prevalence rates of neurologic involvement in BD raises the possibility of subclinical neurologic involvement. For the purpose of explaining the variance in the prevalence rates, 20 patients with BD, but without neurological symptoms and signs, were investigated by using cerebral single photon emission computed tomography (SPECT) which seems to be more convenient for BD than other scanners. A control group of patients with various diseases that were not expected to influence the cerebral blood flow was included. Brain magnetic resonance imaging (MRI) scans were performed in cases in which abnormal SPECT findings were obtained. Decreased and asymmetrical tracer uptakes were detected in 35% of patients with BD. MRI scans were normal in these patients. We concluded that functional imaging using SPECT may detect abnormalities at an initial stage prior to their progression to morphological damage detectable by MRI, and this imaging modality can be used even in cases which show no neurologic symptom to indicate the subclinical neurologic involvement.