Technetium-99m-HMPAO brain SPECT in Behçet's disease

Behçet's disease (BD) is an idiopathic multisystem disorder. Involvement of the central nervous system (CNS) occurs in 4%-48% of cases. The aim of this study was to evaluate 99mTc-hexamethyl propyleneamine oxime (HMPAO) SPECT findings in BD patients and eventually to detect CNS involvement by depicting cerebral blood flow disturbances.

Technetium-99m-HMPAO brain SPECT was performed on 33 consecutive BD patients. Qualitative and quantitative evaluation of the cortical uptake was done using an automatic program that generated 32 regions of interest (ROIs). An uptake index for each ROI was obtained. Reference values were obtained from a healthy control group (n = 20). Twenty-five patients also had an MRI study.

Twelve of 32 patients (36%) presented with a clinical neurological disorder. SPECT and visual evaluation revealed that 17 patients (51.5%) had abnormalities; 9 of 25 MRI studies (36%) were abnormal. Using the quantitative approach for SPECT, 23 patients (69.7%) had abnormally low values. Six of 12 patients with neurological symptoms had a visually abnormal SPECT scan, whereas quantitative analysis showed abnormalities in 11 patients. Of the 21 patients with no neurological findings, 9 had abnormal SPECT results, and 12 had low uptake indexes.

HMPAO brain SPECT shows high rates of cerebral blood flow abnormalities in BD patients presenting with neuropsychiatric symptoms, and it also is frequently abnormal in asymptomatic BD patients who have no abnormalities on MR scans. Compared with visual analysis, quantitative analysis detects an even higher rate of SPECT changes in BD patients.