Background and Aims The non-criteria neuropsychiatric manifestations of antiphospholipid syndrome include headache, dizziness, vertigo, seizure, depression and psychosis. There was still no objective method qualified to detect the early central nervous system involvement in non-criteria antiphospholipid syndrome. We evaluated the effectiveness of Tc-99m ECD SPECT in assessing circulatory insufficiency in the brains of patients with antiphospholipid antibodies and neuropsychiatric symptoms but without thromboembolism.

Methods Patients with a history of positive antiphospholipid antibodies and neuropsychiatric symptoms but without thromboembolism composed the case group; patients without antiphospholipid antibody served as the control group. Subjects with autoantibodies to extractable nuclear antigens were excluded from this study. All patients underwent Tc-99m ECD SPECT and were classified by the number of positive antiphospholipid antibodies they carried. The heterogeneity of brain perfusion was defined as the coefficient of variation. Analysis of variance (ANOVA) was used to evaluate the differences between groups.

Results Total 60 adult patients were included in this study. There were 54 patients in the case group and 6 patients in the control group. The mean age was 38.3±11.5 years. There were 52 women and 8 men. There was no significant difference in mean brain perfusion between groups (p=0.69). However, Tc-99m ECD SPECT demonstrated significant heterogeneity of brain perfusion in relation to the number of antiphospholipid antibodies (p=0.01).

Conclusions This is the first study to show that Tc-99m ECD SPECT can detect the increased heterogeneity of brain circulation in non-criteria antiphospholipid antibody carriers with neuropsychiatric manifestations.