Accuracy of 133-xenon regional cerebral blood flow and quantitative electroencephalography in systemic lupus erythematosus

Objective: comparative assessment of sensitivity and specificity of regional Cerebral Blood Flow (rCBF) by 133-Xenon inhalation and quantitative Electroencephalography (qEEG) in patients with Neuropsychiatric Systemic Lupus Erythematosus (NP-SLE). Methods: Sixty-two combined rCBF and qEEG examinations were performed in fifty-two SLE patients. Group A: 27 SLE patients without NP-SLE; group B: 17 patients with florid (within 1 month) NP-SLE; group C: 12 patients with previous NP-SLE examined in the remission phase (four patients of which already considered in group B). The study also included data deriving from two sets of examinations in ten patients who were observed twice, in different phases of the clinical course of NP-SLE. Results: in comparison to healthy controls, rCBF was lower (p < .001) in group B only, whereas qEEG showed similar increases of both delta and theta relative powers together with a reduction of alpha relative power in groups A-C. As compared to group A, sensitivity and specificity in detecting cerebral abnormalities in group B were 76% and 78% for rCBF, and 59% and 44% for qEEG, respectively. In the ten patients examined twice, rCBF was consistent with clinical course in 90% of cases and qEEG in 60%. Conclusion: total accuracy in detecting cerebral functional abnormalities during florid NP-SLE is better by rCBF than by qEEG. rCBF and, in selected cases, qEEG examinations are reliable markers of NP-SLE.