BRAIN SINGLE-PHOTON EMISSION TOMOGRAPHY WITH TC-99M-HMPAO IN NEUROPSYCHIATRIC SYSTEMIC LUPUS-ERYTHEMATOSUS - RELATIONS WITH EEG AND MRI FINDINGS AND CLINICAL MANIFESTATIONS

Central nervous system (CNS) involvement in patients with systemic lup us erythematosus (SLE) is often difficult to evaluate because of prote an neuropsychiatric (NP) manifestations and lack of reliable diagnosti c markers. In the reported study the role of single-photon emission to mography (SPET) with technetium-99m hexamethylpropylene amine oxime (H MPAO) in the evaluation of CNS involvement in SLE was assessed and the relations between SPET perfusion defects, EEG examination, magnetic r esonance imaging (MRI) findings and clinical presentation were examine d. Twenty SLE patients with different NP manifestations were studied. Multiple areas of hypoperfusion, especially in the territory of the mi ddle cerebral artery, were demonstrated by SPET analysis in all 20 pat ients. The number of hypoperfused areas and the degree of hypoperfusio n, expressed by an asymmetry index (AI), were more marked in patients with multiple NP manifestations, MRI and EEG evaluations were positive for 14 of 18 and for 12 of 20 patients, respectively. In the patients with positive SPET and MRI, 87 MRI focal lesions and 63 hypoperfused areas were found, and for 51 of these 63 at least one MRI lesion was f ound in the same anatomical region. SPET examination of patients with a normal EEC showed fewer hypoperfused areas and a lower degree of asy mmetry compared to patients with an abnormal EEG. SPET of patients wit h focal EEG abnormalities showed more hypoperfused areas (difference n ot statistically significant) and a higher AI than did SPET of the pat ients with diffuse EEG abnormalities. Seven of 11 anatomical regions w ith focal EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities had co-localized hypoperfused areas and in two of t hese seven no detectable MRI lesions were found. The analysis of SPET and NP manifestations showed that 12 of 20 patients had at least one p ositive correlation, always involving the areas with the highest AI. I n total, 51/88 (58%) hypoperfused areas correlated with the MRI findin gs and 31/88 (35%) with NP manifestations; for seven of the latter no concurrent MRI lesions were detected in the same anatomical region. It is concluded that SPET study of brain perfusion is a sensitive method for the evaluation of CNS involvement in SLE; furthermore, it is able to reveal disease progression and the lesions most relevant at the ti me of evaluation, and can objectify those NP manifestations without de tectable MRI abnormalities. Nevertheless, because of the sensitivity o f MRI in detecting morphological lesions, a complete evaluation of CNS involvement should be performed, combining SPET with MRI.