Technetium-99m-HMPAO brain SPECT in systemic lupus erythematosus with CNS involvement

Functional brain SPECT is playing an increasingly important role in evaluating CNS conditions in patients with systemic lupus erythematosus (SLE). However, SPECT findings varied in different studies because of their small population. Furthermore, earlier researchers, being restricted by the resolution of the camera, might not have been able to evaluate deep-seated nuclei such as the basal ganglia and thalamus. In this study, we describe the different patterns of SPECT findings in SLE patients with CNS involvement.

Seventy-two SLE patients (aged 14-67 yr; mean 33.2 yr) were divided into three groups: Group 1 with definite neuro-psychiatric disorder (including stroke, seizures and psychosis); Group 2 with minor neuropsychiatric disorders (headache, dizziness and recent memory impairment); and Group 3 without any neuropsychiatric symptoms or signs. Ninety minutes after injection of 1110 MBq 99mTc-HMPAO, brain SPECT was performed using a dual-head camera and fan-beam collimator. In addition, MRI and an electroencephalography (EEG) were also performed.

SPECT findings were normal in 87% of the Group 3 patients and abnormal in all Group 1 patients; 84.6% of the Group 2 patients had abnormal SPECT findings. The parietal, frontal and temporal lobes were the most common areas of CNS involvement. Parietal lobes were involved in 95.6% of Group 1 patients and 80.7% in Group 2 patients. Frontal lobes were involved in 56.5% of Group 1 patients and 65.3% of Group 2 patients. Temporal lobes were involved in 56.5% of Group 1 patients and 46.1% of Group 2 patients. The basal ganglion was involved in about 30% of Group 1 patients and 11.5% of Group 2 patients, while the thalamus and cerebellum were less involved in neuropsychiatric SLE. MR images showed less sensitivity in the detection of CNS involvement than the SPECT and were normal in 27.3% of patients with definite neuropsychiatric disorders. The EEG and anticardiolipin antibody did not correlate well to the clinical diagnosis.

HMPAO brain SPECT had the best correlation with the clinical diagnosis and may provide additional and objective information on SLE patients with potential CNS involvement.