SPECT Brain imaging in HIV infected individuals with new onset seizures

Objectives New onset seizures (NOS) in HIV infected individuals have been predominantly investigated in the developed world and prior to the availability of anti-retroviral therapy. To our knowledge, no longitudinal study has been conducted, particularly with the use of SPECT imaging. We present here the role of SPECT brain imaging as part of a larger study that we conducted to evaluate the profile of HIV infected individuals who presented with NOS in the South African setting; and to follow up those in whom no cause was identifiable at baseline.

Methods Fifteen of the 22 patients with NOS and no identifiable cause accepted to participate in this long-term study from a large cohort of HIV infected black African patients. They had repeated clinical assessments, laboratory investigations, MRI and SPECT Brain imaging. The recruitment period was over an eighteen months period from January 2013 to June 2014. ^99mTc- HMPAO was used for brain SPECT imaging and the SPECT scans were repeated at 6-monthly intervals for the duration of the patients’ inclusion in the study. The average follow-up period for female participants was 10.2 months and 6.6 months for the male counterparts. We used PMOD base functionality version 3.6 (PBAS 3.6) for quantitative assessment of counts within automatic generated regions of interest (ROIs). A single factor Analysis of Variance (ANOVA) was used to test the hypothesis that the means of cerebral counts were equal in the dominant cerebral regions.

Results There were 10 female and 5 male participants aged between 20-55 years (mean=36.9 years). The female predominance (66.6%) was unexpected in view of male predominance (57.5%) in the larger study population. The refusal of 7 patients (6 being males) to participate in this study most probably skewed the proportions. Five participants were on highly active anti-retroviral therapy (HAART) at baseline and 9 of the remaining 10 were eligible for HAART. Cerebral hypo perfusion on SPECT was noted at baseline mainly in the frontal, cingulate and temporal regions (Kolmogorov-Smirnov test of normality). Significant improvement of cerebral perfusion (p=0.003) was seen in the follow up SPECT scans in 10 of 11 patients with repeated scintigraphy imaging, but more pronounced in 4 participants who initiated HAART during the study (p= 0.001);[ paired sample t-tests].

Conclusions New onset of seizures may represent early stages of the spectrum of neurocognitive dysfunction seen in HIV infected individuals without identifiable cause. Because these individuals are likely to benefit from the initiation of HAART, the introduction of SPECT brain imaging in their follow up may play a role in the assessment of HAART related cognitive improvement.