Brain computed tomography perfusion analysis in HIV-seropositive adults with and without neurocognitive impairment in Nigeria: outcomes and challenges of a pilot study

Introduction: the significance of cerebrovascular disease in HIV-associated neurocognitive disorder (HAND) in a homogeneous black population has not yet been determined. This incident case-control study used CT perfusion imaging to quantify and compare regional cerebral blood flow parameters in neuro-cognitively impaired and unimpaired HIV+ participants of the Ibadan Cohort on Neuro AIDS (ICON) in Nigeria. Methods: this was an incident case-control study consisting of twenty-seven HIV+ adults, classified based on Frascati criteria into neurocognitive impaired (n=18) and unimpaired (n=9) groups, who had brain computed tomographic perfusion (CTP) with a 64-slice Toshiba T scanner. The standard deviation (SD) of regional mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV) values were calculated for bilateral basal ganglia (BG), frontal, parietal, temporal, and occipital regions from CT perfusion maps. The regional mean values and variability (SD) in the CTP measures were compared in the groups using an independent student t-test. Results: differentially higher variability in the bilateral CBF measures in the parietal (right; OR = 1.14, (x) over bar =5.61, p=0.041, CI=0.27-11.35/left; OR = 1.16, (x) over bar =7.01, p=0.03, CI=5.6-13.47) and time to peak (TTP) measures in the basal ganglia (right; OR = 3.78, (x) over bar =0.88, p=0.032, CI=0.081-1.67/left; OR = 2.44, (x) over bar =1.48, p=0.020, CI=0.26-2.71) and occipital (right; OR = 2.18, (x) over bar =1.32, p=0.018, CI=0.25- 2.38/left; OR = 1.93, (x) over bar =1.08, p=0.034, CI=0.0862.06) regions were observed in the cognitively impaired group compared to the unimpaired group. Conclusion: the study evidence suggests that alterations in cerebral perfusion implicated in HIV-associated neurocognitive disorder may be possibly demonstrated using CTP, a readily available resource in most African countries saddled with the highest burden of HIV.