Arterial Spin Labeled (ASL) MRI Differentiates HIV Neurocognitive Impairment (HNCI) Subtypes

Beau Ances, UC-San Diego
Biomedical and Clinical Sciences

Background: Accurate assessment of cognitive impairment due to HIV in the CNS is critical for determining an individual s neurological prognosis and possible response to highly active anti-retroviral therapy (HAART). Neuronal cell damage as well as reversible alterations in neuronal cell function underlies poor neuropsychological performance (NP). Non-invasive brain imaging provides an objective and quantitative assessment of brain integrity and function.

Methods: Arterial Spin Labeled Magnetic Resonance Imaging (ASL-MRI), was used to determine baseline global and regional cerebral blood flow (CBF) changes in 44 HIV associated neurocognitive impairment (HNCI) patients (24 mild cognitive dementia (MCMD) and 20 HIV associated dementia (HAD)) and 10 seronegative controls.

Results: Baseline global CBF values were similar for all groups. However, baseline CBF within areas known to be affected by HIV, the caudate and globus pallidus, was significantly affected in HNCI patients compared to seronegative controls.

Conclusions: These results suggest that HIV downregulates direct subcortical pathways involved in directed movements. Targeted regional ASL-MRI analysis of CBF within subcortical areas of the brain commonly damaged by HIV may predict individuals at risk for development of cognitive impairment and aid in determining responses to HAART or other neuroprotective therapies.