| Abstract |
This pilot project funding enables Dr. Tate to collect prospective neuroimaging data on a small group of HIV infected patients that would be used to apply for future R01 applications aimed at examining dynamic brain changes during the course of HIV infection. Recent studies of HIV patients have demonstrated the utility of using white matter signal abnormalities (WMSA) identified on magnetic resonance imaging (MRI) to accurately predict an autopsy diagnosis of HIV encephalitis and dendritic arbor density loss. Though it has been postulated that HIV encephalitis has a waxing and waning course, this hypothesis has not been tested directly. Thus, this study proposed to utilize four dimensional (4D) neuroimaging methods developed in multiple sclerosis (MS) populations to examine the brains of HIV positive patients for dynamic changes that may serve as surrogate markers of relapsing/remitting HIV encephalitis. Furthermore, he will examine these changes in relation to basic clinical measures of disease severity for relationships that might be indicative of neuroimaging changes. The present study will extend cross-sectional neuroimaging finds of HIV encephalitis by examining prospectively the neuroimaging data of a small cohort (n=10) of HIV infected patients with known WMSA. Each participant will receive a baseline MRI using sequence protocols sensitive to WMSA (i.e., proton density, T1, and FLAIR). Additionally clinical measures of disease severity will be extracted via chart review (i.e., CF4, viral load, and percentage). Each participant will then be imaged at four six-week interval follow-up time points. Clinical data for each participant will also be collected via chart review at the final follow-up appointment. The WMSA volumes for each scan will be quantified using semi-automated imaging methods. WMSA volumes at each time point will be analyzed for change relative to the baseline images. Utilizing these methods, we will be able to monitor and quantify WMSA volumetric variability over time. We expect to demonstrate significant variability in measures of WMSA across time and that these measures of variability might be related to one or more measures of disease severity. This study will be the first to directly address the hypothesis of waxing and waning HIV encephalitis using established surrogate MRI markers.
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