CVR Abnormalities Evaluated in HIV-Infected Women Using Quantitative Whole Brain ASL
Despite viral suppression, individuals living with HIV face increased rates of stroke and neurocognitive impairment compared with the general population. The association of HIV and stroke has been most strongly observed in women living with HIV, who may have up to 75% greater risk of ischemic stroke than uninfected women.
A team of scientists from the UC San Francisco Departments of Radiology and Biomedical Imaging, Neurology, and Division of Infectious Diseases along with the UC Berkeley Department of Mechanical Engineering and Subtle Medical, Inc. (Menlo Park, California) set out to assess whole brain and regional patterns of cerebrovascular reactivity (CVR) abnormalities in HIV-infected women using quantitative whole brain arterial spin labeling (ASL).
They hypothesized that HIV-infected women would demonstrate decreased regional brain CVR despite viral suppression. For the study, the team of scientists recruited subjects from the Bay Area Women's Interagency Health Study (WIHS), a cohort study funded by the National Institutes of Health (NIH) to investigate the progression of HIV in women living in the U.S.
Overall, they evaluated 10 HIV-infected women and seven uninfected, age-matched controls. They evaluated findings on conventional non-contrast cerebral MRI sequences. In addition, cerebrovascular reactivity testing (CVR) was performed in both subjects and age matched controls, to evaluate for "silent markers" of cerebrovascular health. The team of scientists found significant group differences in whole brain and regional CVR between HIV infected and uninfected women, despite similar "traditional" MRI imaging findings in the two groups.
“Women living with HIV face significantly increased rates of stroke and neurocognitive decline compared with the general population” says Andrew Callen, MD, first author on this study, published in the Journal of NeuroVirology. “Despite this, traditional imaging markers of cerebrovascular disease do not appropriately reflect that risk. CVR testing reveals underlying dysfunction at the level of the neurovascular unit. Combined with advanced MR perfusion techniques, these tests may reveal pre-clinical vascular pathology, and allow for earlier clinical interventions towards stroke prevention and risk reduction in this patient population.”
“This work is significant because it further validates a diagnostic tool to reveal otherwise hidden underlying cerebrovascular pathology in vulnerable patient populations, allowing for earlier clinical interventions towards stroke prevention and risk reduction,” continues Dr. Callen. “Long term, CVR testing can contribute to the development of targeted interventions to reduce stroke risk and improve sex-specific risk prediction models to identify HIV+ women and men at greatest risk.”
Dr. Callen was part of the UCSF Radiology Residency Class of 2019. He just completed his neuroradiology fellowship here and was a 2018-19 T32 scholar. This project reflects his work during that T32 year. Dr. Callen has accepted a faculty position at the University of Colorado where he will begin as an Assistant Professor in Neuroradiology this July.
UCSF Radiology faculty members Jason Talbott, MD, PhD, David Saloner, PhD and Jared Narvid, MD along with Evan Calabrese, MD, PhD were authors on this study. Other authors include Sara M. Dupont (Subtle Medical); Jeffrey Pyne, PhD (UC Berkeley); Phyllis Tien, MD (UCSF School of Medicine); and Felicia C. Chow (UCSF Weill Institute for Neurosciences).