Neuroimaging of HIV-associated neurocognitive disorders (HAND)

Abstract

Purpose of review HIV enters the brain after initial infection, and with time can lead to HIV associated neurocognitive disorders (HAND). While the introduction of combination antiretroviral therapy (cART) has reduced the more severe forms of HAND, milder forms are still highly prevalent. The “gold standard” for HAND diagnosis remains detailed neuropsychological performance (NP) testing but additional biomarkers (including neuroimaging) may assist in early detection of HAND. Recent findings We review the application of recently developed non-invasive magnetic resonance imaging (MRI) and positron emission tomography (PET) techniques in HIV+ individuals. In particular, magnetic resonance spectroscopy (MRS) may be more sensitive than conventional MRI alone in detecting HIV associated changes. Diffusion tensor imaging (DTI) has become increasingly popular for assessing changes in white matter structural integrity due to HIV. Both functional MRI and PET have been limitedly performed but could provide keys for characterizing neuropathophysiologic changes due to HIV. Summary It is hoped that continued progress will allow novel neuroimaging methods to be included in future HAND management guidelines.

Neurocognitive Function and Neuroimaging Markers in Virologically Suppressed HIV-positive Patients Randomized to Ritonavir-boosted Protease Inhibitor Monotherapy or Standard Combination ART: A Cross-sectional Substudy From the PIVOT Trial

“…Different neuroimaging techniques have been used to identify markers of HIV-associated neurocognitive impairment, including MRS, and the effect of different treatment options on these markers has been explored in treatment naïve patients starting cART [32]. However, information on effectively suppressed patients is lacking, and in particular there are very limited data comparing neuroimaging markers between patients on PI monotherapy and cART [33].…”

An Overview of Human Immunodeficiency Virus Type 1-Associated Common Neurological Complications: Does Aging Pose a Challenge?

“…However, molecular imaging techniques, such as proton magnetic resonance spectroscopy (MRS), show increases in the levels of choline, a cell proliferation and inflammation marker, and myo-inositol, a tissue glial marker, in almost all cases of HIV infection, even in totally asymptomatic individuals, N-acetyl-aspartate (NAA), a neuronal marker of injury and an indirect measure for brain metabolism, is found to be closely related to the degree of cognitive dysfunction. Also, blood oxygen level-dependent functional magnetic resonance imaging, which can measure the blood flow rate in the brain associated with specific cognitive functions to correlate and understand the extent of damage due to HIV infection in comparison with age-matched healthy individuals [6], could be a promising tool in the diagnosis and treatment of ANI.…”

Immune activation and neuroinflammation in alcohol use and HIV infection: evidence for shared mechanisms

“…Associations between plasma cytokines and cognition support a relationship between peripheral and CNS inflammation, with further studies needed to establish directionality. Third, non-invasive magnetic resonance imaging (MRI) measures of neurometabolism and white matter microstructure give evidence of CNS pathology in HIV infection [see brief review (156)]. Specifically, elevated myo-inositol, elevated choline, decreased N-acetyl-aspartate, and abnormal white matter microstructure in PLWH are consistent with neuroinflammatory processes (156).…”

“…Third, non-invasive magnetic resonance imaging (MRI) measures of neurometabolism and white matter microstructure give evidence of CNS pathology in HIV infection [see brief review (156)]. Specifically, elevated myo-inositol, elevated choline, decreased N-acetyl-aspartate, and abnormal white matter microstructure in PLWH are consistent with neuroinflammatory processes (156). Large neuroimaging studies of PLWH have reported that immune activation markers (e.g., MCP-1, sCD14) in plasma and cerebrospinal fluid are associated with elevated choline, elevated myo-inositol, and decreased N-acetyl-aspartate (149, 157–159).…”