Could MRI scans present a less invasive method of identifying HIV in the nervous system?

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Researchers from University College London (UK) have demonstrated that MRI scans may help to identify when HIV is persisting in the central nervous system. This could present an alternative to current, invasive lumbar puncture procedure, and could help identify individuals at risk.

The study, published recently in Clinical Infectious Diseases, demonstrated that neurological changes, termed diffuse white matter signal abnormalities, observed on patients’ MRI scans were associated with HIV-1 viral escape in the central nervous system.

Senior author Ravi Gupta (University College London) explained: “Before we had effective treatments for HIV, AIDS often led to dementia and other problems in the brain. Thankfully this is less common now that we can treat HIV, but up to half of HIV patients still report cognitive problems.

“We see evidence that HIV has spread to the brain in around 10–15% of these patients, but in most cases the symptoms are down to other causes. At the moment we have to perform a lumbar puncture to confirm this, which involves inserting a needle into the back to draw out the spinal fluid and test it for HIV. This is quite an invasive procedure that requires patients to stay in hospital for several hours. Our new study shows that MRI scans could help to identify high-risk individuals for further follow-up tests.”

The team analyzed data from 146 HIV patients who underwent a lumbar puncture after reporting cognitive problems between 2011 and 2015. The lumbar punctures confirmed cerebrospinal fluid (CSF) discordance in 22 patients (Viral load in CSF 0.5 log10 copies HIV-1 RNA greater than plasma), of which 9 patients had CSF escape (detection of HIV VL >50 copies/ mL).  The researchers then utilized multivariate analysis, demonstrating that both CSF discordance and escape were associated with diffuse white matter signal abnormalities observed on cranial MRI scans.

Patients whose brains were observed to have diffuse white matter signal abnormalities were 10-times more likely to have HIV in the brain than those with normal white matter appearances. In addition, treatment-experienced patients compromised the majority of the group with CSF escape, suggesting that HIV can persist in the brain despite adequate control by antiretroviral drugs.

Gupta commented: “HIV treatments have come a long way, but patients whose HIV is suppressed by drugs can still have cognitive problems due to HIV-related inflammation. MRI scans can help to diagnose these patients, whether showing an elevated risk of HIV-related problems or finding a different cause that can then be treated. Where HIV has spread to the brain, we can change the treatment regime to add drugs that cross the blood–brain barrier more effectively to control the infection.”

Source: Kugathasan R, Collier DA, Haddow LJ et al. Diffuse White Matter Signal Abnormalities on Magnetic Resonance Imaging Are Associated With Human Immunodeficiency Virus Type 1 Viral Escape in the Central Nervous System Among Patients With Neurological Symptoms. Clin. Infect. Dis. doi: 10.1093/cid/cix035 (2017) (Epub ahead of print); http://www.uclh.nhs.uk/News/Pages/MRIscanscanhelpspotHIVinthebrain.aspx

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