7T proton MR spectroscopic imaging can identify brain changes in multiple sclerosis: Study
Austria: A recent study in the journal Radiology suggests that MR spectroscopic imaging at 7.0 T can identify changes in the brains of patients with multiple sclerosis (MS) that were not visible at T1- or T2-weighted MRI. Further, metabolic abnormalities in the normal-appearing white matter and cortical gray matter were found to be related to disability.
Previous studies have shown that MR spectroscopic imaging (MRSI) allows in vivo assessment of brain metabolism. Also, it is of special interest in MS, where morphologic MRI cannot depict major parts of disease activity. Wolfgang Bogner, and the team therefore, aimed to evaluate the ability of 7.0-T MRSI to depict and visualize pathologic alterations in the normal-appearing white matter (NAWM) and cortical gray matter (CGM) in patients with MS and to investigate their relation to disability.
For this purpose, the researchers performed free-induction decay MRSI at 7.0 T. Between January 2016 and December 2017, participants with MS and age- and sex-matched healthy controls were recruited prospectively. Metabolic ratios were obtained in NAWM, white matter lesions, and CGM regions.
The researchers also performed subgroup analysis for MS-related disability based on Expanded Disability Status Scale (EDSS) scores. Associations between metabolic ratios and disability were also explored.
Sixty-five participants with MS and 20 age- and sex-matched healthy controls were evaluated.
Key findings include:
- Higher signal intensity of myo-inositol (mI) with and without reduced signal intensity of N-acetylaspartate (NAA) was visible on metabolic images in the NAWM of participants with MS.
- A higher ratio of mI to total creatine (tCr) was observed in the NAWM of the centrum semiovale of all MS subgroups, including participants without disability (marginal mean ± standard error, healthy controls: 0.78 ± 0.04; EDSS 0–1: 0.86 ± 0.03; EDSS 1.5–3: 0.95 ± 0.04; EDSS ≥3.5: 0.94 ± 0.04).
- A lower ratio of NAA to tCr was found in MS subgroups with disabilities, both in their NAWM (marginal mean ± standard error, healthy controls: 1.46 ± 0.04; EDSS 1.5–3: 1.33 ± 0.03; EDSS ≥3.5: 1.30 ± 0.04) and CGM (marginal mean ± standard error, healthy controls: 1.42 ± 0.05; EDSS ≥3.5: 1.23 ± 0.05).
- mI/NAA correlated with EDSS (NAWM of centrum semiovale: r = 0.47; parietal NAWM: r = 0.43; frontal NAWM: r = 0.34; frontal CGM: r = 0.37).
"Our findings demonstrated that multivoxel 7.0-T free-induction decay MR spectroscopic imaging can depict and visualize pathologic manifestations of multiple sclerosis that is beyond demyelinating lesions that are associated with a disability," wrote the authors.
Considering these invisible changes could enhance measures for ongoing disease activity, and would improve the monitoring of disease progression and efficacy of current treatment and supporting decision-making for treatment switching, they explained.
Reference:
The study titled, "Extensive Brain Pathologic Alterations Detected with 7.0-T MR Spectroscopic Imaging Associated with Disability in Multiple Sclerosis," was published in the journal Radiology.
