Radiology: MRI techniques show gray matter changes in MS patients
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| Image source: Cedars-Sinai Medical Center |
Previous histopathologic studies have shown pathologic changes in the cortex of MS patients, and MRI has shown cortical atrophy is an early and widespread phenomenon for these patients. Double inversion recovery imaging has also allowed the observation of cortical lesions, which increase in number and volume over the course of the disease and correlate with disability and cognitive decline.
Gray matter damage, though, has been more difficult to assess, though the combination of diffusion tensor imaging and double inversion recovery has shown promise in detecting changes in normal-appearing gray matter among small groups of patients in previous studies, according to the authors.
In this latest study, Massimiliano Calabrese, MD, from the department of neurosciences at the University of Padova in Padua, Italy, and colleagues wanted to evaluate whether the combination of diffusion-tensor imaging and double inversion recovery imaging could improve detection of structural changes in the cortex of patients with MS.
Calabrese et al examined 168 patients with relapsing-remitting MS and 45 sex- and age-matched control subjects in the three-year longitudinal study.
Results showed fractional anisotropy of normal-appearing gray matter was higher in MS patients at baseline, and after three years had increased in patients while remaining unchanged in the control subjects. Mean diffusivity of gray matter exhibited similar behavior.
At baseline, fractional anisotropy was significantly correlated with patients’ scores on the Expanded Disability Status Scale (EDSS) and changes in fractional anisotropy predicted EDSS change.
The results indicated that diffusion tensor imaging is very sensitive to gray matter damage and that the damage is more severe in MS patients who exhibit more physical disability, findings that the researchers say could have clinical benefit.
“The combination of double inversion recovery and diffusion-tensor imaging might be helpful in the diagnostic work-up of MS as well as in monitoring the disease progression and response to anti-inflammatory therapy,” wrote the authors.
Calabrese et al considered whether structural changes in the cortex could be the result of local activation of microglia cells. They explained that cortical lesions are characterized by microglia proliferation and activation, and activated microglia changes its morphology to acquire a more anisotropic structure.
“Further investigations are needed to clarify the possible application of cortical [fractional anisotropy] in the diagnostic phase as well as in monitoring the disease progression and the response to anti-inflammatory therapy,” wrote the authors.
Evan Godt, Writer
Evan joined TriMed in 2011, writing primarily for Health Imaging. Prior to diving into medical journalism, Evan worked for the Nine Network of Public Media in St. Louis. He also has worked in public relations and education. Evan studied journalism at the University of Missouri, with an emphasis on broadcast media.