T1-weighted MRI identifies advancing type of multiple sclerosis

Long-standing suspicions about noncontrast T1-weighted MRI's usefulness as a biomarker for multiple sclerosis have been confirmed in a study showing that hyperintense plaques revealed with the technique are associated with brain atrophy, disability, and an advancing course for the disease.

Previous studies with unenhanced T1-weighted MRI suggested a link between hyperintense brain lesions and conditions such as MS that lead to the deposition of paramagnetic substances, remyelination, macrophage infiltration, and free radical generation. Until now, however, the frequency, location, and clinical correlation of these lesions in patients with MS had not been formally assessed.

Those issues were addressed in a study by radiologists and neurologists at Brigham and Women's Hospital, Massachusetts General Hospital, and the University of Buffalo. First author Dr. Vallabh Janardhan and colleagues found a significant correlation between hyperintense lesions, detected with noncontrast T1-weighted MRI, and secondary-progressive MS.

"Based on these findings, physicians may be able to diagnose multiple sclerosis more accurately and identify patients at risk for developing progressive disease," said senior investigator Dr. Rohit Bakshi, an associate professor of neurology and radiology at Brigham and Women's.

Bakshi, Janardhan, and Dr. Sonu Suri, a radiologist at Buffalo, retrospectively reviewed data from 145 MS patients who underwent unenhanced T1-weighted MRI from July 1995 to June 1999. Ninety-two patients had relapsing-remitting MS, and 49 were diagnosed with secondary-progressive MS. The disease type was unknown in four cases.

They found 340 areas of T1 shortening, indicative of hyperintense plaques, in 123 patients. More than two-thirds of patients with secondary-progressive MS had multiple T1-detected hyperintense lesions, compared with 46% of the relapsing-remitting patients.

The presence of such hyperintense plaques correlated significantly with brain atrophy (p≤0.001). According to the report in the September issue of Radiology, the T1 hyperintense lesions were better correlated with disability than T2 hyperintense lesions. They showed better differentiation between recurring-remitting and secondary-progressive MS than did either T2 hyperintense or T1 hypointense lesions.

Janardhan, now an assistant professor of neurology, radiology, and neurologic surgery at the University of Minnesota, told Diagnostic Imaging that this is good news from the patient's standpoint.

"We have a newer surrogate marker in MS that enables physicians to look at the disease activity and helps them understand how many pathologic changes have happened in their patients and in which side of the spectrum they are, whether in an early stage with not much disability or a later stage with disability," he said.

For more information from the Diagnostic Imaging archives:

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7T MR excels in multiple sclerosis detection

Diffusion tensor imaging uncovers hidden brain abnormalities in elderly patients

3T MR improves multiple sclerosis assessment