Spinal cord abnormalities have a strong effect on clinical disability in multiple sclerosis (MS), according to a study published in the November issue of Radiology.
MS is a heterogeneous neurologic disease with a broad range of deficits. Focal abnormalities in the spinal cord are highly common in most patients with MS and most frequently affect the cervical region rather than the thoracic or lumbar.
“Because spinal cord atrophy tends to occur in the first few years of MS, quantification of spinal cord volume or cross-sectional area with MR imaging seems to be a potential marker for monitoring the disease course or treatment effectiveness,” wrote Carsten Lukas, MD, of Ruhr University Bochum, Germany, and colleagues.
The authors designed a study that examined a large cohort of patients with MS in order to determine if spinal cord atrophy differs among disease subtypes in MS and if it offers more diagnostic and clinical correlative information than that given by other MR imaging markers.
Four hundred fifty-eight patients were retrospectively chosen from a genome-wide association study conducted at two centers between May 2004 and December 2007. Participating patients were classified as having relapsing-remitting MS, secondary-progressive MS, or primary-progressive MS. Upper cervical cord cross-sectional area (UCCA), brain and spinal cord lesions, and brain atrophy were measured.
Disability was assessed using the Expanded Disability Status Scale (EDSS) and two subtests of the Multiple Sclerosis Functional Composite Measure—the timed 25-foot walk test to evaluate ambulatory function and the nine-hole peg test to assess upper limb function.
The UCCA in patients with secondary-progressive MS and primary-progressive MS was significantly smaller than that in patients with relapsing-remitting MS, reported Lukas and colleagues. UCCA was inversely correlated with EDSS score, walk test, and nine-hole peg test findings. UCCA, the number of hypointense brain lesions on T1-weighted MR images, presence of diffuse abnormalities, and the number of involved segments in the spinal cord were found to be significant explanatory factors for clinical disability. The UCCA and the number of hypointense brain lesions on T1-weighted images were the strongest MR imaging parameters for explaining physical disability, as measured with the EDSS.
“Overall, our study showed that measurement of the upper cervical cord area is feasible with use of brain data sets, which has important implications for clinical studies, including treatment trials. Without the additional spinal cord examination, total acquisition times can be shorter, reducing both cost and patient burden,” wrote the authors.