MRI-GUIDED BIOPSY IN INFLAMMATORY MYOPATHY - INITIAL RESULTS

The purpose of this report is to describe our initial experience with techniques employing magnetic resonance imaging (MRI) to guide the cho ice of muscle to be biopsied in patients suspected of having inflammat ory myopathy. Five patients with a clinical diagnosis of inflammatory myopathy (IM) were studied. Four were imaged prior to biopsy. Four had repeated examinations, either immediately following biopsy or to eval uate disease progression. Use of MRI to localize muscle lesions was as sociated with abnormal pathologic findings in all cases, including his topathologic demonstration of lymphocyte infiltration in three cases o f idiopathic polymyositis; nonspecific myopathic changes were seen in one patient with probable dermatomyositis and in one patient with chro nic inflammatory polyneuropathy and high serum creatine kinase levels (>45,000 IU/ml). The precise location of the area sampled by biopsy wa s visible in only one of four postbiopsy images. MRI shows promise in identifying pathologic muscle in patients suspected of having one of t he inflammatory myopathies; however, further refinement of localizatio n techniques may be needed to optimize histopathologic diagnoses.