I-123 MIBG cardiac scintigraphy and autonomic test evaluation in multiple sclerosis patients

Autonomic symptoms are common in multiple sclerosis (MS) patients and may cause significant disability. The purpose of this study was to evaluate direct cardiac sympathetic denervation in MS patients with I-123 MIBG cardiac scintigraphy compared with other parasympathetic electrophysiological examinations of autonomic dysfunction. Ten patients with MS and 7 age- and sex-matched control subjects were prospectively evaluated. The neurological deficit and disability stages of the patients were rated according to the Kurtzke Expanded Disability Status Scale (EDSS). Autonomic tests included the R-R interval, Valsalva ratio and standup test. All patients and control subjects had planar and SPECT cardiac scintigraphy with I-123 MIBG injection. Seven MS patients had relapsing-remitting (R-R) type and three had secondary progressive type (SP). A pathological MIBG cardiac washout rate was found in 3/10 MS patients, all of them with SP-MS. The other seven had normal washout rates. No correlation was found between the scan and the individual parasympathetic autonomic test results. I-123 MIBG myocardial scintigraphy may detect direct disturbances of the sympathetic cardiac function in patients with MS in addition to parasympathetic dysfunction tests and can be an important additional means of assessing autonomic pathways. Determination in MS of the co-existence of autonomic dysfunction, especially the cardiac sympathetic involvement in the SP type, may aid in evaluation of disease severity and cardiac function follow-up.