99mTc SESTAMIBI scintigraphic evaluation of skeletal muscle disease in patients with systemic sclerosis: diagnostic reliability and comparison with cardiac function and perfusion.

The diagnosis of skeletal muscle involvement in patients with systemic sclerosis (SSc) is usually based on clinical, laboratory, electromyographic, and bioptic evidence of muscle disorder, whereas SSc cardiac disease is well established by nuclear medicine techniques (radionuclide ventriculography and myocardial scintigraphy). Previous reports have retrospectively hypothesized a possible relationship between cardiac and muscle involvement in scleroderma patients. In order to improve overall diagnostic accuracy in the qualitative/quantitative assessment of skeletal muscle involvement in these patients and to compare these results with those obtained at the cardiac level, diethylenetriaminepentaacetic acid (DTPA)-99mTc radionuclide ventriculography and 99mTc SESTAMIBI myocardial and muscular scintigraphic examinations were performed in 10 SSc patients and in five healthy subjects. Muscular radioactivity, as assessed at thigh and calf levels by means of a segmental score, was significantly decreased in SSc patients in comparison with healthy subjects (global score value 15.6+/-2.2 vs 22.7+/-1.6, p<0.001), as well as right ventricular ejection fraction (RVEF, 34.3%+/-5.3 vs 53.6%+/-4.2, p<0.001) and myocardial segmental perfusion (global score value, 19.6+/-2 vs 25.9+/-1.1, p<0.01). The results show a high frequency of skeletal muscle involvement in patients with SSc. Moreover, scleroderma patients with muscle disorders, as evidenced by scintigraphy, show a comparable occurrence of cardiac involvement, even in the absence of clinical signs of cardiac dysfunction.