Atrophy of Foot Muscles in Diabetic Patients Can Be Detected With Ultrasonography

Abstract

OBJECTIVE—To establish a bedside test with ultrasonography for evaluation of foot muscle atrophy in diabetic patients. RESEARCH DESIGN AND METHODS—Thickness and cross-sectional area (CSA) of the extensor digitorum brevis muscle (EDB) and of the muscles of the first interstitium (MILs) were determined in 26 diabetic patients and in 26 matched control subjects using ultrasonography. To estimate the validity, findings were related to the total volume of all foot muscles determined at magnetic resonance imaging (MRI-FMvol). Furthermore, the relations of ultrasonographic estimates to nerve conduction, sensory perception thresholds, and clinical condition were established. RESULTS—In diabetic patients, the ultrasonographic thickness of EDB (U-EDBt) was (means ± SD) 6.4 ± 2.1 vs. 9.0 ± 1.0 mm in control subjects (P < 0.001), the thickness of MIL (U-MILt) was 29.6 ± 8.3 vs. 40.2 ± 3.6 mm in control subjects (P < 0.001), and the CSA of EDB (U-EDBCSA) was 116 ± 65 vs. 214 ± 38 mm2 in control subjects (P < 0.001). The MRI-FMvol was directly related to U-EDBt (r = 0.77), U-MILt (r = 0.71), and U-EDBCSA (r = 0.74). U-EDBt and U-MILt were thinner in neuropathic than in nonneuropathic diabetic patients (5.8 ± 2.1 vs. 7.5 ± 1.7 mm [P < 0.05] and 28.3 ± 8.8 vs. 35.6 ± 4.3 mm [P < 0.03], respectively). CONCLUSIONS—Atrophy of intrinsic foot muscles determined at ultrasonography is directly related to foot muscle volume determined by MRI and to various measures of diabetic neuropathy. Ultrasonography seems to be useful for detection of foot muscle atrophy in diabetes.