Early Detection of Atrophy of Foot Muscles in Chinese Patients of Type 2 Diabetes Mellitus by High-Frequency Ultrasonography

Abstract

The aim of this study was to evaluate the diagnostic value of high-frequency ultrasonography in detecting atrophy of foot muscles in Chinese patients of type 2 diabetes mellitus (T2DM). Chinese patients of T2DM with (n = 56) or without (n = 50) diabetic peripheral neuropathy (DPN) and the control subjects (n = 50) were enrolled. The nondominant foot of all subjects was examined with high-frequency ultrasonography. The transverse diameter, thickness, and cross-sectional area of the extensor digitorum brevis muscle (EDB) and the thickness of the muscles of the first interstitium (MILs) were measured. The results showed that the ultrasonographic transverse diameter, thickness, and cross-sectional area of EDB and the thickness of MILs in patients of T2DM with DPN were significantly smaller than those in patients of T2DM without DPN (all P < 0.01) and those in the control subjects (all P < 0.01). The transverse diameter and cross-sectional area of the EDB and thickness of MILs in patients of T2DM without DPN were significantly smaller than those of the control subjects (all P < 0.01). In conclusion, the atrophy of foot muscle in Chinese T2DM patients can be detected by high-frequency ultrasonography. Notably, ultrasonography may detect early atrophy of foot muscles in patients without DPN.

Early-Stage Diabetic Neuropathy Reduces Foot Strength and Intrinsic but Not Extrinsic Foot Muscle Size

“…Many of these sensory tests contain subjective components [4], making it difficult to reliably monitor progression [5]. A research focus on motor function has become increasingly more prominent in scientific literature (e.g., Sacco and Sartor [6]), as signs of atrophy have been shown to precede noticeable sensation loss [7][8][9][10]. This atrophy, in part, appears to be due directly to the degenerative effects of DPN as opposed to simple disuse from a more sedentary lifestyle [9,11].…”

“…However, many limitations also exist in muscle evaluations, confining measurements primarily to research settings. For instance, it is difficult to design strength tests that isolate the small muscles of the foot [8,12], while imaging of muscle size often relies on expensive equipment (e.g., MRI) and burdensome processing time [11]. Simple, inexpensive, and reliable objective measurements for evaluating distal muscle weakness could prove useful in tracking and evaluating motor nerve degeneration as a whole and within specific muscles, further providing insight into DPN progression.…”

“…Many imaging studies have examined ankle dorsal and plantar flexors [9,11] and intrinsic [13] or extrinsic [10,14,15] foot muscle compartments. This has been done using crosssectional area (CSA) [8,10,13,16], volume [9,11], thickness [8,15], or transverse diameter [8]. All of these studies showed significant decreases in overall lower leg and foot muscle size in DPN as compared to healthy controls.…”

“…All of these studies showed significant decreases in overall lower leg and foot muscle size in DPN as compared to healthy controls. A few studies segmented muscles further by measuring the CSA of the extensor digitorum brevis (EDB) and the thickness or CSA of the first interstitium (area between the first and second metatarsal bones) [7,8,17], but that was the extent of the segmentation in DPN. Several studies done on healthy participants [18][19][20] have imaged up to seven muscles in the lower leg, showing the potential for individual muscle segmentation.…”

Neuromuscular Ultrasound in the Assessment of Polyneuropathies and Motor Neuron Disease

“…Even more recently, Wang et al were able to measure foot muscle atrophy in diabetic patients with and without polyneuropathy using high-frequency ultrasound (Wang et al, 2014). They measured the diameter, thickness, and CSA of the extensor digitorum brevis (EDB) and thickness of the muscles of the first interstitium.…”