A group of researchers from Taiwan used acoustic radiation force impulse shear-wave elastography (ARFI/SWE) to quantify shear wave velocities (SWVs) of Duchenne muscular dystrophy (DMD) patients’ lower limbs and found “it is a reliable and easily accessible tool for clinically assessing muscle characteristics, monitoring mobility function progression and enabling physicians to establish adequate treatment goals for patients with DMD.”
Patients with DMD (n=39, age, 10.43 ± 3.85 years) presented higher SWVs of the bilateral rectus femoris and medial gastrocnemius muscles when compared to control group individuals (n=36, age, 9.20 ± 4.06 years). No significant difference was reported for bilateral tibialis anterior muscles.
Additional analysis based on DMD patients’ ambulatory stage showed a decrease in SWVs of the bilateral tibialis anterior and medial gastrocnemius muscles from ambulatory (n=23, age, 7.81 ± 1.94 years) to early nonambulatory stage (n=11, age, 2.77 ± 1.35 years), and an increase in the SWVs of the rectus femoris muscle from ambulatory to late nonambulatory stage (n=5, age, 17.35 ± 1.33 years).
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ARFI/SWE is a type of ultrasound elastography that has been used to quantitatively measure tissue stiffness in other diseases. In this technique, short-duration acoustic pulses are used to produce local displacements, ie, shear waves, in target organs. SWV measurements can then be used to calculate tissue stiffness using a specific equation. The higher the SWV, the higher the stiffness of the target tissue.
DMD is a muscular dystrophy characterized by progressive muscle degeneration. In the absence of currently validated imaging tools to evaluate changes in muscle microstructure as DMD progresses, Lin C-W et al believe that ARFI/SWE can be a promising option, though longitudinal follow-up studies are still needed.
Lin C-W, Tsui P-H, Lu C-H, et al. Quantifying lower limb muscle stiffness as ambulation function declines in Duchenne muscular dystrophy with acoustic radiation force impulse shear wave elastography. Ultrasound Med Biol. Published online July 18, 2021. doi:10.1016/j.ultrasmedbio.2021.06.008