Delineating serial mechanical property changes in a dog model of duchenne muscular dystrophy using ARFI ultrasound, in vivo

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder that is caused by a mutation in the gene for dystrophin leading to a loss of the dystrophin protein from the muscle cell (myofiber) membrane. The golden retriever muscular dystrophy (GRMD) model also has a naturally-occurring dystrophin gene mutation and progressive phenotypic features analogous to those seen in DMD. We have investigated the use of Acoustic Radiation Force Impulse (ARFI) imaging in the GRMD canine model. Imaging was performed in vivo on the right rectus femoris (RF) and cranial sartorius (CS) muscles in both transverse and parallel planes. A cohort of 6 normal dogs and 4 GRMD dogs were imaged at 3, 6, and 12 months of age. Results showed significant differences in peak displacement in the RF for GRMD vs normal dog, but similar ARFI results in the CS. These results are consistent with known variations in disease progression in RF versus CS muscles in the dog model and suggest that ARFI could be relevant to monitoring therapy in affected individuals.