INTRODUCTION: In this study we describe a protocol for quantitative ultrasound of facial muscles (procerus, zygomaticus major, levator labii superior, depressor anguli oris, mentalis, orbicularis oris pars labialis, orbicularis oris pars marginalis).
METHODS: Muscle thickness (MT) and echo intensity (EI) were measured in 12 healthy subjects and a myotonic dystrophy type 1 patient.
RESULTS: MTs ranged from 0.15 to 0.30 mm, except for the procerus muscle (0.06 mm). EIs ranged from 1 to 34, except for the procerus muscle. MT reproducibility was fair for the orbicularis oris pars labialis, excellent for the procerus and levator labii, and good for the other muscles. The myotonic dystrophy type 1 patient showed high EIs, outside the range in healthy subjects in 6 of the 7 muscles. MT was lower than the range seen in healthy subjects in 4 muscles.
CONCLUSION: Quantitative muscle ultrasound of the facial muscles is feasible and shows moderate to excellent reproducibility.