Transoesophageal ultrasound and computer tomographic assessment of the equine cricoarytenoid dorsalis muscle: Relationship between muscle geometry and exercising laryngeal function

• Published in: Equine veterinary journal 2017-05, Vol.49 (3), p.395-400
• Main Authors: Kenny, M., Cercone, M., Rawlinson, J. J., Ducharme, N. G., Bookbinder, L., Thompson, M., Cheetham, J.
• Format: Article
• Language: English
• Subjects: Anastomosis; Animals; atrophy; Computed tomography; Electrical stimuli; Female; function; Geometry; Grafting; horse; Horse Diseases - diagnosis; Horse Diseases - diagnostic imaging; Horses; Laryngeal Muscles - diagnostic imaging; Laryngeal Nerve Injuries - diagnosis; Laryngeal Nerve Injuries - veterinary; Laryngeal Nerves - anatomy & histology; larynx; Male; Medical imaging; Muscle, Skeletal - anatomy & histology; Muscles; Physical Conditioning, Animal; Stimulation; Tomography; Tomography, X-Ray Computed; transoesophageal ultrasound; Ultrasonic imaging; Ultrasonography - methods; Ultrasonography - veterinary
• ISSN: 0425-1644; 2042-3306
• DOI: 10.1111/evj.12561

Summary Reasons for performing study Early detection of recurrent laryngeal neuropathy (RLN) is of considerable interest to the equine industry. Objectives To describe two imaging modalities, transoesophageal ultrasound (TEU) and computed tomography (CT) with multiplanar reconstruction to assess laryngeal muscle geometry, and determine the relationship between cricoarytenoid dorsalis (CAD) geometry and function. Study design Two‐phase study evaluating CAD geometry in experimental horses and horses with naturally occurring RLN. Methods Equine CAD muscle volume was determined from CT scan sets using volumetric reconstruction with LiveWire. The midbody and caudal dorsal‐ventral thickness of the CAD muscle was determined using a TEU in the same horses; and in horses with a range of severity of RLN (n = 112). Results Transoesophageal ultrasound was able to readily image the CAD muscles and lower left:right CAD thickness ratios were observed with increasing disease severity. Computed tomography based muscle volume correlated very closely with ex vivo muscle volume (R2 = 0.77). Conclusions Computed tomography reconstruction can accurately determine intrinsic laryngeal muscle geometry. A relationship between TEU measurements of CAD geometry and laryngeal function was established. These imaging techniques could be used to track the response of the CAD muscle to restorative surgical treatments such as nerve muscle pedicle graft, nerve anastomosis and functional electrical stimulation.