Abstract

The purpose of the present study was to describe normal magnetic resonance (MR) imaging anatomy of the
equine larynx and pharynx and to present the optimal protocol, sequences, and possible limitations of this
examination technique. Using a 0.3T unit, the laryngeal and pharyngeal regions was imaged in two horses. The
protocol consisted of sagittal and transverse T2-weighted (T2w) fast spin echo, transverse T1-weighted (T1w)
spin echo, and dorsal high-resolution T1w gradient echo (both pre- and postcontrast enhancement) sequences.
Euthanasia was performed at the end of the imaging procedure. Macroscopic anatomy of the cadaver sections
were compared with the MR images in transverse, midsagittal, and parasagittal planes. There was good
differentiation of anatomic structures, including soft tissues. The laryngeal cartilages, hyoid apparatus, and
upper airway muscle groups with their attachments could be clearly identified. However, it was not always
possible to delineate individual muscles in each plane.Most useful were both T2w and T1w transverse sequences.
Intravenous application of contrast medium was helpful to identify blood vessels. The MR images corresponded
with the macroscopic anatomy of cadaver sections.