The Role of Computed Tomography in Imaging Non-neurologic Disorders of the Head in Equine Patients

Abstract

Computed tomography (CT) imaging of the head in equine patients is now commonly performed as CT scanners are more readily available. Head CT has proven valuable in evaluating spatially complex anatomic structures, where radiographic superimposition, or restricted access via endoscopy or ultrasound, limit complete evaluation of the disease process. Head CT has been demonstrated to be incredibly valuable in the evaluation of dental and paranasal sinus disease, disease of the hyoid apparatus and ear, and in evaluation of skull trauma. CT is an excellent modality for assessment of both osseous and soft tissue structures; however, evaluation of complex vascular anatomy and determination of tissue viability is limited without the use of contrast agents. Therefore, various contrast agent protocols including intravenous and intraarterial iodinated contrast administration techniques have been established. CT also has limitations in the evaluation of brain and spinal cord disease, for which magnetic resonance imaging (MRI) has major advantages. Head CT images are most commonly evaluated in transverse planes. However, standard multiplanar reconstructions of the head including dorsal and parasagittal planes improve the understanding of spatially complex disease processes. These reconstructions can be crucial for accurate identification of diseased teeth and determination of the extent and severity of osseous and paranasal sinus disease. Head CT examinations are becoming an increasingly important diagnostic tool in the evaluation of horses with head disorders, and CT imaging findings are an important aspect in the clinical decision-making process. The following review discusses the indications, benefits, and technical considerations for the use of computed tomography (CT) in evaluating non-neurologic head pathologies in equine patients.

Three-Dimensional Segmentation of Equine Paranasal Sinuses in Multidetector Computed Tomography Datasets: Preliminary Morphometric Assessment Assisted with Clustering Analysis

“…However, more recent reports suggest an increasing use of equine CT [ 10 ]. With recent equipment advancements and modifications allowing for fan-beam CT use in standing sedated horses [ 39 , 40 ], high-resolution standing sedated CT of the equine head is becoming more readily available. Therefore, the use of free software for semiautomated sinus segmentation and the development of automatic segmentation protocols are desirable and necessary directions for further research.…”

Anatomy and computed tomography of the nasal cavity, nasal conchae, and paranasal sinuses of the endangered Patagonian huemul deer (Hippocamelus bisulcus)

“…The postmortem changes and mainly the absence of soft tissue provided a better view of the walls and bony septa. The swelling of the mucosa during anesthesia and the partial volume effect are reported hazards (Stieger‐Vanegas & Hanna, 2022) that could affect the presentation and evaluation of the sinonasal communication channels in in vivo assessments on anaesthetized animals. A macroscopic study of head dissection would be useful to clarify, compare, and complement the background of communication and sinus volumetry.…”

Equine Models of Temporomandibular Joint Osteoarthritis: A Review of Feasibility, Biomarkers, and Molecular Signaling

“…The relatively high prevalence of TMJ OA and the longer lifespan of horses, compared to other domestic animals, offer an opportunity to examine potential age- and OA-related changes in the TMJ, making it easier to form research groups of different ages rather than tracking the slow progression of the disease over time [ 9 ]. Furthermore, recent developments in equine medicine, including the availability of helical fan beam CT imaging of the equine head in a standing position [ 146 , 147 ], have significantly increased the suitability of horses as model animals for TMJ OA. Therefore, the equine naturally occurring model appears to be feasible for studying TMJ OA, including cartilage degradation and bone remodeling.…”

“…The inhibition of Ihh signaling prevents chondrocyte differentiation and maturation [ 151 ] and chondrocyte terminal differentiation in TMJ OA, delaying the overload OA lesions [ 124 ]. Finally, the inhibition of Notch signaling delays the progression of cartilage damage in TMJ OA [ 146 ].…”