Computed tomography and scintigraphy for evaluation of dental disease in the horse

Abstract

Summary Computed tomography (CT) uses x‐ray beams and reconstructive computer technology to create tomographic slices (sections) of the area being imaged. Computed tomography has higher contrast resolution than conventional radiography allowing for more accurate differentiation of soft tissues and fluids. This form of 3D imaging removes problems caused by superimposition of multiple anatomical structures, which is a major impediment when viewing radiographs of the equine head. Once the images are acquired, multi‐planar and 3D reconstructions can be performed to view different teeth or associated structures in an optimal way. Anatomical and pathological changes in the dental tissues, periodontal tissues, alveolar bone and adjacent sinuses can then be assessed. Scintigraphy with 99m technetium methyl‐diphosphate (methylene‐diphosphonate) can detect changes in bone that precede radiographic changes, and this makes it a very useful imaging modality for diagnosis of early periapical infection of the equine cheek teeth. Additionally, it is invaluable for imaging suspected infections of supernumerary or dysplastic teeth where the results of radiography or even CT may be equivocal. Periapical infections of the cheek teeth typically result in focal and intense increased radionuclide uptake located over the apical region of the affected tooth.

Radiographic, computed tomographic, gross pathological and histological findings with suspected apical infection in 32 equine maxillary cheek teeth (2012–2015)

“…Hypoplastic or carious infundibular lesions can look dramatic on imaging, gross and histological examinations, but if the enamel 'cup' of the infundibulum remains intact, none of these lesions can cause endodontic and thus apical infection. However, in some cases extension of infundibular caries through infundibular enamel defects can cause endodontic and apical infection [1,2,9,20,21] as was found in five of the current 32 teeth.…”

Computed tomographic description of the highly variable imaging features of equine oromaxillary sinus and oronasal fistulae

“…Diagnosis of a fistula is most readily made following clinical presentation of a purulent, malodorous, unilateral nasal discharge, commonly accompanied with history of maxillary cheek tooth extraction . Diagnosis is confirmed through a combination of oral examination, oral and sinus videoendoscopy, radiography, and computed tomography (CT) …”

Challenges in developing valid techniques for equine endodontic treatment of apically infected cheek teeth

“…; Kopke et al . ; Barakzai and Barnett ). However, even with CT, the diagnosis of cheek tooth pathology remains challenging (Buhler et al .…”

“…However, even with the advent of digital radiography techniques, the extensive peripheral enamel infolding and enamel-lined infundibulae obscure the radiographic endodontic anatomy of cheek teeth. More recently, the complex endodontic system of the equine cheek tooth has been imaged with greater clarity with computed tomographic (CT) studies (Figs 1-3) (Windley et al 2009a;Kopke et al 2012;Barakzai and Barnett 2015). However, even with CT, the diagnosis of cheek tooth pathology remains challenging (Buhler et al 2014).…”