Use of a novel helical fan beam imaging system for computed tomography of the distal limb in sedated standing horses: 167 cases (2019–2020)

Abstract

OBJECTIVE To evaluate the diagnostic capabilities of a novel helical fan beam CT system used for imaging of horses with a range of clinical distal limb problems. ANIMALS 167 horses. PROCEDURES Medical records were reviewed of horses presented for CT of the distal limb at 2 university-based veterinary hospitals. The following data were recorded: age, sex, breed, presenting complaint, sedation used for imaging, scanning time, procedure time, other diagnostic imaging methods performed, imaging diagnosis, clinical diagnosis, and complications during imaging. RESULTS Most horses were Thoroughbreds and Quarter Horses. Procedure times ranged from 15 to 40 minutes, with scanning completed in 15 to 45 seconds for each region of interest. The foot or pastern region was commonly scanned (88/167 [53%] horses), with navicular bone disease diagnosed in 42 of 88 (48%) horses. The fetlock region was also commonly scanned (42/167 [40%] horses), with palmar or plantar osteochondral disease diagnosed in 17 of 42 (40%) horses. Horses were compliant during scanning, and no complications with sedation or damage to the scanner occurred. A specific imaging diagnosis for the lameness was achieved more frequently with CT imaging (166/167 [99%]) than with planar digital radiography (26/58 [45%]). CLINICAL RELEVANCE The helical fan beam CT system could be used safely to scan sedated standing horses from the carpal or tarsal region distally. Subjectively, the machine was easy to operate, allowing CT to be incorporated into lameness investigations. CT imaging was very likely to result in a clinical diagnosis in horses with distal limb lameness.

Use of a novel helical fan beam imaging system for computed tomography of the head and neck in sedated standing horses: 120 cases (2019–2020)

“…We did find that slight motion could obscure the detail of head structures easily, such that a repeated scan was more often needed when imaging the head and neck, compared with imaging the distal limbs. 20 IV and intra-arterial contrast enhancement techniques have been described for horses. 3,21,22,39 The IV technique uses more contrast medium than the intra-arterial technique, because the contrast medium is diluted before reaching the location of interest, but the contrast enhancement obtained with the 2 techniques is similar.…”

“…Clinical use of this CT system for imaging of the distal limbs in horses has been described. 20 The objective of the retrospective study reported here was to evaluate the diagnostic capabilities of the Equina system when used for imaging of horses with clinical problems of the head and neck.…”

Radiomics Modeling of Catastrophic Proximal Sesamoid Bone Fractures in Thoroughbred Racehorses Using μCT

“…Other non-invasive imaging methods such as MRI, nuclear imaging, and infrared spectroscopy are able to detect lesions and abnormalities before the onset of gross disease [ 8 , 9 , 33 , 34 , 35 , 36 ]. Recently, a commercial option has been proposed for obtaining CT images in anesthetized standing horses [ 7 ]. Whether such systems can provide texture features of the PSBs comparable with μCT and whether those features could be used for modeling the risk of catastrophic injury remains in question.…”

“…Obtaining CT images of the horses under load bearing conditions is challenging as general anesthesia is required for compliance and to minimize the risk of motion artifacts. Some technical advances in standing CT have been suggested but whether these devices can achieve sufficient spatial resolution for diagnosis, mitigate the risk of motion and beam hardening artifacts, and whether these devices could be used in a screening capacity in the horseracing environment remains to be seen [ 7 ]. There have been similar advancements in standing MRI and PET technologies, but operationalizing them as a screening tool in the clinical and commercial setting remains a challenge [ 7 , 8 , 9 ].…”

Comparison of Radiography and Computed Tomography for Evaluation of Third Carpal Bone Fractures in Horses

“…Radiography plays an important role in the diagnosis of carpal injury but has wellrecognized limitations. For some horses with third carpal bone (C3) fractures (Fx), the poor sensitivity of planar radiography to identify fracture configuration and the full extent of comminution and other injury has been reported [1][2][3][4][5][6][7][8]. Additional views to the standard radiographic series can be useful in some cases including those with suspected sagittal Fx of the radial facet of C3 (RaF) [9], but not all limitations can be overcome.…”