A technique for regional delivery of contrast medium to the foot of the horse to increase the diagnostic utility of computed tomography (CT) for the characterization of soft tissue structures within the hoof capsule was developed. An intraarterial catheter was placed under ultrasound guidance into the medial palmar artery at the level of the carpus to facilitate a steady-state infusion of iodinated contrast medium. Two 5 mm collimated contiguous acquisition CT scans were performed in 10 horses without lameness or radiographic evidence of distal sesamoid bone degeneration. CT examination was performed before and during regional arterial infusion of iodinated contrast medium administered at a rate of 2 ml/s. Cross-sectional area and mean pre- and post-contrast attenuation of the deep digital flexor tendon and the collateral ligaments of the distal interphalangeal joint were quantified from CT images. Soft tissue anatomy of the foot was also qualitatively characterized from pre- and postcontrast images. Catheterization was successful and without complication in all horses. The evaluated tendons and ligaments were clearly visible and had a small (8-20 Hounsfield Unit) but significant (P < 0.05, paired t-test) increase in attenuation during the steady-state infusion of contrast medium. This study should enhance the diagnostic potential of CT by providing baseline quantitative data for comparison with horses affected with soft tissue injuries in the distal extremity causing lameness that is alleviated with a palmar digital nerve block.

Background: Facial and vestibulocochlear nerve dysfunction occurs commonly in horses with temporohyoid osteoarthropathy (THO); however, auditory dysfunction has not been thoroughly assessed.Objective: To determine if auditory abnormalities occur in horses with THO. Animals: Eleven diseased and 8 control horses.Methods: This is a prospective study in which brainstem auditory-evoked responses (BAER) were recorded in 11 horses diagnosed with THO through neurologic, endoscopic, radiographic, or computed tomographic examinations. BAER findings were compared with those recorded from 8 adult control horses.Results: All horses with THO were found to have BAER abnormalities that included complete unilateral BAER loss (82%, n 5 9/11), partial unilateral BAER loss (18%, n 5 2/11) on the most affected side, and contralateral partial BAER loss (46%, n 5 5/11). Nine horses had bilateral THO based on diagnostic imaging findings; of these, 5 (56%) horses also had bilateral BAER abnormalities. The complete absence of BAER in affected horses was most consistent with peripheral sensorineural hearing loss. There was a significant association between complete BAER loss and neurologic and diagnostic abnormalities.Conclusions and Clinical Importance: Auditory abnormalities such as complete or partial BAER loss are common in horses with THO. The BAER test is an objective diagnostic tool that can aid along with other diagnostic modalities in the assessment, management, and follow-up of horses with THO. Furthermore, BAER studies may help to elucidate the pathophysiology of THO in horses.

Incisor tooth resorption, in particular external replacement resorption and external inflammatory resorption, is common in horses. Hypercementosis is consistently associated with resorption, but the inverse association is inconsistent.

Equine temporohyoid osteoarthropathy is characterized by progressive osseous proliferation of the temporohyoid articulation and surrounding structures. The diagnosis has generally been made using radiography and endoscopy of the guttural pouch. Recently, computed tomography (CT) has been used in the diagnosis of temporohyoid osteoarthropathy. This study was performed to determine the CT imaging characteristics of temporohyoid osteoarthropathy and to compare these to radiographic and endoscopic findings. CT scans from 16 horses with a final diagnosis of temporohyoid osteoarthropathy were reviewed. Five horses that had undergone CT scan for reasons other than temporohyoid osteoarthropathy were included as controls. Qualitative and quantitative data were used to describe the magnitude of the CT findings. Osseous proliferation of the stylohyoid bone and temporohyoid articulation was found to be a consistent feature of temporohyoid osteoarthropathy. Thickening of the ceratohyoid bone and proliferation of its articulation with the stylohyoid bone was frequently identified and this finding may have surgical implications. Horses with neurologic deficits had increased stylohyoid width that was significantly different than the subclinically affected side. CT evaluation also allowed the identification of subclinical bilateral disease in horses thought to be unilaterally affected based on clinical examination.

We compared contrast-enhanced computed tomography (CT) and high field magnetic resonance (MR) imaging in a horse with deep digital flexor tendonopathy. Lesions in the distal extremity were documented grossly and histopathologically. In contrast-enhanced CT, the deep digital flexor tendon lesions were markedly contrast enhancing with evidence of angiogenesis in the core and dorsal border lesions. The lesion morphology was clearly delineated on MR imaging, but without contrast media angiogenesis cannot be identified. Gross examination, histopathologic examination, and CD31 immunohistochemistry confirmed the tendonopathy and an increased presence of small blood vessels. In this horse, deep digital flexor tendon lesions appeared similarly on contrast-enhanced CT and MR imaging. Contrast-enhanced CT may be an alternative to MR imaging for assessing tendon and ligament injury in the digit of the horse.

Multiple lesions are detected with CT, CECT and LFMRI but there is variability in lesion detection and classification. LFMRI centred only on the podotrochlear apparatus may fail to identify lesions of the pastern or soft tissue mineralisation. Computed tomography may fail to identify DDFT lesions distal to the proximal border of the distal sesamoid.

Computed tomography (CT) with CT myelography is a novel imaging modality for detailed anatomical imaging and precise diagnosis of equine cervical spine pathology. Computed tomography of the complete cervical vertebral column in live horses has not been reported previously. The objectives of this study were to describe the diagnostic utility of CT and CT myelography in horses, the technique, the type and distribution of lesions and procedure-related complications. Medical records of horses subjected to cervical CT and CT myelography between 2013 and 2018 were reviewed for this retrospective descriptive study. The examinations were performed with horses in lateral recumbency using a large-bore CT scanner. In total, 180 horses were included. The study population consisted of 79.4% Warmblood breed horses, 68.3% were male, the mean age was 7.1 years (range 21 days-21 years), and the bodyweight ranged from 61 to 717 kg (mean 530 kg). Pathology of the cervical vertebral column was identified in 176/180 horses (97.8%) and included osteoarthritis of the articular process joints in 83%. Impingement and compression of the spinal cord were detected using CT myelography in 125/147 horses (85%). Pathology was localised caudal to C5 in 90%. The mean AE s.d. anaesthesia time was 34 AE 19 min and 52 AE 13 min for CT examinations, excluding and including myelography, respectively. Adverse events occurred in 7.2% of the examined horses. The caudal location of the majority of lesions emphasises the importance of good-quality imaging of the most caudal cervical vertebrae in horses with suspected cervical spinal pathology and/or spinal cord compression. Computed tomography imaging enables identification of bony and soft tissue lesions of the entire cervical vertebral column in live, large-breed adult horses. Materials and methods Study subjects All horses subjected to CT examination of the cervical vertebral column, with or without CT myelography, at Evidensia Equine Specialist Hospital Helsingborg, Sweden, between June 2013 and February 2018, were included. Data retrieved from the medical records included horse signalment, history and presenting signs, anaesthesia time, adverse events during the CT procedure, anaesthetic recovery or immediate postanaesthetic period.

IV administration of contrast media in anesthetized dogs caused moderate bradycardia, tachycardia, hypotension, or hypertension.