Micro-computed tomography reveals high-density mineralised protrusions and microstructural lesions in equine stifle joint articular cartilage.

BACKGROUND: Stifle osteoarthritis (OA) lesions are most common in the medial femorotibial (MFT) compartment. Their characterisation and mapping will inform equine veterinarians towards an accurate diagnosis of OA. OBJECTIVES: Investigate and map micro-CT (µCT) changes in the hyaline articular cartilage (HAC) in the medial femoral condyle (MFC) and medial tibial plateau (MTP). STUDY DESIGN: Ex vivo cadaveric. METHODS: Stifles (n = 7 OA and 17 control [CO]) were retrieved from a tissue bank. The MFC and MFT were imaged with µCT. Regions of interest (ROIs) were cranial (MFCcr; MTPcr) and caudal (MFCca; MTPca) sites. In each ROI, µCT images were scored for HAC fibrillation, surface mineralisation and for the presence of high-density mineralised protrusions (HDMP). The lesions were mapped, and site-matched histology was performed. RESULTS: The microstructure of healthy and abnormal HAC was discernible on µCT images and confirmed with histology. HAC fibrillation was more prevalent (p = 0.019) in the MFCcr of the OA group (n = 7/7, 100%) when compared with the CO group (n = 7/17, 41%). Score 1 HAC surface mineralisation was more prevalent (p = 0.038) in the OA MFCca (n = 4/7, 57%) when compared with the CO group (n = 2/17, 12%). HDMP were heterogenous and hyperdense mineralised material protruding into the HAC and were more frequent (p = 0.033) in MFCs (n = 12/24, 50%) compared with MTPs (n = 5/24, 20%). Score 3 HDMPs were also more prevalent (p = 0.003) in the MFCcr (n = 7/24, 29%) compared with MFCca (n = 0/24, 0%) and in MFCs (n = 7/24, 29%) compared with MTPs (n = 3/24, 12.5%) (p = 0.046). MAIN LIMITATIONS: Clinical history was not available for all specimens. CONCLUSIONS: Equine HDMP and HAC surface mineralisation are imaged for the first time in the MFT joint. HAC fibrillation and erosion and HDMP are more frequent in the cranial aspect of the MFC. µCT images of OA in equine stifle joints provide a novel perspective of lesions and improve understanding of OA.

Influence of locoregional lymph node aspiration cytology vs sentinel lymph node mapping and biopsy on disease stage assignment in dogs with integumentary mast cell tumors.

OBJECTIVE: To compare the effect of sentinel lymph node (SLN) histology vs locoregional lymph node (LRLN) fine needle aspiration (FNA) cytology on assigned disease stage and adjunctive treatment recommendations and describe the incidence of anatomic disparity between the LRLN and SLN. STUDY DESIGN: A pre-post study refers to a study design type in which subjects are compared pre and post the intervention of interest. ANIMALS: Seventeen dogs undergoing primary excision of 20 cutaneous and subcutaneous mast cell tumors (MCT). METHODS: Client-owned dogs presenting to the Cornell University Hospital for Animals for surgical removal of a cytologically confirmed cutaneous or subcutaneous MCT >1 cm in diameter were enrolled. Cytological examination of FNA from the LRLN was compared with histology of the SLN. The SLN was identified by indirect computed tomographic lymphangiography (ICTL) after peritumoral injection of iopamidol and scanning at 1, 3, 5, 10, and 15 minutes. Histopathologic node score > 1 was considered metastatic. After case review by an oncologist, LRLN FNA cytology was compared with SLN histology for effect on changes in stage assignment and adjunctive treatment recommendations. RESULTS: Mast cell tumors were graded as 2 low (n = 11), 2 high (n = 2), and subcutaneous (n = 7). Optimal scan timing was 10 minutes after injection of iopamidol. Sentinel lymph node differed anatomically from LRLN in 5 of 18 scans. Metastases were detected by histology in 9 of 20 SLN compared with in 1 of 20 FNA of LRLN (P = .001), changing stage and adjunctive treatment recommendations 8 of 20 tumors. Only 6 of 19 LRLN FNA samples were diagnostic. CONCLUSION: Sentinel lymph nodes were consistently identified with ICTL and differed from LRLN in one-quarter of tumors. Histopathological examination of SLN altered recommendations in half of the dogs compared with the previous standard of care. CLINICAL SIGNIFICANCE: Indirect computed tomographic lymphangiography and SLN excision should be considered as a new standard for dogs with MCT.

Auriculectomy for spontaneous thrombosis of the left auricle in a domestic shorthair cat.

A 3-year-old castrated male domestic shorthair cat was presented for evaluation of acute onset tachypnea, dyspnea, and restlessness. Blood analysis revealed markedly elevated creatinine kinase, troponin, and D-dimers, together with azotemia and an inflammatory leukogram. Ultrasonography identified cardiomegaly with pericardial and pleural effusion. Thoracocentesis identified a high protein transudate. Cardiac computed tomographic angiography (CTA) identified an enlarged left auricle containing a non-contrast enhancing mass measuring 1.6 × 1.2 × 1.2 cm subsequently confirmed to be a thrombus. The cat underwent a left cardiac auriculectomy and was discharged on clopidogrel. Post-operative complications, including late-onset hemothorax and dyspnea, were managed to resolution. Key clinical message: A cardiac auriculectomy was effective in management of thromboembolic disease in a domestic cat.

Auriculectomie pour une thrombose spontanée de l'oreillette gauche chez un chat domestique à poils courts. Un chat domestique à poils courts castré âgé de 3ans fut présenté pour évaluation suite à l'apparition soudaine de tachypnée, dyspnée et agitation. L'analyse sanguine révéla une augmentation marquée de la créatine kinase, de la troponine, des dimères-D avec également une azotémie et un leucogramme inflammatoire. L'échographie révéla une cardiomégalie avec effusions péricardique et pleurale. Une thoracocentèse identifia un transsudat élevé en protéine. Une angiographie par tomodensitométrie (CTA) identifia une oreillette gauche augmentée de volume contenant une masse non-contrastante mesurant 1,6 × 1,2 × 1,2 cm qui fut subséquemment confirmée être un thrombus. Le chat subit une auriculectomie cardiaque gauche et obtint son congé avec du clopidogrel. Des complications post-opératoires, incluant un hémothorax qui apparut tardivement et de la dyspnée, furent gérées jusqu'à leur résolution.Message clinique clé :Une auriculectomie cardiaque fut efficace pour gérer un problème thrombo-embolique chez un chat domestique.(Traduit par Dr Serge Messier).

Equine Stereotaxtic Population Average Brain Atlas With Neuroanatomic Correlation.

There is growing interest in the horse for behavioral, neuroanatomic and neuroscientific research due to its large and complex brain, cognitive abilities and long lifespan making it neurologically interesting and a potential large animal model for several neuropsychological diseases. Magnetic resonance imaging (MRI) is a powerful neuroscientific research tool that can be performed in vivo, with adapted equine facilities, or ex-vivo in the research setting. The brain atlas is a fundamental resource for neuroimaging research, and have been created for a multitude animal models, however, none currently exist for the equine brain. In this study, we document the creation of a high-resolution stereotaxic population average brain atlas of the equine. The atlas was generated from nine unfixed equine cadaver brains imaged within 4 h of euthanasia in a 3-tesla MRI. The atlas was generated using linear and non-linear registration methods and quality assessed using signal and contrast to noise calculations. Tissue segmentation maps (TSMs) for white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF), were generated and manually segmented anatomic priors created for multiple subcortical brain structures. The resulting atlas was validated and correlated to gross anatomical specimens and is made freely available at as an online resource for researchers (https://doi.org/10.7298/cyrs-7b51.2). The mean volume metrics for the whole brain, GM and WM for the included subjects were documented and the effect of age and laterality assessed. Alterations in brain volume in relation to age were identified, though these variables were not found to be significantly correlated. All subjects had higher whole brain, GM and WM volumes on the right side, consistent with the well documented right forebrain dominance of horses. This atlas provides an important tool for automated processing in equine and translational neuroimaging research.

ULTRASONOGRAPHIC FINDINGS IN 13 HORSES WITH LYMPHOMA.

Ultrasonography and radiography are commonly used for staging of lymphoma in horses, however there is little published information on imaging characteristics for horses with confirmed disease. The purpose of this retrospective, case series study was to describe ultrasonographic and radiographic findings for a group of horses with a confirmed diagnosis of lymphoma. A total of 13 horses were sampled. Lymphadenopathy (8/13), peritoneal effusion (6/13), splenic (6/13), and hepatic (5/13) lesions were the most frequently identified. The predominant splenic and hepatic ultrasonographic lesions were hypoechoic nodules, organomegaly, and changes in echogenicity. Digestive tract lesions were detected in three horses and these included focal thickening and decreased echogenicity of the small (2/13) and large intestinal (2/13) wall. Thoracic lesions were predominantly pleural effusion (4/13), lymphadenopathy (4/13), and lung parenchymal changes (3/13). Enlarged lymph nodes were detected radiographically (4/13) and/or ultrasonographically (2/13) in the thorax and ultrasonographically in the abdomen (7/13) and in the caudal cervical region (4/13). Findings supported the use of abdominal and thoracic ultrasonography for lymphoma staging in horses. Ultrasound landmarks for localizing cecal and caudal deep cervical lymph nodes were also provided.