CT and CT arthrography were used to accurately identify and characterize osseous and soft tissue structures of the equine stifle joint. This technique may be of value when results from other diagnostic imaging techniques are inconclusive. The images provided will serve as a CT reference for the equine stifle joint.

A 5-year-old Rheinlander gelding was evaluated for left hindlimb stifle lameness. The lameness was localised to the stifle, but source of the lameness was not specifically diagnosed from the physical, radiographic and ultrasonographic examinations. Computed tomography (CT) and CT arthrography were therefore used for further investigation since these imaging techniques image bony structures, cartilage and soft tissues. This examination showed multiple lesions in the stifle: an osteochondrosis dissecans like lesion of the medial femoral condyle, bony fragments, cartilage trauma and caudal cruciate ligament injury. The prognosis for continuing use as a sports horse was regarded as unfavourable. Therefore, the horse was subjected to euthanasia. All CT findings were confirmed by gross pathology. The CT and CT arthrography examination in this case provided a diagnosis not achieved with other conventional imaging techniques.

BackgroundThe anatomical complexity of the horse’s head limits the abilities of radiography. Computed tomography (CT) in combination with contrast enhanced CT is used more often for diagnosing various head pathology in horses. The objective of this study was to compare intravenous and intra-arterial contrast-enhancement techniques and describe normal and abnormal contrast enhancement in the horse’s head.ResultsAll 24 horses included in the study recovered without complication from the procedures. Compared to the pre-contrast studies, post-contrast studies showed significant contrast enhancement in the pituitary gland (IA: p < 0.0001; IV: p < 0.0001), IA nose septum (p = 0.002), nose mucosa (IA: p < 0.0001; IV: p = 0.02), parotid salivary gland (IA: p < 0.0001; IV p < 0.0001), cerebrum (IA: p < 0.0001; IV: p < 0.0001), rectus capitis muscle (IA: p < 0.0001; IV p = 0.001), IA temporal muscle (p < 0.0001), IA masseter muscle (p <0.0001) and IV brainstem (p = 0.01). No significant contrast enhancement was seen in the eye (IA: p = 0.23; IV p = 0.33), tongue (IA p = 0.2; IV p = 0.57), IA brainstem (p = 0.88), IV nose septum (p = 0.26), IV temporal muscle (p = 0.09) and IV masseter muscle (p = 0.46). Three different categories of abnormal enhancement were detected: a strong vascularised mass, an enhanced rim surrounding an unenhanced structure and an inflamed anatomical structure with abnormal contrast enhancement.ConclusionUsing the intra-arterial technique, similar contrast enhancement is achieved using less contrast medium compared to the intravenous technique. And a potential major advantage of the IA technique is the ability to evaluate lesions that are characterized by increased blood flow. Using the intravenous technique, a symmetrical and homogenous enhancement is achieved, however timing is more crucial and the contrast dosage is more of influence in the IV protocol. And a potential major advantage of the IV technique is the ability to evaluate lesions that are characterized by increased vascular permeability. Knowing the different normal contrast enhancement patterns will facilitate the recognition of abnormal contrast enhancements.

ObjectiveUltrasonography (US) is frequently used to evaluate the equine stifle joint. Some soft tissue US findings are known to be clinically relevant, while others are considered incidental. These considerations are not always evidence-based. This study aims to describe the US findings observed in the stifle of clinically sound, active jumping and dressage horses. Procedures:To be included in this study, the horses had to fulfil 4 criteria: (1) in competition at least 1 time/month at national or international level, (2) in full work, (3) free of lameness, (4) no complains of the horse's performances. Both stifle joints of each horse were scanned systematically by US and US findings were recorded. Results:46 Warmblood horses fulfilled the criteria. US was normal in 21 horses, whereas abnormalities were detected in one or both stifles in 7 and 18 horses, respectively.Changes were seen in all compartments of the stifle joints: medial femorotibial joint (18 horses): osteophytes, effusion, subchondral cyst in the medial femoral condyle and lesions in the cranial meniscotibial ligament or medial collateral ligament; lateral femorotibial joint (4 horses): mild effusion, subchondral cyst in lateral femoral condyle; femoropatellar joint (16 horses): effusion, lesions in medial or intermediate patellar ligament or osteochondrotic lesions. Conclusion and Clinical relevance:Mild changes can be found ultrasonographically in the stifles of sport horses. Periarticular new bone formation was observed in 25% of the horses, apparently clinically not relevant. Lesions in the menisci, the tendinous portions of the popliteus muscle, long digital extensor muscle or peroneus tertius muscle or the lateral collateral ligament were not observed.