Casper Crijns

The use of CT and CT arthrography in diagnosing equine stifle injury in a Rheinlander gelding.

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.

Intramodality and intermodality agreement in radiography and computed tomography of equine distal limb fractures

REASONS FOR PERFORMING STUDY Computed tomography (CT) is increasingly accessible in equine referral hospitals. OBJECTIVES To document the level of agreement within and between radiography and CT in characterising equine distal limb fractures. STUDY DESIGN Retrospective descriptive study. METHODS Images from horses that underwent radiographic and CT evaluation for suspected distal limb fractures were reviewed, including 27 horses and 3 negative controls. Using Cohens kappa and weighted kappa analysis, the level of agreement among 4 observers for a predefined set of diagnostic characteristics for radiography and CT separately and for the level of agreement between the 2 imaging modalities were documented. RESULTS AND CONCLUSIONS Both CT and radiography had very good intramodality agreement in identifying fractures, but intermodality agreement was lower. There was good intermodality and intramodality agreement for anatomical localisation and the identification of fracture displacement. Agreement for articular involvement, fracture comminution and fracture fragment number was towards the lower limit of good agreement. There was poor to fair intermodality agreement regarding fracture orientation, fracture width and coalescing cracks; intramodality agreement was higher for CT than for radiography for these features. POTENTIAL RELEVANCE Further studies, including comparisons with surgical and/or post mortem findings, are required to determine the sensitivity and specificity of CT and radiography in the diagnosis and characterisation of equine distal limb fractures.

Late-onset wedge-shaped thoracic vertebrae in a six-month-old pug

A six-month-old pug was presented with kyphosis and pelvic limb lameness. During a routine neurological and radiographic screening of the vertebral column at two months of age, no congenital abnormalities were noted. Four months later, radiography showed marked kyphosis of the thoracic vertebral column with wedge-shaped T8 and T9. After euthanasia, gross examination and CT revealed the same findings as on radiology. Histopathology of the wedge-shaped vertebrae T8 and T9 showed abnormal caudal growth plates possibly due to necrosis or premature partial fusion. It can be concluded that the vertebral malformation of the spine in this pug was latent at birth and became visible during a growth spurt due to growth plate deficiency. The results of this case can be of clinical importance for veterinarians and breeders of brachycephalic breeds as it would be better to perform radiological screening for wedge vertebrae when the vertebral length growth is more advanced.

Intra-arterial versus intra venous contrast-enhanced computed tomography of the equine head

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.

The influence of the size, age and sex on the computed tomographic measured size of the pituitary gland in normal horses

The objective of this study was to examine the influence of the size, age and sex of the horse on the size of the pituitary gland and determine the possibility of using the pituitary gland height‐to‐brain area ratio (P:B ratio) to allow comparison of different sized and aged horses. Thirty‐two horses without pituitary pars inter‐media dysfunction that underwent a contrast‐enhanced computed tomographic (CT) examination were included in a cross‐sectional study. On the CT images, the pituitary gland height was measured and the P:B ratio was calculated. These measurements were correlated to the size, age and sex of the horses. The pituitary gland height was significantly associated with the size (P < 0.001) and the age (P < 0.001), but not with the sex (P = 0.40), of the horses. No significant association was found between the P:B ratio and the size (P = 0.25), the age (P = 0.06) or the sex (P = 0.25) of the horses. In conclusion, the pituitary gland size varies between different sized and aged horses. The use of the P:B ratio is a valuable metric for making comparisons between the pituitary glands of these horses.