The effect of patient positioning on adrenal gland linear measurements estimated from computed tomographic images in healthy beagle dogs.

Considering that recumbency can lead to a change in localization, detectability of distinct margins and thus measurement of the organs and reconstruction quality, it is of value to evaluate the effect of positioning on the objective evaluation of abdominal organs in computed tomography (CT). The objective of the present study was to evaluate the effect of patient decubitus on adrenal gland CT biometry. For this purpose, 6 clinically healthy adult beagle dogs underwent CT examination in 4 recumbencies. The various adrenal gland's size measurements were performed by 2 observers. Statistical analyses revealed that repeatability and reproducibility was the highest on the ventral and right lateral recumbencies, respectively. Significant differences were found in the left adrenal gland's length between the different positions (P < 0.001) and the left adrenal gland's width of the cranial pole measured in the dorsal plane (P < 0.04). The measurements on the parasagittal images differed significantly for the left adrenal length (P = 0.01), cranial pole height (P = 0.03), the right adrenal gland's lateral limb's length (P = 0.05) and medial limb's caudal poles height (P < 0.01). The caudal pole height of the right adrenal gland's medial limb was significantly different (P < 0.01) in all positions on the transverse images. In addition, the adrenal position differed significantly, except for the left adrenal gland relative to the nearest renal vessel (P = 0.1). According to these results, it is recommended to perform a CT of adrenal glands always in the same recumbency. If adrenal glands are evaluated on images taken in various recumbencies, we suggest relying on the measurements made on transverse plane images.

Musculotendon excursion potential, tendon slack and muscle fibre length: the interaction of the canine gastrocnemius muscle and tendon.

Although the form-function relation of muscles and tendons has been studied extensively, little in vivo data exist on the musculotendon properties of the gastrocnemius complex in dogs. Using a combination of ultrasound and 3D motion tracking, musculotendon parameters were obtained in vivo from the lateral gastrocnemius muscle and the gastrocnemius tendon in nine healthy Labrador Retrievers. These parameters include musculotendon length and excursion potential, tendon slack length, muscle belly length, muscle fibre length, pennation angle and architectural index. This study also examined the variation of muscle and tendon length contributions to musculotendon length, as well as the relation between musculotendon excursion potential and muscle fibre length or tendon length. To facilitate comparison between dog breeds, the femur length as a potential scaling parameter was examined. In the Labrador gastrocnemius musculotendon complex, the tendon contributes 41% (± 9%) of musculotendon length. In longer musculotendon complexes, the contribution of the muscle belly increases while the tendon contribution decreases. Longer muscle belly and musculotendon complexes were, however, associated with shorter muscle fibres. No significant relations were found between musculotendon excursion potential and muscle fibre length or tendon slack length, and femur length did not prove to be a reliable scale factor for the length-related musculotendon parameters examined in this study. Longer musculotendon complexes exhibit relatively longer muscle bellies, which are in turn associated with shorter muscle fibre lengths. This trade-off between gastrocnemius muscle belly length and muscle fibre length might have the advantage that muscle volume stays constant regardless of the length of the limbs.

Bone density of elbow joints in Labrador retrievers and Golden retrievers: Comparison of healthy joints and joints with medial coronoid disease.

The aims of this study were: (1) to determine the inter-observer repeatability of particular regions of the canine elbow joints; (2) to assess the effect of age, bodyweight and breed on bone density in healthy young dogs; (3) to compare Hounsfield units (HU) and bone density (BD) measurements between normal elbow joints and diseased elbow joints; and (4) to determine the sensitivity and specificity for HU and BD measurements in specific regions in the canine elbow joint. Regions with the highest repeatability were located at the medial coronoid process (MCP) base and apex, and at the level of the humerus, on the sagittal and sagittal oblique planes of the elbow joint. Age and breed were significantly associated with several regions of interest; conversely, none of the measurements were associated with bodyweight. Increased HU and BD values in the MCP base and apex regions are likely to be related to medial coronoid disease. Labrador retrievers had higher HU and BD values than Golden retrievers and an increase in BD was found in older animals. Cut-offs determined with receiver operating characteristic plots of the MCP base and apex suggested fairly good sensitivity and specificity (base: area under the curve 0.85, sensitivity 75.0%, specificity 88.8%; apex: area under the curve 0.89, sensitivity 80.0%, specificity 92.5%).

Assessment of medial coronoid disease in 180 canine lame elbow joints: a sensitivity and specificity comparison of radiographic, computed tomographic and arthroscopic findings.

BACKGROUND: Diagnostic imaging is essential to assess the lame patient; lesions of the elbow joint have traditionally been evaluated radiographically, however computed tomography (CT) has been suggested as a useful technique to diagnose various elbow pathologies. The primary objective of this study was to determine the sensitivity and specificity of CT to assess medial coronoid disease (MCD), using arthroscopy as gold standard. The secondary objective was to ascertain the radiographic sensitivity and specificity for MCD compared with CT. METHODS: For this study 180 elbow joints were assessed, of which 141 had been examined with radiography, CT and arthroscopy; and 39 joints, had radiographic and CT assessment. Sensitivity and specificity were calculated for CT and radiographic findings using available statistical software. RESULTS: Sensitivity and specificity of CT using arthroscopy as gold standard resulted in high values for sensitivity (100 %) and specificity (93 %) for the assessment of MCD. For the radiographic evaluation, a sensitivity of 98 % and specificity of 64 - 69 % using CT as the technique of reference, were found. DISCUSSION: These results suggest that in case of doubt during radiographic assessment, CT could be used as a non-invasive technique to assess the presence of MCD. CONCLUSION: Based on the high sensitivity and specificity obtained in this study it has been considered that CT, rather than arthroscopy, is the preferred noninvasive technique to assess MCD lesions of the canine elbow joint.

Anatomical study of fibrous structures of the medial aspect of the canine elbow joint.

Forces exerted by fibrous structures on the medial aspect of the canine elbow joint have been reported to be involved in elbow pathology. The purpose of this paper is to assess the relationships of the ligamentous and muscular structures of this region of the canine elbow joint, and how they relate to the medial coronoid process. Six cadavers of adult German shepherd cross-breed dogs were used in this study to make intra-articular and vascular injections of this region. Some joints were dissected and some were frozen to saw sagittal or dorsal cryosections to assess the relationships of the myotendinous structures. The brachialis muscle tendon passed through the division of the bicipital tendon of insertion which formed a fibrous tendon sheath that was reinforced by the oblique ligament. The biceps' brachii's main insertion is the radial tuberosity where it inserts along with the cranial branch of the oblique ligament and the cranial branch of the medial collateral ligament. Rotational and compression forces exerted by the insertion of the biceps brachii-brachialis tendon complex onto the ulna might influence medial coronoid disease. Therefore, sectioning these tendons could be considered as a treatment for medial coronoid disease.