Incidental findings of soft tissue gas in canine and feline thoracic computed tomographic examinations.

Computed tomography (CT) is a commonly used modality in small animal veterinary medicine. Anecdotally, gas bubbles are frequently identified in small animals undergoing thoracic CT examination. The aim of this retrospective observational study was to record the occurrence and prevalence of vascular and extravascular gas in routine thoracic CT examinations in dogs and cats. Patients with any clinical signs of diseases   related to soft tissue gas were excluded. A total of 84 canine studies and 90 feline studies were included, detecting gas in 66.7% of all studies, with gas more likely to be detected in canine studies (75.0%) than in feline cases (58.9%) (P = 0.009). Canine studies were more likely to have gas detected in postcontrast studies than in precontrast studies (P = 0.016). Intravascular gas was detected in 65.5% of all included studies (75% canine and 56.7% feline). Extravascular gas was detected in 13.8% of all studies (14.3% canine, 13.3% feline), with gas detected in the vertebral canal of 8.62% of all studies (canine 11.9%, feline 5.56%) and within fascial planes in 5.75% of all studies (canine 2.38%, feline 8.89%). In conclusion, gas bubbles were identified in the majority of canine and feline thoracic CT studies without clinical evidence of a pathologic etiology.

Anatomy of the congenital calcaneal bursae in the bovine.

OBJECTIVE: The objective of this study was to determine the anatomical relationship of the congenital calcaneal bursae in the bovine, and describe the computed tomography (CT), endoscopic and gross anatomy of these bursae. STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Eighteen clinically normal cadaver bovine hindlimbs. METHODS: Intrasynovial injection of iodinated contrast and methylene blue into the intertendinous calcaneal bursa (ICB) (n = 16) or gastrocnemius calcaneal bursa (GCB) (n = 2). Limbs were imaged post-contrast injection using multidetector CT. Endoscopic examination of the ICB was performed on two randomly selected limbs. All limbs underwent gross anatomical dissection. RESULTS: The anatomy of the congenital calcaneal bursae was consistent between CT imaging, endoscopic examination and gross dissection. The ICB and GCB were two separate synovial structures with no communication in all limbs. The distal and proximal extent of the ICB, defined as the distance from the point of tuber calcanei to the distal/proximal aspect of the ICB, was (median [IQR]) 7.4 (7.4 to 7.8) cm distally and 5.4 (4.7 to 6.0) cm proximally. CONCLUSION: Positive contrast CT and gross anatomical dissection revealed no communication between the congenital calcaneal bursae in any limb. Routine bursoscopy allowed complete endoscopic examination of the ICB. The proximal extent of the ICB is shorter than the distal extent. The use of a collective term for these bursae should be avoided in the bovine, as the ICB and the GCB are two separate synovial structures with no communication. CLINICAL SIGNIFICANCE: Knowledge of distinct anatomy and relationship between the congenital calcaneal bursae in the bovine may facilitate diagnosis and treatment of disorders affecting the region of tuber calcanei, including septic bursitis and osteomyelitis.

Arthroscopic-assisted hip toggle stabilization in cats: An ex vivo feasibility study.

OBJECTIVE: To describe arthroscopic-assisted hip toggle stabilization (AA-HTS) in cats, evaluate its feasibility and associated rate of iatrogenic injury, and assess deviations from planned surgical technique. STUDY DESIGN: Ex vivo study. ANIMALS: Skeletally mature cat cadavers (n = 7). METHODS: Preoperative pelvic computed tomography (CT) was performed for surgical planning and to identify the ideal femoral bone tunnel projection. Ultrasound-guided transection of ligament of head of femur was performed. Following exploratory arthroscopy, AA-HTS was performed using a commercially available aiming device. Surgical time, intraoperative complications, and feasibility of technique were recorded. Iatrogenic injury and technique deviations were assessed by postoperative CT and gross dissection. RESULTS: Diagnostic arthroscopy and AA-HTS were successfully performed in all 14 joints. Median (range) surgical time was 46.5 (29-144) min, including 7 (3-12) min for diagnostic arthroscopy and 40 (26-134) min for AA-HTS. Intraoperative complications occurred in 5 hips, related to bone tunnel creation (4) and toggle dislodgment (1). Toggle passage through the femoral tunnel was the most challenging component of technique, recorded as mildly difficult in 6 joints. No damage to periarticular/intrapelvic structures was identified. Minor articular cartilage damage (<10% total cartilage area) was identified in 10 joints. Thirteen deviations (8 major, 5 minor) in surgical technique from preoperative planning were identified in 7 joints. CONCLUSION: In feline cadavers AA-HTS was feasible but was associated with a high rate of minor cartilage injury, intraoperative complications, and technique deviations. CLINICAL SIGNIFICANCE: Hip toggle stabilization using an arthroscopic-assisted approach may be an effective technique for management of coxofemoral luxation in cats.

Accuracy of pin placement in the canine thoracolumbar spine using a free-hand probing technique versus 3D-printed patient-specific drill guides: An ex-vivo study.

OBJECTIVE: To compare pin placement accuracy, intraoperative technique deviations, and duration of pin placement for pins placed by free-hand probing (FHP) or 3D-printed drill guide (3DPG) technique. SAMPLE POPULATION: Four greyhound cadavers. METHODS: Computed tomography (CT) examinations from T6-sacrum were obtained for determination of optimal pin placement and 3DPG creation. Two 3.2/2.4-mm positive profile pins were inserted per vertebra, one left and one right from T7-L7 (FHP [n = 56]; 3DPG [n = 56]) by one surgeon and removed for repeat CT. Duration of pin placement and intraoperative deviations (unanticipated deviations from planned technique) were recorded. Pin tracts were graded by two blinded observers using modified Zdichavsky classification. Descriptive statistics were used. RESULTS: A total of 54/56 pins placed with 3DPGs were assigned grade I (optimal placement) compared with 49/56 pins using the FHP technique. A total of 2/56 pins placed with 3DPGs and 3/56 pins using the FHP technique were assigned grade IIa (partial medial violation). A total of 4/56 pins placed using the FHP technique were assigned grade IIIa (partial lateral violation). No pins were assigned grade IIb (full medial violation). Intraoperative technique deviations occurred with 6/56 pins placed using the FHP technique and no pins with 3DPGs. Overall, pins were placed faster (mean ± SD 2.6 [1.3] vs. 4.5 [1.8] min) with 3DPGs. CONCLUSIONS: Both techniques were accurate for placement of spinal fixation pins. The 3DPG technique may decrease intraoperative deviations and duration of pin placement. CLINICAL RELEVANCE: Both techniques allow accurate pin placement in the canine thoracolumbar spine. The FHP technique requires specific training and has learning curve, whereas 3DPG technique requires specific software and 3D printers.

Dysplastic gangliocytoma of the cerebellum in a cat.

A 2.5-year-old cat presented with progressive ataxia and lethargy. Magnetic resonance imaging (MRI) showed enlargement of the cerebellum and herniation of cerebellar vermis. Postmortem examination confirmed the MRI findings, and histopathology showed numerous large dysplastic neurons populating and displacing the Purkinje cell layer and extending into the molecular and granular layers of the cerebellum. The lesion was diagnosed as dysplastic gangliocytoma of the cerebellum. In humans, this tumor is often associated with Cowden syndrome, a genetic disorder characterized by multiple hamartomas and an increased risk of developing certain neoplasms, known to be linked to a germline mutation of the phosphatase and tensin homolog (PTEN) gene. Reduction in PTEN nuclear and cytoplasmic immunohistochemical labeling of dysplastic neurons in this case suggested a possible PTEN mutation involved in the tumorigenesis. This report provides a detailed pathology description of the tumor and the use of neuronal and PTEN markers which will help guide pathologists presented with this rare condition in the future.

A threshold volume of 10 ml is suggested for detecting articular cartilage defects in equine carpal joints using CT arthrography: Ex vivo pilot study.

Computed tomographic arthrography (CTA) has been described as a method for detecting articular cartilage defects in equine carpal joints; however, published studies on the effects of contrast volume for lesion detection are currently lacking. The purpose of this prospective, experimental, pilot study was to determine a threshold volume of iodinated contrast for CTA of the antebrachiocarpal (ABC) and middle carpal (MC) joints for detection of articular cartilage surface defects. Articular cartilage defects were iatrogenically created in the surfaces of the ABC and MC joints of 20 equine cadaver limbs using arthroscopy. Unaltered articular surfaces within some joints acted as controls. Joints were imaged precontrast using multidetector CT. The ABC and MC joints were injected with a 150 mg iodine/ml nonionic contrast medium, in 5 ml increments from 5 to 50 ml per joint with CT performed subsequent to each increment. Cartilage defects were measured grossly using a caliper. Detection (qualitative) and measurement (quantitative) of the defects were independently performed by two board-certified radiologists using medical imaging software. At each volume of contrast, the interrater reliability for gross examination and the two observers in the detection of a defect was calculated (Gwet's AC1). Logistic mixed-effects models of selected volumes, 0, 5, 10, 15, and 50 ml, demonstrated that at 10 ml contrast and above, no statistically significant difference between either observer and gross examination for defect detection was identified for either joint. Findings supported using a dose of 10 ml for 150 mg iodine/ml concentration contrast media when performing CTA of equine carpal joints.

Congenital esophageal stenosis in a Labrador retriever.

A 1-year-old neutered male Labrador retriever was presented for investigation of chronic regurgitations that had started at weaning. Contrast radiographs and fluoroscopy of the thorax identified a focal narrowing of the proximal intrathoracic esophagus. Examination with CT-angiography excluded extraluminal causes for the narrowing, e.g., vascular ring anomaly. Esophagoscopy revealed the presence of a muscular stenosis with the appearance of a sphincter at the level of the proximal intrathoracic esophagus, without evidence of stricture. A diagnosis of congenital esophageal stenosis was made, suspected secondary to fibromuscular hypertrophy. Regurgitation resolved with conservative management and the dog was well at a 2-year follow-up examination. This case represents one of few small animal cases of congenital esophageal stenosis reported and apparently the only case successfully managed conservatively. Key clinical message: This report describes the clinical presentation, diagnostic imaging findings, and treatment of a rare case of congenital esophageal stenosis in a Labrador retriever. Medical and conservative therapies alone may be sufficient for treatment of congenital esophageal stenosis depending on presentation and suspected histopathological type. These therapies should be considered before initiating interventional procedures.

Sténose congénitale de l'oesophage chez un Labrador retriever. Un Labrador mâle castré âgé de 1 an a été présenté pour une investigation de régurgitations chroniques qui avaient commencé au sevrage. Les radiographies de contraste et la fluoroscopie du thorax ont identifié un rétrécissement focal de l'oesophage intrathoracique proximal. L'examen par tomodensitométrie-angiographie a exclu les causes extraluminales du rétrécissement, c'est-à-dire une anomalie de l'anneau vasculaire. L'oesophagoscopie a révélé la présence d'une sténose musculaire avec apparition d'un sphincter au niveau de l'oesophage intrathoracique proximal, sans signe de rétrécissement. Un diagnostic de sténose congénitale de l'oesophage a été posé, en raison d'une suspicion d'hypertrophie fibromusculaire. La régurgitation s'est résolue avec une gestion conservatrice et le chien allait bien lors d'un examen de suivi à 2 ans. Ce cas représente l'un des rares cas de sténose congénitale de l'oesophage rapportés chez les petits animaux et apparemment le seul cas traité avec succès de manière conservatrice.Message clinique clé :Ce rapport décrit la présentation clinique, les résultats de l'imagerie diagnostique et le traitement d'un cas rare de sténose congénitale de l'oesophage chez un Labrador. Les thérapies médicales et conservatrices seules peuvent être suffisantes pour le traitement de la sténose congénitale de l'oesophage en fonction de la présentation et du type histopathologique suspecté. Ces thérapies doivent être envisagées avant d'entreprendre des procédures interventionnelles.(Traduit par Dr Serge Messier).

Computed tomography of testicular torsion in a juvenile dog with unilateral cryptorchidism.

A 14-week-old male unilaterally cryptorchid Clumber spaniel was presented for acute lethargy. Physical examination revealed abdominal pain, and a single testis was palpated in the scrotum. Abdominal ultrasound and computed tomography (CT) revealed a poorly vascularized, ovoid structure immediately caudal to the left kidney with scant regional peritoneal effusion. Left intra-abdominal testicular torsion was confirmed at surgery, and routine cryptorchidectomy was performed. The patient recovered uneventfully from anesthesia and surgery. Key clinical message: The most common CT characteristics of testicular torsion were present in this case and correlated well with sonographic findings to allow for rapid, accurate diagnosis and surgical planning of unilateral, non-neoplastic, intra-abdominal cryptorchid testicular torsion in a juvenile dog. Contrast enhanced CT facilitated accurate localization of the undescended testis and evaluation of testicular perfusion and may be a useful alternative to ultrasound for diagnosing testicular torsion, especially in indeterminate cases.

Tomodensitométrie d'une torsion testiculaire chez un chien juvénile atteint de cryptorchidie unilatérale. Un épagneul Clumber avec une cryptorchidie unilatérale âgé de 14 semaines a été présenté pour une léthargie aiguë. L'examen physique a révélé des douleurs abdominales et un seul testicule a été palpé dans le scrotum. L'échographie abdominale et la tomodensitométrie ont révélé une structure ovoïde mal vascularisée immédiatement caudale au rein gauche avec peu d'épanchement péritonéal régional. Une torsion testiculaire intra-abdominale gauche a été confirmée lors de la chirurgie et une cryptorchidectomie de routine a été réalisée. Le patient s'est remis sans incident de l'anesthésie et de la chirurgie.Message clinique clé:Les caractéristiques tomodensitométriques les plus courantes de la torsion testiculaire étaient présentes dans ce cas et bien corrélées avec les résultats échographiques pour permettre un diagnostic rapide et précis et une planification chirurgicale de la torsion testiculaire avec cryptorchidie unilatérale, non néoplasique et intra-abdominale chez un chien juvénile. La tomodensitométrie avec contraste a facilité la localisation précise du testicule non descendu et l'évaluation de la perfusion testiculaire et peut être une alternative utile à l'échographie pour diagnostiquer la torsion testiculaire, en particulier dans les cas indéterminés.(Traduit par Dr Serge Messier).

Diagnosis of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring: Temporal transitions and association with growth rates.

Bovine respiratory disease (BRD) in dairy calves is a multifactorial condition, involving environmental, host, and pathogen factors. Thoracic ultrasound scoring (TUS) has recently been validated as an accurate method of detecting BRD-related lung pathology in dairy calves. Previous studies investigating the use of TUS in preweaned dairy calves have largely been based on cross-sectional data from all-year production systems. The objectives of this longitudinal observational study were to characterize the temporal transitions in TUS scores in dairy calves from pasture-based, seasonal-calving herds using sequential examinations during the preweaning period, and to investigate the relationship between the presence and temporal pattern of BRD, diagnosed by TUS or clinical respiratory scoring (CRS), and average daily gain (ADG). In spring of 2019, 317 preweaned calves from 7 commercial dairy farms were recruited at less than 4 wk old (ranging from 1-27 d of age). Each farm was examined on at least 3 occasions at 20- to 28-d intervals and housed indoors in group or individual pens. At each visit TUS scores, CRS scores based on the University of Wisconsin Calf Respiratory Score Chart (https://www.vetmed.wisc.edu/fapm/wp-content/uploads/2020/01/calf_respiratory_scoring_chart.pdf), and live weight using a dairy breed-specific weigh band were recorded. All data were recorded by the same 2 veterinarians over the course of the study. The final data set consisted of 966 TUS and CRS scores collected from 317 calves over a period of approximately 6 wk from 7 farms. The data were analyzed in multivariable, mixed effects, linear regression models, with separate models constructed for TUS and CRS scores. Random effects (intercepts) were included for calf, farm, and visit week. Additionally, a random slope was included for age at sampling by farm. Median farm TUS score ranged from 0 to 2.5 over the 3 visits (possible range: 0-5). The percentage of calves with a TUS score ≥3 (consolidation of the full thickness of 1 lung lobe), on each farm ranged from 0 to 50%. The median CRS in calves on individual farms ranged from 1 to 3 over the 3 visits (possible range: 0-12). The percentage of calves on each farm with a CRS score ≥5 (possible range: 0-12) ranged from 0 to 26%. The TUS and CRS scores were weakly correlated. The TUS was associated with reduced ADG. Calves with TUS scores ≥3 grew at 126 g/d less than unaffected calves over the 3-wk period before examination. The predicted effect on ADG was dependent on the age and duration over which the animal was affected. Calves affected later (i.e., between visits 2 and 3) had lower predicted weights at 63 d compared with calves with increased TUS scores earlier in the study period. Calves with a TUS score ≥3 at each of the 3 sampling points had the lowest weight at 63 d of age. There was no association of CRS with ADG. This study showed that in contrast to CRS, higher TUS scores are associated with lower ADG, with weight loss being more pronounced in chronic cases.

Effect of stifle flexion on the position of the cranial tibial artery relative to the proximal tibia in dogs.

OBJECTIVE: To determine the effect of stifle flexion on the proximity of the cranial tibial artery to the proximal tibia in canine stifles with an intact or transected cranial cruciate ligament (CCL). STUDY DESIGN: Ex vivo randomized blinded computed tomographic angiographic study. SAMPLE POPULATION: Fifteen pelvic limbs from eight greyhound cadavers. METHODS: The femoral artery and vein were cannulated and injected with 10 mL of iohexol. Each limb was placed in lateral recumbency on an acrylic sheet with predrawn femoral and tibial lines representing angles of stifle extension. Computed tomography was performed before (limbs 1-15) and after (limbs 10-15) CCL transection. The shortest distance between the cranial tibial artery and proximal tibia (dCrTA-PT) was measured at a distance of one patellar length from medial intercondylar tubercle. RESULTS: Median dCrTA-PT in intact specimens at 70°, 90°, 110°, and 135° was 2.04, 2.05, 2.28, and 2.51 mm, respectively (P = .008). Pairwise comparisons identified a difference between 70° and 135° (P = .007). Mean dCrTA-PT in transected specimens at 70°, 90°, 110°, and 135° was 2.60, 2.57, 2.90, and 2.79 mm, respectively (P = .208). Median overall dCrTA-PT was 2.24 mm in intact specimens (limbs 1-15, all four angles of extension combined) and 2.76 mm in transected specimens (limbs 10-15, all angles combined; P = .01). CONCLUSION: Flexion of the stifle resulted in a negligible decrease in dCrTA-PT in intact specimens but had no effect in CCL transected stifles. CLINICAL SIGNIFICANCE: The angle of stifle extension does not appear to have any clinically significant effect on the proximity of cranial tibial artery to the proximal tibia.

Long-term clinical and radiographic results after lag screw ostheosynthesis of short incomplete proximal sagittal fractures of the proximal phalanx in horses not used for racing.

OBJECTIVE: To determine long term outcomes of nonracing equines athletes treated for short incomplete proximal sagittal fractures of the proximal phalanx (SIPSFP1) by lag screw fixation. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Thirty-one horses. METHODS: Medical records from horses with an SIPSFP1 (2008-2014) were reviewed. Long-term (≥12 months) outcomes were assessed with telephone interviews and clinical and radiographic examinations. RESULTS: Warmblood was the predominant breed in cases included in the study. Among horses with long-term interview information, 27 of 31 returned to previous athletic activity level. In total, 15 horses with 19 fractures had clinical and radiographic assessment after a minimum of 12 months. Among those, nine of 15 horses were sound at the trot, and six of 15 were mildly lame. Complete radiographic healing was confirmed in six limbs, and the facture line was evident in 13. The position of the proximal screw was not associated with radiographic fracture healing or return to soundness. CONCLUSION: Most horses treated for SIPSFP1 with lag screw fixation returned to previous activity levels, although radiographic fracture healing remained incomplete 12 months or more after surgery. CLINICAL SIGNIFICANCE: Lag screw fixation is a valid treatment for horses not used for racing that are experiencing an SIPSFP1 and results in a high rate of return to intended use, although complete radiographic fracture healing cannot be expected.

Standing CT of the equine head: Reducing radiation dose maintains image quality.

Multiple published studies involving computed tomographic (CT) examinations of the equine head utilise a wide range of mAs parameters for image acquisition. This prospective, experimental study assessed the effects of lowering mAs during CT image acquisition on image quality and scatter radiation on 10 cadaver equine heads. Each head was scanned three times at 300, 225, and 150 mAs, with all other scanning parameters remaining constant between series. An anthropomorphic phantom was positioned adjacent to each equine head during image acquisition, mimicking a human bystander, with an ionization chamber attached to the phantom at eye level. Each series was reconstructed using filtered back projection, using medium (H30) and high (H80) frequency reconstruction algorithms. Quantitative image quality assessment was performed by calculating signal to noise ratio (SNR) and contrast to noise ratio (CNR). Two qualitative image quality assessments were performed independently by three blinded board certified veterinary radiologists with a 4 week interval, using a visual grade analysis model adapted from peer reviewed medical literature. Ionization chamber measurements, calculated volume CT dose index (CTDIvol), and dose-length product (DLP) were recorded. Halving radiation dose during image acquisition from 300 to 150mAs resulted in comparable image quality between series. There was a statistically significant and linear relationship between mAs and scatter radiation to the bystander; halving mAs during image acquisition resulted in halving of scatter radiation. Results of this cadaveric study support the use of lower mAs settings during standing CT examinations of the equine head.

Flock health survey of Irish Texel society breeders and larynx examination in Texel sheep.

BACKGROUND: Laryngeal chondritis is a disease of undetermined aetiology, characterised by oedema, ulceration, abscessation and necrosis of the laryngeal mucosa and cartilage. The initial aim of the study was to document flock health issues identified by Irish pedigree Texel breeders using a questionnaire survey. Additionally, given the reports of breed predisposition for laryngeal chondritis in Texels, a further aim was to identify if laryngeal problems were perceived as an issue. Work was then conducted to identify if pre-clinical laryngeal mucosal pathology was identifiable in Texel sheep showing no overt clinical signs of respiratory disease and if associations existed between laryngeal measurements and laryngeal pathology.Thirty one larynges were collected from a Texel flock that previously had laryngeal chondritis diagnosed in fallen stock. Gross visual inspection was performed to identify and grade (0-5) laryngeal pathology. A series of measurements were then performed on larynges that had been formalin fixed. Associations between independent variables (larynx measurements) and the dependent variable (laryngeal pathology score) were examined. RESULTS: Respiratory disease was the most frequently identified health issue. Farmer-diagnosed 'throat problems' were reported by over 80% of respondents.Laryngeal pathology was noted in Texels showing no overt clinical signs of respiratory disease. Associations between laryngeal measurements and laryngeal pathology were identified relating to the angle between the cranial point of the cricoid cartilage and the vocal process of the arytenoid cartilage. CONCLUSIONS: Mild laryngeal pathology was noted in animals with no overt clinical signs of respiratory disease. Future research should examine whether significant associations between laryngeal measurements and laryngeal pathology identified in the current study can be measured ante mortem, and whether such ante mortem measurements will allow early identification of sheep at risk of developing laryngeal chondritis.

Comparison between high-field 3 Tesla MRI and computed tomography with and without arthrography for visualization of canine carpal ligaments: A cadaveric study.

OBJECTIVE: To compare the quality of visualization of canine carpal ligaments by using computed tomography (CT), MRI, CT arthrography (CTA), and magnetic resonance arthrography (MRA). STUDY DESIGN: Prospective descriptive study. STUDY POPULATION: Cadavers from dogs weighing more than 20 kg. METHODS: A 16-slice CT scanner and a 3 Tesla MRI were used for the investigation. A dilute contrast medium was injected into the middle carpal and radiocarpal joints under fluoroscopic control, and CTA and MRA images were acquired. To evaluate the difference between imaging modalities, 3 observers graded carpal ligaments of clinical interest using a scale from 0 to 4 for their quality of visualization. Data were analyzed by using a random-effect ordinal logistic regression with Bonferroni adjustment. The interobserver agreement was calculated by using the weighted Cohen's κ. RESULTS: Normal carpal joints (n = 9) were investigated. Magnetic resonance arthrography improved visualization of the majority of carpal ligaments compared with MRI (P < .05) and offered the best visualization overall. Magnetic resonance imaging and MRA offered better visualization compared with both CT and CTA (P < .05). There was no difference between CT and CTA. Interobserver agreement was discrete (0.2 < κ ≤ 0.4) for all observers. CONCLUSION: Arthrography improved the capabilities of MRI but not of CT for visualization of the canine carpal ligaments. Magnetic resonance arthrography was particularly useful for evaluation of the stabilizers of the antebrachiocarpal joint. CLINICAL SIGNIFICANCE: 3 Tesla MRA and MRI allow excellent visualization of the ligamentous morphology and may be helpful in the diagnostic process of carpal sprains in dogs.

Improved visualization of the lumbar spine nerve roots in dogs using water excitation (ProSet) as opposed to short tau inversion recovery: A retrospective study of two fat suppression MRI sequences.

Magnetic resonance imaging fat suppression techniques are commonly used for diagnosis of canine spinal disease, however, studies comparing different techniques are currently lacking. This retrospective, methods comparison study aimed to evaluate water excitation and STIR MRI pulse sequences for visualization of canine lumbar spinal nerve roots. For inclusion, all dogs had to have dorsal planar MRI studies of the lumbar spine using both sequences. Visual grading analysis was used for scoring the following five criteria: degree of fat suppression; nerve root visualization; subjective tissue contrast; presence of noise; and overall better image quality. Scores were independently recorded by three board-certified veterinary radiologists on two separate occasions, 3-6 weeks apart. A total of 90 dogs were sampled. A two-tailed t-test showed that there were significant differences in all scored parameters (P < 0.00001), with the exception of noise (P = 0.47343), and that the water excitation sequence scored higher in all cases excluding noise. A Gwets AC kappa for intraobserver and interobserver reliability showed "almost perfect" agreement for the nerve roots in both tests (intra: k = 0.88; inter: k = 0.90). Intraobserver agreement was "substantial" for the degree of fat suppression (k = 0.68), subjective tissue contrast (k = 0.75), and overall better image quality (k = 0.76) and it was "fair" for the noise (k = 0.46). Interobserver agreement was "moderate" for the degree of fat suppression (k = 0.53), subjective tissue contrast (k = 0.63), and overall better image quality (k = 0.66) and "slight" for noise (k = 0.25). These findings supported using the water excitation pulse sequence for fat-suppressed MRI of canine lumbar spinal nerve roots.

Comparison of T1wFLAIR and T1wTSE sequences in imaging the brain of small animals using high-field MRI.

BACKGROUND: T1w turbo spin echo (TSE) represents a fundamental sequence in magnetic resonance imaging (MRI) protocols investigating the brain. Recent human literature has reported T1w Fluid Attenuated Inversion Recovery's (FLAIR's), superiority to T1wTSE in relation to tissue contrast for grey-to-white matter (GM-WM) and lesion-to-WM, although conflicting results are reported concerning lesion detection.To the author's knowledge, T1wFLAIR has not been investigated in veterinary medicine. The aim of this prospective study was to determine quantitatively and qualitatively which sequence provides better overall better image quality both pre- and post-gadolinium. RESULTS: Twenty-eight animals underwent MRI of the brain with T1wTSE and T1wFLAIR sequences performed with equivalent mean acquisition times. Quantitative assessment of the sequences was undertaken using contrast-to-noise (CNR) and signal-to-noise (SNR) ratios from predefined locations. T1wFLAIR provided a better CNR compared to T1wTSE, while T1wTSE provided better SNR due to the higher noise levels of T1wFLAIR images. Qualitative assessment of the sequences was performed using Visual Grading Analysis Scoring (VGAS) for a number of criteria by three observers on two separate occasions. T1wFLAIR performed better for cerebrospinal fluid (CSF) suppression, white-to-grey matter (WM-GM) and white matter-to-CSF (WM-to-CSF) definition in both pre- and post-contrast images whereas the T1wTSE sequence was less affected by noise levels. The individual parameter for overall image quality found no significant difference between the two sequences. However, the composite VGAS favored T1wFLAIR as the preferred sequence. Although case numbers were insufficient for statistical analysis, comparison of the sequences indicates that lesion definition and margination was better in T1wFLAIR pre-contrast images, however post-contrast lesion detection was almost equivalent between sequences with slightly better margination in the T1wTSE sequence. CONCLUSIONS: T1wFLAIR provides better CNR with better WM-GM and WM-CSF definition both pre- and post-contrast compared to T1wTSE albeit with a higher degree of noise; this was confirmed both quantitatively and qualitatively. Our results also suggest that T1wFLAIR is better for lesion detection and margination pre-contrast administration and sequences are relatively equivocal post-gadolinium administration although further research is required to determine the benefit that inversion recovery sequences make when investigating brain lesions in small animal MRI.

Comparison between magnetic resonance imaging, computed tomography, and arthrography to identify artificially induced cartilage defects of the equine carpal joints.

While articular cartilage changes are considered to be one of the initial events in the pathological cascade leading to osteoarthritis, these changes remain difficult to detect using conventional diagnostic imaging modalities such as plain radiography. The aim of this prospective, experimental, methods comparison study was to compare the sensitivity of magnetic resonance imaging (MRI), magnetic resonance arthrography, computed tomography (CT), and CT arthrography in the detection of artificially induced articular cartilage defects in the equine carpal joints. Defects were created in the antebrachiocarpal and middle carpal joint using curettage by a board-certified equine surgeon. Normal articular cartilage thickness varied from a maximum of 1.22 mm at the level of the distal aspect of the radius to a minimum of 0.17 mm in the proximal articular surface of the third carpal bone. Regarding cartilaginous defect measurements the remaining cartilaginous bed range from a maximum of 0.776 mm in the partial thickness defects, and 0 mm (defect reaches the subchondral bone) when total thickness defect were made. Computed tomography and magnetic resonance imaging were performed followed by CT arthrography and magnetic resonance arthrography after antebrachiocarpal and middle carpal intraarticular contrast administration. All images were reviewed by two board-certified veterinary radiologists, both of whom were blinded to the location, presence of, and thickness of the cartilage defects. A total number of 72 lesions in nine limbs were created. Mean sensitivity for localizing cartilage defects varied between imaging modalities with CT arthrography showing the best sensitivity (69.9%), followed by magnetic resonance arthrography (53.5%), MRI (33.3%), and CT (18.1%) respectively. The addition of contrast arthrography in both magnetic resonance and CT improved the rate of cartilage lesion detection although no statistical significance was found. Computed tomographic arthrography displayed the best sensitivity for detecting articular cartilage defects in the equine antebrachiocarpal and middle-carpal joints, compared to magnetic resonance arthrography, MRI, and CT.

Sub-Tenon's injection in equine cadaver eyes: MRI visualization of anesthetic fluid distribution and comparison of two different volumes.

OBJECTIVE: To compare the localization and distribution of two different anesthetic fluid volumes around equine cadaver eyes to determine an appropriate volume for a single sub-Tenon's injection in horses. PROCEDURE: A single sub-Tenon's injection of 2% lidocaine was performed in 10 equine cadaver heads (20 eyes) using two different volumes (7 mL on one side and 10 mL on the opposite side). The posterior circular distribution of the anesthetic was quantified in sagittal, dorsal, and transverse MRI (T2W-TSE) sequences and evaluated independently by three board-certified radiologists. The distribution of the two fluid volumes was compared via a paired Student's t-test. The interobserver reliability was evaluated via a Kruskal-Wallis test. RESULTS: Extension of the injection fluid was observed along the dorsal and temporal quadrants of the globe within the subconjunctival space, the anterior and posterior sub-Tenon's space, and into the muscle sheaths along the extraocular muscles. Accumulation of anesthetic fluid directly surrounding the optic nerve was detected in three of 20 cadaver eyes. Circular distribution of the 7 and 10 mL anesthetic volumes was not significantly different (P = 0.849). More retrograde leakage of the anesthetic was observed using the 10 mL volume. Evaluation of interobserver reliability revealed no significant differences between observers (P = 0.21-0.92). CONCLUSIONS: Sub-Tenon's anesthesia can have potential as an alternative to retrobulbar anesthesia for ophthalmic surgeries in equines. A 7- to 10-mL injection volume should be appropriate based on the results of this study. The distribution of the anesthetic solution in live tissues, the clinical effects, and the potential for complications will have to be evaluated in vivo.

Assessment of radial torsion using computed tomography in dogs with and without antebrachial limb deformity.

OBJECTIVE: To evaluate the reliability of radial torsion assessment in dogs using computed tomography (CT). STUDY DESIGN: Cadaveric and retrospective observational clinical study. ANIMALS: Thoracic limbs (n = 40) from bilateral normal cadaveric canine specimens (10 pairs) and unilateral antebrachial angular limb deformity (ALD) dogs (10 uniapical and 10 biapical deformities). METHODS: Limbs were evaluated using CT. Frontal, sagittal, and axial plane (torsion) values were obtained using published guidelines and compared between groups and limbs. Radial torsion reliability was assessed among 3 observers using intraclass correlation coefficients (ICC). RESULTS: The mean (±SD) radial torsion of normal dogs was 3.6° ± 6.4° and contained a significant right to left limb variation of 2.6°. Mean radial torsion in uniapical ALD limbs (3.6° ± 18.7°) was not significantly different from biapical ALD limbs (8.9° ± 17.9°). There was a wide range of torsion values in normal and ALD limbs. The interobserver reliability was excellent (ICC > 0.8) for normal dogs, good (0.73) for uniapical, and excellent (0.89) for biapical ALD limbs. The intraobserver reliability was excellent (>0.8) for all groups. CONCLUSION: There was a small side-to-side variation of radial torsion in normal dogs. With directed training, torsion assessment using CT is reliable in dogs with and without antebrachial bone deformity.

IMAGING DIAGNOSIS-COMPUTED TOMOGRAPHY FINDINGS IN A CASE OF METASTATIC OVARIAN ADENOCARCINOMA IN A DOG.

A 5-year-old female entire German Shepherd presented for otitis and lethargy. An incidental abdominal mass was identified on examination. Ultrasound examination (US) identified a heterogeneous left ovarian mass. Computed tomography (CT) was performed for surgical planning and staging. The reproductive tract was removed en bloc and submitted for histopathology. Multiple small (1-5 mm) nodules identified at coeliotomy on the surface of the liver, spleen and peritoneum were biopsied. The lesions were not visible on CT nor US on review. This is the first case report of the CT findings of ovarian papillary adenocarcinoma with carcinomatosis.