DISTRIBUTION AND SHORT- AND LONG-TERM EFFECTS OF INJECTED GELIFIED ETHANOL INTO THE LUMBOSACRAL INTERVERTEBRAL DISC IN HEALTHY DOGS.

Radiopaque gelified ethanol preparation has been described as a useful agent for treatment of humans with intervertebral disc protrusion. The material is injected into the nucleus pulposus under image guidance with intention to cause the protruded disc material to recede. Because treatment options for dogs with chronic protrusions are limited, new and minimally invasive treatments are desirable. The aim of this experimental, descriptive, prospective study was to assess the feasibility and safety of percutaneous injection of gelified ethanol into the lumbosacral intervertebral disc of dogs. Lumbosacral intervertebral discs of normal dogs (n = 9) were imaged with magnetic resonance imaging and then injected with gelified ethanol using image guidance. The accuracy of gelified ethanol placement in the nucleus pulposus and presence of leakage of the injected material were documented. Postinjection computed tomography (CT) findings (n = 9), short-term (n = 9) and long-term (n = 4) follow-up magnetic resonance imaging and CT findings were compared to document the distribution of the injected preparation and identify effects on adjacent tissues. Percutaneous injection of the intervertebral disc was successful in delivering radiopaque gelified ethanol to the nucleus pulposus in all dogs. Leakage of the injected material into the vertebral canal was present in three dogs immediately following injection and in another additional dog at 1 year following injection. All dogs tolerated the injection well and had no clinical adverse reactions within the study period. Findings indicated that injection of the nucleus pulposus of healthy dogs was well tolerated, even in the presence of mild leakage of material from the intervertebral disc.

Ultrasonography detects early laryngeal muscle atrophy in an equine neurectomy model.

INTRODUCTION: A unilateral neurectomy model was used to study the relationship between histologic and ultrasonographic tissue characteristics during muscle atrophy over time. METHODS: This investigation was an in vivo experimental study in an equine model (n = 28). Mean pixel intensity of ultrasonographic images was measured, a muscle appearance grade was assigned weekly, and muscles were harvested from 4 to 32 weeks. Minimum fiber diameter, fiber density per unit area, percent collagen, percent fat, and fiber type profile were measured from muscle cryosections and correlated with the ultrasonographic parameters. RESULTS: A significant relationship was identified between collagen content, minimum fiber diameter, and ultrasonographic muscle appearance by as early as 8 weeks. There was no apparent association between fat content of muscle and the ultrasonographic appearance of atrophy before 28 weeks. CONCLUSIONS: Early muscle atrophy before fatty infiltration is detectable with ultrasound. The effect of muscle collagen content on echointensity may be mediated by reduced fiber diameter.

Ultrasonographic detection of early atrophy of the intrinsic laryngeal muscles of horses.

OBJECTIVE: To describe the ultrasonographic changes in the cricoarytenoideus dorsalis (CAD) and cricoarytenoideus lateralis (CAL) muscles of horses before and at various times during the 32 weeks after unilateral neurectomy of the right recurrent laryngeal nerve. ANIMALS: 28 healthy Standardbreds. PROCEDURES: For each horse, the appearance of the CAD and CAL muscles on the right (neurectomized) and left (control) sides was serially monitored ultrasonographically by percutaneous (CAD and CAL) and transesophageal (CAD) approaches. The ultrasonographic images were assessed to determine the mean pixel intensity, muscle thickness, and appearance grade, and comparisons were made between the muscles of the neurectomized and control sides. RESULTS: The muscle appearance grade and mean pixel intensity for the CAL and CAD muscles on the neurectomized side were significantly increased by 2 and 4 weeks, respectively, after the neurectomy. The transesophageal approach enhanced the ultrasonographic visibility of the CAD muscle and allowed us to detect a significant decrease in the thickness of the CAD muscle on the neurectomized side over time, compared with thickness of the CAD muscle on the control side. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested ultrasonography can be used to successfully assess the CAL and CAD muscles of horses. A qualitative grading scheme was sufficient for successful detection and monitoring of muscle atrophy and reduced the need for image standardization. The transesophageal approach described for assessment of the CAD muscle warrants further investigation.

3D-Ultrasonography for evaluation of facial muscles in patients with chronic facial palsy or defective healing: a pilot study.

BACKGROUND: While standardized methods are established to examine the pathway from motorcortex to the peripheral nerve in patients with facial palsy, a reliable method to evaluate the facial muscles in patients with long-term palsy for therapy planning is lacking. METHODS: A 3D ultrasonographic (US) acquisition system driven by a motorized linear mover combined with conventional US probe was used to acquire 3D data sets of several facial muscles on both sides of the face in a healthy subject and seven patients with different types of unilateral degenerative facial nerve lesions. RESULTS: The US results were correlated to the duration of palsy and the electromyography results. Consistent 3D US based volumetry through bilateral comparison was feasible for parts of the frontalis muscle, orbicularis oculi muscle, depressor anguli oris muscle, depressor labii inferioris muscle, and mentalis muscle. With the exception of the frontal muscle, the facial muscles volumes were much smaller on the palsy side (minimum: 3% for the depressor labii inferior muscle) than on the healthy side in patients with severe facial nerve lesion. In contrast, the frontal muscles did not show a side difference. In the two patients with defective healing after spontaneous regeneration a decrease in muscle volume was not seen. Synkinesis and hyperkinesis was even more correlated to muscle hypertrophy on the palsy compared with the healthy side. CONCLUSION: 3D ultrasonography seems to be a promising tool for regional and quantitative evaluation of facial muscles in patients with facial palsy receiving a facial reconstructive surgery or conservative treatment.

Comparison between computed tomography, fluoroscopy, and ultrasonography for guiding percutaneous injection of the canine intervertebral disc.

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US-guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty-nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.

Imaging diagnosis--temporomandibular joint dysplasia in a Basset Hound.

A 5-month-old intact male Basset Hound presented for evaluation of pain and crepitation during manipulation of the temporomandibular joint, worse on the right side. A computed tomography (CT) scan of the head was performed. The CT images demonstrated the osseous features of temporomandibular joint dysplasia and facilitated a 3D reconstruction, which allowed better visualization of the dysplastic features. The patient responded to conservative management with a tape muzzle with no recurrence reported by the owner 6 months after presentation.

Ultrasound-guided percutaneous antegrade hydropropulsion to relieve ureteral obstruction in a pet guinea pig (Cavia porcellus).

Severe hydroureter and hydronephrosis secondary to ureteral obstruction by calculus were present in a guinea pig. A palliative ultrasound-guided percutaneous antegrade hydropropulsion was performed under general anesthesia to relieve the ureteral obstruction and the associated clinical signs. We describe the technique and the considerations for its potential application in similar cases.

Hydropropulsion antérograde percutanée guidée par échographie pour soulager l'obstruction urétérale d'un cobaye de compagnie(Cavia porcellus). Une urétérohydrose et une hydronéphose graves secondaires à une obstruction urétérale causée par des calculs étaient présentes chez un cobaye. Une hydropropulsion antérograde percutanée guidée par échographie a été réalisée sous anesthésie générale pour soulager l'obstruction urétérale et les signes cliniques connexes. Nous décrivons la technique et les considérations pour son application potentielle dans des cas semblables.(Traduit par Isabelle Vallières).

Experimental transmission of enzootic nasal adenocarcinoma in sheep.

Enzootic nasal adenocarcinoma (ENA) is a contagious neoplasm of the secretory epithelial cells of the nasal mucosa of sheep and goats. It is associated with the betaretrovirus, enzootic nasal tumor virus (ENTV), but a causative relationship has yet to be demonstrated. In this study, 14-day-old lambs were experimentally infected via nebulization with cell-free tumor filtrates derived from naturally occurring cases of ENA. At 12 weeks post-infection (wpi), one of the five infected lambs developed clinical signs, including continuous nasal discharge and open mouth breathing, and was euthanized. Necropsy revealed the presence of a large bilateral tumor occupying the nasal cavity. At 45 wpi, when the study was terminated, none of the remaining infected sheep showed evidence of tumors either by computed tomography or post-mortem examination. ENTV-1 proviral DNA was detected in the nose, lung, spleen, liver and kidney of the animal with experimentally induced ENA, however there was no evidence of viral protein expression in tissues other than the nose. Density gradient analysis of virus particles purified from the experimentally induced nasal tumor revealed a peak reverse transcriptase (RT) activity at a buoyant density of 1.22 g/mL which was higher than the 1.18 g/mL density of peak RT activity of virus purified from naturally induced ENA. While the 1.22 g/mL fraction contained primarily immature unprocessed virus particles, mature virus particles with a similar morphology to naturally occurring ENA could be identified by electron microscopy. Full-length sequence analysis of the ENTV-1 genome from the experimentally induced tumor revealed very few nucleotide changes relative to the original inoculum with only one conservative amino acid change. Taken together, these results demonstrate that ENTV-1 is associated with transmissible ENA in sheep and that under experimental conditions, lethal tumors are capable of developing in as little as 12 wpi demonstrating the acutely oncogenic nature of this ovine betaretrovirus.

The Ontario Veterinary College Hip Certification Program -- assessing inter- and intra-observer repeatability and comparison of findings to those of the Orthopedic Foundation for Animals.

In Canada, the Ontario Veterinary College (OVC) has offered radiographic screening for hip dysplasia for many years, but there are other options for this service including the Orthopedic Foundation for Animals (OFA). There are some differences between the OFA and the OVC methods, and this study compares the OVC and OFA hip certification results in 37 dogs. There was good agreement between the two programs but in some instances there was a difference in the pass/fail status of a dog. Neither the OFA nor the OVC was more likely to fail or pass a given dog. The repeatability of the OVC results was assessed by both inter- and intra-observer comparisons in 100 dogs. There was at least 86% agreement among and within radiologists, but in 5 cases the disagreement resulted in a difference in the pass/fail status of the dog. These results illustrate the inherent variation in radiographic hip evaluation and highlight the importance of consensus grading practices to improve the accuracy of hip evaluation.

Programme de certification des hanches de l'Ontario Veterinary College ­ Évaluation de la reproductibilité inter- et intra-observateur et comparaison des résultats à ceux de l'Orthopedic Foundation for Animals. Au Canada, l'Ontario Veterinary College (OVC) offre le dépistage radiographique de la dysplasie de la hanche depuis de nombreuses années, mais il y a d'autres options pour ce service, incluant l'Orthopedic Foundation for Animals (OFA). Il y a certaines différences entre les méthodes de l'OFA et de l'OVC et cette étude compare les résultats de certification de la hanche de l'OVC et de l'OFA chez 37 chiens. Il y avait une bonne concordance entre les deux programmes, mais dans certains cas, il y avait une différence au niveau du statut d'échec-réussite d'un chien. Ni l'OFA ni l'OVC ne présentait une probabilité accrue de donner un résultat d'échec ou de réussite à un chien particulier. La reproductibilité des résultats de l'OVC a été évaluée par des comparaisons inter- et intra-observateur chez 100 chiens. Il y avait au moins 86 % de concordance entre et parmi les radiologistes, mais dans 5 cas, la discordance s'est traduite par une différence du statut de réussite et d'échec chez le chien. Les résultats illustrent la variation inhérente à l'évaluation radiographique de la hanche et souligne l'importance de pratiques de classification par consensus afin d'améliorer l'exactitude de l'évaluation de la hanche.(Traduit par Isabelle Vallières).

Quantitative ultrasonography of facial muscles.

INTRODUCTION: There is no standardized method for examination of facial muscles with ultrasound. The purpose of this study was to identify those facial muscles accessible for reliable identification and to provide reference data. METHODS: In healthy subjects all facial muscles were screened for visibility, separation from adjacent muscles, and reliability of landmarks. Bilateral scans of reliable muscles were performed in 40 adult volunteers. RESULTS: Six facial muscles were clearly demarcated with ultrasound. These were: frontalis, orbicularis oculi, orbicularis oris, depressor anguli oris, depressor labii inferioris, and mentalis muscles. Cross-sectional area and muscle thickness showed gender differences and were independently related to age for some muscles. A significant left-right side difference was only seen for the orbicularis oculi muscle in women. CONCLUSIONS: These data demonstrate the usefulness of ultrasonography to assess facial muscles and provide reference values that can be applied in the clinical setting.

Diagnostic sensitivity and interobserver agreement of radiography and ultrasonography for detecting trochlear ridge osteochondrosis lesions in the equine stifle.

Osteochondrosis lesions commonly occur on the femoral trochlear ridges in horses and radiography and ultrasonography are routinely used to diagnose these lesions. However, poor correlation has been found between radiographic and arthroscopic findings of affected trochlear ridges. Interobserver agreement for ultrasonographic diagnoses and correlation between ultrasonographic and arthroscopic findings have not been previously described. Objectives of this study were to describe diagnostic sensitivity and interobserver agreement of radiography and ultrasonography for detecting and grading osteochondrosis lesions of the equine trochlear ridges, using arthroscopy as the reference standard. Twenty-two horses were sampled. Two observers independently recorded radiographic and ultrasonographic findings without knowledge of arthroscopic findings. Imaging findings were compared between observers and with arthroscopic findings. Agreement between observers was moderate to excellent (κ 0.48-0.86) for detecting lesions using radiography and good to excellent (κ 0.74-0.87) for grading lesions using radiography. Agreement between observers was good to excellent (κ 0.78-0.94) for detecting lesions using ultrasonography and very good to excellent (κ 0.86-0.93) for grading lesions using ultrasonography. Diagnostic sensitivity was 84-88% for radiography and 100% for ultrasonography. Diagnostic specificity was 89-100% for radiography and 60-82% for ultrasonography. Agreement between radiography and arthroscopy was good (κ 0.64-0.78). Agreement between ultrasonography and arthroscopy was very good to excellent (κ 0.81-0.87). Findings from this study support ultrasound as a preferred method for predicting presence and severity of osteochondrosis lesions involving the femoral trochlear ridges in horses.

Diagnostic sensitivity of subjective and quantitative laryngeal ultrasonography for recurrent laryngeal neuropathy in horses.

Recurrent laryngeal neuropathy (RLN) is the most common cause of laryngeal hemiplegia in horses and causes neurogenic atrophy of the intrinsic laryngeal muscles, including the cricoarytenoideus lateralis muscle. Recurrent laryngeal neuropathy results in paresis to paralysis of the vocal fold and arytenoid cartilage, which limits performance through respiratory compromise. Ultrasound has previously been reported to be a useful diagnostic technique in horses with RLN. In this report, the diagnostic sensitivity of subjective and quantitative laryngeal ultrasonography was evaluated in 154 horses presented for poor performance due to suspected upper airway disease. Ultrasonographic parameters recorded were: cricoarytenoideus lateralis echogenicity (subjective and quantitative), cricoarytenoideus lateralis thickness, vocal fold movement, and arytenoid cartilage movement. Ultrasonographic parameters were then compared with laryngeal grades based on resting and exercising upper airway endoscopy. Subjectively increased left cricoarytenoideus lateralis echogenicity yielded a sensitivity of 94.59% and specificity of 94.54% for detecting RLN, based on the reference standard of exercising laryngeal endoscopy. Quantitative left cricoarytenoideus lateralis echogenicity values differed among resting laryngeal grades I-IV. Findings from this study support previously published findings and the utility of subjective and quantitative laryngeal ultrasound as diagnostic tools for horses with poor performance.

Effects of hypercapnia, hypocapnia, and hyperoxemia on brain morphometrics determined by use of T1-weighted magnetic resonance imaging in isoflurane-anesthetized dogs.

OBJECTIVE: To evaluate the effects of various combinations of PaCO2 and PaO2 values on brain morphometrics. ANIMALS: 6 healthy adult dogs. PROCEDURES: A modified Latin square design for randomization was used. Dogs were anesthetized with propofol (6 to 8 mg/kg, IV), and anesthesia was maintained with isoflurane (1.7%) and atracurium (0.2 mg/kg, IV, q 30 min). Three targeted values of PaCO2 (20, 40, and 80 mm Hg) and 2 values of PaO2 (100 and 500 mm Hg) were achieved in each dog, yielding 6 combinations during a single magnetic resonance (MR) imaging session. When the endpoints were reached, dogs were given at least 5 minutes for physiologic variables to stabilize before T1-weighted MR images were obtained. Total brain volume (TBV) and lateral ventricular volume (LVV) were calculated from manually drawn contours of areas of interest by use of a software program, with each dog serving as its own control animal. Three blinded investigators subjectively evaluated the lateral ventricular size (LVS) and the cerebral sulci width (CSW). Brain morphometric values were compared among the target blood gas states. RESULTS: No significant differences in TBV were found among target states. The LVV was significantly greater during hypocapnia, compared with hypercapnia at the same PaO2 value. With regard to the subjective evaluations, there were no significant differences among evaluators or among combinations of PaO2 and PaCO2 values. CONCLUSIONS AND CLINICAL RELEVANCE: The changes observed in LVV during hypocapnia and hypercapnia may serve as a potential confounding factor when neuromorphometric evaluations are performed in anesthetized dogs.

Ultrasonographic assessment of laryngohyoid position as a predictor of dorsal displacement of the soft palate in horses.

Dorsal displacement of the soft palate is an important cause of poor performance in racehorses, yet its etiology is not fully understood. Diagnosis requires treadmill videoendoscopy, which is not widely available. The relationship of the larynx, the hyoid apparatus, and the remainder of the skull may be important in predisposing horses to dorsal displacement of the soft palate. We hypothesized that this relationship could be accurately assessed in unsedated horses through ultrasonographic examination. Fifty-six racehorses presented for evaluation of poor performance were subjected to treadmill videoendoscopy and resting ultrasonography. Using ultrasound-assisted percutaneous measures of laryngo-hyoid position, the relationship between selected anatomic structures and the occurrence of dorsal displacement of the soft palate was evaluated. A significant relationship was found between the depth of the basihyoid bone at rest and the occurrence of dorsal displacement of the soft palate at exercise (P = 0.03). Other measures of laryngohyoid position were not found to be associated with dorsal displacement of the soft palate. Thus, there is an association between the occurrence of dorsal displacement of the soft palate at exercise and the resting position of the basihyoid bone, whereby on average a more ventral location of the basihyoid bone is present in horses with dorsal displacement of the soft palate. The pathophysiologic implications of this finding are not fully understood but, based on our findings, ultrasound examination is of value in assisting in the diagnosis of dorsal displacement of the soft palate.

Evaluation of agreement between two instruments in measurements of radiation dose rates in cats that underwent iodine I 131 treatment.

OBJECTIVE: To assess agreement between a commercially available Geiger-Meuller (GM) survey meter and millirem tissue-equivalent (TE) meter for measuring radioactivity in cats treated with sodium iodine I 131 ((131)I). ANIMALS: 15 cats with hyperthyroidism and undergoing (131)I treatment. PROCEDURES: Duplicate measurements were obtained at a distance of 30 cm from the thyroid region of each cat's neck by 2 observers who used both meters on day 3 or 5 after(131)I administration. Comparisons of measurements between meters and observers were made, with limits of agreement defined as the mean difference +/- 2 SDs of the differences. RESULTS: For observer 1, the mean of the differences in the 2 meters' measurements in all cats was 0.012 mSv/h (SD, 0.011 mSv/h). For observer 2, the mean of the differences in measurements was 0.012 mSv/h (SD, 0.010 mSv/h). For the GM meter, the mean of the differences of the 2 observers for all cats was 0.003 mSv/h (SD, 0.011 mSv/h). For the TE meter, the mean of the differences of the 2 observers for all cats was 0.003 mSv/h (SD, 0.007 mSv/h). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that there was considerable agreement between meters and observers in measurements of radioactivity in cats treated with (131)I. Measurements obtained by use of the GM meter may be approximately 0.01 mSv/h less than or 0.03 mSv/h higher than those obtained with the TE meter. If this range is acceptable for an institution's release criteria, the 2 meters should be considered interchangeable and acceptable for clinical use.

Assessment of bone mineral density of the femoral head in dogs with early osteoarthritis.

OBJECTIVE: To compare the bone mineral density (BMD) of the proximal portion of the femur in dogs with and without early osteoarthritis secondary to hip dysplasia. ANIMALS: 24 dogs (3 Greyhounds, 6 Labrador-Greyhound crossbreeds, and 15 Labrador Retrievers). PROCEDURE: Computed tomography (CT) of the pelvis, including a bone-density phantom, was performed for each dog. Centrally located transverse CT slices and a computer workstation were used to identify 16 regions of interest (ROIs) in the proximal portion of the femur. For each ROI, the mean Hounsfield unit value was recorded; by use of the bone-density phantom and linear regression analysis, those values were converted to equivalent BMD (eBMD). Mean eBMD values for the subchondral and nonsubchondral ROIs in dogs with and without osteoarthritis (determined at necropsy) were compared. A mixed-model ANOVA and post hoc linear contrasts were used to evaluate the effects of osteoarthritis, breed, and sex on the BMD value. RESULTS: At necropsy, osteoarthritis was detected in 14 hip joints in 9 dogs; all lesions included early cartilage fibrillation. After adjusting for breed and sex, eBMD in subchondral ROIs 8 and 12 (adjacent to the fovea) were 8% and 6% higher, respectively, in osteoarthritis-affected dogs, compared with unaffected dogs; in the nonsubchondral ROIs, eBMD was 10% higher in osteoarthritis-affected dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with findings in unaffected dogs, increased eBMD in hip joints of dogs with early osteoarthritis supports a strong relationship between the subchondral and epiphyseal regions and articular cartilage in the pathogenesis and progression of osteoarthritis.