Efficacy of a novel cervical dislocation tool for humane euthanasia of broilers and broiler breeders.

Euthanasia is an essential task performed daily on commercial poultry farms around the world to safeguard animal welfare. Manual cervical dislocation (MCD) is the most common euthanasia method but can be challenging to perform given the physical strength required to implement this technique. Therefore, the objective of this study was to evaluate the efficacy of a novel cervical dislocation tool (NCDT) compared to MCD. A total of 60 Ross 308 chickens (6-wk old) and 60 Ross 706 parent stock breeders (21-wk old) were enrolled in the study. Birds were sexed, blocked by body weight, and allocated to 1 of 2 treatments: 1) MCD and 2) NCDT. Immediately following euthanasia application, insensibility, and death were monitored. Once death was confirmed, gross evaluation, radiograph, and macroscopic/microscopic scoring were performed. Both euthanasia methods were 100% effective in achieving insensibility followed by cardiac and respiratory arrest in both age groups. In 6-wk-old broilers, there were no differences in insensibility measures or location and severity of the dislocation site by treatment. The NCDT treatment group showed an increased frequency of fractures located at the tooth-like process that projects from the cranial aspect of the centrum of the axis (dens) but had no impact on bird insensibility. For parent stock, differences in nictitating membrane reflex (NMR) and laceration scores for birds euthanized with NCDT were found and likely associated with additional force exerted with the tool. The NCDT is a promising replacement for MCD and future work should address the development of free and accessible training materials for on-farm use.

Clinical and imaging findings in dogs with nerve root signature associated with cervical intervertebral disc herniation.

BACKGROUND: Intervertebral disc herniation (IVDH) is the most common spinal cord disease in dogs. Little information is available regarding the clinical presentation of nerve root signature (NRS) associated with cervical IVDH. HYPOTHESIS/OBJECTIVE: To detail the clinical and magnetic resonance imaging (MRI) findings in dogs with NRS associated with cervical IVDH. ANIMALS: Forty-seven client-owned dogs presenting with thoracic limb NRS and MRI confirmed IVDH. METHODS: Medical records from 2010 to 2020 were retrospectively reviewed for dogs that met inclusion criteria. Imaging studies were evaluated by 2 individuals to characterize location and severity of neural tissue compression. RESULTS: Chondrodystrophoid dogs comprised the majority of the study cohort, with dachshund the most common breed (n = 10). Three-quarters of dogs were ≥7 years of age. Interobserver agreement was moderate or good for all of the imaging variables evaluated. The C6-C7 intervertebral disc space was significantly overrepresented (P = .01), comprising 32% (15/47) of the affected discs. However, 42% (20/47) of cases involved C2-C3 though C4-C5 disc sites. Disc material was more frequently located laterally compared to medially within the vertebral canal (P = .0005), and to be associated with compression of the nerve root at the level of the intervertebral foramen (P = .012). CONCLUSION/CLINICAL IMPORTANCE: NRS is most commonly associated with lateralized or foraminal cervical disc herniations. It is most prevalent with C6-C7 intervertebral disc involvement, suggesting that there might be unique anatomic factors that contribute to development of NRS at this site, but can be a clinical manifestation of IVDH occurring anywhere along the cervical spine.

Calculation of body surface area of corn snakes (Pantherophis guttatus) utilizing computed tomography.

OBJECTIVE: To determine the K-constant for body surface area calculation from body weight in corn snakes (Pantherophis guttatus) through the use of computed tomography (CT) measurements. ANIMALS: 12 adult corn snakes held by North Carolina State University for research purposes underwent CT between November 2022 and January 2023. METHODS: Each snake had a CT scan, physical examination, and body weight measurement. CT images were uploaded into software able to perform 3-D reconstruction and measure body surface area. The species-specific K-constant was determined using nonlinear regression analysis between body surface area and (body weight in grams)2/3. RESULTS: The mean body weight of the 12 adult corn snakes was 228 g, with a mean body surface area of 505.1 cm2. The calculated K-constant was 13.6 (P < .001). The resulting formula for body surface area in corn snakes is BSA in cm2 = 13.6 X (body weight in grams)2/3. CLINICAL RELEVANCE: The body surface area formula developed for corn snakes will allow for improved dosing accuracy for medications with low therapeutic safety margins. Additional pharmacokinetic and pharmacodynamic studies are necessary to determine the safety and efficacy of individual medications.

A comparison of the motor effects and analgesic efficacy following lumbar plexus block combined with sciatic nerve block or epidural in dogs undergoing tibial plateau leveling osteotomy.

OBJECTIVE: To compare motor effects and analgesic efficacy following an ultrasound-guided lateral approach to lumbar plexus blockade at L7 and sciatic nerve blockade (LPSNB) against epidural injection in dogs undergoing tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Prospective, randomized, blinded clinical trial. ANIMALS: A total of 27 healthy adult dogs undergoing unilateral TPLO surgery. METHODS: Dogs were allocated to either LPSNB (bupivacaine 2 mg kg-1, 0.75%) or epidural (morphine PF 0.1 mg kg-1 and bupivacaine 0.5 mg kg-1, 0.75%). Other aspects of clinical management were identical, including anesthetic drug protocol, area of presurgical clipping and bladder care. Time to perform the block, response to surgical stimuli, pain scores, rescue analgesia, time to stand and walk, motor score and time to first urination were recorded. One evaluator, unaware of treatment status, performed all evaluations. Student's t-test or Mann-Whitney U test was used to compare continuous variables between groups, and Fisher's exact test for categorical variables. RESULTS: Median (range) times to stand and walk were shorter for LPSNB [60 (40-120) minutes and 90 (60-150) minutes, respectively, p = 0.003] than for epidural [150 (120-240) minutes and 180 (120-360) minutes, respectively, p = 0.006]. Four dogs required rescue intraoperatively (three in epidural group, one in LPSNB group, p = 0.438). Pain scores over the 24 hour evaluation period were similar, and not significantly different, for each group. Time to spontaneous urination [LPSNB, 330 (240-360) minutes; epidural, 300 (120-1440) minutes, p = 1.0] did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE: An ultrasound-guided lateral paravertebral approach to the lumbar plexus within the psoas compartment at L7, combined with sciatic nerve blockade, allows faster return to normal motor function, with similar pain control and impact on urination when compared with epidural in dogs after TPLO surgery.

Defining a species-specific K constant in American Bullfrogs (Lithobates catesbeianus) through use of computed tomography.

OBJECTIVE: To use CT measurements to define the body surface area (BSA) formula in American bullfrogs (Lithobates catesbeianus) and calculate the species-specific shape constant (K) to suggest chemotherapeutic doses. ANIMALS: 12 American bullfrogs owned by the North Carolina State College of Veterinary Medicine Department of Laboratory Animal Resources underwent CT scans without anesthesia or sedation in November 2022. METHODS: As part of this prospective study, each American bullfrog underwent a complete physical exam and CT scan. 3-D surface models were created using CT data, and the resulting measurements were used for BSA calculations. Animals were grouped by sex. Nonlinear regression analysis of BSA versus body weight was performed, and a species-specific formula was derived for calculating BSA in American bullfrogs. RESULTS: The mean body weight of the bullfrogs was 354 grams. The mean CT-derived BSA was 414.92 cm2. The calculated K constant was 8.28 for the 12 American bullfrogs, and the CT-derived BSA formula was BSA in cm2 = 8.28 X (body weight in g)2/3. The K constant was 8.07 for females and 8.44 for males and was not significantly different between sexes (P = .5). CLINICAL RELEVANCE: Results indicated that the species-specific K constant for American bullfrogs is 8.28. This is the first calculated K constant that exists for amphibians to our knowledge.

General anesthesia does not induce ultrasonographic changes in the pleura of healthy adult horses anesthetized for elective magnetic resonance imaging.

OBJECTIVE: To compare thoracic ultrasonographic findings in healthy horses before and after general anesthesia for elective MRI utilizing a recently developed ultrasonographic scoring system to aid clinicians in the early identification of pneumonia following anesthesia. ANIMALS: 13 adult horses > 3 years of age. PROCEDURES: Prior to anesthesia, horses underwent a thorough physical examination, CBC, thoracic radiography, and thoracic ultrasonography. Horses were then anesthetized for elective MRI, and thoracic ultrasonography was repeated within 3 hours after recovery. Thoracic ultrasonographic findings were scored utilizing a recently developed scoring system, and scores were compared before and after anesthesia. RESULTS: There was no significant difference identified in total thoracic ultrasonography score before and after anesthesia, and there was no correlation between thoracic ultrasonography score following anesthesia and the body weight of the horse, the time recumbent, and the dependent side. CLINICAL RELEVANCE: In healthy horses undergoing anesthesia for elective imaging, there was no significant change in thoracic ultrasonographic findings 3 hours after recovery from anesthesia. These data can aid clinicians in determining the clinical significance of ultrasonographic changes in the lung in the immediate postanesthetic period.

Alterations to the synovial invaginations of the navicular bone are associated with pathology of both the navicular apparatus and distal interphalangeal joint when evaluated using high field MRI.

Limited information exists regarding associations between distal interphalangeal joint (DIPJ) abnormalities and synovial invagination changes in the distal sesamoid (navicular) bone. This retrospective, analytical study aimed to measure specific characteristics of the synovial invaginations of the navicular bone to determine whether any single characteristic was associated with abnormalities in the DIPJ or navicular apparatus (NA) using high field MRI and a sample of 200 horses' feet. The DIPJ and NA were graded independently by three scorers. The grades were averaged, creating a global pathology score for the DIPJ, NA, and synovial invaginations. Higher global scores represented more severe pathology. The number of invaginations, depth of penetration, invagination shape, and cross-sectional area (CSA) of the largest invagination were recorded. Interobserver agreement was measured using Cohen's Kappa. Associations of global scores of the DIPJ and NA with individual invagination characteristics were assessed using linear mixed modeling. A significant relationship was found between the number of invaginations and global DIPJ score, with higher invagination numbers associated with higher DIPJ scores. For invagination depth and CSA, a significant relationship was noted with global scores of both the DIPJ and NA. Reliable relationships between the shape of synovial invaginations and global scores of DIPJ and NA were not found, likely due to poor interobserver scoring (0.305). These findings suggest that primary DIPJ disease and NA pathology should be considered when noticing alterations to navicular synovial invaginations on MRI. This contrasts traditional views that synovial invagination abnormalities are indicative solely of NA pathology.

Use of computed tomography to determine a species-specific formula for body surface area in bearded dragons (Pogona vitticeps).

OBJECTIVE: To use CT-derived measurements to calculate a shape constant (K constant) and create a formula to calculate body surface area (BSA) on the basis of body weight in bearded dragons (Pogona vitticeps). ANIMALS: 12 adult client-owned bearded dragons that underwent CT between December 4, 2019, and April 2, 2020. PROCEDURES: Each bearded dragon in this prospective cohort study underwent physical examination, body weight measurement, and CT. A 3-D surface model was then reconstructed from CT data with available software and used for BSA calculations. Animals were considered collectively and grouped by sex and age. Nonlinear regression analysis of BSA versus body weight was performed, and a species-specific formula was derived for calculating BSA in bearded dragons. RESULTS: Mean age, body weight, and CT-derived BSA were 2.1 years, 356 g, and 580 cm2. The calculated K constant was 11.6 (R2 = 0.994; SE = 0.275) for the 12 bearded dragons, and the CT-derived BSA formula was as follows: BSA in cm2 = 11.6 × (body weight in g)2/3. The K constant differed substantially for bearded dragons grouped by age (12.1 for younger [between 1 and ≤ 2 years of age; n = 8] vs 10.9 for older [> 2 years of age; 4] animals) but did not differ on the basis of sex. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that because the K constant for bearded dragons in the present study was larger than the preexisting K constant of 10 used for reptiles or the various K constants established for some companion mammals, doses of chemotherapeutic drugs needed to treat affected bearded dragons may be higher than previously thought.

Computed tomography in two recumbencies aides in the identification of pulmonary bullae in dogs with spontaneous pneumothorax.

Spontaneous pneumothorax presents a unique diagnostic and therapeutic challenge in veterinary medicine, specifically with regard to accurate identification of bullous lesions. Positioning of dogs with spontaneous pneumothorax during CT has not previously been evaluated. This retrospective, diagnostic accuracy study was performed to evaluate the sensitivity, positive predictive value (PPV), and interobserver variability for detection of pulmonary bullae with dogs positioned in multiple recumbencies. Dogs underwent CT in sternal and dorsal recumbency followed by thoracic exploration via median sternotomy. Three American College of Veterinary Radiology-certified veterinary radiologists blinded to surgical findings reviewed dorsal and sternal images simultaneously. Severity of pneumothorax, degree of atelectasis, lesion location and size, and view in which lesions were most confidently identified were compared to surgical and histologic findings. Sensitivities and PPVs for bulla detection ranged from 57.7% to 69.2% and 62.1% to 78.9%, respectively. For two of the 3 radiologists, the location of bullae in the thorax was significantly associated with the recumbency in which the lesion was best identified. Degree of atelectasis was found to be associated with the ability to identify lesions (P ≤ .02). The interobserver variability for identification was good (κ = 0.670). The sensitivity of CT when performed in both sternal and dorsal recumbency is similar to that previously reported. Because the distribution of bullae is unknown prior to advanced imaging and bulla location affects which recumbency is most useful for identification, acquisition of CT images in both sternal and dorsal recumbency may improve detection of bullous lesions and aid surgical planning.

The impact of tongue dimension on air volume in brachycephalic dogs.

OBJECTIVE: To compare the dimensions and density of the tongue in brachycephalic and mesaticephalic dog breeds and to document the relative extents of the nasopharyngeal and oropharyngeal airways occupied by the tongue and palatal tissues. STUDY DESIGN: Case control study. ANIMALS: Sixteen brachycephalic dogs and 12 mesaticephalic dogs. METHODS: The volume of the tongue was measured with computed tomography in all dogs. Cross-sectional areas of tongue, oropharynx, nasopharynx, and palatal soft tissue were evaluated at two levels, the caudal aspect of the hard palate and the level of the hamulae of the pterygoid. Density of the tongue and soft palate were measured. All variables were compared between brachycephalic and mesaticephalic dogs (P ≤ .05). RESULTS: Absolute tongue volumes did not differ between groups, the volume of the tongue was greater in brachycephalic dogs than in mesaticephalic dogs when expressed relative to (a) body weight (median 5650, interquartile range [IQR] 4833-6522 vs median 4454, IQR 4309-4743, respectively), (b) ratio between skull length/width (70 833, IQR 62490-126 209 vs 48 064, IQR 22984-64 279, respectively), and (c) skull length (689.93, IQR 618.55-970.61 vs 460.04, IQR 288.77-561.69, respectively). The proportion of air (oropharyngeal and nasopharyngeal)/soft tissue (tongue and palatal tissue) in brachycephalic dogs was decreased by approximately 60%, and the tongue was approximately 10 times denser in brachycephalic dogs than in mesaticephalic dogs. CONCLUSION: A relative macroglossia was detected in brachycephalic dogs along with reduced air volume in the upper airway. Tongues of brachycephalic dogs were denser than those of mesaticephalic dogs. CLINICAL SIGNIFICANCE: The relative macroglossia in brachycephalic breeds may contribute to upper airway obstruction.

Evaluation of ultrasonographically determined ratios of kidney length to aorta diameter for assessment of kidney size in healthy young dogs.

OBJECTIVE: To determine whether previously described cutoffs for ultrasonographically determined kidney length-to-aorta diameter ratio (KL:Ao) for evaluation of kidney size in adult dogs are applicable to healthy dogs 1 to 18 months of age and to assess interobserver and intraobserver variability for ultrasonographic kidney and aorta measurements in these dogs grouped according to age. ANIMALS: 82 dogs. PROCEDURES: 41 university-owned dogs and 41 client- or staff-owned dogs of 3 age groups (approx 1, 6, and 12 to 18 months of age) underwent ultrasonographic examination by 3 observers. Kidney length, kidney width, and diameter of the aorta were measured by each observer 3 times, and KL:Ao and kidney length-to-body weight ratio were calculated for each dog. Measurements and calculated ratios for the 3 age groups were compared by statistical methods; interobserver and intraobserver variability were calculated. RESULTS: Mean kidney length, kidney width, and aorta diameter were smaller, and calculated KL:Ao and kidney length-to-body weight ratio were larger, for dogs of the 1-month age group than for dogs of the 6-month and 12 to 18-month age groups. There were significant interobserver differences for ultrasonographic measurements in all age groups; these were most frequent in the youngest group of dogs and affected KL:Ao for that group only. CONCLUSIONS AND CLINICAL RELEVANCE: Results revealed that 1-month-old dogs have larger kidneys relative to body weight and aorta diameter than do older dogs. Interobserver variability for the youngest group of dogs indicated limited usefulness of these measurements and related ratios for neonatal dogs in clinical practice. The KL:Ao values for dogs ≥ 6 months of age in this study were similar to values previously described for dogs > 12 months of age.

Ammonium tetrathiomolybdate treatment of copper-associated hepatopathy in dogs.

BACKGROUND: Copper-associated hepatopathy (CAH) is a common cause of liver disease in dogs. Although d-penicillamine can be an effective treatment, some dogs fail treatment or develop adverse effects. Ammonium tetrathiomolybdate (TTM) has been used to treat pathologic copper accumulation in other species, but its therapeutic potential for CAH is unknown. OBJECTIVES: To investigate short-term safety and efficacy of TTM for treatment of CAH. ANIMALS: Ten dogs with CAH. METHODS: Prospective study. All dogs were treated with TTM PO for 6 weeks, and hepatic biopsies were performed after the treatment course. Dog experiencing initial decreases in hepatic copper concentrations ([Cu]H ) received 6 additional weeks of TTM treatment and underwent 1 additional biopsy. Physical and laboratory examinations were performed every 2 weeks for study duration. RESULTS: Eight of 10 dogs had decreases in [Cu]H . Compared to baseline (median, 1606 µg/g; range, 572-5158 µg/g), [Cu]H were decreased at 6 weeks (1033 µg/g, 450-2975 µg/g; P = .04) and 12 weeks (931 µg/g, 218-1677 µg/g; P = .02). Hepatic molybdenum concentrations increased >50-fold (P < 0.001). Changes in histologic scores and hematologic and biochemical test results were variable and not significantly different from baseline. One dog developed presumed immune-mediated anemia and thrombocytopenia, but it was unclear if this was related to TTM administration. CONCLUSIONS AND CLINICAL IMPORTANCE: Results suggest that TTM can effectively decrease [Cu]H in some dogs with CAH. Larger studies are needed to determine the overall safety and efficacy of TTM for treating CAH and how it compares with current treatments.

Constrictive Bronchiolitis Obliterans in a Dog.

A 2 yr old, neutered male rottweiler was evaluated for a chronic cough that had acutely worsened. Computed tomographic examination revealed a diffuse alveolar pattern in the right, middle, and left cranial lung lobes. Aerated parenchymal tissue was not observed in the left cranial lung lobe, and both lobes were markedly decreased in volume. Lobectomy of the right middle and left cranial lung lobes was performed. Histopathologic examination of both lungs identified alveolar collapse associated with marked chronic bronchial and bronchiolar luminal concentric fibrosis leading to reduced airway lumen diameter and bronchiolar destruction. The clinical signs and airway pathology were consistent with constrictive bronchiolitis obliterans. The dog remained stable for over 2 yr with glucocorticoid therapy and intermittent antimicrobics. Although the polypoid form of bronchiolitis obliterans has been described in cattle and occasionally in dogs, constrictive bronchiolitis obliterans has not been reported previously in veterinary species.

Radioactive iodine uptake in hyperthyroid cats after administration of recombinant human thyroid stimulating hormone.

BACKGROUND: Radioactive iodine therapy is considered the treatment of choice for hyperthyroidism in cats, but the availability of this modality is limited by costs and hospitalization requirements. Administration of recombinant human thyroid stimulating hormone (rh-TSH) to humans with thyroid neoplasia or nodular goiter can increase thyroidal iodine uptake, thereby allowing the use of lower radioactive iodine doses for treatment. Veterinary studies of this subject are limited, and results are conflicting. OBJECTIVE: To investigate the effects of rh-TSH administration on thyroidal iodine uptake in hyperthyroid cats. ANIMALS: Ten client-owned hyperthyroid cats. METHODS: In this prospective clinical study, cats were administered saline (placebo), 50 µg rh-TSH (low-dose), and 100 µg rh-TSH (high-dose) in randomized crossover design with treatments separated by 7-10 days. After each treatment, thyroid scintigraphy was performed by administering 300 µCi 123 I and assessing radionuclide uptake 8 and 24 hours later. Serum thyroid hormone concentrations were measured at each visit. RESULTS: Thyroidal percent iodine uptakes (mean ± SD at 8 and 24 hours) in cats treated with placebo (25.2 ± 13.4%, 30.0 ± 12.8%), low-dose (24.1 ± 12.5%, 29.4 ± 13.7%), and high-dose rh-TSH (24.2 ± 16.3%, 30.8 ± 15.3%) were not different (P = .76). Independent of rh-TSH administration, percent iodine uptakes were positively correlated with serum thyroid hormone concentrations. CONCLUSIONS AND CLINICAL IMPORTANCE: One-time administration of rh-TSH, even at high doses, would not be expected to lower radioactive iodine doses needed for treatment of hyperthyroidism in cats. Investigations of alternate strategies to increase thyroidal uptake of radioactive iodine are warranted.

Influence of immune-mediated hemolytic anemia on flow velocities in the portal vein and caudal vena cava measured by use of pulsed-wave Doppler ultrasonography in dogs.

OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA). ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs. PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups. RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs. CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.

Imaging and Clinical Outcomes in 20 Dogs Treated with Thin Film Banding for Extrahepatic Portosystemic Shunts.

OBJECTIVE: To prospectively evaluate the efficacy of thin film band attenuation of congenital extrahepatic portosystemic shunts (CEPSS) in dogs using clinical, biochemical, and imaging-related outcome measures. STUDY DESIGN: Prospective case series. ANIMALS: Dogs with CEPSS (n=20). METHODS: Client-owned dogs with CEPSS were enrolled and thin film banding of the shunting vessel was performed. Before and at least 6 months after surgery, serum bile acids and computed tomography (CT) angiography were performed and owners completed a health questionnaire regarding the dog's clinical signs. Postoperative CT images were assessed for the effectiveness of band closure, change in portal vein/aorta ratio, change in liver volume/weight ratio, and whether the band was placed in the appropriate location. Preoperative and postoperative health questionnaire data and serum bile acids were compared. RESULTS: The band resulted in complete closure of the vessel around which it was placed in 13 dogs. In the remaining 7 dogs, the vessel lumen was narrowed but not completely closed. In 8 dogs the band location was suboptimal, allowing systemic drainage of visceral blood or secondary shunting branches to persist. Liver volume/body weight ratios and portal vein/aorta diameter ratios increased in most dogs. Serum bile acids decreased in all but 1 dog and owners reported improved health in 19 dogs. CONCLUSION: Thin film banding resulted in complete occlusion of many, but not all vessels around which it was placed. Even in dogs with inappropriate band location or with incomplete closure, clinical improvement can be expected based on our results.

COMBINATION OF COMPUTED TOMOGRAPHIC IMAGING CHARACTERISTICS OF MEDIAL RETROPHARYNGEAL LYMPH NODES AND NASAL PASSAGES AIDS DISCRIMINATION BETWEEN RHINITIS AND NEOPLASIA IN CATS.

Feline nasal diseases are a diagnostic challenge. The objective of this retrospective, cross-sectional study was to determine whether computed tomography (CT) imaging characteristics of the medial retropharyngeal lymph nodes (MRPLN), alone or in combination with CT imaging characteristics of the nasal passages, could aid in differentiation between rhinitis and nasal neoplasia. Cats were recruited from record archives at two veterinary facilities during the period of 2008-2012. Selection criteria were presentation for chronic nasal discharge, contrast-enhanced CT of the head that included the MRPLN, and rhinoscopic nasal biopsy resulting in diagnosis of rhinitis or neoplasia. For each CT scan, two board-certified veterinary radiologists recorded MRPLN size, attenuation, heterogeneity, contrast-medium enhancement, margination, shape, presence of a lymph node hilus, perinodal fat, turbinate lysis, paranasal bone lysis, and nasal mass. Both readers were unaware of patient information at the time of CT interpretation. Thirty-four cats with rhinitis and 22 cats with neoplasia were included. Computed tomographic characteristics significantly associated with neoplasia included abnormal MRPLN hilus (OR 5.1), paranasal bone lysis (OR 5.6), turbinate lysis (5.6), mass (OR 26.1), MRPLN height asymmetry (OR 4.5), and decreased MRPLN precontrast heterogeneity (OR 7.0). The combined features predictive of neoplasia were a nasal mass with abnormal hilus (OR 47.7); lysis of turbinates/paranasal bones with abnormal MRPLN hilus (OR 16.2). Findings supported the hypothesis that combining CT features of the nasal passages and MRPLN aided in differentiating rhinitis from neoplasia in cats.

Comparison of three ultrasound guided approaches to the lumbar plexus in dogs: a cadaveric study.

OBJECTIVE: To assess the accuracy of contrast material injection and the dispersion of injectate following ultrasound guided injections at the level of L6 and L7, in canine cadavers. STUDY DESIGN: Prospective, randomized, experimental study. ANIMALS: Twenty nine mixed breed canine cadavers (28.9 ± 6.0 kg). METHODS: Three ultrasound-guided approaches to the lumbar plexus (LP) were compared: 1) a dorsal pre-iliac approach at the level of L6; 2) a lateral paravertebral approach at mid-L6; and 3) a lateral paravertebral approach at mid-L7. An isovolumic mixture of iodine-based contrast with new methylene blue (0.1 mL kg(-1)) was injected bilaterally in the juxta-foraminal region along the L6 or L7 nerve root. Computed tomography was performed followed by segmentation and 3D reconstruction of the lumbar spine and contrast material volumes using dedicated software. Distances between contrast material and the fifth through seventh lumbar foraminae, and length of femoral (FN) and obturator (ON) nerve staining were measured and compared between approaches (p < 0.05). RESULTS: Injectate moved cranial and caudal to the site of injection, and dispersed into an ovoid shape between the quadratus lumborum, iliopsoas and psoas minor muscles. Injections at L7 resulted in significantly closer contrast proximity to the L6 and L7 foraminae (p < 0.001). Femoral nerve staining was similar for all approaches, ON staining was more consistent after L7 injections (p < 0.001). CONCLUSION AND CLINICAL RELEVANCE: An ultrasound-guided lateral paravertebral approach to the LP proved very practical and accurate, with easy visualization of the plexus and associated nerves. To ensure that the ON is covered by injectate, an approach at the level of L7 is recommended. Further studies are necessary to determine if this correlates with clinically effective local anesthesia.