OBJECTIVE To determine the pharyngeal and laryngeal distribution of radiopaque contrast medium administered orally or via nasopharyngeal catheter to standing horses. ANIMALS 5 healthy adult horses. PROCEDURES A crossover study was conducted. Radiopaque contrast medium (12 mL) was administered orally and via nasopharyngeal catheter to each horse. Pharyngeal and laryngeal distribution of contrast medium was determined by examination of radiographs obtained immediately after administration of contrast medium, compared with those obtained before administration. Regional distribution of contrast medium was graded. Endoscopic examination of the nasopharynx, laryngopharynx, and larynx was performed to confirm radiographic results. RESULTS Examination of radiographs obtained after nasopharyngeal administration revealed contrast medium in the nasopharynx (n = 5), oropharynx (2), laryngopharynx (3), and larynx (5) of the 5 horses. Examination of radiographs obtained after oral administration revealed contrast medium in the oropharynx (n = 4) and larynx (1) of the 5 horses. Endoscopic examination confirmed radiographic findings and was found to be sensitive for detection of contrast medium in the laryngopharynx, whereby detection rates were higher for both administration methods. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that medication administered by use of a nasopharyngeal catheter will result in topical distribution within the nasopharynx, including the dorsal surface of the soft palate, and larynx, although distribution should be evaluated in horses with clinical airway disease to confirm these findings. Oral administration did not result in consistently detectable topical laryngeal distribution but could be used for selected conditions (eg, palatitis).

OBJECTIVE To quantify nausea and sedation scores, gastric emptying time, and gastrointestinal transit time after IV administration of a lidocaine hydrochloride bolus followed by a constant rate infusion (CRI) in clinically normal dogs. ANIMALS 6 Beagles. PROCEDURES In a crossover study, dogs were fed thirty 1.5-mm barium-impregnated spheres (BIPS) and received a saline (0.9% NaCl) solution bolus (0.05 mL/kg) IV (time 0) followed by a CRI at 10 mL/h, a lidocaine bolus (1 mg/kg) IV followed by a CRI at 25 μg/kg/min, or a lidocaine bolus (1 mg/kg) IV followed by a CRI at 50 μg/kg/min; CRIs were for 12 hours. Nausea and sedation scores were assessed and abdominal radiographs obtained immediately after feeding of BIPS and every hour for 12 hours and again 16 hours after CRI start. Percentage of BIPSs in the small and large intestines, gastric emptying time, and gastrointestinal transit time were assessed. RESULTS Gastric emptying time did not differ significantly among treatments. Significantly more BIPS were in the large intestine 4 to 7 hours after treatment start for the 50-μg/kg/min treatment than for the other 2 treatments. Six hours after treatment start, significantly more BIPS were in the large intestine for the 25-μg/kg/min treatment than for the saline solution treatment. Higher sedation and nausea scores were associated with the 50-μg/kg/min CRI. CONCLUSIONS AND CLINICAL RELEVANCE In clinically normal dogs, lidocaine CRI did not significantly affect gastric emptying. However, gastrointestinal transit time was mildly decreased and sedation and nausea scores increased in dogs administered a lidocaine CRI at clinically used doses.

Muscle loss associated with disease (cachexia) or with aging (sarcopenia) is common in dogs, but clinically relevant methods for quantifying muscle loss are needed. We previously validated an ultrasound method of quantifying muscle size in dogs in a single breed. The goal of this study was to assess the variability and reproducibility of the Vertebral Epaxial Muscle Score (VEMS) in other dog breeds. Static ultrasound images were obtained from 38 healthy, neutered dogs of 5 different breeds between 1- and 5-years-old. The maximal transverse right epaxial muscle height and area at the level of the 13th thoracic vertebra (T13) were measured. Length of the 4th thoracic vertebra (T4) was measured from thoracic radiography. Ratios of the muscle height and area to vertebral length (height/T4 and area/T4, respectively) were calculated to account for differences in body size among breeds. Reproducibility testing was performed on 2 dogs of each breed (26% of the total) to determine intra- and inter-investigator reproducibility, as well as intra-class correlation. Mean height/T4 = 1.02 ± 0.18 and mean area/T4 = 3.32 ± 1.68. There was no significant difference for height/T4 (P = 0.10) among breeds, but breeds were significantly different in area/T4 (P < 0.001). Intra-class correlation ranged from 0.80 to 0.99. Testing showed better reproducibility for height/T4 compared to area/T4. The VEMS using height/T4 was valid and reproducible for healthy dogs of different sizes and body conformations. Studies assessing this technique in dogs with congestive heart failure and other diseases associated with muscle loss are warranted.

OBJECTIVE To evaluate the usefulness of excretory urography performed during radiography (REU) and CT (CTEU) in healthy rabbits, determine timings of urogram phases, and compare sensitivities of REU and CTEU for detection of these phases. ANIMALS 13 New Zealand White rabbits (Oryctolagus cuniculus). PROCEDURES Rabbits were screened for signs of systemic and urinary tract disease. An REU examination of each was performed, followed ≥ 5 days later by a CTEU examination. Contrast images from each modality were evaluated for quality of opacification and intervals between initiation of contrast medium administration and detection of various urogram phases. RESULTS Excretory urograms of excellent diagnostic quality were achieved with both imaging modalities. For all rabbits, the nephrographic phase of the urogram appeared in the first postcontrast REU image (obtained between 34 and 40 seconds after initiation of contrast medium administration) and at a median interval of 20 seconds in CTEU images. The pyelographic phase began at a median interval of 1.63 minutes with both imaging modalities. Contrast medium was visible within the urinary bladder at a median interval of 2.20 minutes. Median interval to the point at which the nephrogram and pyelogram were no longer visible in REU images was 8 hours and 2.67 hours, respectively. The CTEU technique was better than the REU technique for evaluating renal parenchyma. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that REU and, particularly, CTEU may be valuable tools for the diagnosis of renal and urinary tract disease in rabbits; however, additional evaluation in diseased rabbits is required.

OBJECTIVE To determine anatomic reference points for 4 turtle species and to evaluate data on relative anatomic dimensions, signal intensities (SIs), and position of selected organs within the coelomic cavity by use of MRI. ANIMALS 3 turtle cadavers (1 red-eared slider [Trachemys scripta elegans], 1 yellow-bellied slider [Trachemys scripta scripta], and 1 Coastal plain cooter [Pseudemys concinna floridana]) and 63 live adult turtles (30 red-eared sliders, 20 yellow-bellied sliders, 5 Coastal plain cooters, and 8 hieroglyphic river cooters [Pseudemys concinna hieroglyphica]). PROCEDURES MRI and necropsy were performed on the 3 turtle cadavers. Physical examination, hematologic evaluation, and whole-body radiography were performed on the 63 live turtles. Turtles were sedated, and MRI in transverse, sagittal, and dorsal planes was used to measure organ dimensions, position within the coelomic cavity, and SIs. Body positioning after sedation was standardized with the head, neck, limbs, and tail positioned in maximum extension. RESULTS Measurements of the heart, liver, gallbladder, and kidneys in sagittal, transverse, and dorsal planes; relative position of those organs within the coelom; and SIs of the kidneys and liver were obtained with MRI and provided anatomic data for these 4 turtle species. CONCLUSIONS AND CLINICAL RELEVANCE MRI was a valuable tool for determining the position, dimensions, and SIs of selected organs. Measurement of organs in freshwater chelonians was achievable with MRI. Further studies are needed to establish reference values for anatomic structures in turtles. Results reported here may serve as guidelines and aid in clinical interpretation of MRI images for these 4 species.

OBJECTIVE To evaluate biomechanical properties of intact feline mandibles, compared with those for mandibles with an experimentally created osteotomy that was stabilized with 1 of 2 internal fixation configurations. SAMPLE 20 mandibles from 10 adult feline cadavers. PROCEDURES An incomplete block study design was used to assign the mandibles of each cadaver to 2 of 3 groups (locking plate with locking screws [locking construct], locking plate with nonlocking screws [nonlocking construct], or intact). Within each cadaver, mandibles were randomly assigned to the assigned treatments. For mandibles assigned to the locking and nonlocking constructs, a simple transverse osteotomy was created caudal to the mandibular first molar tooth after plate application. All mandibles were loaded in cantilever bending in a single-load-to-failure test while simultaneously recording load and actuator displacement. Mode of failure (bone or plate failure) was recorded, and radiographic evidence of tooth root and mandibular canal damage was evaluated. Mechanical properties were compared among the 3 groups. RESULTS Stiffness, bending moments, and most post-yield energies for mandibles with the locking and nonlocking constructs were significantly lower than those for intact mandibles. Peak bending moment and stiffness for mandibles with the locking construct were significantly greater than those for mandibles with the nonlocking construct. Mode of failure and frequency of screw damage to tooth roots and the mandibular canal did not differ between the locking and nonlocking constructs. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that both fixation constructs were mechanically inferior to intact mandibles. The locking construct was mechanically stronger than the nonlocking construct.

OBJECTIVE To determine accuracy for a technique of needle redirection at a single craniolateral site for injection of 3 compartments of the equine stifle joint, describe the external needle position, and identify the location of the needle tip within each joint compartment. SAMPLE 24 equine cadaver stifle joints. PROCEDURES Stifle joints were placed in a customized stand. After the needle was placed, external needle position was measured and recorded. Each joint compartment (medial and lateral compartments of the femorotibial joint and the femoropatellar joint) was injected with a solution containing iodinated contrast medium, water, and dye. Radiography, assessment of intra-articular location of the needle tip, and gross dissection were performed to determine success of entering each joint compartment. Student t tests and an ANOVA were used to compare mean values. RESULTS Overall accuracy was 19 of 24 (79.1%), and accuracy for individual joint compartments was at least 21 of 24 (87.5%). Mean depth of needle insertion to access each compartment of the stifle joint was 5.71 cm. Mean angle of insertion (relative to the long axis of the tibia) was 82.1°, 80.3°, and 18.5° for the medial compartment of the femorotibial joint, lateral compartment of the femorotibial joint, and femoropatellar joint, respectively, and 28° medial, 7.3° lateral, and 1.3° lateral for the medial compartment of the femorotibial joint, lateral compartment of the femorotibial joint, and femoropatellar joint, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results supported that this was an accurate technique for successful injection of the 3 equine stifle joint compartments.

OBJECTIVE To assess 3-D geometry of the humerus of dogs and determine whether the craniocaudal canal flare index (CFI) is associated with specific geometric features. SAMPLE CT images (n = 40) and radiographs (38) for 2 groups of skeletally mature nonchondrodystrophic dogs. PROCEDURES General dimensions (length, CFI, cortical thickness, and humeral head offset), curvature (shaft, humeral head, and glenoid cavity), version (humeral head and greater tubercle), and torsion were evaluated on CT images. Dogs were allocated into 3 groups on the basis of the craniocaudal CFI, and results were compared among these 3 groups. The CT measurements were compared with radiographic measurements obtained for another group of dogs. RESULTS Mean ± SD humeral head version was −75.9 ± 9.6° (range, −100.7° to −59.4°). Mean mechanical lateral distal humeral angle, mechanical caudal proximal humeral angle, and mechanical cranial distal humeral angle were 89.5 ± 3.5°, 50.2 ± 4.5°, and 72.9 ± 7.8°, respectively, and did not differ from corresponding radiographic measurements. Mean humeral curvature was 20.4 ± 4.4° (range, 9.6° to 30.5°). Mean craniocaudal CFI was 1.74 ± 0.18 (range, 1.37 to 2.10). Dogs with a high craniocaudal CFI had thicker cranial and medial cortices than dogs with a low craniocaudal CFI. Increased body weight was associated with a lower craniocaudal CFI. Radiographic and CT measurements of craniocaudal CFI and curvature differed significantly. CONCLUSIONS AND CLINICAL RELEVANCE CT-based 3-D reconstructions allowed the assessment of shaft angulation, torsion, and CFI. Radiographic and CT measurements of shaft curvature and CFI may differ.

OBJECTIVE To determine manubrium heart scores (MHSs) from measurements of cardiac short-axis length (cSAL) and long-axis length (cLAL) relative to the corresponding manubrium length (ML) on thoracic radiographic views of dogs and assess correlation of MHSs with vertebral heart scores (VHSs). ANIMALS 120 clinically normal large-breed dogs (LBDs) and small-breed dogs (SBDs). PROCEDURES On right lateral views (RLVs) and ventrodorsal views (VDVs) for each dog, cSAL and cLAL were measured and expressed as a ratio; the cSAL:ML ratio (short-MHS), cLAL:ML ratio (long-MHS), and cSAL-and-cLAL:ML ratio (overall-MHS) were also calculated. The VHS was determined from the RLV. Correlation of VHS with MHS was assessed. RESULTS On RLVs and VDVs, mean cSAL:cLAL ratios were 0.77 (SD, 0.05) and 0.72 (SD, 0.05), respectively, in 60 LBDs and 0.81 (SD, 0.06) and 0.78 (SD, 0.06), respectively, in 60 SBDs. In LBDs, mean short-MHS, long-MHS, and overall-MHS were 2.1 (SD, 0.22), 2.7 (SD, 0.24), and 4.8 (SD, 0.5), respectively, on RLVs and 2.3 (SD, 0.26), 3.2 (SD, 0.34), and 5.4 (SD, 0.6), respectively, on VDVs. In SBDs, mean short-MHS, long-MHS, and overall-MHS were 2.4 (SD, 0.39), 2.9 (SD, 0.50), and 5.3 (SD, 0.83), respectively, on RLVs and 2.5 (SD, 0.44), 3.2 (SD, 0.51), and 5.8 (SD, 0.92), respectively, on VDVs. Mean VHSs were 10.73 (SD, 0.52) and 10.27 (SD, 0.81) in LBDs and SBDs, respectively. A significant correlation was identified between VHS and each MHS in LBDs. CONCLUSIONS AND CLINICAL RELEVANCE In the dogs evaluated, radiographic cardiac dimensions and MHSs were correlated. Validity of the MHS for cardiac dimension assessment in other healthy dogs and dogs with cardiac disease warrants investigation.