Canine mitral valve size as measured by computed tomography.

OBJECTIVE: To measure the mitral annulus in dogs. Our hypothesis was that mitral measurement would be possible and consistent among observers using CT. SAMPLE: Thoracic CT scans of dogs without known heart disease. PROCEDURES: Five trained investigators measured 4 aspects of the mitral valve and the fourth thoracic vertebrae (T4) length using multiplanar reformatting tools. Ten randomly chosen animals were measured by all investigators to determine interobserver reliability. RESULTS: There were 233 CT scans eligible for inclusion. Dogs weighed 2 to 96 kg (mean, 28.1 kg), with a variety of breeds represented. Golden Retrievers (n = 28) and Labrador Retrievers (n = 37) were overrepresented. The intraclass correlations were all greater than 0.9, showing excellent agreement between observers. The means and SDs of each measurement were as follows: trigone-to-trigone distance, 17.2 ± 4.7 mm; the remaining circumference, 79.0 ± 17.5 mm; commissure-to-commissure distance, 30.8 ± 6.5 mm; septal leaflet-to-lateral leaflet distance, 26.3 ± 6.0 mm; T4 length, 16.9 ± 3.1 mm; and the total circumference normalized by T4, 5.7 ± 0.7 mm. CLINICAL RELEVANCE: This study provides information that may help in the development of future treatment for mitral valve dysfunction and subsequent annular enlargement.

Factors influencing enhancement timing in a triple-phase abdominal CT angiography protocol in dogs.

OBJECTIVE: To evaluate the enhancement accuracy of a triple-phase abdominal CT angiography (CTA) protocol in dogs and explore the patient, scan, and contrast parameters associated with accuracy of enhancement. ANIMALS: 233 client-owned dogs that underwent routine abdominal CTA. PROCEDURES: During each CTA study, the subjective timing accuracy (early, ideal, late) of the 3 obtained vascular phases (arterial, venous, delayed) was scored by consensus (2 reviewers) at 4 target organs (liver, pancreas, left kidney, and spleen). These scores were evaluated for statistical associations with 21 study variables (patient, scan, and contrast medium). The objective enhancement (HU) for each target organ was also compared statistically with subjective timing accuracy scores and the study variables. RESULTS: The study protocol performed best for the pancreas, moderately for the liver, and worse for the spleen and left kidney. Measurements of scan length and time were associated positively with phase lateness for most target organs and phases. Increased heart rate was the most significant patient factor associated positively with phase lateness within the liver (all phases), pancreas (arterial and venous phases), and kidney (arterial phase). Contrast medium variables were less associated with timing accuracy in this protocol. Objective enhancement (HU) correlated poorly with subjective phase timing accuracy and study variables. CLINICAL RELEVANCE: Scan time, scan length, and heart rate were the predominant variables contributing to lateness in this canine abdominal CTA protocol. The findings of this exploratory study may aid in protocol adjustment and choice of included anatomy for dogs undergoing routine abdominal CTA.

Canine sciatic and gluteal lymph nodes can be identified with computed tomography.

Sciatic and gluteal lymph nodes are present in multiple veterinary species, but these lymph nodes are explicitly stated to be absent in dogs. However, structures compatible with lymph nodes have been identified in the appropriate locations in some canine patients undergoing abdominopelvic CT, and the presence of such lymph nodes may have prognostic and therapeutic ramifications in canine patients with abdominopelvic disease. The purpose of this study was to determine the prevalence and characteristics of sciatic and gluteal lymph nodes in dogs on CT. Images of 121 dogs that underwent abdominopelvic CT between September 1, 2020 and December 31, 2020 were reviewed retrospectively by two readers to produce a consensus opinion regarding the presence or absence of sciatic and gluteal lymph nodes. Lymph nodes that were present were measured. Unilateral or bilateral sciatic lymph nodes were present in 19 of 121 dogs (prevalence 15.7%), and bilateral gluteal lymph nodes were identified in one of 121 patients (prevalence 0.8%). Recognition of the presence of sciatic and gluteal lymph nodes in some canine patients may play an important role in the staging of abdominopelvic disease, both in the identification of disease spread and in therapeutic planning.

Use of Educational Puzzles for Learning Concepts of Clinical Diagnostic Imaging in Veterinary Medicine.

Learning the concepts of clinical radiology, including lesion identification and formulation of differential diagnosis lists, can be challenging for veterinary students. A series of educational puzzles with an overarching narrative was developed to help students learn the fundamental concepts of urogenital, thoracic, and spine imaging. Third-year veterinary students had the opportunity to use as many of the puzzles as they wished as a part of their studies in a semester-long imaging course, and students completed surveys to indicate which puzzle sections they used and provide their opinions of the activities. Graded performance in the course was correlated with how many puzzle activities students used. A small but statistically significant correlation was found between the number of puzzle sections used and midterm exam score, final exam score, and overall course score. Although most students who used the puzzles as a part of their studies enjoyed the activities, there was a dramatic decrease in usage over the semester, from 74% of survey respondents using the initial topic to a low of 27% utilization of the sixth topic, followed by a small rebound to 37% for the eighth topic (the review for the final exam). Thus, while developing a puzzle series is achievable and beneficial to student learning, possibly because of improved student engagement through increased variety in learning opportunities, further steps are necessary to encourage continued student engagement throughout the semester.

Computed tomography radiomic features hold prognostic utility for canine lung tumors: An analytical study.

Quantitative analysis of computed tomography (CT) radiomic features is an indirect measure of tumor heterogeneity, which has been associated with prognosis in human lung carcinoma. Canine lung tumors share similar features to human lung tumors and serve as a model in which to investigate the utility of radiomic features in differentiating tumor type and prognostication. The purpose of this study was to correlate first-order radiomic features from canine pulmonary tumors to histopathologic characteristics and outcome. Disease-free survival, overall survival time and tumor-specific survival were calculated as days from the date of CT scan. Sixty-seven tumors from 65 dogs were evaluated. Fifty-six tumors were classified as primary pulmonary adenocarcinomas and 11 were non-adenocarcinomas. All dogs were treated with surgical resection; 14 dogs received adjuvant chemotherapy. Second opinion histopathology in 63 tumors confirmed the histologic diagnosis in all dogs and further characterized 53 adenocarcinomas. The median overall survival time was longer (p = 0.004) for adenocarcinomas (339d) compared to non-adenocarcinomas (55d). There was wide variation in first-order radiomic statistics across tumors. Mean Hounsfield units (HU) ratio (p = 0.042) and median mean HU ratio (p = 0.042) were higher in adenocarcinomas than in non-adenocarcinomas. For dogs with adenocarcinoma, completeness of excision was associated with overall survival (p<0.001) while higher mitotic index (p = 0.007) and histologic score (p = 0.037) were associated with shorter disease-free survival. CT-derived tumor variables prognostic for outcome included volume, maximum axial diameter, and four radiomic features: integral total, integral total mean ratio, total HU, and max mean HU ratio. Tumor volume was also significantly associated with tumor invasion (p = 0.044). Further study of radiomic features in canine lung tumors is warranted as a method to non-invasively interrogate CT images for potential predictive and prognostic utility.

Percutaneous transhepatic cholecystostomy drainage in a dog with extrahepatic biliary obstruction secondary to pancreatitis.

CASE DESCRIPTION: An 8-year-old 36.3-kg (79.9-lb) spayed female Rottweiler was evaluated because of anorexia and vomiting. CLINICAL FINDINGS: Extrahepatic biliary obstruction (EHBO) secondary to pancreatitis was suspected on the basis of results from serum biochemical analyses, CT, and cytologic examination. TREATMENT AND OUTCOME: Only marginal improvement was observed after 24 hours of traditional medical management; therefore, novel continual biliary drainage was achieved with ultrasonographically and fluoroscopically guided placement of a percutaneous transhepatic cholecystostomy drainage (PCD) catheter. Within 24 hours after PCD catheter placement, the dog was eating regularly, had increased intestinal peristaltic sounds on abdominal auscultation, no longer required nasogastric tube feeding, and had decreased serum total bilirubin concentration (7.7 mg/dL, compared with 23.1 mg/dL preoperatively). Bile recycling was performed by administering the drained bile back to the patient through a nasogastric tube. The PCD remained in place for 5 weeks and was successfully removed after follow-up cholangiography confirmed bile duct patency. CLINICAL RELEVANCE: Transhepatic PCD catheter placement provided fast resolution of EHBO secondary to pancreatitis in the dog of the present report. We believe that this minimally invasive, interventional procedure has the potential to decrease morbidity and death in select patients, compared with traditional surgical options, and that additional research is warranted regarding clinical use, safety, and long-term results of this procedure in veterinary patients, particularly those that have transient causes of EHBO, are too unstable to undergo more invasive biliary diversion techniques, or have biliary diseases that could benefit from palliation alone.

Evaluation of diffusion-weighted magnetic resonance imaging at 3.0 Tesla for differentiation between intracranial neoplastic and noninfectious inflammatory lesions in dogs.

OBJECTIVE: To evaluate the utility of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values obtained by diffusion-weighted MRI (DWI) at 3.0 T for differentiating intracranial neoplastic lesions from noninfectious inflammatory lesions (NIILs) in dogs. ANIMALS: 54 dogs that met inclusion criteria (ie, had a histologically confirmed intracranial lesion and DWI of the brain performed) with 5 lesion types: meningioma [n = 18], glioma [14], metastatic hemangiosarcoma [3], other metastatic neoplasms [5], and NIIL [14]). PROCEDURES: Two observers, who were blinded to the histologic diagnoses, independently determined the mean ADC and FA values for each evaluated intracranial lesion on the basis of 3 circular regions of interest on DWI images. Findings were compared among the 5 lesion types, between all neoplasms combined and NIILs, and between the 5 legion types and previously determined values for corresponding locations for neurologically normal dogs. RESULTS: The mean ADC and FA values did not differ significantly among the 5 lesion types or between all neoplasms combined and NIILs. However, 35% (14/40) of the neoplastic lesions had an ADC value ≥ 1.443 × 10-3 mm2/s, whereas all NIILs had ADC values < 1.443 × 10-3 mm2/s. Meningiomas and NIILs had FA values that were significantly lower than those for neurologically normal dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In this population of dogs, the FA values for meningiomas and NIILs differed significantly from those previously reported for neurologically normal dogs. In addition, an ADC cutoff value of 1.443 × 10-3 mm2/s appeared to be highly specific for diagnosing neoplastic lesions (vs NIILs), although the sensitivity and accuracy were low.

Twitter in the Veterinary Diagnostic Imaging Classroom: Examination Outcomes and Student Views.

Radiographic lesion identification and differential diagnosis list generation can be difficult for veterinary students; thus, a novel means of distributing cases for study could improve students' engagement and learning. The goal of this study was to determine whether using Twitter as an adjunct means of studying diagnostic imaging would improve student outcomes on the final exam for a radiology course. A secondary goal was to determine students' preferred means of accessing additional cases for study. Twitter was used in a third-year veterinary radiology course to provide additional optional radiographic cases that were relevant to the topics covered in the course. At the end of the semester, students completed a survey to report their prior and current use of Twitter and to give preferences as to further distribution of optional cases. Mean final examination scores were compared between students who used Twitter in their studies and those who did not. No significant difference was found between the mean final examination score for each group (22.2; p = .98). Only 3% of respondents ( n = 2/79) preferred Twitter as a means of receiving additional radiographic cases; Moodle (the Web platform for classwork used at this institution) and Facebook were the most preferred platforms for further cases, receiving 41% ( n = 32/79) and 23% ( n = 18/79) of votes, respectively. Educational use of Twitter did not improve student examination performance in diagnostic imaging, and other media platforms may be more beneficial than Twitter for encouraging student use of additional resources.

Examination Outcomes Following Use of Card Games for Learning Radiographic Image Quality in Veterinary Medicine.

Understanding the concepts of radiographic image quality and artifact formation can be difficult for veterinary students. Two educational card games were previously developed to help students learn about factors affecting contrast and blackness as well as radiographic artifacts. Second-year veterinary students played one of the two card games as a part of their normal studies for their veterinary imaging course and later took the radiographic physics quiz normally administered during the course. Performance on quiz questions related to each of the two games was compared between students who played each respective game and those who did not. The hypothesis was that students who played a game would perform better on related questions than those who did not play that game. For the contrast and blackness questions, students who played the associated game as part of their studies performed better than those who only studied by conventional means (mean 4.3 vs. 3.8 out of 5 points, p=.02). However, there was no significant difference in results between groups for artifacts questions (mean 4.7 vs. 4.5 out of 5 points, p=.35). Based on these results, educational game play can have benefits to student learning, but performance may be dependent on specific game objectives and play mechanics.

Evaluation of canine hepatic masses by use of triphasic computed tomography and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography and correlation with histopathologic classification.

OBJECTIVE To determine clinical relevance for quantitative and qualitative features of canine hepatic masses evaluated by use of triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography and to compare diagnostic accuracy of these modalities for predicting mass type on the basis of histopathologic classification. ANIMALS 44 client-owned dogs. PROCEDURES Dogs with histopathologic confirmation (needle core, punch, or excisional biopsy) of a hepatic mass were enrolled. Triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography of each hepatic mass were performed. Seventy quantitative and qualitative variables of each hepatic mass were recorded by 5 separate observers and statistically evaluated with discriminant and stepwise analyses. Significant variables were entered in equation-based predictions for the histopathologic diagnosis. RESULTS An equation that included the lowest delayed-phase absolute enhancement of the mass and the highest venous-phase mass conspicuity was used to correctly classify 43 of 46 (93.5%) hepatic masses as benign or malignant. An equation that included only the lowest delayed-phase absolute enhancement of the mass could be used to correctly classify 42 of 46 (91.3%) masses (with expectation of malignancy if this value was < 37 Hounsfield units). For ultrasonography, categorization of the masses with cavitations as malignant achieved a diagnostic accuracy of 80.4%. CONCLUSIONS AND CLINICAL RELEVANCE Triphasic CT had a higher accuracy than ultrasonography for use in predicting hepatic lesion classification. The lowest delayed-phase absolute enhancement of the mass was a simple calculation that required 2 measurements and aided in the differentiation of benign versus malignant hepatic masses.

Diffusion-weighted magnetic resonance imaging of the brain of neurologically normal dogs.

OBJECTIVE To acquire MRI diffusion data (apparent diffusion coefficient [ADC] and fractional anisotropy [FA] values, including separate measures for gray and white matter) at 3.0 T for multiple locations of the brain of neurologically normal dogs. ANIMALS: 13 neurologically normal dogs recruited from a group of patients undergoing tibial plateau leveling osteotomy. PROCEDURES: MRI duration ranged from 20 to 30 minutes, including obtaining preliminary images to exclude pathological changes (T2-weighted fluid-attenuated inversion recovery transverse and dorsal images) and diffusion-weighted images. , RESULTS: Globally, there were significant differences between mean values for gray and white matter in the cerebral lobes and cerebellum for ADC (range of means for gray matter, 0.8349 × 10-3 s/mm2 to 0.9273 × 10-3 s/mm2; range of means for white matter, 0.6897 × 10-3 s/mm2 to 0.7332 × 10-3 s/mm2) and FA (range of means for gray matter, 0.1978 to 0.2364; range of means for white matter, 0.5136 to 0.6144). These values also differed among cerebral lobes. In most areas, a positive correlation was detected between ADC values and patient age but not between FA values and patient age. CONCLUSIONS AND CLINICAL RELEVANCE: Cerebral interlobar and cerebellar diffusion values differed significantly, especially in the gray matter. Information about diffusion values in neurologically normal dogs may be used to diagnose and monitor abnormalities and was the first step in determining the clinical use of diffusion imaging. This information provided an important starting point for the clinical application of diffusion imaging of the canine brain.

Evaluation of 18-F-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) as a staging and monitoring tool for dogs with stage-2 splenic hemangiosarcoma - A pilot study.

Positron Emission Tomography-Computed Tomography (PET-CT) is routinely used for staging and monitoring of human cancer patients and is becoming increasingly available in veterinary medicine. In this study, 18-fluorodeoxyglucose (18FDG)-PET-CT was used in dogs with naturally occurring splenic hemangiosarcoma (HSA) to assess its utility as a staging and monitoring modality as compared to standard radiography and ultrasonography. Nine dogs with stage-2 HSA underwent 18FDG-PET-CT following splenectomy and prior to commencement of chemotherapy. Routine staging (thoracic radiography and abdominal ultrasonography) was performed prior to 18FDG-PET-CT in all dogs. When abnormalities not identified on routine tests were noted on 18FDG-PET-CT, owners were given the option to repeat a PET-CT following treatment with eBAT. A PET-CT scan was repeated on Day 21 in three dogs. Abnormalities not observed on conventional staging tools, and most consistent with malignant disease based on location, appearance, and outcome, were detected in two dogs and included a right atrial mass and a hepatic nodule, respectively. These lesions were larger and had higher metabolic activity on the second scans. 18FDG-PET-CT has potential to provide important prognostic information and influence treatment recommendations for dogs with stage-2 HSA. Additional studies will be needed to precisely define the value of this imaging tool for staging and therapy monitoring in dogs with this and other cancers.

USE OF A NOVEL BOARD GAME IN A CLINICAL ROTATION FOR LEARNING THORACIC DIFFERENTIAL DIAGNOSES IN VETERINARY MEDICAL IMAGING.

When confronted with various findings on thoracic radiographs, fourth-year veterinary students often have difficulty generating appropriate lists of differential diagnoses. The purpose of this one-group, pretest, posttest experimental study was to determine if a game could be used as an adjunct teaching method to improve students' understanding of connections between imaging findings and differential diagnoses. A novel board game focusing on differential diagnoses in thoracic radiography was developed. One hundred fourth-year veterinary students took a brief pretest, played the board game, and took a brief posttest as a part of their respective clinical radiology rotations. Pretest results were compared to posttest results using a paired t-test to determine if playing the game impacted student understanding. Students' mean scores on the posttest were significantly higher than mean pretest scores (P < 0.0001). Thus, results indicate that playing the board game resulted in improved short-term understanding of thoracic differential diagnoses by fourth-year students, and use of the board game on a clinical rotation seems to be a beneficial part of the learning process.

Ureteral obstruction secondary to disseminated penicilliosis in a German shepherd dog.

Abdominal ultrasonographic evaluation of a 2-year-old male German shepherd dog evaluated for weight loss demonstrated a right ureteral mass with ipsilateral hydronephrosis, hypoechoic splenic nodules, and hypoechoic and rounded lymph nodes. A fungal mat extending from the renal pelvis into the ureter secondary to disseminated Penicillium was confirmed at necropsy.

Obstruction urétérale secondaire à une infection disséminée àPenicilliumchez un chien Berger allemand. L'évaluation abdominale par échographie d'un chien Berger allemand mâle âgé de 2 ans qui était évalué pour une perte de poids a révélé une masse urétrale droite avec de l'hydronéphrose ipsilatérale, des nodules spléniques hypoéchogènes et des ganglions lymphatiques arrondis et hypoéchogènes. Une masse fongique s'étendant du pelvis rénal jusqu'à l'urètre secondaire à une infection disséminée à Penicillium a été confirmée à la nécropsie.(Traduit par Isabelle Vallières).

Novel Card Games for Learning Radiographic Image Quality and Urologic Imaging in Veterinary Medicine.

Second-year veterinary students are often challenged by concepts in veterinary radiology, including the fundamentals of image quality and generation of differential lists. Four card games were developed to provide veterinary students with a supplemental means of learning about radiographic image quality and differential diagnoses in urogenital imaging. Students played these games and completed assessments of their subject knowledge before and after playing. The hypothesis was that playing each game would improve students' understanding of the topic area. For each game, students who played the game performed better on the post-test than students who did not play that game (all p<.01). For three of the four games, students who played each respective game demonstrated significant improvement in scores between the pre-test and the post-test (p<.002). The majority of students expressed that the games were both helpful and enjoyable. Educationally focused games can help students learn classroom and laboratory material. However, game design is important, as the game using the most passive learning process also demonstrated the weakest results. In addition, based on participants' comments, the games were very useful in improving student engagement in the learning process. Thus, use of games in the classroom and laboratory setting seems to benefit the learning process.

Multivoxel proton magnetic resonance spectroscopy of inflammatory and neoplastic lesions of the canine brain at 3.0 T.

OBJECTIVE: To describe findings of 3.0-T multivoxel proton magnetic resonance spectroscopy ((1)H-MRS) in dogs with inflammatory and neoplastic intracranial disease and to determine the applicability of (1)H-MRS for differentiating between inflammatory and neoplastic lesions and between meningiomas and gliomas. ANIMALS: 33 dogs with intracranial disease (19 neoplastic [10 meningioma, 7 glioma, and 2 other] and 14 inflammatory). PROCEDURES: 3.0-T multivoxel (1)H-MRS was performed on neoplastic or inflammatory intracranial lesions identified with conventional MRI. N-acetylaspartate (NAA), choline, and creatine concentrations were obtained retrospectively, and metabolite ratios were calculated. Values were compared for metabolites separately, between lesion categories (neoplastic or inflammatory), and between neoplastic lesion types (meningioma or glioma) by means of discriminant analysis and 1-way ANOVA. RESULTS: The NAA-to-choline ratio was 82.7% (62/75) accurate for differentiating neoplastic from inflammatory intracranial lesions. Adding the NAA-to-creatine ratio or choline-to-creatine ratio did not affect the accuracy of differentiation. Neoplastic lesions had lower NAA concentrations and higher choline concentrations than inflammatory lesions, resulting in a lower NAA-to-choline ratio, lower NAA-to-creatine ratio, and higher choline-to-creatine ratio for neoplasia relative to inflammation. No significant metabolite differences between meningiomas and gliomas were detected. CONCLUSIONS AND CLINICAL RELEVANCE: (1)H-MRS was effective for differentiating inflammatory lesions from neoplastic lesions. Metabolite alterations for (1)H-MRS in neoplasia and inflammation in dogs were similar to changes described for humans. Use of (1)H-MRS provided no additional information for differentiating between meningiomas and gliomas. Proton MRS may be a beneficial adjunct to conventional MRI in patients with high clinical suspicion of inflammatory or neoplastic intracranial lesions.

Relative metabolite concentrations and ratios determined by use of 3-T region-specific proton magnetic resonance spectroscopy of the brain of healthy Beagles.

OBJECTIVE: To determine relative concentrations of selected major brain tissue metabolites and their ratios and lobar variations by use of 3-T proton (hydrogen 1 [(1)H]) magnetic resonance spectroscopy (MRS) of the brain of healthy dogs. ANIMALS: 10 healthy Beagles. PROCEDURES: 3-T (1)H MRS at echo times of 144 and 35 milliseconds was performed on 5 transverse slices and 1 sagittal slice of representative brain lobe regions. Intravoxel parenchyma was classified as white matter, gray matter, or mixed (gray and white) and analyzed for relative concentrations (in arbitrary units) of N-acetylaspartate (NAA), choline, and creatine (ie, height at position of peak on MRS graph) as well as their ratios (NAA-to-choline, NAA-to-creatine, and choline-to-creatine ratios). Peak heights for metabolites were compared between echo times. Peak heights for metabolites and their ratios were correlated and evaluated among matter types. Yield was calculated as interpretable voxels divided by available lobar voxels. RESULTS: Reference ranges of the metabolite concentration ratios were determined at an echo time of 35 milliseconds (NAA-to-choline ratio, 1.055 to 2.224; NAA-to-creatine ratio, 1.103 to 2.161; choline-to-creatine ratio, 0.759 to 1.332) and 144 milliseconds (NAA-to-choline ratio, 0.687 to 1.788; NAA-to-creatine ratio, 0.984 to 2.044; choline-to-creatine ratio, 0.828 to 1.853). Metabolite concentration ratios were greater in white matter than in gray matter. Voxel yields ranged from 43% for the temporal lobe to 100% for the thalamus. CONCLUSIONS AND CLINICAL RELEVANCE: Metabolite concentrations and concentration ratios determined with 3-T (1)H MRS were not identical to those in humans and were determined for clinical and research investigations of canine brain disease.

Ultrasound criteria and guided fine-needle aspiration diagnostic yields in small animal peritoneal, mesenteric and omental disease.

Peritoneal, mesenteric, and omental diseases are important causes of morbidity and mortality in humans and animals, although information in the veterinary literature is limited. The purposes of this retrospective study were to determine whether objectively applied ultrasound interpretive criteria are statistically useful in differentiating among cytologically defined normal, inflammatory, and neoplastic peritoneal conditions in dogs and cats. A second goal was to determine the cytologically interpretable yield on ultrasound-guided, fine-needle sampling of peritoneal, mesenteric, or omental structures. Sonographic criteria agreed upon by the authors were retrospectively and independently applied by two radiologists to the available ultrasound images without knowledge of the cytologic diagnosis and statistically compared to the ultrasound-guided, fine-needle aspiration cytologic interpretations. A total of 72 dogs and 49 cats with abdominal peritoneal, mesenteric, or omental (peritoneal) surface or effusive disease and 17 dogs and 3 cats with no cytologic evidence of inflammation or neoplasia were included. The optimized, ultrasound criteria-based statistical model created independently for each radiologist yielded an equation-based diagnostic category placement accuracy of 63.2-69.9% across the two involved radiologists. Regional organ-associated masses or nodules as well as aggregated bowel and peritoneal thickening were more associated with peritoneal neoplasia whereas localized, severely complex fluid collections were more associated with inflammatory peritoneal disease. The cytologically interpretable yield for ultrasound-guided fine-needle sampling was 72.3% with no difference between species, making this a worthwhile clinical procedure.

Optimizing a protocol for (1) H-magnetic resonance spectroscopy of the canine brain at 3T.

Intracranial diseases are common in dogs and improved noninvasive diagnostic tests are needed. Magnetic resonance (MR) spectroscopy is a technique used in conjunction with conventional MR imaging to characterize focal and diffuse pathology, especially in the brain. As with conventional MR imaging, there are numerous technical factors that must be considered to optimize image quality. This study was performed to develop an MR spectroscopy protocol for routine use in dogs undergoing MR imaging of the brain. Fifteen canine cadavers were used for protocol development. Technical factors evaluated included use of single-voxel or multivoxel acquisitions, manual placement of saturation bands, echo time (TE), phase- and frequency-encoding matrix size, radiofrequency coil, and placement of the volume of interest relative to the calvaria. Spectrum quality was found to be best when utilizing a multivoxel acquisition with the volume of interest placed entirely within the brain parenchyma without use of manually placed saturation bands, TE = 144 ms, and a quadrature extremity radiofrequency coil. An 18 × 18 phase- and frequency-encoding matrix size also proved optimal for image quality, specificity of voxel placement, and imaging time.