Enhancing prosthesis stability at the cricoid cartilage in equine laryngoplasty using 3-D-printed laryngeal clamps: An ex vivo model study.

OBJECTIVE: To assess a three-dimensional (3-D)-printed laryngeal clamp (LC) designed to enhance the anchoring of laryngeal prostheses at the cricoid cartilage. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: A total of 22 equine larynges. METHODS: Two experimental groups included larynges with standard prosthetic laryngoplasty (PL; n = 10) and larynges with prosthetic laryngoplasty modified with laryngeal clamps (PLLC; n = 10). All constructs underwent 3000 cycles of tension loading and a single tension to failure. Recorded biomechanical parameters included maximum load, actuator displacement, and construct failure. Finite element analysis (FEA) was performed on one PL and one PLLC construct. RESULTS: The maximum load at single tension to failure was 183.7 ± 46.8 N for the PL construct and 292.7 ± 82.3 N for the PLLC construct (p = .003). Actuator displacement at 30 N was 1.7 ± 0.5 mm and 2.7 ± 0.7 mm for the PL and PLLC constructs, respectively (p = .011). The cause of PL constructs failure was mostly tearing through the cartilage whereas the PLLC constructs failed through fracture of the cricoid cartilage (p = .000). FEA revealed an 11-fold reduction in the maximum equivalent plastic strain, a four-fold reduction in maximum compressive stress, and a two-fold increase in the volume of engaged cartilage in PLLC constructs. CONCLUSION: The PLLC constructs demonstrated superior performance in biomechanical testing and FEA compared to standard PL constructs. CLINICAL SIGNIFICANCE: The use of 3-D-printed laryngeal clamps may enhance the outcomes of laryngoplasty in horses. In vivo studies are necessary to determine the feasibility of performing laryngoplasty using the laryngeal clamp in horses.

Tympanic membrane perforations cannot be reliably detected using computed tomography based on 15 cadaver dogs.

The integrity of the tympanic membrane is an important factor when deciding treatment and therapeutic recommendations for dogs with ear disease; however, otoscopic examination may be difficult to perform due to features of external ear canal disease or patient compliance. CT is useful for the evaluation of middle ear disease, including cases in which middle ear disease is detected incidentally. The tympanic membrane is detectable using CT, but anecdotally, apparent focal defects or discontinuities of the tympanic membrane are often seen in patients with and without ear disease. The purpose of this prospective, observer agreement study was to determine if perforations of the tympanic membrane are reliably detectable on CT. Fifteen cadaver dogs underwent CT and video otoscopy to verify the integrity of each tympanic membrane. Cadavers were randomly assigned to have the tympanic membranes left intact or to undergo a myringotomy on either the left, the right, or both sides. CT was performed immediately following the myringotomies. Four blinded evaluators evaluated the pre- and post-myringotomy scans for a total of 30 scans (60 tympanic membranes). Average accuracy was low (44%), and interobserver agreement for all four evaluators was fair. Although the tympanic membrane is visible on CT, perforations of the tympanic membrane are unlikely to be accurately detected or excluded. The appearance of an intact tympanic membrane or defect in the membrane on CT should not be used as criteria to guide clinical treatment recommendations based on this cadaver model.

Australian perspectives on artificial intelligence in veterinary practice.

While artificial intelligence (AI) and recent developments in deep learning (DL) have sparked interest in medical imaging, there has been little commentary on the impact of AI on the veterinarian and veterinary imaging technologists. This survey study aimed to understand the attitudes, applications, and concerns among veterinarians and radiography professionals in Australia regarding the rapidly emerging applications of AI. An anonymous online survey was circulated to the members of three Australian veterinary professional organizations. The survey invitations were shared via email and social media with the survey open for 5 months. Among the 84 respondents, there was a high level of acceptance of lower order tasks (e.g., patient registration, triage, and dispensing) and less acceptance of high order task automation (e.g., surgery and interpretation). There was a low priority perception for the role of AI in higher order tasks (e.g., diagnosis, interpretation, and decision making) and high priority for those applications that automate complex tasks (e.g., quantitation, segmentation, reconstruction) or improve image quality (e.g., dose/noise reduction and pseudo CT for attenuation correction). Medico-legal, ethical, diversity, and privacy issues posed moderate or high concern while there appeared to be no concern regarding AI being clinically useful and improving efficiency. Mild concerns included redundancy, training bias, transparency, and validity. Australian veterinarians and veterinary professionals recognize important applications of AI for assisting with repetitive tasks, performing less complex tasks, and enhancing the quality of outputs in medical imaging. There are concerns relating to ethical aspects of algorithm development and implementation.

The most common types of uroliths larger than 1 mm are readily visible and accurately measured in an in vitro setting mimicking the canine abdomen using digital radiography.

Abdominal radiography is an important diagnostic to detect uroliths. Cystine and urate uroliths were historically characterized as nonmineral opaque on survey radiographs. However, recent research and clinical observations indicate that pure urate and cystine uroliths may be detected with digital radiography. The primary purpose of this prospective, in vitro, diagnostic accuracy study was to determine the sensitivity of digital radiography in detecting cystoliths of varying size and composition. Forty canine uroliths of pure composition (10 each of calcium oxalate, struvite, cystine, and urate), acquired from Minnesota Urolith Center and ranging from 1 to 10 mm, were placed in phantoms of three various sizes and radiographed. The radiographs, including three sets of each urolith separately, were evaluated by three blinded radiologists on two separate occasions. Evaluation included presence or absence of urolith, number of uroliths, and maximum diameter of the urolith(s). For all four types of uroliths and all readers, the specificity and PPV were 100% with an associated very high sensitivity (94.4%-98.9%) and NPV (94.8%-98.9%). Calcium oxalate uroliths were the most accurately measured and struvite were the least accurately measured when compared with the gross measurement. Smaller uroliths were more accurately measured than larger uroliths. Uroliths placed in smaller bladder phantoms were more accurately measured than in larger bladder phantoms. Though accurate measurement of uroliths is complicated by and dependent on numerous variables, our results reveal that urate and cystine uroliths are visualized on digital radiography making them a relevant differential diagnosis when seen clinically.

Disseminated Mycobacterium genavense infection in a guinea pig (Cavia porcellus): a case report.

BACKGROUND: Mycobacteria are found in many environmental conditions and infect a variety of species, including rodents and rabbits. Guinea pigs are used experimentally as a model for Mycobacterium tuberculosis, but natural mycobacteriosis in guinea pigs has not been reported. CASE PRESENTATION: A 1.5-year-old female guinea pig was found acutely deceased with no premonitory illness. On gross post-mortem examination, multifocal to coalescing, raised, firm, pale tan nodules with discrete, irregular margins were noted over the surfaces of all lung lobes. Histopathology revealed nodules composed of clustered foamy macrophages and multinucleated giant cells containing numerous bacterial rods. Similar bacteria-laden macrophages were noted within sections of the liver, heart, palpebral conjunctiva, duodenum, and cecum. Polymerase chain reaction was performed on tissues collected during post-mortem examination. The 16S rRNA gene product was sequenced and was identical to the Mycobacterium genavense type strain. CONCLUSIONS: To the best of the author's knowledge, this report details the first documented case of Mycobacterium genvaense infection in a guinea pig and a follow up investigation of close-contact animals. Given their experimental susceptibility and this clinical case report, mycobacteriosis should be considered as a differential in guinea pigs exhibiting weight loss in the absence of other clinical signs. With the potential for zoonotic transmission in immunosuppressed individuals, precautions should be taken to safeguard human health in cases of guinea pigs with suspected M. genavense infection.

Artificial intelligence 101 for veterinary diagnostic imaging.

The prevalence and pervasiveness of artificial intelligence (AI) with medical images in veterinary and human medicine is rapidly increasing. This article provides essential definitions of AI with medical images with a focus on veterinary radiology. Machine learning methods common in medical image analysis are compared, and a detailed description of convolutional neural networks commonly used in deep learning classification and regression models is provided. A brief introduction to natural language processing (NLP) and its utility in machine learning is also provided. NLP can economize the creation of "truth-data" needed when training AI systems for both diagnostic radiology and radiation oncology applications. The goal of this publication is to provide veterinarians, veterinary radiologists, and radiation oncologists the necessary background needed to understand and comprehend AI-focused research projects and publications.

Repeatability and accuracy of a novel, quantitative radiographic method for differentiating normal canine sacroiliac joints from joints with subluxation or luxation: Pilot study.

Canine sacroiliac (SI) joint subluxation or luxation is most commonly diagnosed based on qualitative radiographic assessments. Aims of this two-part, retrospective, diagnostic accuracy, pilot study were to develop and evaluate a novel quantitative method based on measuring the angle between a line connecting the iliac wings and parallel lines across three anatomical landmarks (cranial endplate of L7, caudal endplate of L6, cranial endplate of L6) on a single ventrodorsal radiograph. For the first part of the study, angle measurements from a single observer were compared for 20 normal canine pelvic radiographs and 20 pelvic radiographs with SI luxation or subluxation. Mean values significantly differed between datasets (P < 0.001). The angles for the normal pelves ranged from 0.6° to 1.5°, while abnormal angles ranged from 3.8° to 7.1°. For the second part of the study, a dataset of 25 normal and 25 abnormal canine pelvic radiographs was evaluated using the novel technique by three blinded readers with varying levels of expertise at two different time points. There was excellent reliability among the three readers with an intraclass correlation (ICC) value of 0.90 and an excellent agreement between day 0 and day 30 readings with an ICC value of 0.91. It was also determined that a cut-off angle of 2.0°, using the line parallel to the cranial endplate of L6, provided overall the best accuracy, sensitivity, and specificity to differentiate normal versus abnormal pelves. These findings may be helpful for clinical cases with equivocal diagnoses and for future development of automated diagnostic tools.

Inter- and intraobserver agreement for CT measurement of mandibular and medial retropharyngeal lymph nodes is excellent in dogs with histologically confirmed oral melanoma.

Mandibular and medial retropharyngeal lymph nodes are routinely evaluated with CT when staging dogs with oral melanomas. While size alone is considered inadequate for detecting nodal metastasis, it is critical in evaluating treatment response, as clinical decisions are based on changes in size. It is common for different radiologists to measure the size of pre- and posttreatment lymph nodes in the same patient. The objective of this retrospective, observer agreement study was to evaluate the inter- and intraobserver agreement in measuring canine mandibular and medial retropharyngeal lymph nodes by a diverse population of veterinary radiologists and trainees. Fourteen dogs with documented oral melanoma and head CT studies identified from records of a single institution were included in this study. North American veterinary radiologists and trainees were recruited to measure the mandibular and medial retropharyngeal lymph nodes; in triplicate. Prior to performing the study measurements, participants completed a training tool demonstrating the lymph node measurements. Overall, interobserver intraclass correlation coefficient (ICC) was 0.961 (95% confidence interval [CI]: 0.946, 0.972) and intraobserver ICC was 0.977 (95% CI: 0.968, 0.983), indicating excellent agreement (ICC > 0.9 considered excellent). Similar findings were noted following sub-analysis for most variables (experience, size, laterality, axis of measurement). These results suggest that follow-up measurement of the long and short axis of the mandibular lymph nodes and short axis of the medial retropharyngeal lymph nodes in the transverse plane, performed by different veterinary radiologists using the same method of measure, should have minimal impact on clinical decision making.

Evaluation of a microvascular anastomotic coupler for end-to-side arterial and venous anastomosis for feline renal transplantation.

OBJECTIVE: To describe the technique and determine the feasibility of an end-to-side (ETS) anastomosis of the renal vein to vena cava and renal artery to aorta using a microvascular anastomotic coupler (MAC) for feline renal transplantation. STUDY DESIGN: In vivo experimental study. ANIMALS: Six purpose-bred domestic shorthair cats. METHODS: The left kidney was autotransplanted using a MAC for ETS vascular anastomosis. Outcomes included intraoperative hemorrhage from the anastomosis sites, duration of anastomoses, surgical complications, postoperative renal perfusion (including resistive index (RI)) measured by Doppler ultrasonography and computed tomography angiography, and histopathological examination of the left kidney and anastomosis sites (30 days). RESULTS: Anastomosis was successful in all cats, and intraoperative hemorrhage was negligible. Intraoperative renal perfusion was considered excellent. Venous and arterial anastomoses were completed in 11 minutes 20 seconds (range, 6:38-13:27) and 21 minutes 50 seconds (range, 11:05-30:24), respectively. Vascular occlusion time was 32 minutes (17:43-42:03). One cat was euthanized 5 hours postoperatively because of bleeding from a muscular arterial branch of the dorsal aorta causing hemoabdomen. Renal perfusion and RI of the remaining five cats were within normal range (<0.8) and similar to the contralateral kidney at all time points. Endothelialization of the anastomosis was complete with mild-to-moderate fibrosis surrounding the MAC in all cats. CONCLUSION: End-to-side anastomosis of the renal vein and artery to the vena cava and aorta, respectively, was consistently achieved in all six cats with the MAC. CLINICAL SIGNIFICANCE: The use of the MAC may be considered as an alternative to hand suturing for ETS anastomoses for feline renal transplantation.

Small intestinal enterolith in a dog presenting for a suspected gastric foreign body.

A 12-year-old Labrador Retriever presented for an acute onset of anorexia and vomiting. Abdominal ultrasound and abdominal radiographs were performed, and on the latter a large mineral opaque structure with concentric rings within the cranial abdomen was diagnosed as a gastric foreign body. Laparotomy revealed that the suspected gastric foreign body was a large enterolith within the small intestines. Enteroliths should be considered as one of the differential diagnoses for a large mineralized abdominal structure in a dog presented for gastrointestinal clinical signs.

Use of color-coded, three-dimensional-printed equine carpus models is preferred by students but does not result in statistically different academic performance.

Radiology can be a challenging subject for students and finding new techniques that help improve their understanding could have positive effects in their clinical practice. The purpose of this prospective experimental study was to implement the use of color-coded, three-dimensional-printed, handheld equine carpus models into a radiographic anatomy course and evaluate the impact objectively and subjectively using quizzes and student response surveys. A first-year veterinary class was randomly divided into two similarly sized groups (groups A and B) for an equine normal radiographic anatomy laboratory. Both groups experienced the same laboratory structure; however, each student in group B received a handheld three-dimensional-printed equine carpus. Both groups received a quiz at the end of their laboratory consisting of 10 multiple-choice questions related to the equine carpus. An anonymous survey regarding the laboratory was emailed to students after the laboratory. One week later, the same 10 questions in randomized order were administered via a pop-quiz. Students believed both quizzes would count toward their final course grade. There was no statistically significant difference in grades between groups on either quiz (P > .05). However, based on survey responses, group B students felt the carpus made the laboratory more enjoyable and improved their comprehension of the material, whereas group A students felt the carpus would have increased their enjoyment and improved their comprehension. The implementation of three-dimensional-printed anatomic models may be useful to enhance enjoyment and perceived comprehension of veterinary students; however, there is currently insufficient evidence to suggest these models improve academic performance.

Artificial intelligence evaluating primary thoracic lesions has an overall lower error rate compared to veterinarians or veterinarians in conjunction with the artificial intelligence.

To date, deep learning technologies have provided powerful decision support systems to radiologists in human medicine. The aims of this retrospective, exploratory study were to develop and describe an artificial intelligence able to screen thoracic radiographs for primary thoracic lesions in feline and canine patients. Three deep learning networks using three different pretraining strategies to predict 15 types of primary thoracic lesions were created (including tracheal collapse, left atrial enlargement, alveolar pattern, pneumothorax, and pulmonary mass). Upon completion of pretraining, the algorithms were provided with over 22 000 thoracic veterinary radiographs for specific training. All radiographs had a report created by a board-certified veterinary radiologist used as the gold standard. The performances of all three networks were compared to one another. An additional 120 radiographs were then evaluated by three types of observers: the best performing network, veterinarians, and veterinarians aided by the network. The error rates for each of the observers was calculated as an overall and for the 15 labels and were compared using a McNemar's test. The overall error rate of the network was significantly better than the overall error rate of the veterinarians or the veterinarians aided by the network (10.7% vs 16.8% vs17.2%, P = .001). The network's error rate was significantly better to detect cardiac enlargement and for bronchial pattern. The current network only provides help in detecting various lesion types and does not provide a diagnosis. Based on its overall very good performance, this could be used as an aid to general practitioners while waiting for the radiologist's report.

Imaging and clinical features of a true gastrogastric intussusception in a dog.

An 18-month-old male mixed breed dog was evaluated for acute vomiting and hematemesis. Clinical signs and initial radiographic findings shared commonalities with reported cases of pylorogastric intussusception in dogs. However, unlike previously reported cases, additional imaging [including ultrasound and computed tomography (CT)] revealed invagination of the gastric fundus into the gastric body, consistent with true gastrogastric intussusception. These findings were confirmed with histopathology and on necropsy. Key clinical message: Although extremely rare, gastrogastric intussusception should be included as a differential diagnosis for any patient presenting with acute vomiting, abdominal pain, dehydration, or tachycardia in combination with the diagnostic imaging findings described in this report.

Caractéristiques cliniques et d'imagerie d'une intussusception gastro-gastrique vraie chez un chien. Un chien mâle de race croisée âgé de 18 mois fut évalué pour des vomissements aigus et de l'hématémèse. Les signes cliniques et les trouvailles radiographiques initiales partageaient des similarités avec des cas rapportés d'intussusception pyloro-gastrique chez des chiens. Toutefois, contrairement aux cas rapportés précédemment, des examens d'imagerie supplémentaires [incluant l'échographie et la tomodensitométrie (CT)] ont révélé une invagination du fundus gastrique dans le corps de l'estomac, compatible avec une intussusception gastro-gastrique vraie. Ces données furent confirmées lors de l'examen histopathologique et de la nécropsie.Message clinique clé :Bien qu'extrêmement rare, l'intussusception gastro-gastrique devrait être incluse dans le diagnostic différentiel pour tout patient présenté avec des vomissements aigus, de la douleur abdominale, de la déshydratation ou de la tachycardie en combinaison avec les trouvailles en imagerie diagnostique décrites dans le présent rapport.(Traduit par Dr Serge Messier).

Migration of retrobulbar wooden foreign body between diagnostic imaging and surgical extraction in a German shepherd dog.

A 2-year-old, male castrated German shepherd dog was presented to the University of Tennessee Veterinary Medical Center (UTVMC) with periorbital swelling and conjunctival mucopurulent discharge 2 days following removal of a twig from the medial canthus by the owner. Diagnostic imaging was pursued due to the suspicion of a retrobulbar foreign body (FB). A cylindrical FB approximately 3.0 cm in length and 1.0 cm in diameter with concentric rings, suspected to be wooden material, was identified on computed tomography (CT) imaging. An attempt to remove the FB via a stab incision using ultrasound guidance was unsuccessful, and postmanipulation ultrasound confirmed the FB position was unchanged. An exploratory orbitotomy was performed, using the acquired CT images for guidance in locating the FB; however, the FB was not present at the predicted site. The CT imaging was repeated and showed that the FB had migrated rostrally approximately 3.0 cm, compared to the originally acquired study and its same location during attempted ultrasound-guided removal. A combination of CT-guided needle placement and contrast injection was then used with repeat imaging in an attempt to better localize the FB and its soft tissue tract. The dog was taken back into the operating room, and the wooden FB was successfully removed.

RADIOLOGIC MEASUREMENT AND DETERMINATION OF KIDNEY-TO-VERTEBRA RATIOS AS A METHOD OF ESTIMATING RENAL SIZE IN SERVALS (LEPTAILURUS SERVAL).

Numerous conditions, from acute to chronic renal changes, have the potential to alter the renal size on radiographs. However, current literature does not provide any radiographic reference range for the normal renal size in the serval (Leptailurus serval). This retrospective study includes 13 healthy adult servals, seen between 2004 and 2017 at the UTCVM Veterinary Medical Center, deemed healthy based on physical examination and blood work. Orthogonal radiographs were anonymized, calibrated, and evaluated blindly by three observers of different experience levels. Renal and individual lumbar vertebral body lengths were measured on both orthogonal views, and ratios of kidney length to each lumbar vertebral length were calculated on both views. On the ventro-dorsal projection, the kidney length to L5 vertebra ratio had the lowest standard deviation (SD) with a mean of 1.82, SD of 0.27, and 95% confidence interval (CI) (1.63-2.00). On the lateral view, the kidney length to L3 vertebra ratio had the lowest SD with a mean of 2.03, SD of 0.25, and 95% CI(1.86-2.20). Statistically, all three observers were shown to be in agreement, indicating reproducibility of the measurements among observers with different levels of expertise.

Mucopolysaccharidosis-like phenotype in feline Sandhoff disease and partial correction after AAV gene therapy.

Sandhoff disease (SD) is a fatal neurodegenerative disease caused by a mutation in the enzyme ß-N-acetylhexosaminidase. Children with infantile onset SD develop seizures, loss of motor tone and swallowing problems, eventually reaching a vegetative state with death typically by 4years of age. Other symptoms include vertebral gibbus and cardiac abnormalities strikingly similar to those of the mucopolysaccharidoses. Isolated fibroblasts from SD patients have impaired catabolism of glycosaminoglycans (GAGs). To evaluate mucopolysaccharidosis-like features of the feline SD model, we utilized radiography, MRI, echocardiography, histopathology and GAG quantification of both central nervous system and peripheral tissues/fluids. The feline SD model exhibits cardiac valvular and structural abnormalities, skeletal changes and spinal cord compression that are consistent with accumulation of GAGs, but are much less prominent than the severe neurologic disease that defines the humane endpoint (4.5±0.5months). Sixteen weeks after intracranial AAV gene therapy, GAG storage was cleared in the SD cat cerebral cortex and liver, but not in the heart, lung, skeletal muscle, kidney, spleen, pancreas, small intestine, skin, or urine. GAG storage worsens with time and therefore may become a significant source of pathology in humans whose lives are substantially lengthened by gene therapy or other novel treatments for the primary, neurologic disease.

Invited review--Applications for 3D printers in veterinary medicine.

Recent technological advances in 3D printing have resulted in increased use of this technology in human medicine, and decreasing cost is making it more affordable for veterinary use. Rapid prototyping is at its early stage in veterinary medicine but clinical, educational, and experimental possibilities exist. Techniques and applications, both current and future, are explored and illustrated in this article.

Delayed Urethral Obstruction after Migration of a Ballistic Pellet in an Alpine Wether.

A one-year-old alpine wether was presented for emergency evaluation of stranguria. Diagnostics identified a moderately distended bladder and mild dehydration. Preliminary lateral radiographs identified two metallic structures consistent with projectile pellets in the pelvic and perineal regions and no evidence of radiopaque uroliths. A tube cystostomy was performed, and a contrast urethrogram revealed one of the pellets in the perineal region was in proximity to the urethral obstruction. Subsequent radiography and ultrasound identified the pellet as being within the lumen of the urethra. Examination of the trichotomized skin revealed two scars, including a scar over the paralumbar fossa in the region of the urinary bladder suggestive of a projectile injury. The pellet was removed by a perineal urethrotomy. The patient was able to spontaneously urinate after urethrotomy, passed a tube cystostomy challenge two weeks after surgery, and was discharged. No complications were reported. While uncommon in the veterinary and comparative medical literature, clinicians should consider the potential for projectile pellets to migrate into the urinary tract after initial injury.

Body mapping chart for estimation of percentage of body surface area in mesocephalic dogs.

OBJECTIVE: To create a chart for estimating body surface area (BSA) for use in canine burn victims, similar to the human Rule of Nines. DESIGN: Prospective study, from 2016 to 2017. SETTING: University teaching hospital. ANIMALS: Nine adult, medium-sized, mesocephalic dogs (5 females, 4 males). INTERVENTIONS: Sedated dogs and fresh cadavers underwent full-body computed tomography (CT) scans. A 3-dimensional technique was used to calculate the surface area of specific body parts, as well as the surface area of the whole body. With the obtained measurements, a BSA chart was created. MEASUREMENTS AND MAIN RESULTS: Estimates for percent of total BSA obtained with CT images were as follows: head and abdomen 14%, respectively, neck and each of the thoracic limbs 9%, thorax 18%, pelvic limbs 11% each, and pelvis including the tail 5%. The most considerable differences between dogs and people in respect to the Rule of Nines chart were noticed in the head, the pelvic limbs, as well as in the groin region in people as compared with the pelvic/tail area in dogs. The surface areas of the front legs and thorax were the only body parts that corresponded with that of human body surfaces. CONCLUSIONS: A chart for estimating canine body surface was created. Given the diversity of dog breeds, sizes, and body conformation, our results cannot be generalized to all dogs. Studies of more diverse populations are warranted.

Radiographic evidence of metaphyseal sclerosis secondary to canine distemper virus: 4 cases in juvenile dogs.

BACKGROUND: Metaphyseal sclerosis secondary to canine distemper virus has been described histopathologically, but its radiographic appearance has not been described. OBJECTIVES: Describe the radiographic appearance of metaphyseal sclerosis secondary to canine distemper virus in juvenile dogs as distinct from metaphyseal osteopathy (formerly called hypertrophic osteodystrophy). ANIMALS: Four dogs (2 intact females and 2 intact males) between 2.5 and 4 months of age presented to 2 different veterinary teaching hospitals. METHODS: Retrospective case series in which definitive diagnosis of canine distemper virus based on antemortem positive reverse transcription-polymerase chain reaction (RT-PCR) result or necropsy was required. RESULTS: All 4 dogs were presented for evaluation of neurologic abnormalities, respiratory signs, and lethargy; 2 dogs had gastrointestinal signs and ocular abnormalities. Radiographs on all patients featured multifocal, symmetric, metaphyseal sclerosis, with no evidence of lysis or changes to the adjacent growth plate. The metaphyseal sclerosis was most apparent at the proximal humeral diaphyses and other included long bones. Diagnosis of distemper was confirmed by necropsy (2 of 4 dogs) or positive RT-PCR results (2 of 4 dogs). Three dogs were euthanized because of progressive illness, and 1 dog was lost to follow-up. CONCLUSION AND CLINICAL IMPORTANCE: Identification of metaphyseal sclerosis on radiographs during diagnostic evaluation of young dogs should lead to a clinical suspicion of canine distemper virus infection. Sclerosis identified secondary to canine distemper virus is distinct from the necrosis and inflammation of metaphyseal osteopathy.