Computed tomography (CT) of postoperative orthopedic cases can yield valuable clinical information, especially when radiographic findings are equivocal. Image quality can be adversely affected by the presence of metallic implants. Several studies evaluating metal artifacts on CT have been published in humans, but studies involving veterinary patients are limited. This study aimed to assess attenuation value changes caused by metal artifacts on adjacent anatomical structures. This prospective cadaveric study included 20 Greyhound cadaver forelimbs. The limbs underwent CT before and after application of a 316L stainless steel plate and screws along the cranial surface of the radius. Attenuation values of the radial cortex, medulla, and caudal soft tissues were compared before and after implant placement. Five anatomical sites along the antebrachium were selected for comparison: (1) at the level of a non-filled plate hole, (2) along the plate between 2 screws, (3) at the edge of the plate, and (4) 1 and (5) 3 cm proximal to the plate, respectively. The attenuation values between pre- and post-implant images were significantly different in the radial medulla, cranial, and caudal cortices at Sites 2 and 3, and in the cranial radial cortex at Site 1. No significant differences were found in the antebrachial caudal soft tissues at any site, nor at any region at Sites 4 and 5. The presence of stainless steel implants significantly affects the attenuation values of adjacent cortical and medullary bone, which may lead to image interpretation errors.

The presence of adhesion created by an adrenal tumor (AT) with adjacent structures is important information for surgical planning. We aimed to establish the accuracy of computed tomography (CT) in predicting adrenal tumor adhesion (ATA) with adjacent organs and vessels. This prospective multicenter study enrolled 30 dogs and 2 cats with AT, pre- and post-contrast CT, and adrenalectomy. Images were reviewed by five blinded radiologists using consensus-based CT criteria for adhesions (five criteria for vessels and eight for organs). During surgery, ATA was observed in 27/32 patients (84.4%). A single criterion alone could not predict the presence of adhesion. Using a probabilistic classification tree, combinations of two or more criteria with other variables (side, image quality, and tumor rupture) showed good accuracy in predicting ATA for some organs and vessels. For vessels, the combination of some criteria could predict the presence of adhesion: for example, for the caudal vena cava, a combination of criteria 1 + 3 + 4 + 5 in a right AT had an accuracy of 86.2%; for the renal vein, the combined 1 + 2+ 3 + 4 + 5 criteria had an accuracy of 84.8% and 93.8% in a CT study of excellent quality. For organs, a combination of specific criteria could predict adhesion: for the kidney, the combination 1 + 2+ 3 + 4 + 5 had an accuracy of 90%. Radiologist's agreement for detecting ATA was excellent (>80%). A combination of repeatable CT criteria could provide probabilistic information for the presence of ATA with adjacent organs and vessels.

While computed tomography (CT) imaging is commonly used to evaluate canine nasal tumors, the ability to differentiate tumor types based on imaging features remains limited. This retrospective study examined dogs with confirmed nasal neoplasia to determine whether CT characteristics differ between epithelial and mesenchymal tumors. Cases from a single institution (2013-2022) were reviewed, and the frequency of CT features between epithelial and mesenchymal tumors was compared using Fisher's exact test. Also, CT features of less commonly reported nasal neoplasms, including squamous cell carcinomas, polyps, and osteosarcomas, were described. Sixty-seven dogs with nasal neoplasia were identified; 48 (72%) had a type of epithelial neoplasia, and 19 (28%) had mesenchymal neoplasia. Dogs with epithelial neoplasia were more likely to show intracranial mass extension (p = 0.04; OR 5.1; 95% CI 1.1-23.9), cribriform plate lysis (p = 0.03; OR 4.5; 95% CI 1.2-15.8), lysis of ipsilateral sphenoid sinus (p < 0.0001; OR 18.7; 95% CI 3.9-85.9), mass extension into ipsilateral sphenoid sinus (p = 0.01; OR 5.8; 95% CI 1.6-20.2), and frontal sinus fluid (p = 0.05; OR 4.7; 95% CI 1.3-16.2) than dogs with mesenchymal neoplasia. Dogs with mesenchymal neoplasia were more likely to show fluid in the ipsilateral maxillary recess (p = 0.01; OR 5.3; 95% CI 1.4-18.6). Squamous cell carcinoma patients had two distinct presentation patterns: either a small nodule centered on the nasal planum with no associated lysis and mass extension, or a mass centered on and causing lysis of the maxillary or nasal bone. This investigation provides the first comprehensive comparison of CT characteristics between different canine nasal tumor types, offering potential prebiopsy diagnostic indicators.

Little information concerning the CT characteristics of the canine brachial plexus is available. This study aimed to describe size measurements and CT characteristics of the brachial plexus in dogs and explore correlations with patient characteristics to provide clinical interpretation guidelines. A retrospective analysis of 39 thoracic CT studies categorized dogs by weight and breed type (chondrodystrophic/non-chondrodystrophic). The brachial plexus was evaluated at a defined anatomical location in the axillary region, with measurements recorded for size (cross-sectional area, height, and width), attenuation (HU), subjective conspicuity, and the amount of interlying fat tissue. A strong positive correlation was found between dog weight and all brachial plexus size measurements (p < 0.0001). Intra- and interrater reliability of size measurements was moderate to excellent (ICC 0.74-0.92 and 0.77-0.99, respectively), but those with the highest reliability lacked absolute consistency (large standard error of measurement). Age was negatively correlated with size, but this association was confounded by weight. Neither laterality, sex, nor breed type significantly affected size or attenuation. The subjectively estimated amount of interlying fat was significantly associated with minimum precontrast attenuation values and the conspicuity of the brachial plexus, with dogs having more fat showing a blurred plexus appearance. No difference was found for the characteristics of the brachial plexus when evaluating chondrodystrophic breed-type dogs compared to non-chondrodystrophic ones. These descriptive characteristics, stratified by weight, provide valuable guidelines for clinical interpretation of the presumed normal canine brachial plexus on CT.

A 3-year-old male neutered Labrador Retriever was originally presented to his primary care veterinarian for a 3-4-week history of hyporexia, a 1-week history of anorexia, and vomiting. There was moderate gastrointestinal (GI) distention with heterogeneous soft tissue luminal material within the small intestine in screening abdominal radiographs. Referral and computed tomography were performed, identifying a severe generalized dilation of the GI tract but no obstructive lesion. Severe functional intestinal ileus without obstruction was diagnosed. The patient underwent laparotomy with full-thickness intestinal surgical biopsies due to presumptive infiltrative enteropathy, yielding a diagnosis of intestinal leiomyositis.

A 7-year-old female neutered French Bulldog presented with left thoracic limb paresis. Twelve months earlier, the dog had been treated with 3D conformal radiotherapy for a right piriform lobe mass (suspected glioma), which had a strong partial response following treatment. Magnetic resonance imaging (MRI) revealed an intramedullary lesion of the cervical spinal cord, suspected to be drop metastasis. This lesion was treated with intensity-modulated radiotherapy (IMRT) (10 fractions of 3.6 Gy, total 36 Gy), with a response documented on MRI, alongside resolution of clinical signs. The dog died of unrelated causes 647 days following IMRT, and the diagnosis was confirmed at post-mortem examination.

As alpacas (Vicugna pacos) gain popularity globally, the need for improved knowledge about the species grows, including a better understanding of dental pathologies increasingly recognized in domesticated populations. Oral examination and radiology are commonly used tools for the detection of periapical infections and other dental diseases. In this diagnostic accuracy study, we aim to calculate the sensitivity and specificity of these two modalities to determine their agreement with histology in the detection of periodontal (periapical and periradicular) and pulpal pathologies. Seven alpacas were included in the study and underwent oral examination and radiography. After euthanasia, 18 teeth were harvested for histological evaluation. Sensitivity and specificity of radiography in detecting periapical infections were 100% and 85%, respectively, compared to a sensitivity of 54% and a specificity of 75% for clinical evaluation. The level of agreement between these two modalities for the detection of periapical disease was weak (22%). Sensitivity and specificity of radiography in diagnosing periapical periodontal changes were 100% and 83%, compared to clinical evaluation, which had a sensitivity of 100% and a specificity of 36%. The sensitivity of radiology in detecting pulpar changes was low (8%), while it was high (77%) for clinical examination. These findings demonstrate that radiography is a meaningful supplement for confirming suspected clinical diagnoses of periodontal and periapical changes in alpacas.

This study aimed to characterize the computed tomographic (CT) and ultrasonographic features of feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) and its concurrent abnormalities. A retrospective multicenter study was conducted on 16 cats with histopathologically confirmed FGESF. CT and ultrasonographic characteristics were retrospectively evaluated to assess the lesion location, shape, size, and layering patterns. The contrast enhancement patterns, including the attenuation values, were analyzed qualitatively and quantitatively. Concurrent abnormalities, such as lymphadenopathy, gastrointestinal (GI) obstruction, and perforation, were also assessed. FGESF predominantly affected young to middle-aged cats (median age: 3.5 years; range: 9 months-9 years), and Ragdolls were the most overrepresented breed among purebred cats. GI involvement was observed in 14 of 16 cases, most commonly in the proximal duodenum (33%). Lesion growth patterns were significantly associated with anatomical location; all proximal duodenal and pyloric lesions demonstrated endophytic growth (p = 0.018). Common CT findings included heterogeneous contrast enhancement (86%), mucosal layer enhancement (86%), and ulceration (50%). Ultrasonography revealed intraparenchymal hyperechoic areas (100%), heterogeneous echotexture (93%), and mixed echogenicity (93%). Concurrent abdominal lymphadenopathy was present in 93% of cases, with 85% showing marked enlargement (>10 mm). GI obstruction (21%) and perforation (14%) were less common; however, perforation cases exhibited poor prognosis, and none of the affected cats survived beyond 24 h postoperatively. These findings support the inclusion of FGESF in the differential diagnosis of GI mass-forming conditions in cats and highlight the utility of CT and ultrasonography for the comprehensive assessment of primary lesions and concurrent abnormalities.

Aortic body paragangliomas (ABPs) are the most common heart base tumor in dogs; however, descriptions of their computed tomography (CT) and magnetic resonance imaging (MRI) findings are lacking. Although generally considered benign, ABPs can present as malignant neoplasms with local invasion and metastasis. The objectives of this study were to describe the CT and MRI features of confirmed benign and malignant ABPs and identify significant features associated with malignancy. Forty-four dogs with 43 CTs and 3 MRIs were included. Most (68%) dogs were males, and 48% were brachycephalic breeds. At CT, ABPs were mostly heterogeneously contrast-enhancing, well-marginated, lobular or ovoid, and frequently fluid-cavitated. At MRI, ABPs had heterogeneous T2 hyperintensity, uniform contrast enhancement, a variable "salt-and-pepper" sign, and fluid-cavitated regions. Local invasion was noted in 11 cases. Thirteen dogs had confirmed metastatic lesions, with the most common sites being local lymph nodes, heart, and bones. ABPs frequently displaced and compressed regional structures and less often encircled vasculature. Pericardial and peritoneal effusions were significantly associated with confirmed metastasis. Encircling of vessels, mediastinal effusion, and right-sided congestive heart failure were significantly associated with invasion. ABPs may be present in non-brachycephalic breeds, and malignant masses have the potential for regional invasion and distant bone metastasis.

Sialectasis, defined as a dilated salivary duct, is an uncommon salivary disease. There are limited published data regarding salivary gland disease or anatomy of the salivary system in rabbits. In dogs, computed tomography (CT) is described as the imaging modality of choice for salivary gland disease. Identification of the correct diseased gland and respective duct is required for surgical planning. There are currently no studies describing CT features of parotid sialectasis in rabbits. The aim of this single-center, retrospective, and descriptive study was to determine CT features of confirmed and suspected parotid sialectasis in rabbits. Conscious whole-body pre- and postcontrast CT studies from 21 rabbits presenting with dilated parotid ducts were reviewed. Diagnosis was confirmed in 10/21 patients, based on surgery (10/10) and histopathology (4/10), and presumed in 11/21 rabbits on the basis of imaging and clinical findings. A number of 19/21 rabbits had unilateral dilated parotid ducts (15/19 right-sided). All dilated parotid ducts were characterized by tubular (21/23) fluid attenuating, non-contrast-enhancing content (median 27 Hounsfield units) and soft tissue attenuating, thin, and regular contrast-enhancing rims. The 20/23 dilated parotid ducts extended from the parotid salivary gland or the mandibular ramus to the first maxillary premolar. Bacteriological culture was positive in 10/10 patients. Histopathological findings revealed concomitant sialadenitis in all four animals, associated with luminal bacterial colonies and foreign material in 2/4. Parotid sialectasis can therefore be associated with infectious sialadenitis. CT is helpful to precisely identify the affected salivary gland and also to differentiate sialectasis from more common dental-related abscesses in the rabbit species.

A sonographic reticulonodular splenic pattern is characterized by numerous hypoechoic nodules throughout the parenchyma and is commonly associated with benign, neoplastic, or infectious etiologies. However, this has been described as a normal age-related variant in children and puppies up to 1 year old. The purpose of this study was to determine whether the ultrasonographic appearance of the spleens of healthy kittens mimics that of normal puppies. This was a prospective, descriptive study design. Sixty-seven spleens and 50 healthy kittens (13 repeat kittens) were included. Apparently healthy kittens between the ages of 0 months and 1.5 years were scanned using a high-frequency linear transducer. Ultrasonographic patterns of the spleen were graded as follows: grade 1, homogeneous echotexture; grade 2, faint nodules <10% of the parenchyma; grade 3, larger ill-defined nodules involving 10%-25% of the spleen; and grade 4, large well-defined nodules involving >25% of the spleen. A reticulonodular pattern was present in 62 spleens (92%), with grade 2 most common. The grades were highest on average between 0 and 4 months old. Unexpectedly, young cats up to at least 1.5 years old were often noted to have a reticulonodular pattern. After 4 months old, there was a negative association with age and the grade of the spleen. This overall negative association persisted even among kittens that were enrolled serially. The findings of this study suggest that a reticulonodular pattern in young cats and kittens may be a normal finding and should not be mistaken for pathology.

Collet-Sicard syndrome (CSS) is a rare neurological condition characterized by concomitant dysfunction of cranial nerves (CNs) IX-XII, resulting in variable combinations of dysphagia, dysphonia, and tongue paresis or paralysis. This retrospective case series describes three dogs diagnosed with CSS secondary to a suspected brainstem meningioma that were treated with definitive radiotherapy (RT). All dogs received volumetric-modulated arc therapy with a total dose of 50 Gy (20 × 2.5 Gy fractions). Supportive medical management was maintained during and after RT. Clinical signs varied among dogs depending on the severity of CN involvement, and all showed clinical improvement after RT. Two dogs who achieved stable disease post-RT were euthanized due to progressive clinical signs at 344 and 421 days post-RT, while one dog who achieved partial response post-RT remains alive with sustained clinical improvement at 652 days. No early or late adverse effects were recorded. This case series describes the use of RT, follow-up advanced imaging, and medical management for the treatment of CSS in three dogs with suspected neoplastic causes.

Parasites are a major cause of disease in dogs globally; some are well recognized in the veterinary community, whereas others are less well known. This review summarizes and discusses radiological and computed tomographic (CT) findings of 18 helminth and arthropod parasitic diseases in dogs. Each section begins with a summary of the parasites' distribution, life cycle, and clinical manifestations. The review finds that the imaging features of some parasitic diseases are well described in numerous studies, whereas others are found only in case reports. Findings ranged from pathognomonic to nonspecific. The review concludes that diagnostic imaging can be a useful tool in the investigation of parasitic disease and that further research is needed into the radiological and CT characteristics of lesser known and emerging parasitic diseases in dogs.

Transarterial chemoembolization (TACE) has recently emerged as a new alternative and palliative treatment option for head and neck cancers in human medicine, with a few case reports in veterinary medicine also showing good outcomes for canine oronasal tumors. Therefore, this study aimed to analyze the anatomical structures of canine head arteries using computed tomography angiography (CTA), focusing on the feeding arteries of oronasal tumors, as this information is essential for interventional procedures. This retrospective multicenter study used triple-phase CTA images of nasal tumors (n = 30), oral tumors (n = 31) (including one case of a caudal mandibular tumor with two tumors), and a control group (n = 51). Among the 100 feeding arteries identified in the 61 oronasal tumors, the descending palatine artery (27/45; 60%) had the highest prevalence in nasal tumors. In rostral maxillary tumors, the infraorbital artery (10/24; 41.7%) was identified as the major feeding artery, whereas in mandibular tumors, the facial artery was the most prevalent feeder in both the rostral (4/4; 100%) and caudal (6/7; 85.7%) locations. Of the 222 head arteries observed on CTA, all lingual and facial arteries originated separately. The mean diameters of the major head arteries in different groups were significantly and positively correlated with body weight. However, when comparing the diameters of the head arteries normalized to body weight between the tumor feeder group and the control group, no significant difference was observed. This study provided comprehensive information on canine head arteries, including the feeding arteries of oronasal tumors, which is important for preprocedural planning.

A 4-year-old female spayed dog was presented with increased abdominal volume. Physical examination and blood work were unremarkable.Computed tomography (CT) revealed a fluid-filled abdominal mass consistent with an extremely enlarged and distorted right kidney, torsion of the renal vascular pedicle, prerenal caudal vena cava thrombosis, and distal stenosis of the right ureter. Renal torsion was confirmed on surgery. Patient recovered well from nephrectomy and had an excellent long-term prognosis. This is the first report of renal pedicle torsion in a dog. Lack of relevant clinical signs combined with CT identification of a twisted renal pedicle, extreme hydronephrosis, and renal fibrous atrophy on histopathology supported a diagnosis of chronic renal torsion.

Optimal radiation protocols for canine nasal carcinoma are not established. Co-morbidities, access, and owner compliance can influence scheduling. Between 2015 and 2022, two radiotherapy protocols were used in the palliative treatment of canine nasal carcinoma at a single institution. Group A comprised 17 cases receiving 40 Gy in ten 4 Gy fractions delivered Monday, Wednesday, and Friday. Epistaxis was present in 11/17 (65%) cases. Median survival time (MST) was 298 days (95% CI: 163.54-432.45); progression-free survival was 173 days (95% CI: 117.87-228.12). Group B comprised 24 cases receiving 36 Gy in six 6 Gy fractions delivered Monday and Friday. Epistaxis was present in 20/24 (83%) cases. MST was 375 days (95% CI: 240.73-509.27); progression-free survival was 243 days (95% CI: 138.42-347.58). Dogs with Adams Stage 1 disease had the longest median overall (593 days) and progression-free survival (609 days). Four cases each received additional radiation treatment and/or toceranib at relapse. Palliative radiation therapy achieved control of clinical signs in the majority of cases, with an overall response rate of 100% (Group A) and 96% (Group B). In a multivariate Cox regression model with backwards elimination, when cases were stratified for tumor stage, neither the presence of epistaxis nor treatment (6 vs. 10 fractions) was independently associated with significant improvements in survival. Epistaxis at presentation did not appear to influence survival. These results indicate that palliative radiation therapy is highly effective in controlling clinical signs associated with nasal carcinoma. Increasing fractionation may have a limited effect on survival outcome or toxicity in the palliative setting.

While osteomyelitis is not uncommon in veterinary patients, emphysematous osteomyelitis, characterized by the presence of intramedullary gas, is scarcely reported in both veterinary and human literature. This report documents two cases in young, previously healthy dogs that were presented with clinical signs related to infection/inflammation. Multiple imaging modalities were utilized in the workup of one case, while computed tomography (CT) was used as the sole modality in the second. In both cases, peri-femoral abscessation with intramedullary gas was identified, and positive bacterial culture was obtained. One case responded well to treatment and demonstrated expected osseous remodeling consistent with chronic osteomyelitis. The patient in the second case was euthanized secondary to a marked clinical decline. In humans, this condition is often associated with comorbidities, including diabetes mellitus and carries a guarded prognosis, with a 24-32% mortality rate. The presence of multiple, variably sized though small, irregularly marginated foci of gas, without a sclerotic rim within the medullary cavity, without a history of penetrating trauma, necrotic tumor, or recent surgery, should be considered pathognomonic for emphysematous osteomyelitis.

When heart disease progresses to heart failure, congestion develops in various organs, including the liver and kidneys. Although organ congestion is a critical factor closely associated with the prognosis of heart failure, a simple and quantitative method for evaluating the degree of organ congestion has not yet been established. Two-dimensional shear wave elastography (2D-SWE) is a noninvasive ultrasound technique that can estimate tissue stiffness by measuring shear wave speed (SWS), an index of tissue viscoelasticity, and dispersion slope (DS), which reflects tissue viscosity alone. This study aimed to assess the utility of SWS and DS in evaluating hepatic and renal congestion in transfused dogs by performing 2D-SWE before and after blood transfusion. The ratio of the short diameter (SD) to the long diameter (LD) of the caudal vena cava (CVC SD/LD) was used as an index of congestion. Twenty transfusions were administered to 17 dogs. After transfusion, both the liver and kidney SWS and DS, along with CVC SD/LD, significantly increased. A moderate positive correlation was observed between the CVC SD/LD and liver SWS (r = 0.781, p < 0.01) and kidney SWS (r = 0.744, p < 0.01). Conversely, a strong positive correlation was found between the CVC SD/LD and liver DS (r = 0.900, p < 0.01) and kidney DS (r = 0.850, p < 0.01). These findings suggest that 2D-SWE may be a valuable tool for assessing liver and kidney congestion, with DS potentially serving as a reliable indicator of congestion.

A 5-month-old male Maine Coon cat was presented to the hospital with persistent salivation for 2 weeks. Serum biochemistry showed markedly elevated levels of blood ammonia and bile acids. An abdominal computed tomography discovered a shunt from the left gastric to the left phrenic vein, and the right ureter was seen to descend to the level of L4 and L5 normally and then pass dorsally and medially to the caudal vena cava, thus forming a loop. The present case, in which a circumcaval ureter and a congenital extrahepatic portosystemic shunt were diagnosed concurrently in a cat, was extremely rare and was subsequently confirmed by surgery. Based on the reviewed literature, this is the first case report of the concurrence of a circumcaval ureter and a congenital extrahepatic portosystemic shunt in a cat.

A 4-year-old castrated male Pomeranian dog with a 2-year history of necrotizing encephalitis (NE) presented for acute neurological deterioration without trauma. Magnetic resonance imaging (MRI) revealed a broad crescent-shaped lesion with mixed signal intensities on T1- and T2-weighted images, hypointense areas on T2* images, contrast enhancement in the outer membrane, and a mass-like lesion with fluid-fluid layers. The lesion was diagnosed as a chronic subdural hematoma secondary to spontaneous hemorrhage in a dog with NE. A direct causal relationship remains uncertain; however, NE could have contributed to the increased vulnerability of bridging veins. Serial MRI evaluations revealed progression of the lesion. This is the first report describing the MRI features of chronic subdural hematoma in a dog with NE.

A 6-year-old male neutered Jack Russell Terrier presented via the emergency department for subacute progressive asymmetrical tetraparesis and cervical hyperesthesia. MRI showed T2-weighted (T2W) and T1-weighted (T1W) hypointense material, positioned dorsocaudally to the C3-4 intervertebral disc on the right ventrolateral aspect of the spinal cord, causing moderate-to-severe compression of the spinal cord. The material was sharply marginated with a pointed/sharp beak-like appearance (beak sign). On parasagittal images, two hyperintense lines appearing as a "Y" were appreciated (Y-sign). Surgical findings confirmed an intradural/extramedullary intervertebral disc extrusion (IVDE). This is the first report of a cervical intradural/extramedullary IVDE in a dog.