Veterinary Radiology & Ultrasound最新文献

Accurate interpretation of intradiskal signal voids on magnetic resonance imaging (MRI) is essential to avoid misdiagnosis and improve diagnostic decision-making in canine spinal imaging. Gas accumulation within the degenerated canine intervertebral disk (IVD), known as vacuum phenomenon (VP), and IVD mineralization are common findings in computed tomography (CT), with distinctly different x-ray attenuation characteristics. In MRI, both appear as a signal void, which can complicate interpretation. We hypothesized that gas and mineralization would not differ in intensity values on MRI but would differ in location and shape when compared to CT. This exploratory retrospective multicenter study aims to assess the characteristics of VPs and mineralization in MRI, using CT as the gold standard. Imaging archives were searched for matching canine spinal CT and MRI performed within 48 h. Inclusion criteria included mineralization or gas in the IVD on CT images and available sagittal T2W-sequence MRI images of the same vertebral segment. Twenty-six studies were included, contributing 32 IVD spaces. The presence of IVD mineralization and gas in CT, along with the location, shape, and pixel-value of MRI signal intensity in IVD spaces, was recorded. No statistical differences were identified in pixel values between the groups (p = 0.5). However, there were significant changes in the location of the signal void compared to the recorded location in CT, particularly in VP (p = 0.03). These results emphasize that MRI T2 signal voids in canine IVDs may represent gas. No specific MRI characteristics allowed reliable prioritization of VP versus mineralization; therefore, both should be considered differential diagnoses when encountering intradiskal signal voids on MRI.

Equine sarcoidosis is an uncommon disease characterized by granulomatous inflammation presenting in a spectrum of body system involvement and severity. Musculoskeletal manifestations are sporadically reported but without correlation between imaging and pathologic findings. In a mature Quarter Horse mare eventually diagnosed with a progressive form of sarcoidosis, phalangeal osteolysis discovered on radiography prompted further evaluation, revealing diffuse, discrete osteolysis throughout the axial skeleton. Due to disease progression, humane euthanasia was elected, and computed tomography and histopathology were performed. Regions of osteolysis correlated to sites of granulomatous inflammation, providing a novel and possibly underestimated feature of equine sarcoidosis.

A 9-year-old neutered male miniature schnauzer was referred to our facility with polyuria, polydipsia, persistent hypercalcemia, hypophosphatemia, and elevated parathyroid hormone-related protein. Dual-energy computed tomography (DECT) imaging revealed a mass in the left anal gland (LAG) and enlargement of the left medial iliac lymph node (LML) and the left internal iliac lymph node (LIL). The mass was surgically removed, and the histopathological diagnosis was anal sac gland adenocarcinoma, with metastasis to the LML and LIL. The pathological findings were concordant with those obtained from our evaluation of the spectral Hounsfield unit curve and iodine concentration DECT imaging. DECT analysis may be useful for identifying metastatic lymph nodes.

Conventionally fractionated (CFRT) radiotherapy (20 × 2.5 Gy) is commonly used in clinical practice for canine pituitary tumors (PTs), yet published data on long-term outcomes and imaging response remain limited. Medical records were retrospectively reviewed for dogs diagnosed with PTs that received definitive-intent radiation therapy (RT) with a planned total dose of 50 Gy in 20 fractions between 2014 and 2022. Prognostic factors, including age, sex, weight, the presence of neurological signs, pituitary-dependent endocrine abnormalities, pituitary size and ratio to brain, and tumor response according to RECIST, were evaluated for association with outcome measures using Cox proportional hazard models. Twenty-nine dogs were included in this multi-institutional study. Follow-up imaging was available for 14 dogs (48.2%); nine (64.3%) achieved partial response, and five (35.7%) had stable disease, including sustained tumor reduction exceeding 3 years in four dogs. Median progression-free survival was 523 days (95% CI, 57-2469 days), and the median all-cause survival time was 669 days (95% CI, 58-2469 days). Estimated 1-, 2-, and 3-year survival rates were 65%, 48%, and 24%, respectively. Hyperadrenocorticism was significantly associated with reduced all-cause survival (p = 0.02). Three dogs were alive at the time of analysis. Acute Grade 1 brain toxicity occurred in four dogs. Hypoadrenocorticism developed in two dogs at 67 and 232 days after RT initiation. One dog developed a presumptive radiation-induced trigeminal nerve sheath tumor 1724 days after RT, suspected to represent late toxicity. CFRT RT, delivered at 50 Gy in 2.5 Gy fractions, provides durable tumor control with few adverse events. Monitoring for post-RT hypoadrenocorticism is warranted.

This report describes a case of peritoneal splenosis in a dog, identified following the discovery of multiple peritoneal nodules on computed tomography (CT) performed for the evaluation of a compressive myelopathy. Histopathologic analysis confirmed the presence of ectopic splenic tissue without evidence of malignancy. In dogs, splenosis results from autotransplantation of splenic tissue within the peritoneal cavity, following splenic injury or surgery. Although most cases are incidental findings, nodule enlargement or rupture may occasionally lead to clinical consequences. This case emphasizes the importance of considering splenosis in the differential diagnosis of peritoneal nodules, particularly when they are not associated with peritoneal effusion and in animals with a history of splenic disease or abdominal trauma.

Ventricular empyema is a rare but severe complication of central nervous system (CNS) infections in dogs, with a poor prognosis due to limited treatment options. A 6-year-old intact female Pomeranian (1.9 kg) presented with acute-onset nonambulatory tetraparesis, spontaneous nystagmus, and head tilt. Hematological analysis revealed leukopenia with neutropenia and elevated C-reactive protein (CRP), suggesting systemic inflammation. MRI showed ventricular dilation with distinct stratified fluid-fluid levels. The dependent material was hypointense on T2-weighted (T2W) images and unsuppressed on T2W FLAIR (fluid-attenuated inversion recovery). It was hyperintense on diffusion-weighted imaging (DWI) and hypointense on apparent diffusion coefficient (ADC) maps, consistent with restricted diffusion. Its position changed with repositioning, suggesting a gravity-dependent nature. Cervical spinal cord MRI revealed a T2W hyperintense, contrast-enhancing intramedullary lesion from C3 to C7. Cerebrospinal fluid (CSF) analysis confirmed severe neutrophilic pleocytosis with numerous bacilli, later identified as Escherichia coli. Despite antibiotic therapy, the patient's condition deteriorated, leading to euthanasia. No extracranial infectious source was identified, supporting hematogenous dissemination as the most plausible route of infection. This is the first reported case of E. coli-induced ventricular empyema in veterinary medicine confirmed via advanced imaging. This report highlights the diagnostic role of DWI/ADC mapping and the novel use of patient repositioning to assess intraventricular material dynamics, underscoring the need for further research into advanced imaging and treatment strategies.

The aim of this study was to describe the normal anatomy of coelomic organs in three different species of chelonians using high-field magnetic resonance imaging (MRI). This study also describes a rapid study protocol to examine chelonians without the use of sedation. A 1.5-T superconducting magnet with volume or surface coils was used for the study. Sixteen healthy turtles belonging to three different species: 3 yellow-bellied sliders (Trachemys scripta scripta), 3 marginated tortoise (Testudo marginata), and 10 Hermann's tortoises (Testudo hermanni) were considered. The images were obtained using the following sequences: T1-weighted (T1W) turbo spin echo (TSE) acquired in the transverse and dorsal planes, T2-weighted (T2W) TSE 3D acquired in the sagittal plane, and short-tau inversion recovery (STIR) in the transverse plane. No contrast medium was used. All studies were feasible, fast, and yielded images of good quality in all the sequences. TSE T2W images had the best signal-to-noise ratio. The scan time was approximately 15-20 min. The majority of the coelomic organs were clearly identified, with the exception of the pancreas, adrenal glands, and ureters. In conclusion, high-field MRI in unsedated chelonians is feasible and fast and yields diagnostic images of the majority of the coelomic organs in all three species evaluated.

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.

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.

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.