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Simple Summary: This study evaluates the optimization of computed tomographic arthrography (CTA) protocols for delineating ligamentous structures and menisci in the stifle joints of dogs. The motivation stems from existing diagnostic challenges, such as inaccuracies in physical and radiographic assessments often observed in conditions like cranial cruciate ligament rupture and meniscal injuries. Various protocols involving different concentrations and volumes of the contrast medium iohexol were tested to determine the most effective method for enhancing visualization of these structures. The findings reveal that a contrast medium concentration of 100 mgI/mL, administered at volumes of 0.3 or 0.4 mL/kg, significantly improves the clarity and detail of imaging, providing a more accurate diagnostic tool for veterinary practitioners. This optimized protocol could significantly enhance clinical outcomes by facilitating more precise diagnosis of joint diseases in dogs. This study aims to establish an optimized CTA protocol for qualitatively evaluating the ligamentous structures and menisci of the canine stifle. CTA of the stifle joint was conducted on six healthy beagle dogs. Each dog underwent a total of nine scans to evaluate various contrast protocols. These protocols involved three different concentrations of iodine (50, 100, and 150 mgI/mL) and three different volumes of contrast media injection (0.2, 0.3, and 0.4 mL/kg). Subsequently, the acquired arthrographic images were qualitatively assessed to determine the visibility of the stifle ligaments. The quantitative evaluation of CTA revealed that the cranial and caudal cruciate ligaments were more clearly visible in groups M2 (100 mgI/mL, 0.3 mL/kg) and M3 (100 mgI/mL, 0.4 mL/kg) in comparison to S1 (50 mgI/mL, 0.2 mL/kg) and L3 (150 mgI/mL, 0.4 mL/kg). The visibility of the medial meniscus was notably lower in S1 and S2 (50 mgI/mL, 0.3 mL/kg), while the lateral meniscus exhibited reduced visibility in S1. Overall, the high contrast settings (M2, M3) generally improved the visualization of the meniscofemoral ligament, meniscotibial ligament, and the intermeniscal ligament. For optimal evaluation of the canine stifle ligament using CTA, it is recommended to use 100 mgI/mL iodine at a dosage of 0.3 mL/kg or 0.4 mL/kg. [ABSTRACT FROM AUTHOR]

Background: Bone‐subtraction computed tomography angiography (CTA) (BSCTA) is a new technique designed to overcome the limitation of three‐dimensional CTA, where the vessels surrounded by bone and calcification can be obscured. An optimal contrast CT protocol for intracranial artery visualization with BSCTA has yet to be established in dogs. Objectives: The purpose of this study was to determine the optimal contrast protocol of CTA for visualizing intracranial artery using an automatic bone‐subtraction technique in dogs. Methods: Brain CTA was performed four times for each of nine healthy beagle dogs to cover all the contrast protocols: two different contrast iodine concentrations (300 and 370 mgI/mL) and two different contrast media injection rates (2 and 4 mL/s). Bone removal post‐processing was performed automatically by subtracting the non‐enhanced CT data from the contrast CT data using a dedicated workstation. The bone‐subtracted intracranial vessels were analysed for quantitative and qualitative evaluation. Results: Quantitative evaluation showed significantly higher CT attenuation values for the group with a 370 mgI/mL iodine content at a rate of 4 mL/s than the two groups with a 300 mgI/mL iodine content at the rates of 2 and 4 mL/s (p < 0.001). Qualitative assessment revealed significantly higher mean scores for the 370 mgI/mL groups than the 300 mgI/mL groups and significantly higher mean scores for the 4 mL/s groups than the 2 mL/s groups (p < 0.05). Conclusions: The optimal contrast protocol for BSCTA suggests that high iodine material concentration and high injection rate should be used for strong arterial attenuation and great visualization of the intracranial arterial structure in dogs. [ABSTRACT FROM AUTHOR]

Simple Summary: Cerebral perfusion provides important information about capillary-level hemodynamics of the brain parenchyma, especially in conditions such as an ischemic stroke, brain tumors, and inflammation. The assessment of brain perfusion in dogs has been performed using computed tomography (CT), magnetic resonance (MR), sonography, single-photon emission computed tomography (SPECT), and 2-fluoro-2-deoxy-D-glucose positron emission tomography. However, these methods, except for CT, have limitations and difficulties in obtaining quantitative values. In addition, some of them are cost-prohibitive, particularly SPECT and MR imaging. CT scanners are widely available in clinical hospitals, making CT-based perfusion techniques more accessible for studies. The purpose of this study was to investigate the normal range of perfusion determined via CT in the brains of healthy dogs and to compare values between white matter and gray matter, differences in aging, and each hemisphere. The results of our study showed that the cerebral blood volume and cerebral blood flow values of white matter in the frontal, temporal, parietal, and occipital lobes were significantly lower than gray matter values. No significant differences were observed in the age-related variations or between the left and right hemispheres in other brain regions. In addition, quantitative values of CT perfusion parameters in a specific brain region were presented. This information provided by our study might contribute to a better understanding of brain perfusion in healthy dogs, potentially leading to the earlier diagnosis and improved treatment of brain diseases. Brain computed tomography (CT) perfusion is a technique that allows for the fast evaluation of cerebral hemodynamics. However, quantitative studies of brain CT perfusion in veterinary medicine are lacking. The purpose of this study was to investigate the normal range of perfusion determined via CT in brains of healthy dogs and to compare values between white matter and gray matter, differences in aging, and each hemisphere. Nine intact male beagle dogs were prospectively examined using dynamic CT scanning and post-processing for brain perfusion. Regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), mean transit time, and time to peak were calculated. Tissue ROIs were drawn in the gray matter and white matter of the frontal, temporal, parietal, and occipital lobes; caudate nucleus; thalamus; piriform lobe; hippocampus; and cerebellum. Significant differences were observed between the white matter regions and gray matter regions for rCBV and rCBF (p < 0.05). However, no significant differences were identified between hemispheres and between young and old groups in brain regions. The findings obtained in this study involving healthy beagle dogs might serve as a reference for regional CT perfusion values in specific brain regions. These results may aid in the characterization of various brain diseases in dogs. [ABSTRACT FROM AUTHOR]

Background: Combination therapy with glucocorticoids and adjunctive immunomodulating drugs has been generally accepted as a standard treatment regimen for meningoencephalomyelitis of unknown etiology (MUE). We hypothesized that treatment with MMF as an adjunctive agent along with glucocorticoids would be effective and well-tolerated protocol in dogs with MUE. Eighty-six dogs with MUE between May 2009 and June 2017 were included (59 females and 27 males; mean age of 5.93 years; mean body weight of 3.83 kg). The medical records of dogs with MUE treated with prednisolone and MMF were retrospectively evaluated to determine the therapeutic response, survival time, and treatment-related adverse effects. Results: A partial or complete response (CR) was recorded for 75 dogs. The overall median survival time from the initiation of treatment was 558 days. Dogs that showed CR with no relapse over the treatment period (from diagnosis to death) had significantly longer median survival times. A significantly higher mortality hazard ratio of 4.546 was recorded in dogs that failed to achieve CR. The interval between the onset of clinical signs and the clinical presentation was not significantly associated with CR, relapse rate, and survival time. Adverse effects included gastrointestinal upsets in 26 dogs (30.23%), sporadic infections in 17 dogs (19.77%), and pancreatitis in seven dogs (8.14%). Conclusions: The results suggest that adjunctive MMF treatment for MUE is safe and comparable to other immunosuppressive protocols. The treatment should focus on the achievement of CR and preventing relapse for successful management. [ABSTRACT FROM AUTHOR]