Feline SCCs of the Head and Neck Display Partial Epithelial-Mesenchymal Transition and Harbor Stem Cell-like Cancer Cells.

Squamous cell carcinoma of the head and neck (HNSCC) is a malignant cancer disease in humans and animals. There is ample evidence that the high plasticity of cancer cells, i.e., their ability to switch from an epithelial to a mesenchymal, endothelial, and stem cell-like phenotype, chiefly contributes to progression, metastasis, and multidrug resistance of human HNSCCs. In feline HNSCC, the field of cancer cell plasticity is still unexplored. In this study, fourteen feline HNSCCs with a known feline papillomavirus (FPV) infection status were subjected to histopathological grading and subsequent screening for expression of epithelial, mesenchymal, and stem cell markers by immunohistochemistry (IHC) and immunofluorescence staining (IF). Irrespective of the FPV infection status, all tumors except one corresponded to high-grade, invasive lesions and concurrently expressed epithelial (keratins, E-cadherin, ß-catenin) and mesenchymal (vimentin, N-cadherin, CD146) proteins. This finding is indicative for partial epithelial-mesenchymal transition (pEMT) events in the lesions, as similarly described for human HNSCCs. IF double staining revealed the presence of CD44/CD271 double-positive cells notably within the tumors' invasive fronts that likely correspond to cancer stem cells. Taken together, the obtained findings suggest that feline HNSCCs closely resemble their human counterparts with respect to tumor cell plasticity.

Flipped Classroom to Facilitate Deeper Learning in Veterinary Undergraduate Students: An Educational Change Pilot Study Limited to the Imaging Module Bones.

In a flipped classroom, learners study at home and do the 'homework' in class. This approach respects the limitations of memory and allows more interaction between learners. The overall vision is self-paced activities for learners with decreased boredom and greater task value, which should facilitate deeper learning. To implement a flipped classroom, a bumpy incremental change process characterized by periods of relative stillness punctuated by the acceleration of pace was planned. All veterinary undergraduate students used an existing eLearning platform to access relevant text and selected image examples before class. Only for the randomly selected students in the flipped classroom (FC) was this content amended with purposeful audio content and concrete tasks. Further, FC learners discussed their opinions in an online class forum. To measure the educational change, a pre- and post-class formative test and a standardized questionnaire for students in the FC versus in the traditional classroom (TC) were performed. To assess engagement, students were invited to measure all learning activities, categorized into attendance, or self-study. The educational change project resulted in more commitment and less resistance from teachers. The FC consisted of 20 students, while the TC had 40. The mean pre-class scores difference between FC students and TC students was +1.7/20 points, and the mean post-class scores difference was +3/20 points. The chance of answering item 10 of the formative test (describe site of the fracture) correctly was about seven times higher for FC compared to TC learners (OR = 6.96; p = 0.002). The questionnaire revealed more satisfaction and greater task value in the FC compared to TC (p = 0.048). FC students invested 21 h into the course on average, while TC students invested 16 h. The results of this pilot agree with previous reports: A transparent process was helpful to initiate mainly positive interactions between teachers and students. Higher scores, higher chance to give the correct answer, greater task value, and more positive emotions are observed in the FC compared to the TC. Higher measures of learning time are not expected to affect exam results but indicate more engagement.

Radiographic Diagnosis of Hip Laxity in Rottweilers: Interobserver Agreement at Eight- and Twelve-Months of Age.

Hip laxity is one of the predisposing factors of canine hip dysplasia. The early diagnosis of hip laxity allows veterinarians to prevent the participation of dysplastic dogs in breeding programs, which could lower the disease's prevalence due to its genetic background. Furthermore, it allows them to plan preventive/therapeutic procedures for mild/near-normal hips to reduce the symptoms of the disease at older ages. A reliable screening program must be repeatable and reproducible, and intra- and inter-observer studies can help us to determine the best methods. In this study, we aimed to evaluate the radiographic parameters used for the early diagnosis of hip dysplasia in Rottweilers at 8 and 12 months of age with five observers to assess the interobserver agreements. According to our findings, there were high interobserver agreements at both ages for the quantitative values, such as the center edge angle (CEA), dorsal acetabular rim slope (DARS), distraction index (DI), and Norberg angle (NA), whereas we recorded from poor to moderate agreements for the qualitative values, such as the grading of the dorsal acetabular rim (GDAR), grading of the degenerative joint disease (GDJD), location of the center of the femoral head (LCFH), and sclerosis of the cranial acetabular rim (SCAR).

Measuring Time Load Using a Mobile Application to Monitor Curriculum Workload.

Insuffient time for learning activities makes learning very difficult. Weaker students need more time to appropriately manage their learning objectives. To ensure enough study time, curriculum designers must monitor potential mismatches between needed versus provided study time. This study was conducted to measure students' time loads and compare them to the workload determined by the curriculum and measured in European Credit Transfer and Accumulation System (ECTS) credits. Time load entry using the Studo mobile application consisted of entering the time required for all learning activities, categorized into attendance, self-study, and writing student papers, per course. In addition to time load measures, socio-demographic information on travel time, care obligations, and employment status was recorded. Over six semesters (2018/2019-2021), the average response rate per semester was low (8%-17%). Of the 75 piloted courses (4-16 per semester), 2 exceeded the number of hours specified in the curriculum. Regarding socio-demographic data, 3%-34% of the evaluated students worked part time (≥ 10 hours per week). In summary, students were disinclined to measure their learning time. With consideration of potential nonresponse bias, no significant evidence of curriculum workload exceedance was found for the evaluated courses at the University of Veterinary Medicine, Vienna. However, some students are under increased individual time pressure due to part-time employment. The ratio of measured to estimated time should be monitored as a key component to improve performance and enhance student learning.

Abstrakt Lernprozesse können nicht optimal gesteuert werden, wenn dafür zu wenig Zeit zur Verfügung steht. Insbesondere schwächere Studierende benötigen mehr Zeit. Um sicherzustellen, dass Studierenden ausreichend Lernzeit zur Verfügung steht, müssen Curriculumgestalter∗innen mögliche Diskrepanzen zwischen benötigter und bereitgestellter Lernzeit überwachen. Diese Studie wurde durchgeführt, um die tatsächliche Zeitbelastung von Studierenden (Timeload) zu dokumentieren und sie mit der durch das Curriculum festgelegten Arbeitsbelastung (Workload), gemessen in Anrechnungspunkten des European Credit Transfer and Accumulation Systems (ECTS), zu vergleichen. Die unterschiedlichen Lernzeiten wurden mit Hilfe der mobilen Anwendung Studo eingegeben und setzen sich aus den Zeitaufwänden für Anwesenheit, Selbststudium und Verfassen von wissenschaftlichen Arbeiten pro Lehrveranstaltung zusammen. Neben den Lernzeiten wurden in der Applikation zusätzlich soziodemographische Angaben zu Betreuungspflichten, Beschäftigungsausmaß und Anfahrtszeiten erfasst. Die durchschnittliche Rücklaufquote pro Semester betrug zwischen 2017/18 und 2021 (6 Semester) 8% bis 17%. Von 75 erfassten Lehrveranstaltungen (4 bis 16 pro Semester) wurde die im Curriculum festgelegte Arbeitsbelastung in zwei überschritten. Bezogen auf die soziodemographischen Daten arbeiteten 3% bis 34% der Studierenden laut Auswertung in Teilzeit (≥ 10 Stunden pro Woche). Zusammenfassend waren die Studierenden zurückhaltend, ihre Lernzeit zu erfassen. Unter Berücksichtigung einer möglichen Schweigeverzerrung durch Antwortausfälle wurden für die evaluierten Lehrveranstaltungen an der Veterinärmedizinischen Universität Wien keine Hinweise auf eine Überschreitung der im Curriculum festgelegten Arbeitsbelastung gefunden. Einige Studierende stehen jedoch aufgrund von Teilzeitbeschäftigung unter erhöhtem individuellen Zeitdruck. Das Verhältnis von gemessener (Timeload) zu geschätzter Zeit (Workload) sollte als qualitativer Indikator für Studierbarkeit überwacht werden, um die Leistung und die Lernsituation der Studierenden zu verbessern.

Inter-Observer Agreement in Radiographic Diagnosis of Coxofemoral Joint Disease in a Closed Cohort of Four-Month-Old Rottweilers.

Canine hip dysplasia is a complex and multifactorial disease. The early diagnosis of dysplastic dogs under one year of age helps veterinarians to plan proper preventive/therapeutic methods. Having an accurate screening method increases the chance of the early detection of dysplasia. The goal of our study was to assess the inter-observer reliability of eight radiographic parameters in four-month-old Rottweilers. Radiographs of the 28 Rottweilers were investigated by five experienced observers. The radiographs were taken in ventrodorsal view with extended legs, frog-leg ventrodorsal view, distraction view, and dorsal acetabular rim view. Four quantitative parameters such as Norberg angle (NA), distraction index (DI), dorsal acetabular rim slope (DARS), and center edge angle (CEA) and four qualitative parameters such as sclerosis of the cranial acetabular rim (SCAR), location of the center of the femoral head (LCFH), grading of the degenerative joint disease (GDJD), and grading of the dorsal acetabular rim (GDAR) were evaluated. High inter-observer agreements were recorded for quantitative values, whereas the inter-observer agreement of the qualitative parameters was low. It can be deduced that the evaluated quantitative parameters are reliable, and a combination of these methods with clinical examinations might increase the accuracy of the examinations.

Tumor Cell Plasticity in Equine Papillomavirus-Positive Versus-Negative Squamous Cell Carcinoma of the Head and Neck.

Squamous cell carcinoma of the head and neck (HNSCC) is a common malignant tumor in humans and animals. In humans, papillomavirus (PV)-induced HNSCCs have a better prognosis than papillomavirus-unrelated HNSCCs. The ability of tumor cells to switch from epithelial to mesenchymal, endothelial, or therapy-resistant stem-cell-like phenotypes promotes disease progression and metastasis. In equine HNSCC, PV-association and tumor cell phenotype switching are poorly understood. We screened 49 equine HNSCCs for equine PV (EcPV) type 2, 3 and 5 infection. Subsequently, PV-positive versus -negative lesions were analyzed for expression of selected epithelial (keratins, ß-catenin), mesenchymal (vimentin), endothelial (COX-2), and stem-cell markers (CD271, CD44) by immunohistochemistry (IHC) and immunofluorescence (IF; keratins/vimentin, CD44/CD271 double-staining) to address tumor cell plasticity in relation to PV infection. Only EcPV2 PCR scored positive for 11/49 equine HNSCCs. IHC and IF from 11 EcPV2-positive and 11 EcPV2-negative tumors revealed epithelial-to-mesenchymal transition events, with vimentin-positive cells ranging between <10 and >50%. CD44- and CD271-staining disclosed the intralesional presence of infiltrative tumor cell fronts and double-positive tumor cell subsets independently of the PV infection status. Our findings are indicative of (partial) epithelial-mesenchymal transition events giving rise to hybrid epithelial/mesenchymal and stem-cell-like tumor cell phenotypes in equine HNSCCs and suggest CD44 and CD271 as potential malignancy markers that merit to be further explored in the horse.

Does intravenous contrast medium administration result in altered renal biomarkers? A study in clinically stable cats with and without azotemia.

OBJECTIVES: The aim of this study was to determine the prevalence of post-contrast acute kidney injury or comparable side effects on kidney function in cats receiving the non-ionic, iodinated agent ioversol and/or paramagnetic agent gadoteric acid. METHODS: Fifty-two animals were divided into four groups on the basis of contrast medium administration for imaging: ioversol (n = 27), gadoteric acid (n = 12), dual contrast media (n = 4) or control, which received an infusion of isotone intravenous fluids only during anaesthesia (n = 9). Blood and urine samples were obtained three times after contrast administration and compared with values obtained prior to administration of the contrast medium. Creatinine (<1.60 mg/dl), symmetric dimethylarginine (SDMA; ⩽14 µg/dl), urine protein:creatinine ratio (UPC; <0.2) and critical differences for creatinine (<0.3 mg/dl) and SDMA (<5.98 µg/dl) were measured. RESULTS: No significant short-term effects on mean creatinine, SDMA and UPC measurements were seen. Borderline proteinuria (UPC, 0.2-0.4) was detected in 11.4% of cases after contrast media administration. A UPC of more than 0.2 in five cases indicated that contrast media may affect kidney function, leading to (transient) proteinuria. CONCLUSIONS AND RELEVANCE: This study found no side effect on renal function following the administration of ioversol or gadoteric acid, provided patients were adequately hydrated. However, the clinical relevance of proteinuria in some cats needs to be evaluated in future studies.

Correlated Imaging of the Equine Hyoid Apparatus Using CT, Micro-CT, and Histology.

Background: Detailed radiological evaluation of the normal hyoid apparatus by computed tomography (CT) has not yet been conducted. Thus, it is unclear what type of junction connects the different parts of the equine hyoid apparatus. Objectives: To describe the normal CT anatomy of the equine hyoid apparatus, and to determine the junction type that connects the different parts of the hyoid apparatus. Study Design: Combination of retrospective study and prospective cadaver study. Methods: The medical records of horses that underwent head CT scans from 2009 to 2018 were retrieved. Inclusion criteria for the CT scans were visibility of at least two of the four junctions of the hyoid apparatus. CT images were analyzed in three different planes. Additionally, 10 cadaver heads were processed using CT, micro-CT of selected joints, and histology of all joints. Results: CT scans of 200 horses fulfilled the inclusion criteria. The tympanohyoid cartilage consisted of hyaline cartilage. Areas of mineralization within the cartilage were visible on CT scans as early as 2 years of age. The epihyoid was not fused with the stylohyoid in one-third of the horses. All horses younger than 2.5 years showed three ossification centers of the basihyoid, and all horses younger than 1.5 years had a non-fullydeveloped lingual process. In total, 10 of 11 horses between 1.5 and 3 years had separate ossification centers of the lingual process. We found a synchondrosis between the styloid process and the stylohyoid bone. The basihyoid and thyrohyoid, as well as the stylohyoid and epiyhoid were connected by a synostosis in two-thirds of the horses. The remaining parts were connected to one another by synovial joints. Main limitations: The junctions studied by histologic examination were from older horses, therefore growing patterns of different bones could not be totally clarified. Conclusion: The temporohyoid joint is a synchondrosis. The epihyoid is an ossification center of the stylohyoid and fuses with the stylohyoid in two-thirds of horses. The lingual process has a separate ossification center.

Computed Tomographic and Histopathological Characteristics of 13 Equine and 10 Feline Oral and Sinonasal Squamous Cell Carcinomas.

Squamous cell carcinoma (SCC) is the most common equine sinonasal and feline oral tumour. This study aimed to describe the computed tomographic and histopathological characteristics of equine and feline SCC. Thirteen horses and 10 cats that had been histopathologically diagnosed with oral or sinonasal SCC and had undergone computed tomography (CT) of the head were retrospectively included in the study. CT characteristics of the mass and involved structures were noted. Histological examinations were evaluated according to a human malignancy grading system for oral SCC, which considered four grades of increasing aggressiveness. In horses, the masses were at the levels of the paranasal sinuses (n = 8), mandible (n = 3), tongue (n = 1), and nasal cavity (n = 1). In cats, the masses were at the levels of the maxilla (n = 4), mandible (n = 3), tongue (n = 1), and buccal region (n = 1) and were diffusely distributed (facial and cranial bones; n = 1). Masses in the equine paranasal sinuses showed only mild, solid/laminar, periosteal reactions with variable cortical destruction. However, maxillary lesions in cats showed severe cortical destruction and irregular, amorphous/pumice stone-like, periosteal reactions. CT revealed different SCC phenotypes that were unrelated to the histological grade. For morphologic parameters of the tumour cell population, a variability for the degree of keratinization and number of mitotic cells was noted in horses and cats. Concerning the tumour-host relationship a marked, extensive and deep invasion into the bone in the majority of horses and cats was seen. Most cases in both the horses and cats were categorized as histological grade III (n = 8); four horses and one cat were categorized as grade IV, and one horse and one cat were categorized as grade II. In this study, we examined the diagnostic images and corresponding applied human histopathological grading of SCC to further elucidate the correlations between pathology and oral and sinonasal SCC imaging in horses and cats.

Delineation of the Feline Hippocampal Formation: A Comparison of Magnetic Resonance Images With Anatomic Slices.

The hippocampal formation (HF) is a relevant brain structure that is involved in several neurological and psychiatric diseases. In cats, structural changes of the HF are associated with epilepsy. The knowledge of a detailed anatomy of this brain region may lead to the accurate diagnosis and development of better therapies. There are, however, discrepancies among the research findings, which may be due to different definitions being used, according to anatomical guidelines and boundaries, as well as different magnetic resonance (MR) protocols. The aim of this study is to evaluate the anatomical borders of the HF on transverse MR images and the correlated anatomic sections in three cats. The boundaries of the HF were mostly visible in the formalin fixed anatomic sections, except in the areas where the hippocampus proper exchanges into the subicular complex. Also, the delineation of the anteroventral part and the latero-caudal borders of the HF were not clearly defined. Based on our preliminary results these problems are reinforced on MR images, and further histological and anatomical research must be done to find a way to delineate these neurological structures accurately.

Femoral and tibial alignments in chihuahuas with patellar luxation by radiograph: Angular values and intra- and inter-observer agreement of measurements.

Measurement of fore and pelvic limb alignment in veterinary orthopedics is significant, as it is in human medicine. The establishment of reference ranges for alignments and comparing measured ranges in diseased animals to these reference values would allow veterinarians to specify the quantitative degree of an angular deformity, plan suitable treatments and evaluate treatment outcomes. Patellar luxation is a common orthopedic disease in small animal clinics. Severe grades of MPL may present with bone deformities or abnormal alignments; therefore, evaluation of the measurement methods of femoral and tibial alignment in dogs with different grades of patellar luxation to assess the accuracy and reliability of the measurements could be useful. In this retrospective study radiographs of 21 client-owned Chihuahuas that had been presented to the Small Animal Surgery of Vetmeduni Vienna from 2012-2016 with a diagnose of patellar luxation were selected. The measurements were performed on frontal, lateral and axial view radiographs to determine the femoral and tibial angles and to evaluate the intra- and inter-observer variabilities of the protocol. Radiographs of each dog were investigated by three observers. Intra-observer variability was based on measurements by each observer who repeated the protocol two times to evaluate repeatability. Inter-observer variability was based on the measurements between the three observers to evaluate the reproducibility of the protocol. The results of the study showed that 92.85% of inter-observer ICC (intra-class correlation coefficient) had high correlation, and the remaining 7.15% had good correlation. Intra-observer ICCs for measurements of the first observer were 28.57% high correlation and 50% good correlation. For the second observer, 100% high correlation was recorded, and for the third observer 71.42% high correlation and 14.28% good correlation was recorded. These results show that the selected methods have high correlation and could be used as a reliable method in veterinary orthopedics.

Evaluation of a novel, patient-mounted system for CT-guided needle navigation-an ex vivo study.

PURPOSE: To describe the features of a novel patient-mounted system for CT-guided needle navigation, the Puncture Cube System (PCS), and to evaluate the accuracy and efficiency of the PCS by (a) applying numerical simulations and (b) by conducting punctures using the system in comparison to punctures using the free-hand method (FHM). METHODS: The PCS consists of a self-adhesive cube that is attached to the patient, with multiple through-holes in the upper and lower template plate and dedicated software that, using a computer vision algorithm, recognizes the cube in a planning scan. The target in the image dataset is connected by a line, here "virtual needle," which passes through the cube. For any chosen path of the virtual needle, the entry points for the needle into the cube are displayed by the software for the upper and lower template on-the-fly. The possible exactness of the system was investigated by using numerical simulations. Next, 72 punctures were performed by 6 interventionists using a phantom to compare for accuracy, time requirement, and number of CT scans for punctures with the system to the FHM ex vivo (phantom study). RESULTS: The theoretical precision to arrive at targets increased with the distance of the target but remained low. The mean error for targets up to 20 cm below the lower plate was computed to be well below 0.5 mm, and the worst-case error stayed below 1.3 mm. Compared to a conventional free-hand procedure, the use of the navigation system resulted in a statistically significantly improved accuracy (3.4 mm ± 2.3 mm versus FHM 4.9 mm ± 3.2 mm) and overall lower intervention time (168 s ± 28.5 s versus FHM 200 s ± 44.8 s). Furthermore, the number of CT scans was reduced to 2.3 versus FHM 2.8). CONCLUSION: The PCS is a promising technique to improve accuracy and reduce intervention time in CT-guided needle navigations compared to the FHM.

IMAGING DIAGNOSIS-RADIOGRAPHY AND COMPUTED TOMOGRAPHY OF RADIOULNAR ISCHEMIC NECROSIS IN A JACK RUSSELL TERRIER.

A 7-year-old Jack Russell Terrier with a history of minor trauma was presented for lameness of the left forelimb. Radiography and computed tomography demonstrated a localized radioulnar osteolytic lesion with cortical bone loss and enthesiophytes. Based on results of diagnostic imaging and histopathological examination, the final diagnosis was radioulnar ischemic necrosis (RUIN), complicated by pathologic fracture. A rare disorder of unknown etiology, RUIN may be secondary to tearing of the interosseous ligament and potential ischemia. It should be differentiated from neoplastic or fungal disease. To the authors´ knowledge, this is the first canine case report describing RUIN.

Selective Limbic Blood-Brain Barrier Breakdown in a Feline Model of Limbic Encephalitis with LGI1 Antibodies.

Human leucine-rich glioma-inactivated protein 1 encephalitis (LGI1) is an autoimmune limbic encephalitis in which serum and cerebrospinal fluid contain antibodies targeting LGI1, a protein of the voltage gated potassium channel (VGKC) complex. Recently, we showed that a feline model of limbic encephalitis with LGI1 antibodies, called feline complex partial seizures with orofacial involvement (FEPSO), is highly comparable to human LGI1 encephalitis. In human LGI1 encephalitis, neuropathological investigations are difficult because very little material is available. Taking advantage of this natural animal model to study pathological mechanisms will, therefore, contribute to a better understanding of its human counterpart. Here, we present a brain-wide histopathological analysis of FEPSO. We discovered that blood-brain barrier (BBB) leakage was present not only in all regions of the hippocampus but also in other limbic structures such as the subiculum, amygdale, and piriform lobe. However, in other regions, such as the cerebellum, no leakage was observed. In addition, this brain-region-specific immunoglobulin leakage was associated with the breakdown of endothelial tight junctions. Brain areas affected by BBB dysfunction also revealed immunoglobulin and complement deposition as well as neuronal cell death. These neuropathological findings were supported by magnetic resonance imaging showing signal and volume increase in the amygdala and the piriform lobe. Importantly, we could show that BBB disturbance in LGI1 encephalitis does not depend on T cell infiltrates, which were present brain-wide. This finding points toward another, so far unknown, mechanism of opening the BBB. The limbic predilection sites of immunoglobulin antibody leakage into the brain may explain why most patients with LGI1 antibodies have a limbic phenotype even though LGI1, the target protein, is ubiquitously distributed across the central nervous system.

Pneumocystis carinii infection with severe pneumomediastinum and lymph node involvement in a Whippet mixed-breed dog.

A 3.5-y-old Whippet mixed-breed dog was presented with a history of respiratory distress, exercise intolerance, and generalized demodicosis. Hematologic alterations included marked leukocytosis and neutrophilia. Radiographic examination showed a diffuse interstitial and mild peripheral alveolar lung pattern and pneumomediastinum. Because the cytologic examination of the bronchoalveolar aspirate was not diagnostic and a persistent perforation of the upper respiratory tract could not be ruled out, the dog was submitted to thoracoscopy, and subsequently the left cranial lung lobe as well as mediastinal and sternal lymph nodes were resected. Pulmonary pneumocystosis with spread to the thoracic lymph nodes was suspected after histologic investigation of lung and lymph nodes, which was confirmed by in situ hybridization, PCR, and subsequent Sanger sequencing. We document a rare, simultaneous occurrence of severe pulmonary and thoracic lymph node pneumocystosis with spontaneous pneumomediastinum in a dog. Definitive diagnosis was achieved through the use of Grocott methenamine silver staining, in situ hybridization, and PCR.

An experimental animal model for percutaneous procedures used in trigeminal neuralgia.

OBJECT: This study describes an experimental rabbit model that allows the reproduction of percutaneous operations that are used in patients with trigeminal neuralgia (TN). Attention was given to an exact anatomical description of the rabbit's middle cranial fossa as well as the establishment of conditions for a successful procedure. METHODS: Morphometric measurements were taken from 20 rabbit skulls and CT scans. The anatomy of the trigeminal nerve, as well as its surrounding structures, was assessed by bilateral dissection of 13 New Zealand white rabbits (NWR). An ideal approach of placing a needle through the foramen ovale to reach the TG was sought. Validation of correct placement was realized by fluoroscopy and confirmed by dissection. RESULTS: Precise instructions for successful reproduction of percutaneous procedures in NWR were described. According to morphological measurements, for balloon compression of the trigeminal ganglion (TG) the maximal diameter of an introducing cannula is 1.85 mm. The diameter of an empty balloon catheter should not exceed 1.19 mm, and the length of the inflatable part of the balloon can range up to 4 mm. For thermocoagulation the needle electrodes must not exceed an external diameter of 1.39, mm and the length of the non-insolated tip can range up to 4 mm. Glycerol rhizolysis can be achieved because the trigeminal cistern in the NWR is a closed space that allows a long dwelling time (>10 min) of the contrast agent. CONCLUSIONS: An experimental NWR model intended for the reproduction of percutaneous procedures on the TG has been meticulously described. This provides a tool that enables further standardized animal research in the field of surgical treatment of TN.

Magnetic resonance features of the feline hippocampus in epileptic and non-epileptic cats: a blinded, retrospective, multi-observer study.

BACKGROUND: Hippocampal necrosis in cats has been reported to be associated with epileptic seizures. Magnetic resonance imaging (MRI) features of temporal lobe (TL) abnormalities in epileptic cats have been described but MR images from epileptic and non-epileptic individuals have not yet been systematically compared. TL abnormalities are highly variable in shape, size and signal, and therefore may lead to varying evaluations by different specialists. The aim of this study was to investigate whether there were differences in the appearance of the TL between epileptic and non-epileptic cats, and whether there were any relationships between TL abnormalities and seizure semiologies or other clinical findings. We also investigated interobserver agreement among three specialists. METHODS: The MR images of 46 cats were reviewed independently by three observers, who were blinded to patient data, examination findings and the review of the other observers. Images were evaluated using a multiparametric scoring system developed for this study. Mann-Whitney U-tests and chi-square were used to analyse the differences between observers' evaluations. The kappa coefficient (k) and Fleiss' kappa coefficient were used to quantify interobserver agreement. RESULTS: The overall interobserver agreement was moderate to good (k =0.405 to 0.615). The MR scores between epileptic and non-epileptic cats did not differ significantly. However, there was a significant difference between the MR scores of epileptic cats with and without orofacial involvement according to all three observers. Likewise, MR scores of cats with cluster seizures were higher than those of cats without clusters. CONCLUSION: Cats presenting with recurrent epileptic seizures with orofacial involvement are more likely to have hippocampal pathologies, which suggests that TL abnormalities are not merely unspecific epileptic findings, but are associated with a certain type of epilepsy. TL signal alterations are more likely to be detected on FLAIR sequences. In contrast to severe changes in the TL which were described similarly among specialists, mild TL abnormalities may be difficult to interpret, thus leading to different assessments among observers.

COMPUTED TOMOGRAPHIC APPEARANCE OF THE TEMPOROMANDIBULAR JOINT IN 1018 ASYMPTOMATIC HORSES: A MULTI-INSTITUTION STUDY.

Published descriptions of nonseptic arthritis of the equine temporomandibular joint (TMJ) are rare and large studies investigating variations in the TMJ for asymptomatic horses are lacking. The objectives of this cross-sectional, retrospective, multi-institutional study were to describe anatomical variations in the TMJ detected using computed tomography (CT) in an equid population asymptomatic for TMJ disease and determine whether these variations were associated with patient signalment, reason for CT examination, or CT slice width. Medical records at eight hospitals were searched for horses that had head/neck CT scans and no clinical signs of TMJ disease. Age, breed, sex, clinical presentation, and CT slice width data were recorded. Alterations in CT contour and density of the mandibular condyles, mandibular fossae, and TMJ intra-articular discs were described for each horse. Generalized logistic regression was used to test associations between anatomical variations and horse age. A total of 1018 horses were sampled. Anatomical variations were found in TMJ CT images for 40% of horses and 29% of joints. These were dichotomous with regard to age. Horses <1 year old commonly had alterations in the shape and density of the mandibular condyle. Older horses commonly had spherical hypodensities within the mandibular condyles consistent with bone cysts; and hyperdense regions of the intra-articular disc consistent with dystrophic mineralization. Findings indicated that TMJ anatomic variations were common in CT images of younger and older horses asymptomatic for TMJ disease. Future studies are needed to more definitively characterize these CT variations using gross pathology and histopathology.