Iatrogenic air embolism: influence of air bubble size on cerebral infarctions in an experimental in vivo and numerical simulation model.

BACKGROUND: Cerebral infarctions resulting from iatrogenic air embolism (AE), mainly caused by small air bubbles, are a well-known and often overlooked event in endovascular interventions. Despite their significance, the underlying pathophysiology remains largely unclear. METHODS: In 24 rats, AEs were induced using a microcatheter, positioned in the carotid artery via femoral access. Rats were divided into two study groups, based on the size of the bubbles (85 and 120 µm) and two sub-groups, differing in air volume (0.39 and 0.64 µl). Ultra-high-field magnetic resonance imaging (MRI) was performed 1.5 hours after intervention. MRI findings including the number, single volume and total volume of the infarctions were assessed. A software-based numerical simulation was performed to qualitatively assess the microvascular pathomechanisms. RESULTS: In the study groups 22 of 24 rats (92%) revealed cerebral infarctions. The number of infarctions per rat was higher for the smaller bubbles, for the lower (medians: 5 vs 3; p=0.049) and higher air volume sub-groups (medians: 6 vs 4; p=0.012). Correspondingly, total infarction volume was higher for the smaller bubbles (1.67 vs 0.5 mm³; p=0.042). Simulations confirmed the results of the experiments and suggested that fusion of microbubbles to larger bubbles is the underlying pathomechanism of vascular occlusions. CONCLUSION: In iatrogenic AE, the size of the bubbles can have a major impact on the number and total volume of cerebral infarctions. These findings can help to better understand the pathophysiology of this frequent, often underestimated adverse event in endovascular interventions.

Implementation and evaluation of a complex intervention to improve information availability at the interface between inpatient and outpatient care in older patients with multimorbidity and polypharmacy (HYPERION-TransCare) - study protocol for a pilot and feasibility cluster-randomized controlled trial in general practice in Germany.

BACKGROUND: Despite attempts to improve the cross-sectoral flow of information, difficulties remain in routine healthcare. The resulting negative impact on continuity of care is often associated with poor health outcomes, especially in older patients. Our intervention aims to increase information availability with respect to medications and health conditions at the interface between inpatient and outpatient care and to contribute towards improving the quality of care in older patients. This pilot study focuses on feasibility and implementability. METHODS: The idea of the complex intervention has been developed in a previous study. This intervention will be tested in a prospective, multicenter, cluster-randomized (via web tool), controlled pilot trial with two parallel study arms (intervention and control group). The pilot study will be conducted in 20 general practices in Hesse and Saxony (Germany) and include 200 patients (≥ 65 years of age with multimorbidity and polypharmacy) recruited by the practices. Practice staff and patients will be blinded. We will use qualitative and quantitative methods to assess the feasibility and implementability of the intervention and the study design in a process evaluation covering topics ranging from expectations to experiences. In addition, the feasibility of proposed outcome parameters for the future definitive trial will be explored. The composite endpoint will include health-related patient outcomes (hospitalization, falls, and mortality using, e.g., the FIMA questionnaire), and we will assess information on medications (SIMS questionnaire), symptoms and side effects of the medication (pro-CTCAE questionnaire), and health literacy (HLQ questionnaire). Data will be collected at study begin (baseline) and after 6 months. Furthermore, the study will include surveys and interviews with patients, general practitioners, and healthcare assistants. DISCUSSION: The intervention was developed using a participatory approach involving stakeholders and patients. It aims to empower general practice teams as they provide patient-centered care and play a key role in the coordination and continuity of care. We aim to encourage patients to adopt an active role in their health care. Overall, we want to increase the availability of health-related information for patients and healthcare providers. The results of the pilot study will be used in the design and implementation of the future definitive trial. TRIAL REGISTRATION: The study was registered in DRKS-German Clinical Trials Register: registration number DRKS00027649 (date: 19 January 2022). Date and version identifier 10.07.2023; Version 1.3.

Hepatic passaging of NRAS-mutant melanoma influences adhesive properties and metastatic pattern.

BACKGROUND: Liver metastasis is a poor prognostic factor for treatment of advanced cutaneous melanoma with either immunotherapy or targeted therapies. In this study we focused on NRAS mutated melanoma, a cohort with high unmet clinical need. METHODS: WT31 melanoma was repeatedly passaged over the liver after intravenous injections five times generating the subline WT31_P5IV. The colonization of target organs, morphology, vascularization and the gene expression profiles of metastases were analyzed. RESULTS: After intravenous injection lung metastasis was significantly decreased and a trend towards increased liver metastasis was detected for WT31_P5IV as compared to parental WT31. Besides, the ratio of lung to liver metastases was significantly smaller. Histology of lung metastases revealed reduced proliferation of WT31_P5IV in relation to WT31 while both size and necrotic areas were unaltered. Liver metastases of both sublines showed no differences in vascularization, proliferation or necrosis. To identify tumor-intrinsic factors that altered the metastatic pattern of WT31_P5IV RNA sequencing was performed and revealed a differential regulation of pathways involved in cell adhesion. Ex vivo fluorescence imaging confirmed that initial tumor cell retention in the lungs was significantly reduced in WT31_P5IV in comparison to WT31. CONCLUSION: This study demonstrates that tumor-intrinsic properties influencing the metastatic pattern of NRAS mutated melanoma are strongly affected by hepatic passaging and the hematogenous route tumor cells take. It has implications for the clinical setting as such effects might also occur during metastatic spread or disease progression in melanoma patients.

Whole-body diffusion magnetic resonance imaging with simultaneous multi-slice excitation in children and adolescents.

BACKGROUND: Whole-body magnetic resonance imaging (WB-MRI) is an increasingly used guideline-based imaging modality for oncological and non-oncological pathologies during childhood and adolescence. While diffusion-weighted imaging (DWI), a part of WB-MRI, enhances image interpretation and improves sensitivity, it also requires the longest acquisition time during a typical WB-MRI scan protocol. Interleaved short tau inversion recovery (STIR) DWI with simultaneous multi-slice (SMS) acquisition is an effective way to speed up examinations. OBJECTIVE: In this study of children and adolescents, we compared the acquisition time, image quality, signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) values of an interleaved STIR SMS-DWI sequence with a standard non-accelerated DWI sequence for WB-MRI. MATERIALS AND METHODS: Twenty children and adolescents (mean age: 13.9 years) who received two WB-MRI scans at a maximum interval of 18 months, consisting of either standard DWI or SMS-DWI MRI, respectively, were included. For quantitative evaluation, the signal-to-noise ratio (SNR) was determined for b800 images and ADC maps of seven anatomical regions. Image quality evaluation was independently performed by two experienced paediatric radiologists using a 5-point Likert scale. The measurement time per slice stack, pause between measurements including shim and total measurement time of DWI for standard DWI and SMS-DWI were extracted directly from the scan data. RESULTS: When including the shim duration, the acquisition time for SMS-DWI was 43% faster than for standard DWI. Qualitatively, the scores of SMS-DWI were higher in six locations in the b800 images and four locations in the ADC maps. There was substantial agreement between both readers, with a Cohen's kappa of 0.75. Quantitatively, the SNR in the b800 images and the ADC maps did not differ significantly from one another. CONCLUSION: Whole body-MRI with SMS-DWI provided equivalent image quality and reduced the acquisition time almost by half compared to the standard WB-DWI protocol.

The Role of Femoral Head Size and Femoral Head Coverage in Dogs with and without Hip Dysplasia.

The subject of hip dysplasia in dogs is still current and preoccupies both animal owners and veterinarians. Major factors affecting the development of the disorder are hip laxity and incongruent joints. Many studies on etiology, pathogenesis, and early diagnosis have been performed to reduce prevalence and select healthy dogs for breeding. The purpose of the present study was to investigate a possible relationship between dysplasia and femoral head area (FHA), femoral coverage by the acetabulum (CFH) and cranio-caudal distance of the dorsal acetabular rim (CrCdAR). Radiographs of a total of 264 skeletally mature dogs with similar physical characteristics (German wirehaired pointers (GWP), German shepherd dogs (GSD) and Labrador retrievers (LAB)) presented for routine hip dysplasia screening were recruited for the study. FHA, CFH and CrCdAR were measured and related to dysplasia status. Evaluations of FHA (p = 0.011), CFH (p < 0.001) and CrCdAR length (p = 0.003) measurements revealed significant interactions between breed, sex and FCI scores, so they had to be assessed separately. The results revealed that FHA tends to decrease as the hip dysplasia score worsens. There was no significant relationship between FHA and dysplasia assessment. FHA is breed-specific and is larger in normal and near-normal male (p = 0.001, p = 0.020) and female (p = 0.001, p = 0.013) GWP compared to GSD, respectively. FHA is greater in normal male GWP (p = 0.011) and GSD (p = 0.040) compared to females. There was a significant and strong positive correlation between FHA and CrCdAR in all breeds and sexes. Additionally, FCI scoring had a medium (GWP, GSD) to strong (LAB) negative correlation with CFH.

A novel free-breathing abdominal RAVE T2/T1 hybrid MRI sequence in patients with cystic fibrosis: Preliminary results.

OBJECTIVES: Patients with cystic fibrosis (CF) increasingly require imaging for the diagnosis of abdominal complications. We prospectively evaluated the image quality and signal-to-noise ratio (SNR) of a modern radial volumetric encoding (RAVE) T2/T1 hybrid sequence for abdominal magnetic resonance imaging (MRI). RAVET2/T1 is a three-dimensional radial sequence with fat saturation and blood flow suppression that acquires T2- and T1-weighted contrasts in one scan in an identical slice position during free-breathing. METHODS: Sixteen CF patients underwent axial T2 HASTE (1000 ms/93 ms TR/TE), T1 DIXON (6.8 ms/2.4 ms/4.8 ms TR/TE1/TE2), and RAVE T2/T1 hybrid sequence (1200 ms/1.7 ms/3.3 ms/4.9 ms/102 ms TR/TE1/TE2/TE3/TE4) of the upper abdomen at 1.5 Tesla. The SNR values in six different regions were assessed and compared using the Wilcoxon signed-rank test. The image quality criteria were rated on a 5-point Likert scale. RESULTS: In all regions, the SNR was significantly higher in the T2 weighted aspect of the RAVE T2/T1 hybrid sequence compared to T2 HASTE (p < 0.05) and significantly lower in the T1 weighted in-phase aspect of the RAVE T2/T1 hybrid sequence compared to the T1 DIXON sequence (p < 0.05). Qualitatively the T2 weighted aspect of the RAVE T2/T1 hybrid sequence was rated significantly higher than the T2 HASTE in 6 of 7 categories (p < 0.05) and the T1 weighted in-phase aspect of the RAVE T2/T1 hybrid sequence was rated significantly higher than the T1 DIXON in 2 of 6 categories (p < 0.05). CONCLUSIONS: The abdominal radial RAVE T2/T1 hybrid sequence provided higher image quality and SNR than the T2HASTEsequence. Together with increased robustness against motion artifacts, the RAVE T2/T1 hybrid sequence appears to be a good tool for abdominal imaging in CF patients.

MRI Tracking of Iron Oxide Labelled Canine Mesenchymal Stem Cells in Artificial Stifle Defects.

OBJECTIVES: The aim of this study was to describe ultrasmall superparamagnetic iron oxides labelling of canine adipose-derived mesenchymal stem cells (AdMSCs) and the detection and semiquantitative evaluation of the labelled cells after implantation in artificial canine stifle defects using magnetic resonance imaging. METHODS: Magnetic resonance imaging examinations of 10 paired (n = 20) cadaveric stifle joints were evaluated after creation of chondral defects and embedding of ultrasmall superparamagnetic iron oxides labelled canine mesenchymal stem cells. To prove the feasibility of the labelling for in vivo usage, Prussian blue staining, cell vitality tests and intralesional administration of labelled cells were conducted. Magnetic resonance imaging of ex vivo defects filled with different cell concentrations was obtained to depict the cell content semiquantitatively via signal intensity measurements (region of interest). RESULTS: Prussian blue staining showed that the labelling was effective. According to the vitality tests, it had no significant short-term influence on cell viability and proliferation rate. For the evaluation of the defect T2* sequences were feasible and stifle defects were visible allowing measurements of the signal intensity in all cases. Increasing the cell concentration within the chondral defects resulted in an inversely proportional, significant reduction of signal intensity according to the region of interest. CLINICAL SIGNIFICANCE: Ultrasmall superparamagnetic iron oxides labelling was effective. The detection of the AdMSCs in a complex anatomical structure like the surface of the femoral condyle was possible and the T2* signal intensity of the implant region was significantly correlated with the concentration of the AdMSCs.

Characterization of microparticles of iron oxide for magnetic resonance imaging.

Microparticles of iron oxide (MPIOs) are increasingly used for contrast generation in magnetic resonance imaging (MRI). In particular, Dynabeads® MyOne™ Tosylactivated MPIOs have enabled sensitive and targeted molecular imaging, e.g., to detect vascular inflammation. For the first time we measured the relaxivities as well as the molar susceptibility χM of these MPIOs at 7 T in agarose gels. They are r1 = 0.69 ± 0.03 s-1/mM, r2 = 220 ± 6 s-1/mM, r2* = 679 ± 14 s-1/mM, and χM = 0.66 ± 0.05 ppm/mM, when expressed with respect to the iron concentration. These material parameters are essential to optimize MRI protocols and progress toward quantitative imaging. To address the heterogeneous nature of the MPIO distributions over the size of a typical MRI voxel, we coupled the MPIOs to a fluorophore to create a bimodal phantom that can be imaged by both Light Sheet microscopy and MRI. In this phantom, the MPIOs produced contrast similar to that found in vivo . The submicron resolution of Light Sheet microscopy images provided a precise measurement of the MPIO spatial distribution in phantoms also imaged by MRI. MPIO aggregates occupying less than one MRI voxel were responsible for alterations in R2* and magnetic susceptibility χ across several MRI voxels. In these cases, the sum of R2* or χ over the affected MRI volume correlated better with the microscopically determined number of MPIOs. These findings were confirmed with simulations performed in the static dephasing regime. The microscopically determined MPIO distribution was also entered directly into the simulation framework, indicating that the bimodal phantom is a useful tool to test theoretical models against experimental measurements.

A Novel Dipotassium Hydrogen Phosphate Phantom for Calibrating Computed Tomographic Bone Density Measurements in Birds.

The objective of this study was to construct a calibration phantom for bone mineral density (BMD) measurements adapted to avian anatomy by quantitative computed tomography. The determination of BMD is important to assess avian osteoporosis in poultry at production facilities and to study biological features in association with flight patterns in birds. Quantitative computed tomography measured in Hounsfield units is a well-established technique for BMD measurements. Translation of Hounsfield units into the International System of Units (mg/cm3) requires the use of a calibration phantom. Although calibration phantoms for routine use in humans are commercially available, phantoms suited to avian anatomy are not. A liquid dipotassium hydrogen phosphate calibration standard was constructed out of commercially available materials, easily allowing for variations in size, bone diameter, and adaptation to avian skeletal anatomy. Periodically, quantitative computed tomography scans were performed to monitor constant correlation to the calibration standard over 3 months and to monitor for the potential influence of gas bubbling and water evaporation in the rods on BMD measurements. Finally, the calibration phantom was tested for BMD measurements with carcasses from 2 bird species, including 3 peregrine falcons (Falco peregrinus; 2 juvenile males, 1 adult female with inactive reproductive status) and 4 Eurasian kestrels (Falco tinnunculus; 1 juvenile and 2 adult males, 1 adult female with inactive reproductive status). Results demonstrated stability of the calibration phantom without the need to refill or replace rods, plus a stable correlation line (R 2 = .99) over the 3-month evaluation period. It was possible to place the phantom directly on the bird carcasses, close to the measured bones, to improve BMD analysis. As evaluated, the phantom appeared to be adaptive to avian skeletal anatomy. Moreover, it was possible to build the phantom within 24 hours from commercially available materials.

Preliminary results of abdominal simultaneous multi-slice accelerated diffusion-weighted imaging with motion-correction in patients with cystic fibrosis and impaired compliance.

OBJECTIVES: The aim of this prospective study was to compare scan time, image quality, signal-to-noise Ratio (SNR), and apparent diffusion coefficient (ADC) values of simultaneous multi-slice accelerated diffusion-weighted imaging with motion-correction (DWI SMS Moco) to standard diffusion-weighted imaging (sDWI) in free-breathing abdominal magnetic resonance imaging (MRI) in pediatric and young adult patients with cystic fibrosis (CF). MATERIAL AND METHODS: 16 patients (7 male and 9 female, 12-41 years old) with CF were examined prospectively in a single-center from November 2020 to March 2021 on a 1.5 Tesla clinical MR scanner. The characteristics of overall image quality and delimitability of mesenteric lymph nodes were evaluated using a 5-point Likert scale by two experienced pediatric radiologists independently from each other. Quantitative parameters with SNR and ADC values were assessed in 8 different locations and compared using a Wilcoxon signed-rank test. RESULTS: The acquisition time for DWI SMS Moco was 32% shorter than for sDWI. Regarding quality comparison, overall image quality and delimitability of mesenteric lymph nodes were significant higher in DWI SMS Moco (p ≤ 0.05 for both readers). The readers preferred DWI SMS Moco to sDWI in all cases (16/16). Mean SNR values from DWI SMS Moco and sDWI were similar in 7 from 8 locations. The ADC values showed no significant difference between DWI SMS Moco and sDWI in any of the evaluated locations (p > 0.05). CONCLUSIONS: The DWI SMS Moco improves overall image quality and delimitability of mesenteric lymph nodes compared to sDWI with similar SNR and ADC values and a distinguished reduction of scan time in free-breathing by one third. We conclude that MRI with DWI SMS Moco could be helpful in monitoring the effect of the high-efficiency modulator (HEM) therapy in cystic fibrosis (CF) patients homozygous or heterozygous for F508del in the abdomen.

Development of an intervention to improve informational continuity of care in older patients with polypharmacy at the interface between general practice and hospital care: protocol for a participatory qualitative study in Germany.

INTRODUCTION: Older patients with multimorbidity, polypharmacy and related complex care needs represent a growing proportion of the population and a challenge for healthcare systems. Particularly in transitional care (hospital admission and hospital discharge), medical errors, inappropriate treatment, patient concerns and lack of confidence in healthcare are major problems that may arise from a lack of information continuity. The aim of this study is to develop an intervention to improve informational continuity of care at the interface between general practice and hospital care. METHODS AND ANALYSIS: A qualitative approach will be used to develop our participatory intervention. Overall, 32 semistructured interviews with relevant stakeholders will be conducted and analysed. The stakeholders will include healthcare professionals from the outpatient setting (general practitioners, healthcare assistants, ambulatory care nurses) and the inpatient setting (clinical doctors, nurses, pharmacists, clinical information scientists) as well as patients and informal caregivers. At a series of workshops based on the results of the stakeholder analyses, we aim to develop a participatory intervention that will then be implemented in a subsequent pilot study. The same stakeholder groups will be invited for participation in the workshops. ETHICS AND DISSEMINATION: Ethical approval for this study was waived by the Ethics Committee of Goethe University Frankfurt because of the nature of the proposed study. Written informed consent will be obtained from all study participants prior to participation. Results will be tested in a pilot study and disseminated at (inter)national conferences and via publication in peer-reviewed journals. TRIAL REGISTATION NUMBER: Clinical Trials Register: registration number DRKS00027649.

Biomechanical comparison of screw and suture fixation for temporary transarticular tarsocrural immobilization in canine cadavers.

OBJECTIVE: To biomechanically evaluate an ultrahigh-molecular-weight polyethylene (UWMWPE) suture for temporary tarsocrural immobilization as a potential alternative to the existing surgical method, which uses a 4.5 AO/ASIF calcaneotibial cortical screw. STUDY DESIGN: Randomized in vitro biomechanical study. ANIMALS: Pelvic limbs (n = 20) from 10 euthanized adult dogs (average bodyweight of 29.9 kg ± 1.9 kg). METHODS: Tarsocrural joints were immobilized either with a 4.5 AO/ASIF screw or a 1 mm diameter UHMWPE suture. Limbs were loaded with 60 N, 120 N, and 180 N, each for 100 cycles. After cyclic loading, immobilizations were loaded until failure. Load at failure and mode of failure were recorded. RESULTS: Both immobilization methods remained intact during loading with 60 N, 120 N, and 180 N. Mean and standard deviation (± SD) failure loads were higher for the cortical screw (524.9 N ± 148.7 N) than for the UHMWPE suture (387.8 N ± 105.6 N), P = .0084. The stiffness of both systems was equivalent. CONCLUSION: Both techniques were suitable for transarticular tarsocrural immobilization in large-breed canine cadavers. While load at failure was higher for the screw compared to the suture construct, stiffness of both methods was comparable based on the laboratory settings in this in vitro study. CLINICAL SIGNIFICANCE: Based on the results of this study, both the cortical screw and the UHMWPE suture stabilized the tibiotarsal joint at clinically relevant loads. However, when exposed to high loads, the cortical screw provides increased tibiotarsal stability. Comparative data need to be collected prior to widespread use of UHMWPE sutures in clinical cases.

Correlation of brachycephaly grade with level of exophthalmos, reduced airway passages and degree of dental malalignment' in Persian cats.

For many years, there has been a trend to breed cats with an increasing degree of brachycephalic head features, which are known to have a severe impact on the animals' health and welfare. The direct relation between different grades of brachycephaly and their negative implications have not been researched in this species. The aim of this study was therefore to establish correlations between the different grades of brachycephaly and reduced upper respiratory airways, exophthalmos of the eye globes and malalignment of the teeth in Persian cats. Sixty-nine Persian cats of various skull dimensions and ten Domestic shorthair cats were recruited for the study. The cats' skulls were examined using three-dimensional reconstructions created from Computed Tomography datasets. Brachycephaly was graded using established craniometric measurements (facial index, cranial index, skull index, craniofacial angle). The flow area of the nasal passageways at different locations, the amount of the eye globe not supported by the bony orbit and the axial deviation of the teeth were quantified and evaluated for a correlation with the grade of brachycephaly. The results of this study clearly show that increased grades of brachycephaly in Persian cats resulted in larger extra-orbital parts of the ocular bulbs. The brachycephalic skull dimension also resulted in a lower height of the naso-osseal aperture, while other areas of the nasal airways were not correlated with the severity of brachycephaly. Persian cats showed a significantly increased occurrence of premolar tooth displacement in the upper jaw with increasing brachycephaly grades. It was interesting to note that the measured values had a broad range and values of some individual Persian cats showed an overlap with those of Domestic shorthair cats.

Prevalence of seizures in dogs and cats with idiopathic internal hydrocephalus and seizure prevalence after implantation of a ventriculo-peritoneal shunt.

BACKGROUND: Seizures are considered a clinical sign in dogs with internal hydrocephalus but are not found in recent studies. Seizure prevalence due to ventricular enlargement and the prevalence of postoperative seizures in animals is not known. OBJECTIVES: To determine seizure prevalence in dogs and cats with idiopathic internal hydrocephalus, to identify risk factors for seizure development, and to determine seizure prevalence in a 2-year period after ventriculo-peritoneal shunting (VPS). ANIMALS: Records and MRIs of 197 animals from 2001 to December 2019 were investigated. A total of 121 animals (98 dogs and 23 cats) were included in the study. METHODS: A retrospective multicenter case cohort study was conducted. Databases were searched for dogs and cats with internal hydrocephalus. MRI and CSF examinations were evaluated for signs of additional underlying disorders. Prevalence of seizures was estimated for animals showing only hydrocephalus internus. Risk factors were evaluated according to age, morphometric and morphological findings in the brain. All animals that underwent surgery were reexamined 2 years after surgery. RESULTS: One hundred twenty-one animals (98 dogs and 23 cats) with internal hydrocephalus met the inclusion criteria. Seizure prevalence in dogs and cats with internal hydrocephalus was low (1.7%; <5.8% CI 95%). Seizures were not observed in the 2-year period after surgery. CONCLUSION AND CLINICAL IMPORTANCE: Seizure prevalence in dogs and cats diagnosed with hydrocephalus internus is low. Seizures in association with VPS do not seem to be a complication of the procedure.

[Computed tomography based elbow joint morphology and incidence of elbow dysplasia in the red fox (Vulpes vulpes)]. / Computertomografische Morphologie des Ellbogengelenks und Vorkommen der Ellbogengelenkdysplasie beim Rotfuchs (Vulpes vulpes).

OBJECTIVE: Elbow dysplasia (ED) is a common developmental disease of the canine elbow joint and one of the most frequent causes of forelimb lameness in domestic dogs (Canis lupus familiaris). ED is predominantly present in medium to large breed dogs, but has also been described in mixed breed dogs and smaller breeds. In the literature, no information is available concerning the existence of ED in wildlife species. The purpose of the present study was to obtain an overview of the elbow joint anatomy of the red fox as well as to demonstrate the incidence of ED in red foxes. Knowledge regarding the elbow conformation in red foxes may help to understand the effect of anatomical difference onto the pathogenesis of developmental elbow disease. MATERIAL AND METHODS: A total 94 elbow joints of 49 red foxes (Vulpes vulpes) were evaluated using computed tomography (CT) and were compared to canine elbow joints. RESULTS: Apart from size differences and minor species-specific variations, the anatomy of the elbow joints of red foxes and domestic dogs proved to be very similar. In the red foxes, the rounded conformation of the medial coronoid process was shown to be present in 76 % of the individuals. Two elbow joints in 2 red foxes exhibited pathological changes of the medial coronoid process in the CT imaging. CONCLUSION: The prevalence of medial coronoid disease in red foxes amounted to 2.1 % in the presented population. This observation is comparable to the prevalence of elbow dysplasia in small breed dogs. The rounded conformation of the medial coronoid process was found in more than three-quarters of the examined red foxes. This leads to the hypothesis that this conformation of the medial coronoid process could be the original, physiological variant. Selective breeding for such a morphological feature may be an approach to reduce the frequency of canine elbow dysplasia. CLINICAL RELEVANCE: The significance of anatomical characteristics in the development of elbow dysplasia is still unknown. Therefore, research concerning the pathogenesis of medial coronoid disease should set its focus not only on elbow joint anatomy, but also on other influencing factors, such as biomechanics, genetics and environmental parameters.

Longitudinal imaging and evaluation of SAH-associated cerebral large artery vasospasm in mice using micro-CT and angiography.

Longitudinal in vivo imaging studies characterizing subarachnoid hemorrhage (SAH)-induced large artery vasospasm (LAV) in mice are lacking. We developed a SAH-scoring system to assess SAH severity in mice using micro CT and longitudinally analysed LAV by intravenous digital subtraction angiography (i.v. DSA). Thirty female C57Bl/6J-mice (7 sham, 23 SAH) were implanted with central venous ports for repetitive contrast agent administration. SAH was induced by filament perforation. LAV was assessed up to 14 days after induction of SAH by i.v. DSA. SAH-score and neuroscore showed a highly significant positive correlation (rsp = 0.803, p < 0.001). SAH-score and survival showed a negative significant correlation (rsp = -0.71, p < 0.001). LAV peaked between days 3-5 and normalized on days 7-15. Most severe LAV was observed in the internal carotid (Δmax = 30.5%, p < 0.001), anterior cerebral (Δmax = 21.2%, p = 0.014), middle cerebral (Δmax = 28.16%, p < 0.001) and basilar artery (Δmax = 23.49%, p < 0.001). Cerebral perfusion on day 5 correlated negatively with survival time (rPe = -0.54, p = 0.04). Arterial diameter of the left MCA correlated negatively with cerebral perfusion on day 3 (rPe = -0.72, p = 0.005). In addition, pseudoaneurysms arising from the filament perforation site were visualized in three mice using i.v. DSA. Thus, micro-CT and DSA are valuable tools to assess SAH severity and to longitudinally monitor LAV in living mice.

Intraoperative measurement of intraventricular pressure in dogs with communicating internal hydrocephalus.

Collapse of the lateral cerebral ventricles after ventriculo-peritoneal drainage is a fatal complication in dogs with internal hydrocephalus. It occurs due to excessive outflow of cerebrospinal fluid into the peritoneal cavity (overshunting). In most shunt systems, one-way valves with different pressure settings regulate flow into the distal catheter to avoid overshunting. The rationale for the choice of an appropriate opening pressure is a setting at the upper limit of normal intracranial pressure in dogs. However, physiological intraventricular pressure in normal dogs vary between 5 and 12 mm Hg. Furthermore, we hypothesise that intraventricular pressure in hydrocephalic dogs might differ from pressure in normal dogs and we also consider that normotensive hydrocephalus exists in dogs, as in humans. In order to evaluate intraventricular pressure in hydrocephalic dogs, twenty-three client owned dogs with newly diagnosed communicating internal hydrocephalus were examined before implantation of a ventriculo-peritoneal shunt using a single use piezo-resistive strain-gauge sensor (MicroSensor ICP probe). Ventricular volume and brain volume were measured before surgery, based on magnetic resonance images. Total ventricular volume was calculated and expressed in relation to the total volume of the brain, including the cerebrum, cerebellum, and brainstem (ventricle-brain index). Multiple logistic regression analysis was performed to assess the influence of the covariates "age", "gender", "duration of clinical signs", "body weight", and "ventricle-brain index" on intraventricular pressure. The mean cerebrospinal fluid pressure in the hydrocephalic dogs was 8.8 mm Hg (standard deviation 4.22), ranging from 3-18 mm Hg. The covariates "age", (P = 0.782), "gender" (P = 0.162), "body weight", (P = 0.065), or ventricle-brain index (P = 0.27)" were not correlated with intraventricular pressure. The duration of clinical signs before surgery, however, was correlated with intraventricular pressure (P< 0.0001). Dogs with internal hydrocephalus do not necessarily have increased intraventricular pressure. Normotensive communicating hydrocephalus exists in dogs.

Platelet function testing in pigs using the Multiplate® Analyzer.

For endovascular research pigs are an established animal model. However, experiences regarding analyses of platelet inhibition in pigs using the Multiplate® Analyzer are limited. The aims of the present study were to investigate if (1) the Multiplate® Analyzer is a suitable method for examination of porcine platelet function using manufacturers' recommendations for human blood, and (2) platelet inhibition can be induced with acetylsalicylic acid (ASA) and clopidogrel in pigs reliably, and if (3) non-responders to one of the drug can be detected. Additionally we examined differences in (4) the effectiveness of ASA between oral administration and intravenous application, and (5) between domestic pigs (German Landrace; GL) and miniature pigs (MP). We investigated platelet function of 36 unmedicated pigs (GL n = 28; MP n = 8). In addition, 32 blood samples taken from medicated pigs (GL n = 15; MP n = 17) were analysed. Platelet inhibition was induced in four different ways: (1) 500 mg ASA intravenously (n = 11), (2) 500 mg ASA intravenously and 450 mg clopidogrel orally (n = 5), (3) 250 mg ASA orally (n = 11), (4) 250 mg ASA orally and 75 mg clopidogrel orally (n = 5). Results of the ASPI and ADP test of the Multiplate® Analyzer subtests in unmedicated and medicated pigs were in a comparable range to results known from humans. Application of ASA decreased the mean values of the ASPI test significantly regardless of the application method. Joined administration of ASA and clopidogrel also decreased the mean values of the ADP test significantly. Both, oral and intravenous administrations of ASA as well as oral administration of clopidogrel effectively inhibited platelet function in pigs. One pig did not respond to clopidogrel. We found no differences between domestic and miniature pigs regarding reference values in unmedicated pigs and the effectiveness of ASA and clopidogrel.

Inadvertent iatrogenic prostatectomy and urethrectomy in 2 dogs.

Two dogs were referred because of dysuria following inadvertent iatrogenic total prostatectomy and urethrectomy. In both cases an existing perineal hernia was not recognized by the referring veterinarians and the caudally herniated prostate gland was diagnosed as a perianal neoplasia and subsequently removed. Both dogs were treated with isolation of the urinary bladder from the urethra and a permanent prepubic cystostomy tube.

Predominance of hypoechoic tissue changes in nine dogs with malignant prostatic lymphoma.

Neoplasia of the prostate is relatively uncommon in dogs with adenocarcinoma being the most common type. Non-epithelial tumors are rare and only individual cases of malignant lymphoma affecting the prostate have been reported. The purpose of this multi-institutional, retrospective, descriptive study was to characterize the ultrasonographic features of canine prostatic lymphoma. Inclusion criteria were an abdominal ultrasound and cytological/histological diagnosis of malignant prostatic lymphoma. Ultrasonographic features were recorded based on the original ultrasonographic reports and consensus opinion of two readers on the available image sets retrospectively. Nine dogs met the inclusion criteria with a mean age of 6.5 years. Seven dogs were intact and two neutered. Subjective prostatomegaly was noted in all patients however not reproducible by objective measurements. Altered shape with rounded/irregular margins was detected in 78% of the cases. All prostates presented either diffuse (three dogs) or focal/periurethral (four dogs) and/or multifocal areas of hypoechogenicity (three dogs). In one dog, focal and multifocal hypoechoic changes co-occurred. Prostatic mineralization was not present in any of the cases. Ultrasonographic features of infiltrative disease of multiple organs and/or lymphadenopathy was found in all cases. Even though malignant lymphoma is rare in the prostate, it should be included in the list of differentials in patients with hypoechoic lesions/areas, altered shape, lack of mineralization of the prostatic parenchyma and evidence of multiorgan involvement.