Arthrographic description of the canine carpal joint cavities and its recesses.

Joint effusion is diagnostically important. The canine carpal joint effusion, which is sometimes difficult to detect clinically, has received less attention in diagnostic ultrasound (US) studies. The aim of the present study was to provide a description of the morphological appearance of the canine carpal joint cavities and recesses using US, radiography, helical computed tomography (CT) and three-dimensional volume rendering technique (3D-VRT) images and to prove the applicability of musculoskeletal US for the detection of artificial carpal joint effusion in dogs. The understanding of the characteristics of these structures in normal patients is essential in the diagnosis. Twenty-eight clinically and radiologically unremarkable canine carpal cadavers of different breeds were examined, representative images were selected and anatomical structures were labelled. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs: Antebrachiocarpal joint: dorsoproximal antebrachiocarpal recess, dorsodistal antebrachiocarpal recess, medial antebrachiocarpal recess, lateral antebrachiocarpal recess and five palmar antebrachiocarpal recesses. Middle carpal joint: two dorsal middle carpal recesses, medial common middle carpal and carpometacarpal recess, lateral common middle carpal and carpometacarpal recess, four palmar middle carpal recesses. The carpometacarpal joint had dorsal and palmar funnel-shaped and irregular, finely tubular extensions, the most prominent ran dorsal to metacarpal III, the maximum distal end represented the proximal metacarpal diaphysis. All recesses presented ultrasonographically as a generalized anechogenic to hypoechoic filled continuation of the articular capsule with an indistinct peripheral hypoechogenic to isoechogenic fine capsule, the synovial-connective tissue interface was difficult to identify. The novel results of this study provide the first morphological description of the ultrasonographic, radiographic and computed tomographic arthrographic appearance of the canine carpal joint cavities and recesses with different injection volumes. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs. The applicability of musculoskeletal US to visualize an artificial carpal effusion has been demonstrated. The results of this study, and in particular US, give the practitioner an advantage in visualizing joint effusion and assist in the decision to perform arthrocentesis.

3D Slicer open-source software plug-in for vector-based angle calculation of canine hind limb alignment in computed tomographic images.

BACKGROUND: Severe and complex angular limb deformities in dogs require accurate morphological assessment using diagnostic imaging to achieve successful orthopedic surgery. Computed tomography (CT) is commonly used to overcome projection errors in two-dimensional angular measurements of dog hindlimb alignment. Three-dimensional volume rendering (VR) techniques permit virtual positioning and variable projection, but the final CT-image that defines the projection plane for angular measurements remains two-dimensional. OBJECTIVE: We wanted to develop a true three-dimensional open-source technique to measure the alignments of the hind limbs of dogs in CT scanners. METHODS: We developed an open-source 3D Slicer plug-in, to perform angular measurements using vector calculations in three-dimensional space. In 113 CT-scans of canine pelvic limbs, femoral torsion, femoral varus, femorotibial rotation, tibial torsion, tibial varus and tibiotalar rotation angles were calculated and compared to an already validated technique using VoXim®. RESULTS: Reference points were identified and measurements were possible in the 113 acquisitions. The greatest difference between the two techniques was 1.4° at only one tibial torsion angle. Mean values for all Bland-Altman plots did not show significant differences and were less than 0.07° for all comparisons. DISCUSSION: Based on these results we considered angular measurements of canine hind limb alignment in CT scans using the 3D Slicer extension program sufficiently accurate for clinical orthopedic and surgical purposes in veterinary medicine. CONCLUSION: With our open-source 3D Slicer extension software, we provide a free accessible tool for veterinary orthopedic surgeons and thus we hope to improve angular measurements in CT-scans of canine hind limb deformities through true three-dimensionality.

Influence of Femoral Position and Pelvic Projection on Norberg Angle Measurements.

OBJECTIVE: Canine hip dysplasia is a common orthopaedic disease in dogs. The Norberg angle value is a measure of hip joint laxity. The aim of this study was to quantify the degree of rotation necessary to consider the radiograph as inadequately positioned and to determine the influence of rotation on the Norberg angle. STUDY DESIGN: Three sets of radiographs with different positioning and projections were acquired using 10 canine cadavers. Rotation of the pelvis was simulated by rotating the X-ray tube without changing the position of the patient. RESULTS: In dorsoventral projections, the Norberg angle value is increased by 3.2 to 5.8%. Due to rotation along the long axis, the Norberg angle increases on one side and decreases on the contralateral side by approximately the same value. Rotation of greater than 2 degrees in a lateral direction is visually perceived by the observer as tilted. Rotation of the projection in the caudoventral to craniodorsal direction causes mild increase of the Norberg angle (≤1%), while rotation of the projection in a cranioventral to caudodorsal direction causes moderate (≤2%) decrease of the Norberg angle. Rotation of less than -10 degrees (caudoventral to craniodorsal) or greater than 10 degrees (cranioventral to caudodorsal) is visually perceived as tilted. CONCLUSION: Tilted images that are subjectively perceived evaluable have only little effect on the Norberg angle and are therefore probably acceptable. Dorsoventral projections can be recognized based on the proximal position of the patella and should be excluded from evaluation, as the Norberg angle value can be falsely increased.

Comparison of CT-measured angles of pelvic limbs without patellar luxation of six canine breeds.

Introduction: Dogs with medial patellar luxation can be affected by pelvic limb deformities whose corrective osteotomies and associated biomechanical rebalancing might provide higher success rates than standard surgical procedures limited to the stifle joint. In bilaterally affected canine patients, comparison with the contralateral normal limb is impossible. Reference values are useful for orthopedic decision-making. Inconsistency of published reference values might depend on methodology or canine breed. We hypothesized that canine pelvic limb alignment is breed-specific. Methods: CT scans of 42 pelvic limbs of dog breeds predisposed for medial patellar luxation, with an orthotopic patellar position and stability were studied. Several angleswere measured with an open-source 3D Slicer plugin using vector calculations. The breeds were compared with a general linear model with a Bonferonni adjustment using SPSS. Results: Chihuahuas, Pomeranians, Jack Russel Terriers, Pugs, French Bulldogs, Maltese were examined. In the order of the listed breeds, the angles were as follows: 28.3°±10.7°, 20.1°±2.9°, 35.4°±6.9°, 32.8°±3.0°, 19.0°±7.1°, 26.6°±5.3° for the antetorsion, 5.3°±1.8°, 2.8°±2.8°, 8°±4.4°, 3.8 °±3.1°, 4.7°±3.3°, 2.3°±3.3° for the femoral varus, of -5.5°±6.2°, 1.1°±4.1°, -5.2°±9.5°, 6.1°±8.0°, -0.1°±5.9°, -9.2°±4.7° for the tibial torsion, 2.0°±2.9°, 2.1°±2.7°, 6.4°±6.8°, 0.0°±5.7°, 3.0°±5.8°, 8.8°±8.6° for the tibial valgus, 1.2°±10.4°, 1.8°±3.4°, -1.7°±4.9°, -1.7°±9.4°, 5.1°±8.8°, -0.2°±8.6° for the femorotibial rotation and -3.4°±2.2°, 1.1°±4.1°, -2.8°±3.4°, -5.2°±4.0°, -2.1°±4.4°, -5.4°±3.7° for the tibiotalar rotation. There were significant differences between breeds in femoral torsion, femoral varus, and tibial torsion angles, but no significant differences in tibial valgus, femorotibial, and tibiotalar rotation angles. Discussion: Our hypothesis is therefore partially correct. Our results are limited to small dogs prone to medial patellar luxation and might not be generalized. To establish robust reference values larger case numbers and more breeds should be evaluated. In conclusion, canine pelvic limb alignment reference values for small dogs with a predisposition for medial patellar luxation should be considered breed-specific.

Three-dimensional computed tomographic angular measurements of the canine tibia using a bone-centered coordinate system.

Introduction: Canine tibial alignment is determined by two-dimensional angular measurements, and tibial torsion is challenging. Aim of the study was the development and evaluation of a CT technique to measure canine tibial varus and torsion angles independent from positioning and truly three-dimensional. Materials and methods: A bone-centered 3D cartesian coordinate system was introduced into the CT-scans of canine tibiae and aligned with the anatomical planes of the bone based on osseous reference points. Tibial torsion, and varus (or valgus) angles were calculated based on geometric definition of projection planes with VoXim® medical imaging software using 3D coordinates of the reference points. To test accuracy of the tibial torsion angle measurements, CT scans of a tibial torsion model were performed in 12 different hinge rotation setups ranging from the normal anatomical situation up to +/ 90° and compared to goniometer measurements. Independency of tibial positioning on the CT scanner table was evaluated in 20 normal canine tibiae that were scanned in a position parallel to the z-axis and two additional off-angle double oblique positions having 15° and 45° deviation in direction of the x- and y-axes. Angular measurements in oblique positions were compared with the normal parallel position by subtraction. Precision was tested using clinical CT scans of 34 canine patients with a clinical diagnosis of patellar luxation. Results: Accuracy testing in the tibial torsional deformity model revealed a difference of 0.2° demonstrated by Passing-Bablok analysis and Bland-Altman-Plots. Testing for independency from tibial positioning resulted in mean differences less than 1.3°. Precision testing in clinical patients resulted in coefficients of variation for repeated measurements of 2.35% (intraobserver agreement) and 0.60% (interobserver agreement) for the tibial torsion angle, and 2.70% (intraobserver agreement) and 0.97% (interobserver agreement) for the tibial varus (or valgus) angle. Discussion: The technique is lacking determination of bone deformities in the sagittal plane, and demonstration of accuracy in severe complex bone deformities in multiple planes.In conclusion, we developed a method to measure canine tibial torsional and varus or valgus deformities, that calculates in 3D space, and we demonstrated its accuracy in a torsional deformity model, and its precision in CT data of clinical patients.

Computed tomographic angular measurements using a bone-centered three-dimensional coordinate system are accurate in a femoral torsional deformity model and precise in clinical canine patients.

Introduction: In small animal orthopedics, angular measurements in the canine femur are often applied in clinical patients with bone deformities and especially in complex and severe cases. Computed tomography (CT) has been shown to be more precise and accurate than two-dimensional radiography, and several methods are described. Measurement techniques evaluated in normal bones must prove accuracy in deformed bones in clinical settings. Objectives: The goals of our study were to evaluate the accuracy of canine femoral torsion angle measurements in a femoral torsional deformity model and to test repeatability and reproducibility of canine femoral neck inclination, torsion, and varus angle measurements in CT datasets of dogs applying a CT-based technique using a three-dimensional (3D) bone-centered coordinate system. Materials and methods: For precision testing, femoral torsion, femoral neck inclination, and femoral varus angles were measured in CT data of 68 canine hind limbs by two operators, and their results were compared. For accuracy testing, a femoral torsional deformity model was preset from 0° to +/-90° with a goniometer and scanned. Torsion angles were measured in the CT data and compared to the preset value. Results: In the femoral torsion model, the Bland-Altman plots demonstrated a mean difference of 2.11°, and the Passing-Bablok analysis demonstrated a correlation between goniometer and CT-based measurements. In the clinical CT scans, intra- and interobserver agreement resulted in coefficients of variation for repeated measurements (%) between 1.99 and 8.26 for the femoral torsion, between 0.59 and 4.47 for the femoral neck inclination, and between 1.06 and 5.15 for the femoral varus angles. Discussion: Evaluation of femoral malformations with torsional deformities is the target area of this technique. Further studies are required to assess its value in different types, degrees, and combinations of osseous deformities and to establish normal reference values and guidelines for corrective osteotomies. Conclusion: Based on the results of this study, the accuracy of the torsion angle measurements and the precision of inclination, torsion, and the varus angle measurements were considered acceptable for clinical application.

Introduction of a bone-centered three-dimensional coordinate system enables computed tomographic canine femoral angle measurements independent of positioning.

Introduction: Measurement of torsional deformities and varus alignment in the canine femur is clinically and surgically important but difficult. Computed tomography (CT) generates true three-dimensional (3D) information and is used to overcome the limitations of radiography. The 3D CT images can be rotated freely, but the final view for angle measurements remains a subjective variable decision, especially in severe and complex angular and torsional deformities. The aim of this study was the development of a technique to measure femoral angles in a truly three-dimensional way, independent of femoral positioning. Methods: To be able to set reference points in any image and at arbitrary positions of the CT series, the 3D coordinates of the reference points were used for mathematical calculation of the angle measurements using the 3D medical imaging Software VoXim®. Anatomical reference points were described in multiplanar reconstructions and volume rendering CT. A 3D bone-centered coordinate system was introduced and aligned with the anatomical planes of the femur. For torsion angle measurements, the transverse projection plane was mathematically defined by orthogonality to the longitudinal diaphyseal axis. For varus angle measurements, the dorsal plane was defined by a femoral retrocondylar axis. Independence positioning was tested by comparison of angle measurement results in repeated scans of 13 femur bones in different parallel and two double oblique (15/45°) positions in the gantry. Femoralvarus (or valgus), neck version (torsion), and inclination angles were measured, each in two variations. Results: Resulting mean differences ranged between -0.9° and 1.3° for all six determined types of angles and in a difference of <1° for 17 out of 18 comparisons by subtraction of the mean angles between different positions, with one outlier of 1.3°. Intra- and inter-observer agreements determined by repeated measurements resulted in coefficients of variation for repeated measurements between 0.2 and 13.5%. Discussion: The introduction of a bone-centered 3D coordinate system and mathematical definition of projection planes enabled 3D CT measurements of canine femoral varus and neck version and inclination angles. Agreement between angular measurements results of bones scanned in different positions on the CT table demonstrated that the technique is independent of femoral positioning.

Computed tomography venography description of the normal anatomy of the canine hindlimb venous system.

This study was performed to provide a description of the normal anatomy of the canine hindlimb veins using helical CT images. The studies of 30 dogs that underwent CT venography with a 64-slice helical CT scanner were retrospectively reviewed. The dogs were positioned in a head-first prone or head-first supine body position. A topogram CT scan was performed from the pelvic limbs cranial to the iliac wings to the tips of the paws. Bolus-tracking software was used for the dual-phase angiogram, and contrast medium was administered in a cephalic vein. The venous phase was scanned after a delay time of a few seconds after the arterial phase in a caudocranial direction. Three-dimensional images were generated using maximum intensity projections and volume rendering technique. Representative images of three of the 30 dogs were selected and anatomic structures labelled.

Evaluation and Comparison of Self-Made and Commercial Calibration Markers for Radiographic Magnification Correction in Veterinary Digital Radiography.

OBJECTIVE: Magnification error is always present in radiography and calibration is necessary, if high accuracy is required in pre-surgical planning. The goal of this study was to verify the use of self-made markers and calibration techniques and to establish guidelines for magnification correction. STUDY DESIGN: We evaluated and compared spherical and linear markers of different sizes with focus on practicability, accuracy and precision. Markers were placed on foam pads or attached to flexible arms. RESULTS: Vertical marker deviation of 1 cm from the anatomical reference point corresponded to ∼1% of magnification error in our setting. Marker placement along the horizontal plane showed no significant magnification in the periphery of the radiograph. All markers showed good accuracy and the commercial spherical marker with a flexible segment arm had the best results regarding practicability. CONCLUSION: Our study suggests that marker type is not solely responsible for usability and accuracy but also the type of fixation. In the absence of a calibration marker, calculation of the magnification factor using a measurement tape during radiography is equally reliable. Use of a fixed averaged calculated calibration factor showed poor agreement compared with the marker calibration, probably due to variability in size of the animals. In conclusion, if precision matters, use of a calibration marker, which could be purchased or self-made, is advised.

A hypomyelinating leukodystrophy in German Shepherd dogs.

BACKGROUND: Shaking puppy syndrome is commonly attributed to abnormal myelination of the central nervous system. HYPOTHESIS/OBJECTIVES: To report the long-term clinical course and the imaging characteristics of hypomyelinating leukodystrophy in German Shepherd dogs. ANIMALS AND METHODS: Three related litters with 11 affected dogs. RESULTS: The 11 affected dogs experienced coarse, side-to-side tremors of the head and trunk, which interfered with normal goal-oriented movements and disappeared at rest. Signs were noticed shortly after birth. Nine dogs were euthanized, 3 dogs underwent pathological examination, and 2 littermates were raised by their breeder. Tremors improved gradually until 6 to 7 months of age. Adult dogs walked with severe residual pelvic limb ataxia. One dog developed epilepsy with tonic-clonic seizures at 15 months of age. Conventional magnetic resonance imaging (MRI) disclosed homogenous hyperintense signal of the entire subcortical white matter in 3 affected 7-week-old dogs and a hypointense signal in a presumably unaffected littermate. Subcortical white matter appeared isointense to gray matter at 15 and 27 weeks of age on repeated MRI. Abnormal white matter signal with failure to display normal gray-white matter contrast persisted into adulthood. Cerebellar arbor vitae was not visible at any time point. Clinical signs, MRI findings, and pathological examinations were indicative of a hypomyelinating leukodystrophy. All parents of the affected litters shared a common ancestor and relatedness of the puppies suggested an autosomal recessive mode of inheritance. CONCLUSION: We describe a novel hypomyelinating leukodystrophy in German Shepherd dogs with a suspected inherited origin.

Distraction index and Norberg angle to distinguish dysplastic and non-dysplastic hips based on FCI score.

OBJECTIVE: Radiographic hip scoring according to the Fédération Cynologique Internationale (FCI) and PennHIP (Pennsylvania Hip Improvement Program) method was performed with the purpose to compare the PennHIP and FCI results as well as coxofemoral joint laxity by correlation of Norberg angle and distraction index measurements. MATERIALS AND METHODS: A total of 167 dogs of various breeds presented for official screening examination in a veterinary teaching hospital in Germany were included. Using receiver operating characteristic analysis, the best Norberg angle and distraction index cut-off values to distinguish between dysplastic and non-dysplastic groups based on FCI grades and to distinguish between lax and tight hip joints according to the PennHIP proposal were calculated. RESULTS: More than one third (38.2 %) of dogs that passed the breeding criterions according to FCI (grades A and B) were in the half of the population with lax hip joints and should not be used for breeding according to the PennHIP proposal. A cut-off value for the distraction index of 0.44 with sensitivity of 82.7 % and specificity of 84.2 % was superior to the best cut-off value for the Norberg angle at 101.8° with sensitivity of 82.7 % and specificity of 71.9 % to discriminate between non-dysplastic joints (A, B) and dysplastic joints (C, D, E). CONCLUSIONS AND CLINICAL RELEVANCE: Our results show a limited impact of laxity on the FCI grading. Breeding selection processes that are based on the FCI method could profit by an additional and complementary use of the distraction index.

Comparison of Reliability of Norberg Angle and Distraction Index as Measurements for Hip Laxity in Dogs.

OBJECTIVE: The main purpose of the study was to compare reliability of measurements for the evaluation of hip joint laxity in 59 dogs. MATERIALS AND METHODS: Measurement of the distraction index (DI) of the PennHIP method and the Norberg angle (NA) of the Fédération Cynologique Internationale (FCI) scoring scheme as well as scoring according to the FCI scheme and the Swiss scoring scheme were performed by three observers at different level of experience. For each dog, two radiographs were acquired with each method by the same operator to evaluate intraoperator-reliability. RESULTS: Intraoperator-reliability was slightly better for the NA compared with the DI with an intraclass correlation coefficient (ICC) of 0.962 and 0.892 respectively. The ICC showed excellent results in intraobserver-reliability and interobserver-reliability for both the NA (ICC 0.975; 0.969) and the DI (ICC 0.986; 0.972). Thus, the NA as well as the DI can be considered as reliable measurements. The FCI scheme and the Swiss scoring scheme provide similar reliability. While the FCI scheme seems to be slightly more reliable in experienced observers (Kappa FCI 0.687; Kappa Swiss 0.681), the Swiss scoring scheme had a noticeable better reliability for the unexperienced observer (Kappa FCI 0.465; Kappa Swiss 0.514). CLINICAL SIGNIFICANCE: The Swiss scoring scheme provides a structured guideline for the interpretation of hip radiographs and can thus be recommended to unexperienced observers.

Suspected bilateral adrenal gland tumour causing primary Addison's disease in a dog.

A 13-year old miniature poodle presented with a 3-day episode of vomiting, anorexia, and lethargy. Lack of micturition had been noted for 2 days. Clinical examination indicated dehydration and a tense, painful abdomen. Laboratory parameters (severe azotaemia, hyperkalaemia, severe hyponatraemia, hypochloraemia, and hyperphosphataemia with glucosuria and proteinuria) were consistent with anuric acute kidney injury (AKI). Abdominal ultrasound revealed bilateral adrenal masses. ACTH stimulation test was diagnostic for Addison's disease. Computed tomography confirmed bilateral adrenal masses and indicated multifocal liver nodules. Additionally, infiltration of the caudal vena cava with partial luminal occlusion was demonstrated. Surgical removal of the adrenal masses with venous plasty intervention and stenting of the vessels deemed unrewarding in this patient in respect to progressed tumour growth with assumed metastatic spread. The dog was treated for Addison's disease and discharged with good overall condition. Eight weeks later, the dog was euthanized due to progressive caudal vena cava occlusion. Whilst hypoadrenocoticism typically affects young to middle aged dogs, in old dogs primary Addison's disease might be caused by neoplastic bilateral adrenal gland destruction. This is the first case report of hypovolaemia leading to AKI secondary to bilateral adrenal masses causing Addison's disease in a dog.

Occurrence of tympanic bone spicules and bone crests in domestic cats.

Small and hyperostotic tympanic bone spicules (STBS and HTBS) extending from the tympanic wall or from the septum bullae into the tympanic cavity have been described in large feline species such as Siberian tigers or African lions and in canids such as dogs, red foxes and wolves. Detailed descriptions of prevalence, location and orientation were performed for dogs and African lions by means of necropsy and conventional computed tomography (cCT). Aims of the current study were to describe same characteristics for domestic cats by means of microcomputed tomography (µCT) and cCT. A total of 15 cats or rather 30 ears were examined. Furthermore, new bone formations extending into the tympanic cavity shaped like small lamellae were found and named "tympanic bone crests" (TBCs). The registered phenomenon of a thickened tympanic wall in some cats was named "tympanic wall thickening" (TWT). STBS appeared in 43% of the ears being bilateral in 44% of the cases, whereas HTBS appeared in one ear. TBC was present in 33% of the ears with a bilateral prevalence of 67%, and TWT could be detected in 13% of the ears. The mentioned structures are just barely or not at all detectable with cCT; therefore, µCT is necessary for an identification and detailed description. The origin and the factors inducing the development of examined phenomena are unknown, and it is hypothesized that the occurrence can be assessed as anatomical norm variations.

Free DICOM-Viewers for Veterinary Medicine : Survey and Comparison of Functionality and User-Friendliness of Medical Imaging PACS-DICOM-Viewer Freeware for Specific Use in Veterinary Medicine Practices.

There is increasing prevalence of digital diagnostic imaging in veterinary medicine with a progressive need to use medical imaging software. As Digital Imaging and Communications in Medicine (DICOM)-viewers for veterinary use do not require medical device approval in many countries, freeware viewers might be a practical alternative. The aim of this study was to identify and evaluate free DICOM-viewer software for veterinary purposes. The functionality and user-friendliness of various DICOM-viewers from the internet were analyzed and compared. Inclusion criteria for the evaluation were free availability, PACS (picture archiving and communication system)-connectivity, and stand-alone and client-based software. Based on this, eight viewers were found: Ginkgo CADx, Horos, K-PACS, MAYAM, MITO, OsiriX Lite, RadiAnt, Synedra personal. In these DICOM-viewers, 14 core tools were tested and rated on a score from 1 to 10 by multiple observers with different levels of training, using studies of four imaging modalities. Criteria were functionality and user-friendliness. For each viewer, the total number of a predefined set of 47 important tools was counted. The ranking based on functionality and user-friendliness of 14 core tools (mean score in brackets) was as follows: 1. Horos/OsiriX Lite (8.96), 2. RadiAnt (8.90), 3. K-PACS (8.02), 4. Synedra (7.43), 5. MAYAM (6.05), 6. Ginkgo CADx (5.53), 7. MITO (3.74). The DICOM-viewers offered between 20 and 44 tools of the predefined important tool set and are sufficient for most veterinary purposes. An increasing number of tools did not necessarily impair user-friendliness, if the user interface is well designed. Based on the results of this study, veterinarians will find suitable free DICOM-viewers for their individual needs. In combination with PACS-freeware, this allows veterinary practices to run a low-budget digital imaging environment.

Radiation therapy planning using MRI-CT fusion in dogs and cats with brain tumors.

INTRODUCTION: Volume definition is a delicate step within the radiation treatment planning process and the precision of defining the volumes to irradiate is important for the success of the radiation treatment. Traditionally, radiation plans are created using computed tomography (CT) studies. Due to its different mechanism of action, magnetic resonance imaging (MRI) is more sensitive for detection of brain lesions. Therefore, using fused images of both imaging modalities should result in a more precise definition of the volumes to irradiate. The feasibility to fuse CT and MRI studies performed at different institutions was tested to subsequently analyse the influence of the fused images on target volume definition. MATERIALS AND METHODS: Fourteen dogs and four cats with brain lesions having MR- and CT-imaging were included. Contrast-enhanced radiotherapy planning CT scans were fused to T1-weighted post-contrast and T2-weighted MRI scans. The gross tumor volume (GTV), the clinical tumor volume (CTV) and the planning target volume (PTV) were delineated on CT- and MRI studies. CT and MRI volumes were compared with regard to volumetric and spatial differences. RESULTS: The mean GTV was larger on MRI than on CT (2.15 vs.1.54 cm3). Also the mean CTV was larger on MRI than on CT (5.34 vs. 4.38 cm3). Consequently, the mean PTV was larger on MRI than on CT (14.20 vs. 10.82 cm3) as well. None of the differences in defined volumes were significant. Fusion images were accepted showing mean errors of 1.32 mm (mean error) and 1.73 mm (maximal error). CONCLUSION: CT-MRI fusion was feasible especially when defined, reliable, and consistent anatomic landmarks were used as registration points. Volumetric differences between CT and MRI were insignificant. In general, GTV and CTV were easier identified on MRI.

[Technopathies of the limbs in finishing pigs: risk factors, origin and impact on animal welfare - Study phase 1]. / Technopathien der Gliedmaßen bei Mastschweinen: Ursachen, Entstehung, Tierschutzrelevanz.

OBJECTIVE: The aim of the first part of the present study was to specify risk factors for the development of adventitious bursae on the limbs of weaning and finishing pigs. MATERIAL AND METHODS: In total, 192 pigs were examined weekly, recording the following parameters: general condition, number, size and localization of adventitious bursae on the limbs and sternum, gait and claws. RESULTS: Adventitious bursae can occur at 13 positions on the limbs or sternum. These adventitious bursae were already evident when pigs were moved to the nursery. The prevalence of adventitious bursae increased constantly from weaning to slaughter. At the age of 24 weeks, 97.8 % of all investigated pigs displayed adventitious bursae (aged 4 weeks: 25.5 %; aged 12 weeks: 67.6 %). Heavier pigs had significantly more and larger adventitious bursae than lighter pigs of the same age. Furthermore, heavier pigs retrieved feed from the automatic feeder less frequently but ate larger amounts each time. In addition, pigs with poorer gait displayed significantly more adventitious bursae. In 95.6 % of all investigated pigs, claw lesions were evident at slaughter. The general condition was unaffected by adventitious bursae. CONCLUSION AND CLINICAL RELEVANCE: Referring to the results of the present study and the general function of bursae protecting underlying structure against pressure, there is no indication that adventitious bursae affect the animal welfare in terms of the sensation of pain. Influenced by various factors, adventitious bursae develop with high prevalence and number per animal over the course of the life of pigs and can be described as a technopathy. Because of the exposure of adventitious bursae, there is a risk to become an ulcerated bursa of degree three in relation to injuries.

DICOM Standard Conformance in Veterinary Medicine in Germany: a Survey of Imaging Studies in Referral Cases.

In 2016, the recommendations of the DICOM Standards Committee for the use of veterinary identification DICOM tags had its 10th anniversary. The goal of our study was to survey veterinary DICOM standard conformance in Germany regarding the specific identification tags veterinarians should use in veterinary diagnostic imaging. We hypothesized that most veterinarians in Germany do not follow the guidelines of the DICOM Standards Committee. We analyzed the metadata of 488 imaging studies of referral cases from 115 different veterinary institutions in Germany by computer-aided DICOM header readout. We found that 25 (5.1%) of the imaging studies fully complied with the "veterinary DICOM standard" in this survey. The results confirmed our hypothesis that the recommendations of the DICOM Standards Committee for the consistent and advantageous use of veterinary identification tags have found minimal acceptance amongst German veterinarians. DICOM does not only enable connectivity between machines, DICOM also improves communication between veterinarians by sharing correct and valuable metadata for better patient care. Therefore, we recommend that lecturers, universities, societies, authorities, vendors, and other stakeholders should increase their effort to improve the spread of the veterinary DICOM standard in the veterinary world.

Evaluation of Intra- and Inter-observer Measurement Variability of a Radiographic Stifle Osteoarthritis Scoring System in Dogs.

Objectives To evaluate the intra- and inter-observer measurement variability of an existing osteoarthritis (OA) stifle scoring system. Methods Paired caudocranial and mediolateral canine stifle radiographs were selected randomly. A total of 15 assessment points were evaluated independently and graded twice (integer numeric scale: 1-4) at an interval of 2 weeks by three observers with different levels of experience. The grades for each of the 15 factors were summed to obtain the OA score for each patient. Results The 15 independent assessment points measured by the three observers showed high reproducibility and low intra-observer variability. Inter-observer variability was also low (mean: 1.09 ± 4.99, 95% CI [confidence interval]: -0.35 to 2.55). The most discordant ratings among the three observers involved sesamoid bones of gastrocnemius muscle (assessment point 11 of 15) and popliteal surface of femur (assessment point 10 of 15). Clinical Significance A validated and feasible OA scoring method is prerequisite for reliable radiographic assessment of OA progression. The low overall inter- and intra-observer variabilities among the 15 independent measures of the OA scoring system presented herein support its feasibility for application in clinical practice as an objective tool for radiographic scoring of stifle OA.

The Munich MIDY Pig Biobank - A unique resource for studying organ crosstalk in diabetes.

OBJECTIVE: The prevalence of diabetes mellitus and associated complications is steadily increasing. As a resource for studying systemic consequences of chronic insulin insufficiency and hyperglycemia, we established a comprehensive biobank of long-term diabetic INSC94Y transgenic pigs, a model of mutant INS gene-induced diabetes of youth (MIDY), and of wild-type (WT) littermates. METHODS: Female MIDY pigs (n = 4) were maintained with suboptimal insulin treatment for 2 years, together with female WT littermates (n = 5). Plasma insulin, C-peptide and glucagon levels were regularly determined using specific immunoassays. In addition, clinical chemical, targeted metabolomics, and lipidomics analyses were performed. At age 2 years, all pigs were euthanized, necropsied, and a broad spectrum of tissues was taken by systematic uniform random sampling procedures. Total beta cell volume was determined by stereological methods. A pilot proteome analysis of pancreas, liver, and kidney cortex was performed by label free proteomics. RESULTS: MIDY pigs had elevated fasting plasma glucose and fructosamine concentrations, C-peptide levels that decreased with age and were undetectable at 2 years, and an 82% reduced total beta cell volume compared to WT. Plasma glucagon and beta hydroxybutyrate levels of MIDY pigs were chronically elevated, reflecting hallmarks of poorly controlled diabetes in humans. In total, ∼1900 samples of different body fluids (blood, serum, plasma, urine, cerebrospinal fluid, and synovial fluid) as well as ∼17,000 samples from ∼50 different tissues and organs were preserved to facilitate a plethora of morphological and molecular analyses. Principal component analyses of plasma targeted metabolomics and lipidomics data and of proteome profiles from pancreas, liver, and kidney cortex clearly separated MIDY and WT samples. CONCLUSIONS: The broad spectrum of well-defined biosamples in the Munich MIDY Pig Biobank that will be available to the scientific community provides a unique resource for systematic studies of organ crosstalk in diabetes in a multi-organ, multi-omics dimension.