Eberhard Ludewig

Diagnostic Accuracy of Electrocardiography and Thoracic Radiography in the Assessment of Left Atrial Size in Cats: Comparison with Transthoracic 2‐Dimensional Echocardiography

BACKGROUND Left atrial (LA) enlargement (LAE) is a morphologic expression of the severity and chronicity of left ventricular (LV) diastolic dysfunction, volume overload, and increased atrial pressure and has diagnostic, therapeutic, and prognostic importance in cats. The noninvasive gold standard for assessing LA size is 2-dimensional echocardiography (2DE). HYPOTHESIS ECG and thoracic radiography may be used to predict LAE in cats. ANIMALS Twenty-one healthy control cats and 31 cats with cardiomyopathy were prospectively studied. METHODS 2DE studies, including determination of the maximum LA dimension (LAD) and area (LAA), were performed prospectively in all cats and compared to the assessment of LA size based on thoracic radiography and indices obtained from a 6-lead ECG. Results obtained from healthy cats were used to generate discrimination limits suggestive of LAE as defined by LAD > 1.57 cm and LAA > 2.75 cm2. RESULTS In cats with LAE, P wave duration and PR interval were prolonged and radiographic LA vertebral heart size (LA-VHS) was increased (P < .05). P wave-related indices had low sensitivity (Se; range, 0.12 to 0.60) but high specificity (Sp; range, 0.81 to 1.00) for the prediction of LAE. Radiographic indices had low Se (range, 0.28 to 0.72) and high Sp (range, 0.74 to 0.95) for the prediction of LAE. Correlation analyses identified correlations between LAA and P wave duration (r = 0.47, P = .003) and LAD and LA-VHS (r = 0.70, P < .001). CONCLUSION AND CLINICAL IMPORTANCE ECG and thoracic radiography are reasonably specific but less sensitive predictors of LAE in cats.

Brachycephalic Feline Noses: CT and Anatomical Study of the Relationship between Head Conformation and the Nasolacrimal Drainage System

Aims A study was designed to evaluate the influence of head conformation on the course of the nasolacrimal drainage system (NDS) in 31 brachycephalic and 15 mesocephalic cats using computed tomography (CT), CT-dacryocystography and anatomical methods. Findings The higher the degree of brachycephalia, the more the facial bones and upper canine teeth are displaced dorsally (ie, the more pronounced the dorsorotation). Dorsorotation leads to abnormal dislocation of the ventral nasal concha and to almost horizontally rotated upper canine teeth, and thus a steeply oriented NDS. In severe brachycephalia the NDS is forced to pass below the canine tooth (adopt a V-shaped course) and the drainage function seems to be inefficient. Practical relevance The rotation of the upper canine teeth appears to provide a basis for classification of brachycephalia in cats. The authors recommend that breeders avoid breeding from individuals affected by this condition and to give preference to cats with longer facial bones.

Visual Estimation of Radioulnar Incongruence in Dogs Using Three‐Dimensional Image Rendering: An In Vitro Study Based on Computed Tomographic Imaging

OBJECTIVE To determine the sensitivity and specificity of visual estimation of radioulnar incongruence (RUI) in the canine elbow by use of 3-dimensional (3D) image rendering. STUDY DESIGN Experimentally induced negative and positive RUI. SAMPLE POPULATION Canine (>20 kg) cadaveric right thoracic limbs (n=8). METHODS Radial shortening and lengthening of 1 and 2 mm were performed extending an established surgical in vitro model of RUI. Based on transverse computed tomographic (CT) scans of each radioulnar conformation, the subchondral radioulnar joint surface was reconstructed and visualized. A total of 64 3D models of RUI were blindly evaluated in a random manner by 3 independent observers. RUI was estimated subjectively at 1 mm precisely (-2, -1, 0, +1, +2) by visual inspection of the 3D models. RESULTS Median sensitivity for identifying an incongruent joint was 0.86. Median specificity for identification of a congruent joint was 0.77. Analyzing the data only in respect to a congruent joint versus one with a shortened radius (positive RUI) resulted in a median sensitivity of 0.82, and a median specificity of 1.00. Interobserver agreement was 0.87. Repeatability was 0.96. CONCLUSION Estimation of positive and negative RUI based on 3D surface models of the radioulnar articulation mimics gross inspection in a noninvasive manner, the latter being the ultimate gold standard for definitive diagnosis of any radioulnar step. The proposed technique is precise, reliable, and repeatable in vitro. CLINICAL RELEVANCE Preoperative estimation of the type and degree of RUI is the basis for deciding which type of corrective or modifying osteotomy might be best suited to restore normal joint loads in vivo.

Value of low-field magnetic resonance imaging in diagnosing meniscal tears in the canine stifle: a prospective study evaluating sensitivity and specificity in naturally occurring cranial cruciate ligament deficiency with arthroscopy as the gold standard.

OBJECTIVE To evaluate the sensitivity and specificity of low-field magnetic resonance imaging (lfMRI) for detection of meniscal tears in the canine stifle. STUDY DESIGN Double-blinded prospective clinical study. ANIMALS Forty-two consecutive stifles of dogs (>or=20 kg; n=34) with clinical and radiologic signs suspicious for cranial cruciate ligament (CCL) insufficiency. METHODS Each stifle had 7 predefined lfMRI sequences using a 0.5 T magnet with a human knee coil. After lfMRI, diagnostic arthroscopy was performed by 1 surgeon unaware of the MRI findings. After completion of the study MRI images were read by 1 investigator, unaware of the intraoperative findings. RESULTS At arthroscopy, 22 stifles had meniscal tears requiring subtotal meniscectomy. Of these only 14 were identified by lfMRI. Overall sensitivity and specificity of lfMRI for detection of meniscal tears were 0.64 (95% confidence interval [95% CI]=0.43, 0.80) and 0.90 (95% CI=0.70, 0.97), respectively. Positive and negative predictive values were 0.88 (95% CI=0.64, 0.97) and 0.69 (95% CI=0.50, 0.83), respectively. Neither the state of dislocation of vertical longitudinal tears nor the amount of CCL rupture had an influence on lfMRI accuracy (P=1.00). CONCLUSION lfMRI was of low diagnostic accuracy in detecting meniscal tears, when compared with arthroscopy. Especially negative lfMRI findings should be interpreted with caution. CLINICAL RELEVANCE When using lfMRI as a noninvasive preoperative screening tool for the diagnosis of meniscal tears, a high percentage of missed meniscal tears has to be expected.

Effekte einer niedrig dosierten Co-60-Bestrahlung auf den Verlauf einer aseptischen Arthritis am Kniegelenk des Kaninchens

ZusammenfassungZielZahlreiche klinisch-empirische Erhebungen zeigten die Effektivität niedriger Strahlendosen in der Therapie schmerzhafter entzündlich-degenerativer Gelenkerkrankungen. Experimentelle Untersuchungen liegen jedoch kaum vor. Wir untersuchten die Effekte einer lokalen fraktionierten Co-60-Bestrahlung mit 5mal 1,0 Gy auf eine artifizielle aseptische Arthritis am Kniegelenk des Kaninchens.Material und MethodenEs wurden drei Einzelversuche (EV) mit jeweils zehn Kaninchen (fünf Versuchs-und fünf Kontrolltiere) durchgeführt (Versuchsdauer: EV1: 18 Tage; EV2: sechs Tage; EV3: 29 Tage). Die Induktion der aseptischen Arthritis erfolgte am Tag 0 durch intraartikuläre Injektion von 0,5 ml einer 3% igen Papainlösung (30 000 USP/mg) in das rechte Kniegelenk. Die täglich fraktionierte lokale Bestrahlung des arthritischen Gelenks mit 5mal 1,0 Gy wurde an den Tagen 1 bis 5 während einer Kurznarkose durchgeführt. Die Kontrollgruppen wurden in analoger Technik an den Tagen 1 bis 5 scheinbestrahlt. Der Verlauf der Arthritis in den Versuchs-und Kontrollgruppen wurde anhand klinischer, laborchemischer und morphometrischer Parameter charakterisiert. Die klinische Untersuchung erfolgte täglich, die Punktion der Kniegelenke in EV1 wiederholt, in EV2 und EV3 am letzten Versuchstag. Jeweils am Versuchsende wurden die Kniegelenke zur histologischen Analyse nach erfolgter Euthanasie entnommen.ErgebnisseDie intraartikuläre Injektion von Papain führte bei allen Tieren zu einer perakuten entzündlichen Reaktion, welche nach einer Woche in die chronische Phase überging und sich über mehrere Wochen kontinuierlich zurückbildete. Die lokal bestrahlten Versuchstiere zeigten klinisch eine signifikant schnellere Rückbildung der entzündlichen Gelenkschwellung. Am Tag 6 lag ein signifikant geringeres Synovialflüssigkeitsvolumen in bestrahlten Kniegelenken vor. Die morphometrischen Daten wiesen auf eine Reduktion der Verdickung der Synovialmembran, eine Abnahme der Synovialzellreihen und eine verkürzte Distanz zwischen Kapillaren und Synovialmembranoberfläche nach lokaler Bestrallung hin. Infolge beträchtlicher individueller Schwankungen waren diese Befunde zum Teil statistisch nicht signifikant.SchlußfolgerungDie Experimente weisen einen antiphlogistischen Effekt der Bestrahlung mit 5 mal 1,0 Gy in vivo nach und unterstützen damit klinische Beobachtungen der Effektivität von Entzündungsbestrahlungen.AbstractPurposeNumerous clinical observations demonstrate the efficacy of low radiation doses in the treatment of painful osteoarthritis. Experimental investigations remain scarce. We investigated the effects of locally daily 5 times 1.0 Gy 60-Co irradiation on an artificially induced aseptic gonarthritis in rabbits.Material and MethodsThree separate experiments (EV) were performed (10 rabbits per experiment, 5 treated/5 controls; duration: EV1: 18 days; EV2: 6 days; EV3: 29 days). An aseptic arthritis in the right knee joint of rabbits was induced by intraarticular injection of 0.5 ml papain solution (3%, 30,000 USP/mg) on day 0. The arthritic knee joint of the anesthesized animals was irradiated daily from day 1 to 5 with 5 times 1.0 Gy. The controls were sham-irradiated under the same conditions. The time course of arthritis in treated animals and sham-treated controls was evaluated by clinical laboratory-chemical and histological criteria. The clinical investigation was performed daily, the puncture of the kneejoints was carried out several times in EV1, and at the end of experiments in EV2 and EV3. At the end of the observation period, animals were killed and the knee joints excised for histological analysis.ResultsThe intraarticular injection of papain caused a peracute inflammatory response in all animals. After 1 week the chronical stage was reached, and the experimental arthritis resolved slowly within several weeks. Local irradiation accelerated the decrease of inflammatory joint swelling, being significant by day 4. On day 6 the volume of synovial fluid in irradiated knee-joints was significantly smaller. The morphometric data indicated a reduction in thickness of synovial membrane, a decrease in number of synovial cell layers, and a decrease in distance between capillaries and the synovial membrane surface following irradiation of arthritic joints. Due to considerable individual variability, the morphometric data partially did not reach statistically significance.ConclusionThe experiments provide evidence for an antiphlogistic effect of irradiation with 5 times 1.0 Gy in vivo. They support the clinical observations of the efficacy of anti-inflammatory radiotherapy.PURPOSE Numerous clinical observations demonstrate the efficacy of low radiation doses in the treatment of painful osteoarthritis. Experimental investigations remain scarce. We investigated the effects of locally daily 5 times 1.0 Gy 60-Co irradiation on an artificially induced aseptic gonarthritis in rabbits. MATERIAL AND METHODS Three separate experiments (EV) were performed (10 rabbits per experiment, 5 treated/5 controls; duration: EV1: 18 days; EV2: 6 days; EV3: 29 days). An aseptic arthritis in the right knee joint of rabbits was induced by intraarticular injection of 0.5 ml papain solution (3%, 30,000 USP/mg) on day 0. The arthritic knee joint of the anesthesized animals was irradiated daily from day 1 to 5 with 5 times 1.0 Gy. The controls were sham-irradiated under the same conditions. The time course of arthritis in treated animals and sham-treated controls was evaluated by clinical, laboratory-chemical and histological criteria. The clinical investigation was performed daily, the puncture of the knee-joints was carried out several times in EV1, and at the end of experiments in EV2 and EV3. At the end of the observation period, animals were killed and the knee joints excised for histological analysis. RESULTS The intraarticular injection of papain caused a peracute inflammatory response in all animals. After 1 week the chronic stage was reached, and the experimental arthritis resolved slowly within several weeks. Local irradiation accelerated the decrease of inflammatory joint swelling, being significant by day 4. On day 6 the volume of synovial fluid in irradiated knee-joints was significantly smaller. The morphometric data indicated a reduction in thickness of synovial membrane, a decrease in number of synovial cell layers, and a decrease in distance between capillaries and the synovial membrane surface following irradiation of arthritic joints. Due to considerable individual variability, the morphometric data partially did not reach statistically significance. CONCLUSION The experiments provide evidence for an antiphlogistic effect of irradiation with 5 times 1.0 Gy in vivo. They support the clinical observations of the efficacy of anti-inflammatory radiotherapy.

Partial Lateral Corpectomy of the Thoracolumbar Spine in 51 Dogs: Assessment of Slot Morphometry and Spinal Cord Decompression

Objective: To report slot morphometry, degree of spinal decompression, and factors influencing decompression after partial lateral corpectomy (PLC) of the thoracolumbar spine in dogs with intervertebral disc disease. Study Design: Case series. Animals: Dogs (n=51) with predominantly ventrally located spinal cord compression. Methods: PLC (n=60) were performed. Spinal cord compression was determined by computed tomographic (CT) myelography (n=46), myelography (n=2) or magnetic resonance imaging (n=3). Postsurgical CT images were used to evaluate slot dimensions and orientation, and spinal cord decompression. The influence of age, body weight, breed, breed type (chondrodystrophic, nonchondrodystrophic), disc location, lateralization and mineralization, presurgical compression, slot morphometry, and surgeon on degree of decompression were evaluated. Results: Mean slot depth was 64.1% of vertebral body width; mean height, 43.0% of vertebral body height; mean cranial extension, 29.5%; median caudal extension, 22.0% vertebral body length; mean angulation from horizontal, 6.3°. Decompression was satisfactory in 90% of sites after PLC (58% complete, 32% good). None of the analyzed factors significantly influenced decompression. All lumbar spine PLC resulted in complete or good decompression compared with 83% after thoracic PLC (P=.052). Deeper slots tended to allow more complete decompression (P=.058). Conclusions: Thoracolumbar PLC results in satisfactory decompression in most cases with a better outcome in the lumbar spine than the thoracic spine. Achieving a slot depth equal to 2/3 of vertebral body width might facilitate complete decompression.OBJECTIVE To report slot morphometry, degree of spinal decompression, and factors influencing decompression after partial lateral corpectomy (PLC) of the thoracolumbar spine in dogs with intervertebral disc disease. STUDY DESIGN Case series. ANIMALS Dogs (n=51) with predominantly ventrally located spinal cord compression. METHODS PLC (n=60) were performed. Spinal cord compression was determined by computed tomographic (CT) myelography (n=46), myelography (n=2) or magnetic resonance imaging (n=3). Postsurgical CT images were used to evaluate slot dimensions and orientation, and spinal cord decompression. The influence of age, body weight, breed, breed type (chondrodystrophic, nonchondrodystrophic), disc location, lateralization and mineralization, presurgical compression, slot morphometry, and surgeon on degree of decompression were evaluated. RESULTS Mean slot depth was 64.1% of vertebral body width; mean height, 43.0% of vertebral body height; mean cranial extension, 29.5%; median caudal extension, 22.0% vertebral body length; mean angulation from horizontal, 6.3°. Decompression was satisfactory in 90% of sites after PLC (58% complete, 32% good). None of the analyzed factors significantly influenced decompression. All lumbar spine PLC resulted in complete or good decompression compared with 83% after thoracic PLC (P=.052). Deeper slots tended to allow more complete decompression (P=.058). CONCLUSIONS Thoracolumbar PLC results in satisfactory decompression in most cases with a better outcome in the lumbar spine than the thoracic spine. Achieving a slot depth equal to 2/3 of vertebral body width might facilitate complete decompression.

Diagnostic imaging – evaluating image quality using visual grading characteristic (VGC) analysis

Radiologists are regularly faced with the task of comparing image quality obtained using different imaging systems or settings. Visual grading techniques can be used to evaluate the quality of images by grading the clarity of reproduction of anatomical or pathological structures. The methods, which include “visual grading analysis (VGA)” and the “image criteria (IC) study”, are characterised by their attractive simplicity and reliability. Non-parametric rank-invariant statistical methods are suitable techniques for statistical analysis of VGA-data. Båth and Månsson (2007) introduced such a method and termed it “visual grading characteristics (VGC) analysis”. This paper gives an overview of the principle together with an example of its use in veterinary radiology. The aim of this review article is to encourage veterinary researchers to apply this method which has proven valuable in the human field. Basically, the method can also be applied for the analysis of other categories of images (e.g. histological sections, cytological smears) in cases where the task is to evaluate features subjectively on the basis of a score, allowing some degree of freedom of decision. Furthermore, the aim of the investigation is not necessarily restricted to quality aspects. Other questions such as the effects of treatment options on the appearance of certain structures can be compared as well.

A Novel Approach to Brachycephalic Syndrome. 1. Evaluation of Anatomical Intranasal Airway Obstruction.

OBJECTIVE To evaluate airway obstruction due to abnormal intranasal anatomy in 3 brachycephalic dog breeds using computed tomography and rhinoscopy. STUDY DESIGN Prospective clinical study. ANIMALS A total of 132 brachycephalic dogs (66 Pugs, 55 French Bulldogs, and 11 English Bulldogs) with severe respiratory distress due to brachycephalic syndrome. METHODS Computed tomography and anterior and posterior rhinoscopy were performed to evaluate endonasal obstruction. RESULTS All dogs had abnormal conchal growth that obstructed the intranasal airways. Rostral aberrant turbinates (RAT) were common in Pugs (90.9%) but less frequent in French (56.4%) and English (36.4%) Bulldogs. Caudal aberrant turbinates (CAT) obstructing the nasopharyngeal meatus were commonly found in all breeds (66.7%). Deviation of the nasal septum was an almost consistent finding in Pugs (98.5%) but was less common in bulldogs. Obstructing turbinates had multiple points of mucosal contact responsible for obstruction of the intranasal airway. Interconchal and intraconchal mucosal contacts were evident in 91.7% of dogs. CONCLUSION Selective breeding for short head conformation reduces the size of the nasal cavities to such an extent that intranasal structures grow aberrantly and malformed, leading to obstructed air conducting spaces. Intranasal airway obstruction of brachycephalic dogs may contribute to their exercise and heat intolerance because of impaired pulmonary ventilation and compromised thermoregulatory functions of the canine nose. Failure to address intranasal obstruction might be an explanation for lack of therapeutic success after conventional surgery for brachycephalic syndrome. Future consideration should be given to the diagnosis, management, and treatment of this newly described aspect of airway obstruction.

Longitudinal evaluation of effects of intra-articular mesenchymal stromal cell administration for the treatment of osteoarthritis in an ovine model.

In this study, the therapeutic effect of intra-articularly injected autologous mesenchymal stromal cells (MSCs) was evaluated in an ovine osteoarthritis (OA) model using consecutive magnetic resonance imaging (MRI), radiography, and macroscopic and histologic postmortem examination. In 12 sheep, OA was induced by bilateral, lateral meniscectomy. After 6 weeks, 20 × 106 bone marrow-derived MSCs (50% MSCs were superparamagnetic iron oxide particle labeled) were injected intra-articularly into one knee joint. The contralateral knee served as negative control. MR images were acquired before OA induction, immediately before and after MSC injection, and 1, 4, 8, and 12 weeks thereafter using a 0.5T unit and a T2* gradient echo sequence. Radiographs were obtained before OA induction, at MSC injection, and 12 weeks thereafter. The MRI scoring system included articular cartilage, bone, joint capsule, and synovial fluid evaluation. The radiographic scoring system included the joint space and bone. Postmortem evaluation entailed macroscopic and histologic assessment. Longitudinal MRI revealed a significant deceleration of OA progression in MSC-treated joints. However, at the conclusion of the study, there was no significant difference in the degree of OA detected by MRI, radiography, and postmortem evaluation between the treatment and control group. The degree of OA on MRI varied among the 12 animals at the time of injection, but there was no difference between the left and right limb. In conclusion, intra-articular MSCs decreased OA progression. However, no significant treatment effects were seen at the conclusion of the study at 12 weeks. This somewhat contradicts previously published results. Nevertheless, the choice of OA model, outcome measures, or lack of additional medication might explain the differences. Our results indicate that OA might benefit from intra-articular MSC injection, but further studies are needed to refine patient selection and injection parameters for a more substantially improved outcome.

Magnetic resonance imaging diagnosis: incomplete ossification of the humeral condyle in a German shepherd dog.

Clinical signs, radiological, arthroscopic findings and magnetic resonance imaging features of a male German shepherd dog with incomplete ossification of the humeral condyle are described. The dog showed recurrent left forelimb lameness and pain on elbow palpation. In routine radiographs, the lesion was obscured. In oblique radiographs, a radiolucent line was detected, and magnetic resonance imaging clearly demonstrated a defect in the humeral condyle. However, arthroscopy showed no changes or discontinuity of the humeral cartilage. Incomplete ossification of the humeral condyle may be underrepresented in conventional, routine studies because if there is concurrent additional elbow pathology (for example fragmented coronoid process), treatment may lead to clinical improvement and further diagnostic techniques may not be performed. The benefit of magnetic resonance imaging in this case is demonstrated.