Bilateral laryngeal paralysis in a dog secondary to laryngeal osseous metaplasia.

A 7-year-old spayed female Lurcher was evaluated for a chronic history of increased upper respiratory noise. Advanced imaging including digital radiography and pre- and post-contrast computed tomography (CT) scan confirmed the presence of an ill-defined soft tissue mineralized mass of the ventral larynx. Histopathology demonstrated pleocellular myositis and fasciitis with osseous metaplasia.

Paralysie laryngée bilatérale chez un chien secondaire à la métaplasie osseuse. Une chienne Lurcher stérilisée âgée de 7 ans a été évaluée pour une anamnèse chronique de bruit des voies respiratoires supérieures. Une imagerie avancée, dont une radiographie numérique et une image par tomodensitométrie avant et après contraste a confirmé la présence d'une masse minéralisée floue de tissus mous dans le larynx ventral. Unexamen histopathologique a démontré une myosite pléocellulaire et une fasciite avec une métaplasie osseuse.(Traduit par Isabelle Vallières).

Effects of increasing doses of samarium-153-ethylenediaminetetramethylene phosphonate on axial and appendicular skeletal growth in juvenile rabbits.

INTRODUCTION: Targeted radiotherapy using samarium-153-ethylenediaminetetramethylene phosphonate (153 Sm-EDTMP) is currently under investigation for treatment of osteosarcoma. Osteosarcoma often occurs in children, and previous studies on a juvenile rabbit model demonstrated that clinically significant damage to developing physeal cartilage may occur as a result of systemic 153 Sm-EDTMP therapy. The aim of this study was to evaluate the late effects of 153 Sm-EDTMP on skeletal structures during growth to maturity and to determine if there is a dose response of 153 Sm-EDTMP on growth of long bones. METHODS: Female 8-week-old New Zealand white rabbits were divided into three treatment groups plus controls. Each rabbit was intravenously administered a predetermined dose of 153 Sm-EDTMP. Multiple bones of each rabbit were radiographed every 2 months until physeal closure, with subsequent measurements made to assess for abbreviated bone growth. Statistical analyses were performed to determine the differences in bone length between groups, with significance set at P<.05. RESULTS: Significant differences in lengths of multiple bones were detected between the high-dose group and other treatment groups and controls at each time interval. A significant difference in lengths of the tibias was also noted in the medium-treatment group, compared to controls. Mean reduction of bone length was first detected at 4 months and did not increase significantly over time. CONCLUSIONS: These data suggest that clinically significant bone shortening may occur as a result of high-dosage administration of 153 Sm-EDTMP. Further investigation regarding the effects of bone-seeking radiopharmaceuticals on bone growth and physeal cartilage is warranted.

Use of radiographic measures and three-dimensional computed tomographic imaging in surgical correction of an antebrachial deformity in a dog.

CASE DESCRIPTION: A 1-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of intermittent lameness and an antebrachial angular limb deformity. CLINICAL FINDINGS: The left forelimb had gross antebrachial external rotation (approx 90 degrees ) and marked procurvatum. Radiography revealed a severe partially compensated biapical antebrachial angular limb deformity. Measurements of medial proximal radial angle (MPRA) and lateral distal radial angle (LDRA) were obtained from orthogonal radiographs of the proximal and distal segments of the radius, respectively. Elbow joint-to-carpus translation was quantified. Deformities were localized and quantified by the center of rotation of angulation (CORA) method. Computed tomographic 3-dimensional image reconstructions of the antebrachium and carpus were completed to create 3 life-size stereolithographic models. TREATMENT AND OUTCOME: 2 closing wedge radial osteotomies were performed at the level of the CORAs and stabilized with bone plates and screws. RESULTS: Frontal and sagittal plane alignments were corrected to 8 degrees and 15 degrees , respectively (reference limits, 0 degrees to 8 degrees and 8 degrees to 35 degrees , respectively). The MPRA was corrected from 55 degrees to 68 degrees , and LDRA was corrected from 32 degrees to 76 degrees (values considered normal are approx 85 degrees and 87 degrees , respectively). Elbow joint-to-carpus translation was improved by 42.5%. After 8 weeks, radiography revealed bone union. Owners considered the outcome acceptable, on the basis of limb appearance and lack of lameness at 1 year after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: A segmental radiographic planning technique combined with the CORA method, computed tomography, and stereolithography may be useful in the characterization of and planning corrective surgery for forelimb deformities in dogs.

Determination of pelvic limb alignment in the large-breed dog: a cadaveric radiographic study in the frontal plane.

OBJECTIVES: To report a method for radiographic determination of the mechanical axis of the canine pelvic limb and its relationship to the joints and bone axes. To report reference ranges for the relationships between the axes of the pelvic limb and for joint position relative to the pelvic limb axis. STUDY DESIGN: Cadaveric radiographic anatomic study. ANIMALS: Pelvic limbs (n=101) from normal midsized to large breed dogs; tibiae (n=105) from dogs with cranial cruciate ligament disease (previous study). METHODS: Extended full-limb radiography was performed and images analyzed to determine: mechanical joint reference angles (femur, tibia), pelvic limb axis, tibiofemoral and metatarsotibial angle, mechanical axis-femur/metatarsus angle, and mechanical axis deviation (MAD) of the stifle/tarsus. RESULTS: Mean mechanical angles were: lateral proximal femoral (103.7 degrees +/-5.4 degrees ), lateral distal femoral (98.6 degrees +/-2.5 degrees ), medial proximal tibial (92.2 degrees +/-1.8 degrees ), medial distal tibial (95.9 degrees +/-2.2 degrees ), tibiofemoral (9.1 degrees varus +/-2.8 degrees ), metatarsotibial (0.6 degrees valgus +/-2.1 degrees ). Mean mechanical axis-femur and-metatarsus angles were 5.6 degrees (+/-1.7 degrees ) and 2.9 degrees (+/-1.5 degrees ), respectively. Mean MAD of the stifle and tarsus were 3.6% (+/-1.1%) and 1.2% (+/-0.6%), respectively. Tibial angles were not different between dogs with and without cranial cruciate ligament disease. CONCLUSIONS: Mechanical axes of the canine pelvic limb and their relationship to the joints can be determined by full-limb radiography. CLINICAL RELEVANCE: Techniques and reference ranges may be useful for diagnosis, surgical planning, and postoperative assessment of pelvic limb deformities.

Comparison of digitized and conventional radiographic images for assessment of hip joint conformation in dogs.

OBJECTIVE: To determine agreement between assessments of canine hip joint conformation provided by board-certified radiologists after evaluation of digitized and conventional radiographic images. SAMPLE POPULATION: 200 pelvic radiographs previously evaluated by radiologists using the Orthopedic Foundation for Animals standard grading system for canine hip joint conformation. PROCEDURES: Each of 20 board-certified radiologists evaluated conventional and digitized pelvic radiographs from each of 200 dogs for hip joint conformation. A weighted kappa coefficient and intraclass correlation were used to determine agreement between assessments derived from digitized radiographic images and conventional radiographs and between the original Orthopedic Foundation for Animals conformation ratings and assessments derived from each image format. RESULTS: Overall, agreement between assessments derived from the digitized images and conventional radiographs was good, with all but 1 radiologist attaining a weighted kappa coefficient > 0.61. Intraclass correlation for each radiologist ranged from 0.75 to 0.98 (95% confidence interval, 0.67 to 0.984). On comparison of conformation assessments, 95.7% of those derived from conventional radiographs and digitized images were within 1 grade. On comparison of digitized radiographic conformation assessments and conformation ratings, 94.2% were within 1 grade. On comparison of conventional radiographic conformation assessments and conformation ratings, 92.3% were within 1 grade. CONCLUSIONS AND CLINICAL RELEVANCE: The use of digitized radiographic images does not appear to impact the radiographic assessments of canine hip joint conformation made by consultant radiologists. Compared with conventional radiographs, the use of digitized radiographic images decreases storage space requirements and enables more rapid reporting of assessment results for individual dogs.

Intraorgan biodistribution and dosimetry of 153Sm-ethylenediaminetetramethylene phosphonate in juvenile rabbit tibia: implications for targeted radiotherapy of osteosarcoma.

UNLABELLED: Targeted radiotherapy using 153Sm-ethylenediaminetetramethylene phosphonate (153Sm-EDTMP) is currently under investigation for treatment of primary osteosarcoma. Human osteosarcoma most frequently occurs in skeletally immature individuals, and previous studies in a juvenile rabbit model demonstrated that clinically significant damage to developing physeal cartilage might occur as a result of systemic 153Sm-EDTMP therapy. The aim of this study was to determine the distribution of 153Sm-EDTMP within the tibias of juvenile rabbits and estimate the radiation-absorbed doses delivered to the physeal cartilage. METHODS: Eight-week-old New Zealand White rabbits were injected intravenously with 7.57 kBq (280 microCi) of 153Sm-EDTMP. At 21 h after injection, the biodistribution of 153Sm in the epiphysis, metaphysis, diaphysis, and red marrow of the tibia was obtained. Two-dimensional digital autoradiography was performed on 2-mm sections of tibias for qualitative comparison with the biodistribution data. Self-tissue and cross-tissue absorbed doses were calculated using absorbed fractions generated by the Monte Carlo particle transport code MCNP-4C. RESULTS: The highest uptakes (percentage injected dose per gram [%ID/g] of tissue) of 153Sm, 1.99-2.56 %ID/g, were found in the proximal and distal metaphyses, 70%-73% of which localized within 3 mm of the physeal cartilage. The second highest tissues of uptake were the proximal and distal epiphyses, at 0.33-0.62%ID/g. Digital autoradiography imaging confirmed that the majority of 153Sm deposited in the tibia localized to these tissues. Radiation-absorbed doses to the proximal and distal metaphyses were 183 and 130 mGy/MBq, respectively, and those to the proximal and distal epiphyses were 141 and 43.4 mGy/MBq, respectively. These tissues represented the only source compartments contributing to the physeal cartilage doses of 50.0 mGy/MBq for the proximal physis and 39.2 mGy/MBq for the distal physis. CONCLUSION: The 153Sm absorbed doses to the physeal cartilage were consistent with values that can cause dose-limiting damage to rapidly proliferating and differentiating chondrocytes. The pronounced uptake in the juvenile epiphysis indicates that the proliferating zone of the physis can be irradiated from multiple areas, which could increase the expression and degree of radiation damage. Further investigation of the effects of 153Sm-EDTMP on immature physeal cartilage is warranted to develop optimized treatment regimens.

Contrast cystography.

Cystography is a radiographic study performed to aid in evaluation of the urinary bladder for extramural, mural, or intraluminal lesions. These lesions may primarily involve the urinary bladder or may be an extension of disease from adjacent organs. Cystography is easy to perform with relatively few complications. Different types of cystography (positive versus negative contrast) may be used depending on the type of information that the clinician hopes to obtain. Although a valuable technique, it is important to correlate the findings on cystography with other clinical information to arrive at the final diagnosis.

Effects of 153Sm-ethylenediaminetetramethylene phosphonate on physeal and articular cartilage in juvenile rabbits.

UNLABELLED: Previous studies reported that the radiopharmaceutical (153)Sm-ethylenediaminetetramethylene phosphonate ((153)Sm-EDTMP) is an effective component of multimodality therapy for the treatment of primary bone tumors. Therefore, (153)Sm-EDTMP may prove to be an integral component of therapy for the treatment of juvenile osteosarcoma. The purpose of this study was to determine the effects of intravenous administration of (153)Sm-EDTMP on the developing physeal and articular cartilage of healthy, juvenile rabbits. METHODS: Sixteen healthy 8-wk-old male New Zealand White rabbits were assigned to 1 of 2 groups: treatment (n = 12) and control (n = 4). (153)Sm-EDTMP was administered to the treatment group at 37 MBq/kg (1 mCi/kg). The animals were sacrificed at 16 wk of age, and the physeal cartilage of multiple bones was evaluated by use of histologic, immunohistochemical, and histomorphometric analyses. The overall changes in the lengths of the radius and the tibia between control and treatment groups were calculated and compared. Measurement data were combined for each group, and means +/- SEMs were determined. RESULTS: Significant differences in radial bone growth were present between the groups. Histologically, the physes of the treatment group were disrupted and chaotic in appearance. Significant differences in the immunoreactivity of type X collagen and matrix metalloproteinase-13 were seen between the groups, as these markers were positively expressed in the zone of hypertrophy of the control rabbits. CONCLUSION: Clinically significant damage to the developing physeal cartilage may occur as a result of the intravenous administration of (153)Sm-EDTMP at the dose studied.

Exophthalmia associated with paranasal sinus osteoma in a Quarterhorse mare.

An 11-year-old Quarterhorse mare developed a paranasal sinus osteoma that extended into the right orbit and led to ipsilateral exophthalmia. Although the tumor was radiographically evident in the paranasal sinuses, ultrasonography was used to demonstrate extension of the tumor into the retrobulbar space, and endoscopy was used to identify its extension into the nasopharynx. Biopsies were obtained using both fine-needle aspiration and paranasal sinus trephination. Despite numerous antemortem diagnostic tests, only postmortem histologic analysis of the mass afforded the diagnosis of osteoma.

Surgical treatment of noncommunicating duplication of the colon in a dog.

A 4-month-old sexually intact male Jack Russell Terrier was evaluated because of stranguria and tenesmus. A tubular abdominal mass was palpable abdominally and rectally. Radiographic examination of the abdomen revealed a soft tissue mass located laterally and to the left of the descending colon, which was associated with extraluminal colonic obstruction and urethral compression. During abdominal exploratory surgery, a large cystic mass that was adhered to the antimesenteric border of the descending colon was removed. Porcine small intestinal submucosa was used to reinforce repair of the excision site. Histologic examination of samples of excised tissue identified normal colonic epithelium supported by submucosa and muscular tunics, which was consistent with duplication of the colon. The embryologic etiology of alimentary duplication is poorly understood, and colonic duplication is an extremely rare congenital anomaly.

Effects of furosemide on ureteral diameter and attenuation using computed tomographic excretory urography in normal dogs.

One of the limitations of computed tomographic excretory urography (CTEU) for diagnosis of ureteral disease in dogs is that normal ureteral peristalsis can cause intermittent and inconsistent filling. The aims of this study were to determine if the addition of furosemide to a standard CTEU protocol would increase identification of the ureteral segments, increase ureteral attenuation and increase ureteral diameter in normal dogs. Standard and furosemide-enhanced CTEU scans were acquired in 14 healthy dogs 3 and 10 minutes postcontrast. Ureteral diameters, attenuation values, and percent ureteral filling scores were recorded without the knowledge of furosemide treatment. Comparisons were made between treatments for each postcontrast scan time. The addition of furosemide to the CTEU protocol improved visualization of the ureters by significantly increasing the number of ureteral segments that were able to be identified, as well as their diameter when imaging the patient 3 min following contrast injection (P = 0.012). No major side effects were observed at the dose of 4 mg/kg. There was no advantage to imaging dogs 10 min following contrast administration as the ureteral segments were less attenuating and a smaller percentage of the ureter could be identified. We conclude that the addition of furosemide to canine CTEU studies is safe and may help improve visualization of the ureters.

Targeted combined aerosol chemotherapy in dogs and radiologic toxicity grading.

BACKGROUND: We investigated whether combination chemotherapy, targeted with the AeroProbe® Intracorporeal Nebulizing Catheter (INC), could be safely administered, and developed a radiologic grading scheme to monitor subclinical effects on the lungs. METHODS: In anesthetized and mechanically ventilated healthy dogs (n = 3), we introduced the INC via a flexible bronchoscope into the right caudal lung lobe and administered escalating dosages of gemcitabine (1, 2, 3, or 6 mg/kg) followed by cisplatin (10 mg/m(2)). Treatments were performed every 2 weeks for 4 treatments and dogs were monitored weekly with physical examination, biochemical tests, and thoracic radiographs. Dogs were sacrificed 2 weeks after the final treatment and tissues examined histologically. A radiologic grading scheme was developed to monitor subclinical pulmonary toxicity. RESULTS: No significant side effects occurred in any dog. All dogs developed focal pneumonitis radiographically, and chronic, severe pneumonia with fibrosis histologically limited to the treated portion of the lung. Radiologic scores increased over time following increasing doses of chemotherapy. CONCLUSIONS: Targeted aerosol delivery of gemcitabine and cisplatin by INC was clinically well tolerated. This minimally invasive method is promising for lung cancer treatment, especially given the lack of clinical toxicity. The proposed radiologic grading scheme provides a method to monitor subclinical local drug toxicity.

Intracranial subarachnoid hemorrhage following lumbar myelography in two dogs.

Intracranial subarachnoid hemorrhage is a rare but serious complication of lumbar puncture in humans. Possible sequelae include increased intracranial pressure, cerebral vasospasm, or mass effect, which can result in dysfunction or brain herniation. We describe two dogs that developed intracranial subarachnoid hemorrhage following lumbar myelography. In both dogs, myelography was performed by lumbar injection of iohexol (Omnipaque). Both the dogs underwent uneventful ventral decompressive surgery for disk herniation; however, the dogs failed to recover consciousness or spontaneous respiration following anesthesia. Neurologic assessment in both dogs postoperatively suggested loss of brain stem function, and the dogs were euthanized. There was diffuse subarachnoid hemorrhage and leptomeningeal hemorrhage throughout the entire length of the spinal cord, brain stem, and ventrum of brain. No evidence of infectious or inflammatory etiology was identified. The diagnosis for cause of brain death was acute subarachnoid hemorrhage. Our findings suggest that fatal subarachnoid hemorrhage is a potential complication of lumbar myelography in dogs. The cause of subarachnoid hemorrhage is not known, but may be due to traumatic lumbar tap or idiosyncratic response to contrast medium. Subsequent brain death may be a result of mass effect and increased intracranial pressure, cerebral vasospasm, or interaction between subarachnoid hemorrhage and contrast medium.

Radiographic features of Golden Retriever muscular dystrophy.

Golden Retriever muscular dystrophy is an inherited, degenerative myopathy due to the absence of dystrophin and is used as a model of Duchenne muscular dystrophy of young boys. This report describes the radiographic abnormalities of Golden Retriever muscular dystrophy in 26 dogs. The thoracic abnormalities included diaphragmatic asymmetry (18/26), diaphragmatic undulation (18/26), and gastro-esophageal hiatal hernia (6/26). Pelvic abnormalities included narrowing of the body of the ilia (14/19), ventral deviation and curvature of the tuber ischii (14/19), elongation of the obturator foramen with a decrease in opacity of the surrounding bone (12/19), and lateral flaring of the wings of the ilia (12/19). Abdominal abnormalities consisted of hepatomegaly (14/22) and poor serosal detail (12/22). The unique thoracic abnormalities were a consistent finding in affected Golden Retriever muscular dystrophy dogs. The diagnosis of muscular dystrophy should be included in the differential list if the combination of diaphragm undulation and asymmetry, and gastro-esophageal hiatal hernia are identified. These diaphragmatic abnormalities are related to hypertrophy and hyperplasia of the diaphragm. Additionally, the skeletal changes of pelvic tilt, elongation of the pelvis, widening of the obturator foramina and thinning of the ischiatic tables appear to be specific to Golden Retriever muscular dystrophy in dogs. These pelvic abnormalities are most likely secondary to bone remodeling associated with the progressive skeletal myopathy and subsequent contracture/fibrosis.

An intrathoracic malignant peripheral nerve sheath tumor in a dog.

A 7-year-old, neutered male Labrador Retriever presented for a persistent, productive cough and regurgitation. Radiography, ultrasonography, and computed tomography confirmed a large, smoothly marginated intrathoracic mass causing tracheal compression. The mass was removed via a thoracotomy, and a malignant peripheral nerve sheath tumor, most likely originating from the ventral spinal nerve roots, was confirmed using immunohistochemistry.