ACVR and ECVDI consensus statement for teleradiology.

Increased demand for the interpretation of diagnostic images by board-certified radiologists and profound advancements in technology have led to extremely rapid growth in the field of veterinary teleradiology over the past decade. The aim of this consensus statement is to provide a guideline for best practices for quality and safety in veterinary teleradiology. The statement addresses appropriate image acquisition and transmission, the creation of teleradiology submissions, quality control in teleradiology, and appropriate documentation of imaging reports, as deficiencies in any of these areas may directly affect the standard of patient care. The consensus statement may be used as a guide for radiologists, primary care veterinarians, technicians, and students for the use of teleradiology in practice.

Verminous myelopathy secondary to aberrant Dirofilaria immitis migrans was detected in the cervical subarachnoid space of four dogs using MRI and CT.

Aberrant Dirofilaria immitis migrans is a rare cause of neurologic signs in dogs, however, published studies describing the computed tomographic (CT) and magnetic resonance imaging (MRI) characteristics of this problem are currently lacking. The objective of this retrospective case series study was to describe the clinical and imaging findings for four adult dogs with verminous myelopathy due to aberrant Dirofilaria immitis migrans within the cervical subarachnoid space. All dogs were toy breeds, were heartworm antigen positive, had neurologic signs (ranging from cervical hyperesthesia to tetraparesis), and similar MRI findings. In two patients additionally imaged with CT, findings were variable. On MRI, each dog had a single large, dorsal- to laterally located, intradural-extramedullary, fusiform mass with characteristic stippled, mixed T2-weighted and T1-weighted signal intensity, hypo-to-iso T1-weighted signal intensity, and spinal cord compression. Nematodes were identified as serpentine or circular subarachnoid structures with low T2-weighted and T1-weighted signal in the sagittal and transverse image planes, respectively. CT (n = 2 dogs) demonstrated focal regions of mildly enhancing intradural-extramedullary spinal cord compression in 1 dog. Dorsal laminectomy and durotomy were performed in two dogs at C3-C4. A C4-5 hemilaminectomy with durotomy and dural biopsy was performed in one dog. Extraction of live, immature adult, female D. immitis worms was performed in three dogs. Operated dogs had complete post-surgical resolution of clinical signs. One dog was euthanized without surgery; necropsy revealed an adult heartworm in the spinal subarachnoid space at C2. Findings indicated that cervical spinal subarachnoid D. immitis aberrant migration should be considered as a differential diagnosis for dogs with this combination of clinical and CT/MRI imaging findings, and that the prognosis may be good with early detection and surgical removal.

Diaphragmatic dysfunction in dogs with cervical spinal disorders before and after surgery using fluoroscopy, motion-mode ultrasound and radiography was not different than a group of control dogs.

Cervical spinal disorders can lead to life-threatening respiratory complications. Diaphragmatic dysfunction is attributed to spinal cord morbidity secondary to cervical myelopathy or decompressive surgical intervention. The purpose of this observational case-control study was to determine the frequency of diaphragmatic dysfunction in dogs with cervical spinal disorders and a control group, the strength of association between cervical myelopathies and decompressive surgery with diaphragm paresis, and the agreement between and clinical usefulness of fluoroscopy, motion-mode ultrasonography, and radiography for diagnosing diaphragmatic dysfunction. Thirty-five client-owned dogs were recruited with 14 control dogs and 21 test dogs. Dogs were evaluated for the presence of diaphragmatic dysfunction using radiography, M-mode ultrasonography, and fluoroscopy before and after an anesthetic or surgical event. Diaphragmatic dysfunction was observed more frequently in dogs with cervical spinal disease prior to surgery (8/21; 38.1%) compared to control dogs (3/14; 21.4%) but was not statistically significant (P = .30). The occurrence of diaphragmatic dysfunction did not significantly increase following surgical decompression in either group. There was no to slight agreement between all imaging modalities. Most dogs with diaphragmatic dysfunction were asymptomatic. Diaphragmatic dysfunction was not statistically associated with cervical myelopathy or decompressive surgery. Ultrasonography and radiography were not useful diagnostic tests for determining diaphragmatic dysfunction in asymptomatic dogs when compared to fluoroscopy.

Single-voxel and multi-voxel spectroscopy yield comparable results in the normal juvenile canine brain when using 3 Tesla magnetic resonance imaging.

Conventional magnetic resonance imaging (MRI) characteristics of canine brain diseases are often nonspecific. Single- and multi-voxel spectroscopy techniques allow quantification of chemical biomarkers for tissues of interest and may help to improve diagnostic specificity. However, published information is currently lacking for the in vivo performance of these two techniques in dogs. The aim of this prospective, methods comparison study was to compare the performance of single- and multi-voxel spectroscopy in the brains of eight healthy, juvenile dogs using 3 Tesla MRI. Ipsilateral regions of single- and multi-voxel spectroscopy were performed in symmetric regions of interest of each brain in the parietal (n = 3), thalamic (n = 2), and piriform lobes (n = 3). In vivo single-voxel spectroscopy and multi-voxel spectroscopy metabolite ratios from the same size and multi-voxel spectroscopy ratios from different sized regions of interest were compared. No significant difference was seen between single-voxel spectroscopy and multi-voxel spectroscopy metabolite ratios for any lobe when regions of interest were similar in size and shape. Significant lobar single-voxel spectroscopy and multi-voxel spectroscopy differences were seen between the parietal lobe and thalamus (P = 0.047) for the choline to N-acetyl aspartase ratios when large multi-voxel spectroscopy regions of interest were compared to very small multi-voxel spectroscopy regions of interest within the same lobe; and for the N-acetyl aspartase to creatine ratios in all lobes when single-voxel spectroscopy was compared to combined (pooled) multi-voxel spectroscopy datasets. Findings from this preliminary study indicated that single- and multi-voxel spectroscopy techniques using 3T MRI yield comparable results for similar sized regions of interest in the normal canine brain. Findings also supported using the contralateral side as an internal control for dogs with brain lesions.

Acute cerebrovascular event in a dog with polycythemia vera.

A 1-year-old neutered male Labrador retriever mixed breed dog was referred for peracute onset of ataxia and seizures. Hematocrit at presentation was 84%. Magnetic resonance imaging of the brain revealed a lesion in the right caudate nucleus consistent with infarction. Postmortem findings were consistent with polycythemia vera and presumed secondary cerebral infarction.

Événement cérébrovasculaire aigu chez un chien atteint de polycythémie vraie. Un Labrador retriever mâle âgé de 1 an a été référé pour l'apparition suraiguë d'ataxie et de crises d'épilepsie. L'hématocrite était de 84 % à la présentation. L'imagerie par résonance magnétique du cerveau a révélé une lésion dans le noyau caudé droit compatible avec à un infarcissement. Les résultats post mortem étaient conformes à une polycythémie vraie et à un infarcissement cérébral secondaire présumé.(Traduit par Isabelle Vallières).

The wedge sign: A possible lung ultrasound sign for pulmonary thromboembolism.

OBJECTIVE: To describe the finding of the lung ultrasound (LUS) "wedge sign" in dogs with presumptive pulmonary thromboembolism (PTE). CASE SERIES SUMMARY: This case series describes 2 dogs with predisposing risk factors of (1) right transvenous pacemaker terminating in its right ventricle, severe protein-losing nephropathy, and glucocorticoid therapy, and (2) caval syndrome, each having the LUS "wedge sign" in upper lung regions, a sign consistent with pulmonary infarction and peripheral PTE. NEW OR UNIQUE INFORMATION PROVIDED: Historically, the diagnosis of canine PTE has been made through supportive findings because the gold standard test, computed tomography pulmonary angiography (CTPA), poses limitations. The use of LUS has shown promise in people for detecting PTE, with the advantages of availability, being radiation- and contrast medium-sparing, rapid (<90 s), point-of-care, real-time information. Our cases suggest a possible new first-line approach for suspecting canine PTE by using LUS and the finding of the "wedge sign" in nongravity-dependent caudodorsal and perihilar lung regions.

Thirteen dogs and a cat with ultrasonographically detected gallbladder wall edema associated with cardiac disease.

BACKGROUND: Ultrasonographically detected gallbladder wall edema (GBWE) is a marker for anaphylaxis in dogs. Cardiac disease can cause GBWE with similar signs and should be included as a differential diagnosis to prevent interpretation errors. HYPOTHESIS/OBJECTIVES: Document GBWE associated with cardiac disease. ANIMALS: Fourteen client-owned animals. METHODS: Prospective case series with abdominal focused assessment with abdominal sonography in trauma, triage and tracking (AFAST), and thoracic focused assessment with abdominal sonography in trauma, triage, and tracking (TFAST) performed at triage. Animals with GBWE and cardiac disease were enrolled. A board-certified radiologist reviewed images to confirm cardiac disease, GBWE, and characterize the caudal vena cava (CVC) and hepatic veins. RESULTS: Thirteen dogs and 1 cat had GBWE associated with cardiac disease. Gallbladder findings included mural thickness ranging from 3 to 5 mm, mild to moderate sludge (n = 3), and mild to moderate luminal distension (n = 6). CVC and hepatic venous distension were found in 5/6. Cardiac diagnoses in dogs included 11 with pericardial effusion (PCE) and 1 each with dilated cardiomyopathy and right-sided myocardial failure. Severity of PCE was rated as mild (n = 1), moderate (n = 6), or severe (n = 4). Seven of 11 had pericardiocentesis performed. Nine of 13 had ascites with 4 having abdominal fluid scores of 1 (n = 2), 2 (n = 2), 3 (n = 1), and 4 (n = 0). Lung ultrasound findings were as follows: dry lung (n = 6), B-lines (n = 4), and nodules (n = 1). The cat had moderate PCE, ascites scored as 1, and severe right-sided ventricular enlargement associated with a ventricular septal defect. Primary presenting complaints included acute weakness (n = 9), acute collapse (n = 5), gastrointestinal signs (n = 3), respiratory distress (n = 2), and need for cardiopulmonary resuscitation (n = 1). CONCLUSIONS AND CLINICAL IMPORTANCE: Ultrasonographically detected GBWE was associated with PCE in this small cohort of cases.

Neurolymphomatosis caused by T-cell lymphosarcoma in a cat: imaging description and treatment review.

CASE SUMMARY: A 16-year-old domestic shorthair cat was evaluated for acute-onset right pelvic limb monoparesis localized to the sciatic nerve. MRI revealed a homogeneously contrast-enhancing, well-demarcated mass effacing the right sciatic nerve from its intravertebral origin to the end of the viewable field (mid-femur). Abdominal ultrasound revealed thickened small intestinal loops and enlarged mesenteric lymph nodes. Cytology of the small intestine was suggestive of lymphosarcoma. T-cell lymphosarcoma of the sciatic nerve and small intestines was confirmed with incisional biopsy. Treatment consisted of systemic chemotherapy with vincristine followed by the Wisconsin-Madison feline lymphosarcoma protocol, but despite treatment the patient neurologically worsened and was euthanized after 54 days. RELEVANCE AND NOVEL INFORMATION: We present herein one of the first descriptions of neurolymphomatosis in the domestic cat that included post-intravenous contrast MRI. Treatment options based on recommendations for people with neurolymphomatosis include systemic chemotherapy, intrathecal chemotherapy and/or localized radiation chemotherapy. The authors recommend that all cats be screened for concurrent non-neuronal areas of lymphosarcoma before undergoing treatment for neurolymphomatosis, regardless of clinical signs.

Assessment of humaneness using gunshot targeting the brain and cervical spine for cervid depopulation under field conditions.

Population reduction or eradication of domestic or non-domestic species may be required to address their impacts on the environment, other species, or human interests. Firearms are often used to accomplish these practical management objectives, and there is increased concern that the methods used may compromise animal welfare. We document the accuracy and humaneness of gunshot placement to the brain and cervical vertebrae of Philippine deer (Rusa marianna) on Guam during depopulation activities as a model for meeting AVMA standards of euthanasia under field conditions (e.g., animal is not in hand). Deer were shot with a .223 caliber rifle from 10-125 m and approached immediately (<20 s) for assessment. A subset of adult deer was further evaluated for physiological responses including cessation of heart rate, respiration, ocular reflexes, and post-mortem spasms. All deer shot in the brain (n = 132) and upper cervical spine (C1-C3; n = 18) died immediately due to the destruction of the brain or spinal tissue. Shot placements were all within 1.9 cm of the point of aim (i.e., the center of the target region). The accuracy and immediate insensibility resulting from targeting of C1-C3 demonstrates that this is an alternative target site when animal positioning is not optimal for targeting the brain, or there is a need to preserve brain tissue (e.g., Chronic Wasting Disease testing). While targeting of C4 -C7 vertebrae (n = 6) was accurate and resulted in immediate incapacitation, the failure to produce immediate insensibility does not support the use of this shot placement when upper cervical or brain shot placement is an option. It is reasonable to achieve sufficient accuracy to target the brain or upper cervical vertebrae of deer under field conditions and meet standards of euthanasia while accomplishing management objectives.

Physeal Acetabular Fracture in a Dog Treated with External Fixation.

An acetabular physeal fracture in a 13 wk old dog was treated with open fixation using Kirschner wire cross pins and a four-pin Type 1A external fixator, resulting in successful healing of the fracture. Three years following the surgery, marked osteoarthrosis of the affected hip was noted, although clinical function of the hip was good. The authors suggest this fixation method be considered a viable option for fixation of acetabular physeal fractures in dogs.

Retention of gadolinium in the brains of healthy dogs after a single intravenous administration of gadodiamide.

OBJECTIVE To determine brain region affinity for and retention of gadolinium in dogs after administration of gadodiamide and whether formalin fixation affects quantification. ANIMALS 14 healthy dogs. PROCEDURES 13 dogs received gadodiamide (range, 0.006 to 0.1 mmol/kg, IV); 1 control dog received a placebo. Dogs received gadodiamide 3 to 7 days (n = 8) or 9 hours (5) before euthanasia and sample collection. Brain regions were analyzed with inductively coupled mass spectrometry (ICP-MS) and transmission electron microscopy. Associations between dose, time to euthanasia, and gadolinium retention quantities (before and after fixation in 5 dogs) were evaluated. RESULTS Gadolinium retention was seen in all brain regions at all doses, except for the control dog. Exposure 3 to 7 days before euthanasia resulted in 1.7 to 162.5 ng of gadolinium/g of brain tissue (dose-dependent effect), with cerebellum, parietal lobe, and brainstem affinity. Exposure 9 hours before euthanasia resulted in 67.3 to 1,216.4 ng of gadolinium/g of brain tissue without dose dependency. Transmission electron microscopy revealed gadolinium in examined tissues. Fixation did not affect quantification in samples immersed for up to 69 days. CONCLUSIONS AND CLINICAL RELEVANCE Gadodiamide exposure resulted in gadolinium retention in the brain of healthy dogs. Cerebellum, parietal lobe, and brainstem affinity was detected with dose dependency only in dogs exposed 3 to 7 days before euthanasia. Fixation had no effect on quantification when tissues were immersed for up to 69 days. Physiologic mechanisms for gadolinium retention remained unclear. The importance of gadolinium retention requires further investigation.

Computed tomography, magnetic resonance imaging and a novel surgical approach of atlanto-axial instability with incongruence in dogs.

Atlanto-axial (AA) instability due to ligament insufficiency is a common cause of cervical spinal cord compression in toy breeds. However, in some dogs a difference in size between the atlas and the axis leads to joint incongruence that exacerbates AA subluxation and makes surgical treatment challenging. Twelve dogs with AA instability with incongruence were enrolled in a single institution prospective observational study. Computed tomography (CT) and magnetic resonance imaging (MRI) of the AA joint were compared to a retrospectively reviewed control group. A novel surgical approach consisting of a dorsal internal fixation technique was performed in six dogs. For affected dogs, the mean normalised difference between the dorso-ventral atlas canal and the dorso-ventral axis canal was 29.67% (median of 35.07%, standard deviation 25.64%), while in normal dogs a mean difference of 4.67% (median of 3.95%, standard deviation 5.21%) was observed. On MRI, 12/12 affected dogs had spinal cord compression, which was classified as reducible (3/12), partially reducible (6/12) and non-reducible (3/12). In surgically operated dogs, follow-up CT showed a partial or complete reduction of the previous spinal cord compression with a consistent amelioration or resolution of the presenting complaints. The proposed surgical technique was safe and effective in dogs with partially or completely reducible spinal cord compression.

Repair of a sliding (type I) hiatal hernia in a cat via herniorrhaphy, esophagoplasty and floppy Nissen fundoplication.

CASE SUMMARY: A 10-month-old domestic shorthair cat was evaluated for severe esophagitis and protracted vomiting and regurgitation secondary to a sliding (type I) hiatal hernia. The hernia and concurrent upper airway obstruction (nasopharyngeal polyp) were diagnosed with a multi-modality approach, including thoracic and abdominal radiographs, abdominal ultrasound, computed tomography and endoscopy. Following unsuccessful attempts at medical management, lower esophageal incompetence was successfully treated by employing a combination of surgical techniques, including herniorrhaphy, esophagopexy and modified (floppy) Nissen fundoplication. RELEVANCE AND NOVEL INFORMATION: A multi-modality imaging approach was valuable in completely assessing the extent of this cat's disease. Although an untraditional approach, the authors report herein the first clinical description of the use of combined surgical techniques with the floppy Nissen fundoplication technique (an antireflux procedure) in a cat. This procedure was used as a first-line surgical technique in this cat with severe lower esophageal incompetence, and may be a viable option for cases non-responsive to other therapeutic interventions. Further investigation of this surgical technique is warranted.

Treatment of pyloric stenosis in a cat via pylorectomy and gastroduodenostomy (Billroth I procedure).

CASE DESCRIPTION: A 5-month-old 1.9-kg (4.2-lb) spayed female Siamese cat was evaluated because of a history of decreased appetite, regurgitation, vomiting, and lack of weight gain. CLINICAL FINDINGS: Radiographic findings included a fluid- and gas-distended stomach with a small accumulation of mineral opacities. Ultrasonographic examination confirmed severe fluid distention of the stomach with multiple hyperechoic structures present and revealed protrusion of the thickened pylorus into the gastric lumen, with normal pylorogastric serosal continuity. Endoscopy of the upper gastrointestinal tract revealed an abnormally shortened pyloric antrum and stenotic pyloric outflow orifice. Pyloric stenosis resulting in pyloric outflow obstruction was diagnosed. TREATMENT AND OUTCOME: A pylorectomy with end-to-end gastroduodenostomy (Billroth I procedure) was successfully performed, and a temporary gastrostomy tube was placed. Six days after surgery, the cat was eating and drinking normally, with the tube only used for administration of medications. The gastrostomy tube was removed 12 days after surgery. Results of follow-up examination by the referring veterinarian 3 weeks after surgery were normal. Occasional vomiting approximately 2 months after surgery was managed medically. Fifteen months after surgery, the owners reported that the cat seemed completely normal in appearance and behavior. CLINICAL RELEVANCE: Pyloric stenosis should be considered a differential diagnosis for young cats with pyloric outflow obstruction. The cat of this report was treated successfully with a Billroth I procedure. Histologic examination and immunohistochemical analysis of the excised tissue showed the stenosis to be associated with hypertrophy of the tunica muscularis.