Diagnostic accuracy of optical coherence tomography for assessing surgical margins of canine soft tissue sarcomas in observers of different specialties.

OBJECTIVE: To determine the diagnostic accuracy of optical coherence tomography (OCT) to assess surgical margins of canine soft tissue sarcoma (STS) and determine the influence of observer specialty and training. STUDY DESIGN: Blinded clinical prospective study. ANIMALS: Twenty-five dogs undergoing surgical excision of STS. METHODS: In vivo and ex vivo surgical margins were imaged with OCT after tumor resection. Representative images and videos were used to generate a training presentation and data sets. These were completed by 16 observers of four specialties (surgery, radiology, pathology, and OCT researchers). Images and videos from data sets were classified as cancerous or noncancerous. RESULTS: The overall sensitivity and specificity were 88.2% and 92.8%, respectively, for in vivo tissues and 82.5% and 93.3%, respectively, for ex vivo specimens. The overall accurate classification for all specimens was 91.4% in vivo and 89.5% ex vivo. There was no difference in accuracy of interpretation of OCT imaging by observers of different specialties or experience levels. CONCLUSION: Use of OCT to accurately assess surgical margins after STS excision was associated with a high sensitivity and specificity among various specialties. Personnel of all specialties and experience levels could effectively be trained to interpret OCT imaging. CLINICAL SIGNIFICANCE: Optical coherence tomography can be used by personnel of different specialty experience levels and from various specialties to accurately identify canine STS in vivo and ex vivo after a short training session. These encouraging results provide evidence to justify further research to assess the ability of OCT to provide real-time assessments of surgical margins and its applicability to other neoplasms.

Percutaneous microwave ablation of solitary presumptive pulmonary metastases in two dogs with appendicular osteosarcoma.

OBJECTIVE: To describe percutaneous microwave ablation (MWA) of presumptive pulmonary metastases and the outcome of two dogs. ANIMALS: Two dogs with pulmonary lesions after treatment of spontaneously occurring appendicular osteosarcoma. STUDY DESIGN: Preliminary prospective clinical study. METHODS: Two large-breed dogs were referred from tertiary veterinary hospitals 146 and 217 days after limb amputation to pursue MWA as an alternative therapy to metastasectomy. Both dogs had been receiving chemotherapy protocols at their respective referral centers. RESULTS: A novel percutaneous approach for MWA with ultrasonographic or computed tomographic (CT) guidance was successfully performed. The only complications consisted of pneumothoraxes, requiring treatment in one dog. In the weeks after their procedures, both dogs were reported to do well at home. Dog 1 died and dog 2 was euthanized 82 and 19 days, respectively, after their MWA of confirmed (dog 1) or presumed (dog 2) metastatic disease. CONCLUSION: Percutaneous MWA of pulmonary nodules was technically feasible in two dogs without major complications. CLINICAL SIGNIFICANCE: Percutaneous MWA may provide a minimally invasive option for treatment of osteosarcoma pulmonary metastases. Additional studies are required to evaluate the benefits of MWA on survival and confirm histologic cell death within pulmonary neoplastic lesions.

CT attenuation values and mineral distribution can be used to differentiate dogs with and without gallbladder mucoceles.

Gallbladder mucoceles are potentially fatal in dogs. Multiphase CT angiography was performed to evaluate the canine gallbladder in three conditions: no sludge, sludge occupying ≥25% of the lumen, and mucoceles. Twenty dogs with normal hepatobiliary bloodwork and no-to-minimal gallbladder sludge, 13 dogs with normal bloodwork and ≥25% sludge in the gallbladder lumen, and 18 dogs with histologically confirmed gallbladder mucoceles were enrolled in a prospective, observational diagnostic accuracy study. Three regions of interest (ROI) were stratified in the dorsal-ventral orientation and a single ROI was measured within the hepatic parenchyma. Mean attenuation and presence of mineral were recorded. Average Hounsfield units (HU) were recorded for precontrast, arterial, portovenous, and late venous phases. The overall median HU value for mucoceles was significantly higher than gallbladders without sludge and with sludge; precontrast median overall attenuation was 49.3, 35.8, and 39.7 HU, respectively (P < .000004). Mineral was seen in four (20%) dogs with no sludge, seven (56%) dogs with sludge, and nine (50%) dogs with mucoceles. Mineral in the dogs with mucoceles was located within the central aspect of the gallbladder lumen in 67% of mucoceles; this mineral distribution was not seen in any dog without a mucocele. Computed tomography can differentiate a subset of gallbladder mucoceles from dogs with and without gallbladder sludge, especially in the precontrast series. An HU value of 48.6 is 52% sensitive and 96% specific for a gallbladder mucocele. A hyperattenuating gallbladder on precontrast CT images and centrally distributed mineral can be a gallbladder mucocele.

COMPUTED TOMOGRAPHIC FINDINGS IN 24 DOGS WITH LIPOSARCOMA.

Computed tomography (CT) continues to become more widely available for assessment of tumors in dogs, yet there are no studies describing the CT appearance of canine liposarcomas. In this retrospective, multicenter study, CT images of dogs with histologically confirmed liposarcomas were reviewed for size, location, attenuation, contrast enhancement, border definition, internal homogeneity, local infiltration, and mineralization. A total of 24 dogs with 26 liposarcomas were sampled. Mean attenuation was +15.2 (SD = 22.3) Hounsfield units (HU) with a range of -36 to +47.5 HU based on representative regions of interest. Twenty tumors (77%) contained focal areas of fat attenuation. All masses enhanced with contrast medium administration, which is distinct from what has been reported previously in infiltrative lipomas. Other CT features associated with canine liposarcomas included heterogeneous internal attenuation (81%) and lack of a clearly defined capsule (38%) suggesting infiltration of local structures. Six tumors (23%) had foci of mineralization. Findings from the current study indicated that liposarcoma should be considered as a differential diagnosis for mixed-attenuation, contrast-enhancing masses in dogs that contain at least one focus of fat attenuation on precontrast images; however, presence of foci of fat attenuation was not a necessary finding for the diagnosis of canine liposarcoma.