The most common types of uroliths larger than 1 mm are readily visible and accurately measured in an in vitro setting mimicking the canine abdomen using digital radiography.

Abdominal radiography is an important diagnostic to detect uroliths. Cystine and urate uroliths were historically characterized as nonmineral opaque on survey radiographs. However, recent research and clinical observations indicate that pure urate and cystine uroliths may be detected with digital radiography. The primary purpose of this prospective, in vitro, diagnostic accuracy study was to determine the sensitivity of digital radiography in detecting cystoliths of varying size and composition. Forty canine uroliths of pure composition (10 each of calcium oxalate, struvite, cystine, and urate), acquired from Minnesota Urolith Center and ranging from 1 to 10 mm, were placed in phantoms of three various sizes and radiographed. The radiographs, including three sets of each urolith separately, were evaluated by three blinded radiologists on two separate occasions. Evaluation included presence or absence of urolith, number of uroliths, and maximum diameter of the urolith(s). For all four types of uroliths and all readers, the specificity and PPV were 100% with an associated very high sensitivity (94.4%-98.9%) and NPV (94.8%-98.9%). Calcium oxalate uroliths were the most accurately measured and struvite were the least accurately measured when compared with the gross measurement. Smaller uroliths were more accurately measured than larger uroliths. Uroliths placed in smaller bladder phantoms were more accurately measured than in larger bladder phantoms. Though accurate measurement of uroliths is complicated by and dependent on numerous variables, our results reveal that urate and cystine uroliths are visualized on digital radiography making them a relevant differential diagnosis when seen clinically.

Magnetic Resonance Imaging Features of Extradural Spinal Neoplasia in 60 Dogs and Seven Cats.

This retrospective study describes the MRI features of extradural spinal neoplasia in 60 dogs and seven cats to identify potential distinguishing features between tumor classes and individual tumor types within each class. In dogs, mesenchymal tumors were most common (48%), with undifferentiated sarcomas being the predominant tumor type. Round cell neoplasms were second most common (35%), with lymphoma and multiple myeloma/plasma cell tumor comprising the majority of cases. Only two benign tumors were identified. In cats, lymphoma was most common (5/7), with one case of mesenchymal neoplasia and one case of metastatic carcinoma. Despite some overlap, certain imaging features were able to help prioritize differential diagnoses. The combined features that predicted round cell neoplasia (84%) included the preservation of vertebral shape, homogeneous contrast enhancement, and lesion centering on bone. The combined features that predicted mesenchymal neoplasia (73%) included altered vertebral shape, heterogeneous contrast enhancement, and lesion centering on paraspinal soft tissues. Round cell neoplasms were more likely to have cortical sparing, preservation of overall shape, lesion centering on bone, small soft tissue tumor size, and homogeneous contrast enhancement. Both epithelial and mesenchymal neoplasms were more likely to have cortical lysis, a cavitary component to the soft tissue mass and medium to large soft tissue mass size. The findings of this study can aid in prioritizing differential diagnoses in cases of extradural spinal neoplasia in cats and dogs, which can impact case management, but tissue sampling remains the gold standard for definitive diagnosis.

Novel CT Features of an Abdominal Gossypiboma in a Female Dog.

CASE DESCRIPTION: An eight-year-old Golden Retriever was presented with hypercalcemia and a complex abdominal mass. CLINICAL FINDINGS: A well-defined, heterogeneously contrast-enhancing, cavitary, soft tissue attenuating, non-organ associated abdominal mass was identified caudal to the right kidney. This mass was confluent with the distal tip of the right limb of the pancreas. A connected large, rim enhancing, cystic subcutaneous mass was also present in the right lumbar subcutaneous tissues, and there were multiple fistulous tracts through the hypaxial musculature. TREATMENT AND OUTCOME: The dog underwent a surgical exploratory laparotomy and a gossypiboma was removed from the intra-abdominal mass; the cystic extra-abdominal mass was drained percutaneously. Surgical recovery was uneventful and a follow-up CT after 3 months was consistent with resolving granulomatous inflammation and fibrosis. CLINICAL RELEVANCE: The presence of multiple peripherally enhancing tracts extending from the abdominal mass through the hypaxial musculature is a CT feature which has not yet been described in the veterinary literature. Additionally, incorporation of the pancreas into the abdominal mass has also not yet been described in the veterinary literature.

Use of cystoscopic-guided laser ablation for treatment of unilateral ureterovesicular stenosis and secondary orthotopic ureterocele in a female dog.

CASE DESCRIPTION A 4-year-old spayed female Beagle was evaluated because of a 2-month history of intermittent pollakiuria, stranguria, dysuria, and abdominal pain. A diagnosis of bacterial cystitis was initially made, but clinical signs persisted despite appropriate antimicrobial treatment, so the dog was referred for further evaluation and treatment. CLINICAL FINDINGS Abdominal ultrasonography revealed a large, thin-walled, cystic structure in the urinary bladder at the level of the expected right ureterovesicular junction that communicated with the uniformly dilated right ureter. Severe right-sided pyelectasia was also detected. A presumptive diagnosis was made of a right-sided orthotopic ureterocele with secondary hydroureter and pyelectasia. TREATMENT AND OUTCOME Cystoscopy revealed a large cystic structure in the region of the right ureterovesicular junction without obvious communication between the ureter and urinary bladder. Portable C-arm fluoroscopy was used to confirm the presence of an intramural orthotopic tract and to measure the diameter of the ureter and renal pelvis via retrograde contrast ureteropyelography. Complete laser ablation of the ureterocele was performed by incising it circumferentially near its base. Clinical signs resolved immediately following the procedure. Six weeks later, the dog remained free of clinical signs and abdominal ultrasonography revealed resolution of hydroureter with persistence of mild right-sided pyelectasia. CLINICAL RELEVANCE Cystoscopic-guided laser ablation of an orthotopic ureterocele secondary to ureterovesicular stenosis was a safe and effective minimally invasive treatment for the dog of this report, resulting in immediate and continued improvement of clinical signs and ultrasonographic changes. Laser ablation should be considered as an alternative to surgery for the treatment of orthotopic ureteroceles in dogs.