What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Multicenter evaluation of decompressive cystocentesis in the treatment of cats with urethral obstruction.

OBJECTIVE: To investigate whether decompressive cystocentesis (DC) safely facilitates urethral catheterization (UC) in cats with urethral obstruction (UO). ANIMALS: 88 male cats with UO. PROCEDURES: Cats were randomly assigned to receive DC prior to UC (ie, DC group cats; n = 44) or UC only (ie, UC group cats; 44). Abdominal effusion was monitored by serial ultrasonographic examination of the urinary bladder before DC and UC or before UC (DC and UC group cats, respectively), immediately after UC, and 4 hours after UC. Total abdominal effusion score at each time point ranged from 0 (no effusion) to 16 (extensive effusion). Ease of UC (score, 0 [easy passage] to 4 [unable to pass]), time to place urinary catheter, and adverse events were recorded. RESULTS: No significant difference was found in median time to place the urinary catheter in UC group cats (132 seconds), compared with DC group cats (120 seconds). Median score for ease of UC was not significantly different between UC group cats (score, 1; range, 0 to 3) and DC group cats (score, 1; range, 0 to 4). Median change in total abdominal effusion score from before UC and DC to immediately after UC was 0 and nonsignificant in UC group cats (range, -5 to 12) and DC group cats (range, -4 to 8). Median change in effusion score from immediately after UC to 4 hours after UC was not significantly different between UC group cats (score, -1; range, -9 to 5) and DC group cats (score, -1; range, -7 to 5). CONCLUSIONS AND CLINICAL RELEVANCE: DC did not improve time to place the urinary catheter or ease of UC in cats with UO.

Serial abdominal radiographs do not significantly increase accuracy of diagnosis of gastrointestinal mechanical obstruction due to occult foreign bodies in dogs and cats.

Abdominal radiographs are commonly used in dogs and cats that present with gastrointestinal signs. When initial abdominal radiographs are equivocal for the presence or absence of gastrointestinal mechanical obstruction, follow-up abdominal radiographs may be recommended. Based on our review of the literature, no published study has been performed to evaluate the clinical utility of serial abdominal radiographs in such cases. The purpose of this study is to determine whether follow-up abdominal radiographs increase diagnostic accuracy for mechanical obstruction. A prospective cohort study was performed on client-owned dogs and cats with clinical concern for gastrointestinal mechanical obstruction and initial abdominal radiographs inconclusive for the presence of obstruction. Follow-up abdominal radiographs were performed between 7 and 28 h of the initial radiographs; an abdominal ultrasound performed within 3 h of the follow-up study served as the gold standard. A total of 57 patients (40 dogs and 17 cats) were recruited; 19 of 57 cases (11 dogs; 8 cats) were mechanically obstructed, all with nonradiopaque foreign bodies. Four blinded reviewers (2 radiologists, 1 radiology resident, 1 criticalist) separately assessed the initial and the combined initial/follow-up radiographic studies for diagnosis of mechanical obstruction; for each observer, there was no significant change in accuracy (P = .058-.87) for the diagnosis of mechanical obstruction. Given the lack of significant increase in diagnostic accuracy using follow-up radiographs in cases of occult gastrointestinal mechanical obstruction, other diagnostic options (eg, abdominal ultrasonography) could be considered when survey abdominal radiographs are inconclusive for the diagnosis of mechanical obstruction in dogs and cats.

Radiography and ultrasonography of pneumatosis intestinalis in a cat.

An adult cat was presented for acute history of vomiting and collapse. Radiographs showed the presence of air within small intestinal walls and arborizing gas patterns within the liver, compatible with pneumatosis intestinalis and presumed portal venous gas, respectively. An abdominal ultrasound the following day was suggestive of gas within the intestinal wall, however, gas within the hepatic vasculature, parenchyma, or biliary tree was not evident. Due to progressive clinical deterioration of the patient, the owners elected humane euthanasia. Necropsy revealed severe necrotizing hemorrhagic enterotyphlocolitis secondary to Clostridium difficile toxin.

Nodules and masses are associated with malignant pleural effusion in dogs and cats but many other intrathoracic CT features are poor predictors of the effusion type.

Thoracic CT may be used in the workup of patients with pleural effusion. In humans, certain pleural features on CT aid in diagnosing an underlying cause for pleural effusion, whereas this is not well studied in veterinary medicine. This retrospective cross-sectional analytical study assessed pleural and other intrathoracic abnormalities on CT in dogs and cats with pleural effusion and explored potential discriminatory features between effusion types. Eighty-nine dogs and 32 cats with pleural cytology and/or histopathology were categorized into malignant pleural disease (15 dogs and 11 cats), pyothorax (34 dogs and 7 cats), chylothorax (20 dogs and 11 cats), transudative (11 dogs and 2 cats), and hemorrhagic effusion (9 dogs and 1 cat). Multivariable logistic regression analysis comparing malignancy to other effusions found that older patient age (dogs: odds ratio 1.28, P = 0.015; cats: odds ratio 1.53, P = 0.005), nodular diaphragmatic pleural thickening (dogs: odds ratio 7.64, P = 0.021; cats: odds ratio 13.67, P = 0.031), costal pleural masses (dogs: odds ratio 21.50, P = 0.018; cats: odds ratio 32.74, P = 0.019), and pulmonary masses (dogs: odds ratio 44.67, P = 0.002; cats: odds ratio 18.26, P = 0.077) were associated with malignancy. In dogs, any costal pleural abnormality (odds ratio 47.55, P = 0.002) and pulmonary masses (odds ratio 10.05, P = 0.004) were associated with malignancy/pyothorax, whereas any costal pleural abnormality (odds ratio 0.14, P = 0.006) and sternal lymphadenopathy (odds ratio 0.22, P = 0.040) were inversely associated with transudates. There were, however, many overlapping abnormalities between effusion types, so further diagnostic testing remains important for diagnosis.

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING OF A NEURONAL HETEROTOPIA IN THE BRAIN OF A CAT.

A domestic shorthair kitten was presented for evaluation and further treatment of seizures. Magnetic resonance imaging of the brain revealed a large multilobulated mass in the third ventricle extending into the right lateral ventricle with secondary obstructive hydrocephalus. The mass was homogeneously isointense to gray matter on T2W, T2-FLAIR, T2* W, T1W, and ADC images, and hyperintense on DW-EPI. There was no appreciable contrast enhancement. Seizures were managed medically and with subsequent ventriculoperitoneal shunt placement. Clinical status later deteriorated and the cat was euthanized. Histopathology confirmed that the mass was the result of neuronal heterotopia. To the authors' knowledge this is the first report of neuronal heterotopia in a cat.

MAGNETIC RESONANCE IMAGING FEATURES OF INTRAVENTRICULAR EPENDYMOMAS IN Five CATS.

Intraventricular ependymoma is a rare type of feline intracranial neoplasia and published information on magnetic resonance imaging (MRI) characteristics is currently lacking. The purpose of this retrospective case series study was to describe the clinical and MRI characteristics of histopathologically confirmed intraventricular ependymomas in a group of cats. Five cats met inclusion criteria. In relation to normal gray matter, ependymomas appeared hyperintense on T2W, T2W-FLAIR, PD, and DW-EPI images; isointense on ADC images; and had subtle to strong contrast enhancement. Some variability was seen on T2*GRE and on T1W images with masses being isointense to hyperintense. Four ependymomas were small and homogeneous, and one was centrally cavitated. All cats had obstructive hydrocephalus, transtentorial herniation, and foramen magnum herniation. Perilesional edema was identified in most cats but was questionable in one. Intraventricular ependymoma should be considered as a differential diagnosis for cats with this combination of MRI signs.

Factors associated with pathological fractures in dogs with appendicular primary bone neoplasia: 84 cases (2007-2013).

OBJECTIVE: To determine the incidence of pathological fractures associated with appendicular primary bone tumors in dogs managed medically and to identify potential risk factors at the time of radiographic diagnosis that may be associated with eventual pathological fracture. DESIGN: Retrospective case series. ANIMALS: 84 dogs with primary long bone neoplasia treated medically. PROCEDURES: Medical records for dogs with a diagnosis of primary long bone neoplasia based on results of radiography that was confirmed subsequently at necropsy were reviewed. Owners elected medical treatment at a pain clinic. Data regarding clinical signs, diagnostic testing, pathological findings, and outcome were evaluated. RESULTS: 84 dogs met study inclusion criteria with 85 limbs affected. Osteosarcoma was the most common tumor and was identified in 78 of 85 (91.8%) limbs. The median time from diagnosis to euthanasia was 111 days (range, 28 to 447 days). Pathological fractures were identified in 33 of 85 limbs (38%), with the femur most commonly affected, (8/14 [57.1%]), followed by the tibia (9/17 [52.9%]), humerus (10/27 [37%]), radius (5/25 [20%]), and ulna (1/2 [50%]). Logistic regression analysis indicated that tumors arising from long bones other than the radius had odds of eventual fracture 5.05 as great as the odds for tumors of the radius, and lytic tumors had odds of eventual fracture 3.22 as great as the odds for tumors that appeared blastic or mixed lytic-blastic. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that radial primary bone tumors were less likely and lytic tumors were more likely to fracture. The overall incidence of pathological fractures secondary to appendicular primary bone neoplasia in this study with patients treated by means of intensive management for bone pain was higher than previously reported.

Computed tomographic features of pneumothorax secondary to a bronchopleural fistula in two dogs.

A bronchopleural fistula (BPF) can lead to continuous pneumothorax and is rarely reported clinically in dogs. This report describes computed tomographic (CT) findings in two dogs with BPFs and subsequent continuous pneumothoraces that necessitated thoracotomy. Both dogs had a peripheral BPF in the right caudal lung lobe. The fistula in one dog was secondary to a previous foreign body migration, and the fistula in the other was thought to be secondary to dirofilariasis. On both CT examinations, a dilated subsegmental bronchus was seen communicating with the pleural space at the center of a focal, concave region of parenchymal consolidation. Multiplanar reformatting aided in identification and characterization of the BPF. The pneumothoraces resolved after right caudal lobectomy in both dogs. CT has the potential to identify BPFs, such as secondary to foreign body migration or dirofilariasis.

Sensitivity, positive predictive value, and interobserver variability of computed tomography in the diagnosis of bullae associated with spontaneous pneumothorax in dogs: 19 cases (2003-2012).

OBJECTIVE: To determine the sensitivity, positive predictive value, and interobserver variability of CT in the detection of bullae associated with spontaneous pneumothorax in dogs. DESIGN: Retrospective case series. ANIMALS: 19 dogs with spontaneous pneumothorax caused by rupture of bullae. PROCEDURES: Dogs that had CT for spontaneous pneumothorax caused by rupture of bullae confirmed at surgery (median sternotomy) or necropsy were included. Patient signalment, CT protocols, and bulla location, size, and number were obtained from the medical records. Computed tomographic images were reviewed by 3 board-certified radiologists who reported on the location, size, and number of bullae as well as the subjective severity of pneumothorax. RESULTS: Sensitivities of the 3 readers for bulla detection were 42.3%, 57.7%, and 57.7%, with positive predictive values of 52.4%, 14.2%, and 8.4%, respectively, with the latter 2 readers having a high rate of false-positive diagnoses. There was good interobserver agreement (κ = 0.640) for correct identification of bullae. Increasing size of the bulla was significantly associated with a correct CT diagnosis in 1 reader but not in the other 2 readers. Correct diagnosis was not associated with slice thickness, ventilation protocol, or degree of pneumothorax. CONCLUSIONS AND CLINICAL RELEVANCE: Sensitivity and positive predictive value of CT for bulla detection were low. Results suggested that CT is potentially an ineffective preoperative diagnostic technique in dogs with spontaneous pneumothorax caused by bulla rupture because lesions can be missed or incorrectly diagnosed. Bulla size may affect visibility on CT.

Imaging findings in 14 domestic ferrets (Mustela putorius furo) with lymphoma.

Lymphoma is the most common malignant neoplasia in domestic ferrets, Mustela putorius furo. However, imaging findings in ferrets with lymphoma have primarily been described in single case reports. The purpose of this retrospective study was to describe imaging findings in a group of ferrets with confirmed lymphoma. Medical records were searched between 2002 and 2012. A total of 14 ferrets were included. Radiographs (n = 12), ultrasound (n = 14), computed tomography (CT; n = 1), and magnetic resonance imaging (MRI; n = 1) images were available for review. Median age at the time of diagnosis was 5.2 years (range 3.25-7.6 years). Clinical signs were predominantly nonspecific (8/14). The time between the first imaging study and lymphoma diagnosis was 1 day or less in most ferrets (12). Imaging lesions were predominantly detected in the abdomen, and most frequently included intra-abdominal lymphadenopathy (12/14), splenomegaly (8/14), and peritoneal effusion (11/14). Lymphadenopathy and mass lesions were typically hypoechoic on ultrasound. Mild peritoneal effusion was the only detected abnormality in two ferrets. Mild pleural effusion was the most common thoracic abnormality (3/12). Expansile lytic lesions were present in the vertebrae of two ferrets with T3-L3 myelopathy and the femur in a ferret with lameness. Hyperattenuating, enhancing masses with secondary spinal cord compression were associated with vertebral lysis in CT images of one ferret. The MRI study in one ferret with myelopathy was inconclusive. Findings indicated that imaging characteristics of lymphoma in ferrets are similar to those previously reported in dogs, cats, and humans.

Comparison between bolus tracking and timing-bolus techniques for renal computed tomographic angiography in normal cats.

Renal dual-phase computed tomograpic angiography (CTA) is used to assess suitability of feline donors prior to transplantation. A prerequisite for successful CTA is optimal synchronization between the arterial passage of contrast material and CT data acquisition. This retrospective study was conducted to compare quality of renal vascular enhancement at dual-phase CTA in normal cats between two techniques of timing of data acquisition: the timing-bolus and the bolus tracking method. Nine cats were scanned using the timing-bolus technique and 14 with the bolus tracking technique using otherwise similar scanning parameters in a 16-slice multidetector row CT scanner. The quality of enhancement of the renal vessels at the scanned arterial phase and venous phase was assessed both subjectively and objectively by three board-certified radiologists. Arterial enhancement was not observed at the scanned arterial phase in three of the nine cats with the timing-bolus technique but only 1 of the 14 cats with the bolus tracking technique. Early venous enhancement at the scanned arterial phase was common with the bolus tracking technique. Data acquisition was significantly faster with the bolus tracking technique. We conclude that the bolus tracking technique is a valid technique that could be integrated into the routine protocol for 16-detector row CT renal angiography in cats.

Presumptive central nervous system cuterebriasis and concurrent protein-losing nephropathy in a dog.

OBJECTIVE: To describe the clinical course and successful management of a dog suspected to have central nervous system (CNS) Cuterebra larval migration and concurrent protein-losing nephropathy (PLN). CASE SUMMARY: A 1-year-old castrated male mixed breed dog was diagnosed with presumptive CNS cuterebriasis based on history, progressively deteriorating mentation, seizures, and magnetic resonance images showing a tubular lesion consistent with a migrating Cuterebra tract. Additionally, serum biochemistry and urine analyses revealed the development of a severe PLN. Surgical removal of the Cuterebra was attempted unsuccessfully, and subsequently, the dog was treated with ivermectin, antihistamines, anticonvulsants, and a tapering dose of glucocorticoids. Over several weeks the dog's neurologic status improved and the PLN resolved completely. NEW OR UNIQUE INFORMATION PROVIDED: This case describes successful management of presumptive CNS cuterebriasis in a dog. It is also, to our knowledge, the first report of PLN associated with cuterebriasis in the veterinary literature.

Usefulness of a half-fourier acquisition single-shot turbo spin-echo pulse sequence in identifying arachnoid diverticula in dogs.

Single-shot turbo spin-echo sequences are heavily T2-weighted sequences that are exceptionally well suited to evaluate the subarachnoid space. In the T2-weighted fast spin-echo sequences that are used routinely in spinal magnetic resonance (MR) imaging, the subarachnoid space is not well differentiated from the surrounding epidural fat, which could lead to decreased detection of lesions of the subarachnoid space such as arachnoid diverticula. Our purpose was to determine the added value of a single-shot turbo spin-echo sequence in identifying cystic lesions of the subarachnoid space in dogs. MR images of six dogs with a confirmed arachnoid diverticulum and 24 dogs with other spinal disease were included. Six observers were asked to interpret only T2-weighted images initially, and in a second session, T2-weighted and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. The MR images were anonymized, and no signalment, history, or clinical information was provided. Without the HASTE sequences, 25% of arachnoid diverticula were identified. Adding the HASTE sequence increased the diagnosis of arachnoid diverticulum to 52.8%. The resulting difference, after adding the HASTE sequence, of 27.8% was statistically significant (P = 0.002). No false-positive diagnoses of arachnoid diverticulum were made with either sequence. Although sensitivity in this study was likely artificially low, the significantly increased detection rate of arachnoid diverticula when using HASTE imaging indicates that this sequence is a valuable addition to MR imaging protocols for the canine spine.

Contrast enhancement of extradural compressive material on magnetic resonance imaging.

Gadolinium-enhancement of compressive extradural material is detected occasionally with magnetic resonance (MR) imaging in dogs. Our goal was to characterize contrast enhancement of extradural compressive material associated with intervertebral disc herniation, and to evaluate the association between enhancement and histopathologic findings and the onset of clinical signs. Ninety-three dogs with a total of 99 lesions diagnosed as intervertebral disc herniation on MR imaging were assessed. Images were evaluated for lesion location, type of herniation, degree of compression, intramedullary T2-weighted (T2W) intensities, and contrast enhancement. In 23 dogs, surgically removed compressive material was evaluated histopathologically for hemorrhage, inflammation, neovascularization, fibroplasia, fibrosis, mineralization, necrosis, and chronicity. Contrast enhancement of extradural compressive material, meninges, and both the compressive materials and meninges was present in 51.5%, 39.4%, and 17.2% of lesions, respectively. Extradural enhancement occurred more frequently in extrusions than protrusions (P = 0.001). Meningeal enhancement and more severe neurologic deficits were significantly associated with a shorter duration of clinical signs (P = 0.04 and 0.01, respectively). Intramedullary T2W hyperintensities, present with 44.4% of lesions, were associated with more severe neurologic deficits (P = 0.001). Lesions with extradural enhancement were more often considered subacute to chronic in duration and more frequently associated with hemorrhage compared with nonenhancing material; however, no statistically significant association was established between contrast enhancement and histopathologic findings. Contrast enhancement of extradural compressive material and the meninges was found to be common with intervertebral disc herniation, and should not be interpreted as a specific sign of a mass lesion such as neoplasia.