Kenji Kutara

Triple-phase helical computed tomography in dogs with hepatic masses.

The purpose of this study was to determine the utility of triple-phase helical computed tomography (CT) for differentiating canine hepatic masses. Seventy dogs with hepatic masses underwent triple-phase CT followed by surgical removal of the hepatic masses. Triple-phase helical CT scans for each dog included precontrast, arterial phase, portal venous phase, and delayed phase studies. The removed hepatic masses were histopathologically classified as hepatocellular carcinoma (n = 47), nodular hyperplasia (n = 14), and hepatic metastatic tumors (n = 9) in dogs. Of the 47 hepatocellular carcinomas, the most common CT findings included a heterogeneous pattern with hyper-, iso-, and hypoenhancement in both the arterial and portal venous phases (40/47, 85.1%). Of the 14 nodular hyperplasias, the most common CT findings were a homogeneous pattern with hyper- and isoenhancement in both the portal venous and delayed phases (13/14, 92.9%). Of nine hepatic metastatic tumors, the most common CT findings included a homogeneous hypoenhancement pattern in both the arterial and portal venous phases (8/9, 88.9%). In addition, 5 (55.6%) showed homogeneous hypoenhancement patterns in the delayed phase. Findings from our study indicated that triple-phase CT is a useful tool for preoperative differentiation of hepatocellular carcinoma, nodular hyperplasia, and hepatic metastatic tumors in dogs.

Preoperative Differential Diagnosis of Canine Adrenal Tumors Using Triple-Phase Helical Computed Tomography.

OBJECTIVE To characterize the computed tomography (CT) findings for canine adrenal tumors, including cortical adenoma, cortical adenocarcinoma, and pheochromocytoma, and to evaluate the feasibility and usefulness of preoperative triple-phase helical CT for differentiation of tumor types and surgical planning. STUDY DESIGN Retrospective study. ANIMALS Dogs with adrenal tumors (n=36). METHODS All dogs underwent triple-phase helical CT, followed by adrenalectomy and histopathological diagnosis of the resected mass. Precontrast images, arterial, venous, and delayed phase images were obtained. In all cases, morphological characteristics and CT values and calculations, including the percentage enhancement washout ratio, relative percentage washout, enhancement washin, and enhancement washout, were analyzed and compared among the tumor types. RESULTS Of the 36 dogs with adrenal masses, cortical adenocarcinoma was most commonly diagnosed (16 dogs), followed by pheochromocytoma (13 dogs), and cortical adenoma (7 dogs). The precontrast minimum CT value and enhancement washout between venous and delayed phases in the cortical adenoma were significantly higher than those in the cortical adenocarcinoma. The maximum CT values of the precontrast image and arterial and venous phases, the enhancement washin and washouts, percentage enhancement washout ratio, and relative percentage washout in the pheochromocytomas were significantly higher than those in cortical adenocarcinoma. CONCLUSION The differential diagnosis of canine adrenal tumors was feasible based on triple-phase CT findings, including morphological features, CT values, and intratumoral contrast attenuation. Preoperative diagnosis using triple-phase helical CT may be useful for surgical planning in dogs with adrenal tumors.

Determination of Porto-Azygos Shunt Anatomy in Dogs by Computed Tomography Angiography

OBJECTIVE To describe the morphology of porto-azygos shunts in a large series of dogs using computed tomography (CT) angiography. STUDY DESIGN Retrospective study. ANIMALS Dogs (n=36) with porto-azygos shunts. METHODS CT angiography was performed in dogs subsequently proven to have a porto-azygos shunt. The origin and insertion of the shunts were assessed on native images. The diameter of the porto-azygos shunt and the portal vein, cranial and caudal to the shunt origin, were measured. The porto-azygos shunt anatomy was studied on three-dimensional images. RESULTS All porto-azygos shunts originated either in the left gastric vein (33 left gastro-azygos shunts) or the right gastric vein (3 right gastro-azygos shunts). Two left gastro-azygos shunts had concurrent caval-azygos continuation and 2 right gastro-azygos shunts had a caudal splenic loop. All shunts crossed the diaphragm through the esophageal hiatus. The majority of porto-azygos shunts (32) followed a straight pathway after traversing the diaphragm, although 4 shunts followed a tortuous route. All shunts terminated in the thoracic part of the azygos vein, perpendicular to the aorta. The shunt diameter at insertion was only 3 mm on average. The insertion site was consistently the narrowest part of the shunt. CONCLUSION CT angiography was well suited to provide anatomic details of porto-azygos shunts and comprehensively documented that all porto-azygos shunts had a thoracic terminus, after crossing the diaphragm through the esophageal hiatus. Different shunt types existed with minor variations.

Gallbladder Agenesis in 17 Dogs: 2006-2016

Background Gallbladder agenesis (GBA) is extremely rare in dogs. Hypothesis/Objectives To describe the history, clinical signs, diagnosis, treatment, and outcomes of dogs with GBA. Animals Seventeen client‐owned dogs with GBA. Methods Medical records from 2006 through 2016 were retrospectively reviewed. Dogs were included when GBA was suspected on abdominal ultrasonography and confirmed by gross evaluation. Signalment, clinical signs, clinicopathological data, diagnostic imaging, histopathology, treatment, and outcome were recorded. Results Dogs were of 6 different breeds, and Chihuahuas (10 of 17) were most common. Median age at presentation was 1.9 (range, 0.7–7.4) years. Clinical signs included vomiting (5 of 17), anorexia (2 of 17), ascites (2 of 17), diarrhea (1 of 17), lethargy (1 of 17), and seizures (1 of 17). All dogs had increased serum activity of at least 1 liver enzyme, most commonly alanine aminotransferase (15 of 17). Fifteen dogs underwent computed tomography (CT) cholangiography; common bile duct (CBD) dilatation was confirmed in 12, without evidence of bile duct obstruction. Gross evaluation confirmed malformation of the liver lobes in 14 of 17 dogs and acquired portosystemic collaterals in 5 of 17. Ductal plate malformation was confirmed histologically in 16 of 17 dogs. During follow‐up (range, 4–3,379 days), 16 of 17 dogs remained alive. Conclusions and Clinical Importance Dogs with GBA exhibit clinicopathological signs of hepatobiliary injury and hepatic histopathological changes consistent with a ductal plate abnormality. Computed tomography cholangiography was superior to ultrasound examination in identifying accompanying nonobstructive CBD distention. Computed tomography cholangiography combined with laparoscopic liver biopsy is the preferable approach to characterize the full disease spectrum accompanying GBA in dogs.

CT cholangiography in dogs with gallbladder mucocoele

OBJECTIVES To summarise CT cholangiography findings in dogs with gallbladder mucocoele. MATERIALS AND METHODS Each of 10 dogs with gallbladder mucocoele underwent CT cholangiography using meglumine iotroxate before cholecystectomy. The following structures of the biliary system were evaluated: the right and left hepatic ducts, common hepatic duct, cystic duct, common bile duct and gallbladder. RESULTS The hepatic duct, cystic duct, common bile duct and gallbladder were imaged by contrast-enhanced CT cholangiography. The passage of the contrast medium through the bile duct into the duodenum was visible in nine dogs. The curved planar reformation images of two dogs showed they had filling defects in the bile duct system. In one dog with hyperbilirubinaemia due to chronic hepatitis, the bile duct system was not completely contrast-enhanced. Surgical exploration revealed no evidence of common bile duct obstruction in any dog. CLINICAL SIGNIFICANCE CT cholangiography delineates the structural characteristics of the biliary system and partially estimates its patency in dogs with gallbladder mucocoele. Therefore this procedure may be useful as a preoperative screen of the bile duct system in dogs with gallbladder mucocoele.

IMAGING DIAGNOSIS - ECTOPIC SPLEEN MIMICKING HEPATIC TUMOR WITH INTRA-ABDOMINAL METASTASES INVESTIGATED VIA TRIPLE-PHASE HELICAL COMPUTED TOMOGRAPHY IN A DOG.

A 10-year-old castrated male miniature dachshund was presented with an abdominal mass. The dog had a history of splenectomy. Triple-phase helical computed tomography was utilized, revealing a hepatic mass and multiple intra-abdominal solid masses. In triple-phase helical computed tomography the images, hepatic mass and two of four intra-abdominal masses were heterogenous in all phases. Therefore, we diagnosed a malignant hepatic tumor and presumed intra-abdominal metastases. The masses were surgically removed and were histologically composed of normal spleen tissues, findings which were consistent with ectopic spleen.

Triple-phase helical computed tomography in dogs with solid splenic masses

We investigated the utility of triple-phase helical computed tomography (CT) in differentiating between benign and malignant splenic masses in dogs. Forty-two dogs with primary splenic masses underwent triple-phase helical CT scanning (before administration of contrast, and in the arterial phase, portal venous phase, and delayed phase) prior to splenectomy. Tissue specimens were sent for pathological diagnosis; these included hematomas (n=14), nodular hyperplasias (n=12), hemangiosarcomas (n=11), and undifferentiated sarcomas (n=5). The CT findings were compared with the histological findings. Nodular hyperplasia significantly displayed a homogeneous normal enhancement pattern in all phases. Hemangiosarcoma displayed 2 significant contrast-enhancement patterns, including a homogeneous pattern of poor enhancement in all phases, and a heterogeneous remarkable enhancement pattern in the arterial and portal venous phases. Hematoma and undifferentiated sarcoma displayed a heterogeneous normal enhancement pattern in all phases. The contrast-enhanced volumetric ratios of hematoma tended to be greater than those of undifferentiated sarcoma. Our study demonstrated that the characteristic findings on triple-phase helical CT could be useful for the preoperative differentiation of hematoma, nodular hyperplasia, hemangiosarcoma, and undifferentiated sarcoma in dogs. Triple-phase helical CT may be a useful diagnostic tool in dogs with splenic masses.

Triple-phase helical computed tomography of an arterio-hepatic venous shunt in a hepatic tumor in a dog

A 10-year-old French bulldog presented with an abdominal tumor. Triple-phase helical computed tomography was performed, revealing a hepatic tumor, an enlarged hepatic lymph node, and no masses in other organs. The hepatic tumor demonstrated marked enhancement, similar to that of the aorta in the arterial phase. The tumor had rich vascularization and a hepatic arterio-venous shunt formed between the hepatic artery and middle hepatic vein. The hepatic tumor was surgically removed and histological diagnosis revealed a hepatic carcinoid tumor. During surgery, rapid massive arterial hemorrhage occurred from the site of the incision. The animal died without improvement post-surgery. In the case of an arterio-venous shunt in a hepatic tumor, it is important to be careful to avoid perioperative bleeding.

Gene Expression of Growth Factors and Growth Factor Receptors for Potential Targeted Therapy of Canine Hepatocellular Carcinoma

ABSTRACT The purpose of this study was to evaluate the gene expression of growth factors and growth factor receptors of primary hepatic masses, including hepatocellular carcinoma (HCC) and nodular hyperplasia (NH), in dogs. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed to measure the expression of 18 genes in 18 HCCs, 10 NHs, 11 surrounding non-cancerous liver tissues and 4 healthy control liver tissues. Platelet-derived growth factor-B (PDGF-B), transforming growth factor-α, epidermal growth factor receptor, epidermal growth factor and hepatocyte growth factor were found to be differentially expressed in HCC compared with NH and the surrounding non-cancerous and healthy control liver tissues. PDGF-B is suggested to have the potential to become a valuable ancillary target for the treatment of canine HCC.