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.

Epidemiologic study of dogs with the displacement or deformity of the medial and lateral fabellae in Japan.

The prevalences of displacement and deformity of the medial and lateral fabellae in dogs were investigated. This was a retrospective epidemiologic study. Radiographs of canine stifle joints (1022 limbs, 534 dogs) were obtained. The images were taken at the Nihon University Animal Medical Center and three private animal hospitals from January 2003 to July 2012. The position and morphology of the medial or lateral fabella were evaluated on the radiographs. The prevalence of displacement of the medial and lateral fabellae was 1.7% and 0.3%, respectively. The prevalence of deformity of the medial and lateral fabellae was 6.9% and 4.6%, respectively. Aplasia or hypoplasia of the fabella was detected more frequently in the medial fabella. On the other hand, a bipartite or multipartite fabella was observed more frequently in the lateral fabella. Nearly all cases of displacement or deformity of the fabella occurred in dogs weighing less than 10 kg. Abnormalities of the fabella were observed in the medial and lateral fabella. We found that abnormal fabellae were closely associated with medial patellar luxation and to a lesser extent with cranial cruciate ligament rupture. No clinical signs were associated with an abnormality of the fabella, with the exception of two dogs with traumatic avulsion of the lateral head of the gastrocnemius muscle.

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.

Retrospective analysis of perineal herniorrhaphy with cone-shaped polypropylene mesh in dogs: technique description and outcome.

Introduction: This study aimed to describe the technique for the surgical repair of perineal hernia (PH) in dogs using a polypropylene mesh (PM) and to evaluate its outcomes. Methods: All dogs were placed in the Trendelenburg position. Castration and caudal celiotomy for cystopexy and colopexy were performed as needed. Ipsilateral perianal incision was performed in the affected hernia side. A PM was formed a cone-shape with suturing and placed in hernial foramen. The PH was repaired with suturing between PH and pelvic diaphragm including the sacrotuberous ligament, internal obturator muscle, and external anal sphincter muscle. The medical records of all dogs were reviewed to evaluate signalment, perioperative findings, postoperative complications, and prognosis. Results: Of the 22 dogs, 15 were intact, and 7 were previously neutered. The median age and body weight were 10 years and 6.8 kg, respectively. The PH reconstruction using a cone-shaped PM was feasible in all dogs. The median operative time was 60.5 min for unilateral PH and 109 min for bilateral PH. Major postoperative complications occurred in seven dogs (32%), and three dogs (14%) had a recurrence of PH. In the long-term (> 2 weeks) follow-up period, 16 dogs (73%) had an excellent prognosis. Discussion: Our study suggests that PH reconstruction surgery using a cone-shaped PM may be a viable treatment method for PH in dogs. Therefore, a cone-shaped PM could serve as an alternative treatment option for canine PH reconstruction.

Perineal herniorrhaphy with pedunculated tunica vaginalis communis in dogs: Description of the technique and clinical case series.

Background: Perineal hernia (PH) in dogs is caused by the separation of the anal septal muscles and the displacement of pelvic/abdominal organs under the perineal skin. Reconstruction of the pelvic septum by surgical repositioning is the only curative treatment. Objectives: To describe the procedure and outcomes of surgical repair using the pedunculated tunica vaginalis communis (TVC) for PH in dogs. Methods: Intact male dogs diagnosed with PH were included in this study. For surgery, each dog was positioned in the Trendelenburg position. Castration was performed with the open technique, followed by colopexy and cystopexy via laparotomy. The remaining bilateral TVCs transposed to the opening of PH were used for the perineal herniorrhaphy. Intraoperative findings, complications, and outcomes were evaluated and recorded. Results: Eight dogs [median age 10.5 years (range, 9-13 years); median body weight 4.9 kg (range, 1.6-12.3 kg)] were treated using the TVC surgical technique. Perineal herniorrhaphy with the TVC was feasible in all dogs. The median operation time was 105.5 min (range, 46-149 min) in unilateral PH, and 92 and 122 min in two dogs with bilateral PH. Short-term postoperative complications during hospitalization did not occur in six dogs, whereas the residual two dogs had a temporary local infection as a minor complication. Postoperative recurrence occurred in one dog (13%) on postoperative day 136. Conclusions: Our study suggests that the herniorrhaphy technique using the pedunculated TVC is an alternative option for the repair of PH in dogs.

En block resection of a large hepatocellular carcinoma involving the caudal vena cava in a dog.

A 13-year-old neutered female Shih Tzu was referred for investigation of a cranial abdominal mass. Investigations including conventional radiography, abdominal ultrasonography and computed tomography confirmed the mass in the caudate lobe of the liver. As a collateral vein originating from the caudal vena cava (CVC) communicated with the azygos vein, the CVC was ligated and transected cranial to the right renal vein and cranial to the mass under temporary occlusion of the thoracic descending aorta and posthepatic CVC. The mass combined with the CVC was excised. The mass was confirmed as hepatocellular carcinoma (HCC). This report describes the first case with successful en bloc resection of a large HCC involving the CVC in a dog.

Cloning of prepro-adrenomedullin and mRNA expression in cats.

The objective of this paper was to evaluate the sequence of feline prepro-adrenomedullin (AM) and its tissue distribution and to investigate whether expression of feline AM mRNA increases in association with spontaneous cardiomyopathy. The feline prepro-AM cDNA sequence and deduced amino acids were 564 base pairs and 188 residues, respectively. The cDNA sequences of feline prepro-AM including AM and proadrenomedullin N-terminal 20 peptide showed high homology with those of other mammalian species. The mRNA expression of AM was detectable in various normal tissues. The mRNA levels of AM were elevated in hearts with cardiomyopathy compared with normal hearts. This study suggests that AM has an important role as a neurohumoral factor in cats with spontaneous heart diseases.

Pharyngeal contraction secondary to its collapse in dogs with brachycephalic airway syndrome.

Brachycephalic airway syndrome (BAS) is a common disease in certain "flat-faced" dog breeds. This syndrome includes stenotic nares, elongated and thickened soft palate, laryngeal collapse, and tracheal hypoplasia. Pharyngeal collapse is also commonly observed, but it is unclear if laryngopharynx motions are merely sequelae or actually contribute to BAS respiratory symptoms. Laryngopharynx motion was imaged using dynamic four-dimensional computed tomography (4D-CT) during spontaneous respiration in four dogs with different BAS types. Dynamic 4D-CT showed laryngopharynx motion in the following order during inspiration: pharyngeal collapse, contraction, and laryngospasm. We concluded that dynamic 4D-CT is a highly-detailed diagnostic approach for detecting laryngopharynx motion. Pharyngeal contraction during inspiration appears to contribute toward the worsening of clinical respiratory signs of BAS.

Hemodynamic and biochemical changes during total hepatic vascular exclusion in dogs.

Twelve healthy Beagles were divided into 3 groups of 4 dogs each. To compare 2 methods of total hepatic vascular exclusion (THVE), we investigated the hemodynamic changes during THVE and assessed the influences on hepatic, renal and pancreatic biochemistry and the complications after THVE. In Group A, the thoracic aorta, hepatic pedicle and prehepatic and posthepatic caudal vena cava were occluded for 20 min, while in Group B, the celiac and cranial mesenteric arteries, hepatic pedicle and prehepatic and posthepatic caudal vena cava were occluded for 20 min. In Group C, a sham operation was performed. The arterial, venous and portal venous pressures and serum biochemistry parameters were measured before and during THVE and for 30 min after reperfusion. The carotid arterial pressure did not change in Group A during THVE, but decreased in Group B. The femoral and portal venous pressures in Group B increased significantly during THVE compared with those in Group C. With the exception of alanine aminotransferase, the serum biochemical profiles remained unchanged after the operation. For 7 days after the operation, no complications were observed in any of the dogs. In conclusion, occlusion of thoracic aorta, hepatic pedicle and prehepatic and posthepatic caudal vena cava is a feasible and safe method of hepatic vascular occlusion. This technique appears to be effective for canine hepatic surgery, such as removal of a large right-divisional hepatic tumor and attenuation of intrahepatic portosystemic shunt.

Gene expression of adrenomedullin in canine normal tissues and diseased hearts.

The purposes of this study were to determine the tissue distribution of canine adrenomedullin (AM) and to determine whether increased canine AM mRNA expression is associated with congestive heart failure (CHF) due to mitral regurgitation (MR). Canine AM mRNA expression was detectable in various normal tissues, including cardiovascular tissues. In addition, the AM mRNA expression in the left atrium of dogs with MR was significantly higher than that in normal subjects. In conclusion, AM is a potential neurohumoral factor in dogs with CHF due to MR.

Arterial blood gas analysis in dogs with bronchomalacia.

Canine bronchomalacia (CBM) is a structural airway disease leading to chronic cough and intermittent respiratory distress, primarily affecting elderly dogs of small breeds. Results of blood gas analysis have been reported in dogs with several diseases, but not yet in those with CBM. Eleven dogs with CBM were recruited in this study. Most dogs presented with mild hypoxemia and normocapnia, and all with increased alveolar-arterial difference for O2 (A-aDO2). In computed tomography, abnormal lung patterns, such as atelectasis and parenchymal band, were detected in all dogs, consistent with the regions affected by CBM. We conclude that CBM causes abnormal lung patterns and results in impaired oxygenation. Blood gas analysis is a useful tool for detecting mild pulmonary lesions and concurrent CBM.

Impact of intracranial hypertension on the short-term prognosis in dogs undergoing brain tumor surgery.

The present study used data from anesthetic records to analyze variables of intracranial pressure (ICP) during brain tumor surgery or in the early postoperative period as prognostic indicators in dogs. Data from 17 dogs which were scheduled to undergo elective craniotomy for brain tumor surgery from 2009 to 2012 were included. Of these, five (29.4%) died during 14 days after the surgery because of respiratory failure following pneumonia (n=2), euthanasia due to difficulty in treatment of status epilepticus (n=1), tumor-bed hematoma (n=1), and unknown reason (n=1). In the 12 surviving dogs, neurological signs were improved or resolved at discharge. All dogs were administered midazolam and droperidol-fentanyl as premedication. General anesthesia was induced using propofol maintained on isoflurane and oxygen. Direct ICP was obtained via a Codman Microsensor strain gauge transducer. ICP hypertension (>13 mmHg) measured after 15 min of recovery from the moment after discontinuation of anesthesia by turning off the vaporizer dial was associated with poor prognosis (odds ratio, 20.00; 95% confidence interval, 1.39-287.60, P=0.028). This suggests that intracranial pressure influences the postoperative mortality rate in dogs undergoing brain tumor surgery.

Surgery for partial atrioventricular septal defect with pulmonary hypertension in an adult dog.

A 4-year-old, 5.9-kg female Japanese Spitz presented with syncope and exercise intolerance. Echocardiography revealed an ostium primum atrial septal defect (ASD), a cleft mitral valve, mitral valve regurgitation (MR), and tricuspid regurgitation (TR) (velocity: 3.6 m/sec, pressure gradient: 52 mmHg), leading to a diagnosis of partial atrioventricular septal defect (AVSD) with moderate pulmonary hypertension (PH). Open-heart surgery using cardiopulmonary bypass was performed through right atriotomy. The cleft of the mitral valve was sutured with polypropylene and the AVSD was closed using an autologous pericardial patch fixed with glutaraldehyde. No postoperative pulmonary hypertensive crisis occurred. Shunting flow through the ASD, TR and PH had completely disappeared 2 months postoperatively; however, moderate MR persisted. The dog is still alive 5 years postoperatively without clinical signs.

Clinical significance of circulating vascular endothelial growth factor in dogs with mammary gland tumors.

Increase in circulating vascular endothelial growth factor (VEGF) is suggested as a prognostic indicator in human patients with malignant tumors. The purpose of this study was to evaluate the clinical significance of circulating VEGF in dogs with mammary gland tumors (MGT). Both plasma and serum VEGF were significantly higher in dogs with MGT when compared with those in the healthy dogs. In dogs with MGT, the plasma and serum VEGF of the malignant group increased significantly compared with those of the benign group. Additionally, there was a significant difference between the plasma and serum VEGF in the groups with postoperative metastasis and no metastasis. Circulating VEGF is expected to be clinically available for the determination of prognosis in canine MGT.

Evaluation of left ventricular Tei index (index of myocardial performance) in healthy dogs and dogs with mitral regurgitation.

The left ventricular (LV) Tei index (index of myocardial performance) has been demonstrated to be clinically useful in estimating comprehensive LV function, including the systolic and diastolic performances, in various human cardiac diseases. The purposes of this study were to validate the correlation between the LV Tei index and LV function obtained by cardiac catheterization in healthy dogs, and to evaluate the LV Tei index in dogs with naturally occurring mitral regurgitation (MR). In healthy dogs, the LV Tei index was significantly correlated with the LV peak +dP/dt (r = -0.89) and LV peak -dP/dt (r=0.87). The LV Tei index significantly increased in dogs with MR compared with normal dogs and significantly increased with progressively more severe clinical signs due to heart failure. The elevation of the LV Tei index in dogs with symptomatic MR appears to be associated with shortening of ejection time. The LV Tei index significantly increased with age and was not correlated with heart rate and body weight in normal dogs. In conclusion, our study demonstrated that the LV Tei index was measurable in dogs and not influenced by heart rate and body weight. The LV Tei index significantly increased with the progression of clinical signs in MR dogs. In particular, the elevation of the LV Tei index in dogs with symptomatic MR due to shortening of ejection time may suggest LV systolic dysfunction and the decrement of forward stroke volume.

Changes in the myocardial performance index during dobutamine administration in anesthetized cats.

OBJECTIVE: To investigate the relationship between myocardial performance index (MPI; also known as the Tei index) and cardiac function in anesthetized cats administered dobutamine. ANIMALS: 6 adult cats. PROCEDURES: Cats were anesthetized by administration of propofol (6 mg/kg, IV), and anesthesia was maintained by administration of isoflurane. Heart rate and systolic arterial pressure (SAP) were monitored. Stroke volume, cardiac output, and aortic blood flow (ABF) were measured by use of transesophageal ultrasonography. Left ventricular fractional shortening (LVFS), mitral E-wave velocity-to-A-wave velocity (E:A) ratio, and ejection time were measured by use of transthoracic echocardiography. Dobutamine was administrated via a cephalic vein at rates of 2.5, 5.0, and 10 microg/kg/min. RESULTS: Heart rate, SAP, cardiac output, and ABF increased with dobutamine administration, whereas stroke volume significantly decreased. The LVFS significantly increased, and the E:A ratio significantly decreased. Total isovolumic time and the MPI significantly decreased. The MPI was negatively correlated (r=-0.63) with LVFS. Conversely, the MPI was positively correlated with the E:A ratio (r=0.47), stroke volume (r=0.66), and total isovolumic time (r=0.95). However, the MPI was not significantly correlated with heart rate, SAP, cardiac output, or ABF. CONCLUSION AND CLINICAL RELEVANCE: Analysis suggested that the MPI provides a sensitive clinical assessment of cardiac response to medication in cats, which may be similar to the usefulness of the MPI reported in humans.

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.

Fibrodysplasia ossificans progressiva-like condition in a cat.

Fibrodysplasia ossificans progressiva (FOP)-like condition was diagnosed in a Japanese domestic cat with stiffness, marked atrophy of the muscles, and limited mobility of all joints in both the pelvic limbs. Etretinate, a retinoid, was used for medical management; however, no improvement in the clinical signs was observed. Inheritance of the disorder has not yet been demonstrated. Furthermore, the clinical signs and histopathological findings of feline FOP-like condition in the present case differed from those of the previously reported cases.

Periorbital cyst with bone defect in a dog.

A 4-year-old female Miniature Dachshund was referred with a chief complaint of right periorbital swelling that had not responded to antibiotic therapy. Ultrasonography and fine-needle aspiration revealed that the periorbital lesion had a cystic structure without any inflammatory or neoplastic cells. Computed tomography (CT) showed that the cyst occupied a defect in the periorbital maxillary, lacrimal, and frontal bones and had invaded the nasal cavity. The lesion was histologically suspected by incisional biopsy as an epithelial cyst.

Evaluation of right ventricular Tei index (index of myocardial performance) in healthy dogs and dogs with tricuspid regurgitation.

Right ventricular (RV) Tei index (index of myocardial performance) has been demonstrated to be clinically useful in estimating RV function in various human cardiac diseases. The purposes of this study were to validate the correlation between RV Tei index and RV function obtained by cardiac catheterization in healthy dogs, and to evaluate the RV Tei index in dogs with tricuspid regurgitation (TR). In healthy dogs, the RV Tei index significantly correlated with the RV peak +dP/dt (r=-0.80, p<0.0001) and -dP/dt (r=0.69, p=0.0001). In normal dogs, the RV Tei index was not significantly correlated with heart rate, body weight, and age. The RV Tei index significantly increased in dogs with moderate to severe TR (0.39 +/- 0.35, p=0.0015), filariasis (0.46 +/- 0.16, p=0.0131), and trivial to mild TR and severe mitral regurgitation (MR; 0.61 +/- 0.14, p=0.0017) when compared with the normal dogs (0.17 +/- 0.10). In addition, the RV Tei index in dogs with TR significantly increased in association with pulmonary hypertension [PH(-), 0.19 +/- 0.09; PH(+), 0.65 +/- 0.14; respectively p<0.0001]. Our study has demonstrated that RV Tei index is a feasible approach to estimate RV function in dogs and is not influenced by heart rate, body weight, and aging. Further investigations are required to clarify the clinical significance of RV Tei index in dogs with right-sided cardiac diseases.