Endoscopic ultrasonographic evaluation of the esophagus in healthy dogs.

OBJECTIVE: To characterize the ultrasonographic appearance of the canine esophagus. ANIMALS: 14 healthy Beagles. PROCEDURES: Endoscopic ultrasonography (EUS) examinations were performed with a radial ultrasonographic gastrovideoscope in anesthetized dogs. Images were obtained at 3-cm intervals along the esophageal length to allow evaluation of the esophageal wall. Images were obtained with the probe in direct contact with the esophageal wall and with a water-filled balloon as a standoff. RESULTS: Images were obtained with (12 dogs) and without (10) the water-filled balloon. Median thickness of the esophageal wall was 2.19 mm (range, 1.03 to 5.62 mm) in the proximal third of the esophagus, 2.15 mm (range, 1.10 to 4.45 mm) in the middle third, and 2.84 mm (range, 1.35 to 5.92 mm) in the distal third. Wall thickness differed significantly between proximal and distal thirds. Results were similar when the water-filled balloon was used. Esophageal wall layers appeared as 5 alternating hyperechoic and hypoechoic bands that could not be consistently identified in all dogs. All layers could be identified in 26 of 198 (13%) images, 3 layers could be identified in 67 of 198 (34%) images, and 105 of 198 (53%) images had no layers. Visual identification of layers in images obtained with and without the balloon did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: EUS appeared to be a useful technique for assessing esophageal wall integrity in dogs; however, complete evaluation of all layers could not be accomplished in all instances. Further studies with this technique in dogs are needed.

Magnetic resonance (MR) imaging and MR cholangiopancreatography findings in cats with cholangitis and pancreatitis.

Cholangiohepatitis/cholangitis is second only to hepatic lipidosis as the most common liver disease in cats and is often associated with concurrent pancreatitis. Magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP) have developed into an accurate, highly sensitive and specific imaging tool for the diagnosis of biliary and pancreatic duct disorders in humans. In this prospective case series, 10 cats with suspected cholangitis and/or pancreatitis were enrolled based on clinical history, physical examination and appropriate diagnostic test results. MRI and MRCP sequences with secretin stimulation of the cranial abdomen were performed, and sonography and laparoscopic biopsies for histologic diagnosis were obtained for comparison. MRI detected pancreatic abnormalities in cats suspected of pancreatitis, including T1 pre-contrast hypointense and T2 hyperintense pancreatic parenchyma and a dilated pancreatic duct. The MRI findings of the liver were non-specific. Nine of 10 cats had biliary abnormalities, including gall bladder wall thickening, gall bladder wall moderate contrast enhancement and/or gall bladder debris. Eight of 10 cats had histologic evidence of pancreatitis, as well as hepatitis or cholangitis, with one cat diagnosed with hepatic lymphoma. The advantages of MRI/MRCP over sonography of these cats included the striking pancreatic signal changes associated with pancreatitis and the ability to comprehensibly assess and measure the pancreas and hepatobiliary structures without operator dependence or interference from bowel gas. MRI/MRCP imaging of the feline abdomen may be beneficial in cases with equivocal ultrasound imaging findings.

Feasibility and safety of endoscopic ultrasound-guided fine needle aspiration of the pancreas in dogs.

BACKGROUND: Endoscopic ultrasound (EUS)-guided fine needle aspiration (EUS-FNA) has proven a useful and safe diagnostic tool for assessing pancreatic disease in human medicine. No information about pancreatic EUS-FNA is available in dogs. OBJECTIVES: To assess the feasibility and safety of pancreatic EUS-FNA in healthy dogs. ANIMALS: Thirteen beagles with a median body weight of 13.4 kg. METHODS: Experimental study. An ultrasound endoscope (insertion tube outer diameter 11.8 mm) was used, and FNA was carried out with 19 G needles. The optimal puncture site was chosen with the aid of Doppler imaging. Complete clinicopathologic assessments including pain scoring and pancreas-specific lipase measurements were obtained before EUS as well as on day 1 and day 2 after EUS-FNA. RESULTS: The pancreatic body was identified in all dogs, the left lobe was clearly identified in 9/13 and appeared indistinctly marginated in 4/13 dogs, and the distal third of the right lobe could not be identified in 7/13 dogs. EUS-FNA was carried out in 12/13 dogs. Cellularity of smears was adequate for evaluation in 8/12 cases, in which samples were obtained transgastrically (n = 4) or transduodenally (n = 4). All dogs recovered uneventfully and no clinical and laboratory abnormalities occurred during the 48 hour monitoring period after the procedure. CONCLUSION AND CLINICAL IMPORTANCE: Although the healthy canine pancreas is difficult to visualize in its entirety with EUS, pancreatic EUS-FNA with a 19 G needle is feasible in medium-sized dogs and can be considered a safe procedure. Its diagnostic usefulness should be evaluated in dogs with pancreatic disease.

The role of endoscopic ultrasound in the evaluation of rectal polypoid lesions in 25 dogs.

We investigated the role of endoscopic ultrasound in the evaluation of rectal polypoid lesions in 25 dogs. Twenty-five cases of rectal polypoid lesions in dogs who underwent surgery after endoscopic and EUS assessment were studied. The invasion depth of the polypoid lesion was classified as M stage (lesions in the mucosa only), SM stage (lesions in the mucosa and submucosa), and MP stage (lesions extending to the muscularis propria). Transabdominal ultrasound was performed in nine cases, but not all were evaluated in detail. EUS provided detailed images for all cases and showed a significant correlation with surgical pathology in the T stage (accuracy, 92%; K = 0.77). As per classification by invasion depth, inflammatory polyps were only M polypoid lesions, whereas SM and MP polypoid lesions were only adenocarcinomas (P < 0.05). The average survival time according to specific condition was as follows: 1,235 days for inflammatory polyps, and 804 days for M adenocarcinoma. The survival time of two SM adenocarcinoma cases was 756 and 2,114 days, respectively, and the survival time of two MP adenocarcinoma cases was 16 and 42 days, respectively. EUS were useful for the evaluation of rectal polypoid lesions in dogs, whereas transabdominal ultrasound was not. Determination of the invasion depth of polypoid lesions using EUS may be useful for the evaluation of malignancy and prognosis.

[Sonographic examination of the soft palate in dogs]. / Sonografische Untersuchung des weichen Gaumens beim Hund.

PURPOSE: The aim of this study was to characterize the normal sonographic anatomy of the soft palate in dogs. MATERIALS AND METHODS: The study was performed on seven canine heads via a submental and intraoral approach. The detected anatomical structures were then reexamined via a submental approach in a water bath. Each anatomic layer was subsequently dissected starting with the submental layers and working towards the soft palate. After every preparation a sonographic examination was carried out. RESULTS: Differentiation between the soft palate and the surrounding oropharyngeal tissue can be effectively achieved. Using the submental approach, the transition between hard palate and soft palate as well as the middle section of the soft palate were distinguished from other oropharyngeal structures in all cases. Visualization of the caudal part of the velum and evaluation of the echogenicity of the soft palate were difficult and not always possible. In the two brachycephalic dogs of the study, it was challenging to distinguish the soft palate from the surrounding tissue. CONCLUSION: The sonographic appearance of the canine soft palate in cadavers was described in this study. The submental approach allows differentiation between intraoral structures. Evaluation of the echogenicity and length of the soft palate is limited.

Intraoperative contrast-enhanced ultrasonography of normal canine jejunum.

Nine normal juvenile dogs were evaluated with direct jejunal contrast-enhanced ultrasonography via midline celiotomy. Three different doses of ultrasound contrast medium (Definity®) were injected through a peripheral venous catheter. Time-intensity curves were used to calculate baseline, time to initial rise, inflow slope, time-to-peak, peak intensity (PI), and outflow slope for each administered dose. PI was directly proportional to dose. Outflow slope was similar for all patients, independent of dose. The most favorable images were acquired with a dose of 0.030 ml/kg given as a rapid intravenous manual bolus. The technique and normal jejunal perfusion pattern described herein may provide useful data for evaluation of intestinal vascular, inflammatory, and neoplastic disease in the dog.

Evaluation of endosonography as a new diagnostic tool for feline pancreatitis.

The purpose of this study was to evaluate endosonography (EUS) as a potential diagnostic tool for feline pancreatitis. Eleven healthy cats and six cats diagnosed with pancreatitis based on an increased serum feline pancreatic lipase immunoreactivity (fPLI) concentration were included. Transabdominal ultrasound (AUS) and EUS were performed in all cats. The widths of both pancreatic limbs and echogenicity and homogenicity were assessed by AUS and EUS. Finally, findings from both modalities were subjectively compared. In the healthy cats, the right pancreatic limb was significantly smaller on EUS compared to AUS. Also, subjectively, general visualization of the normal pancreas was superior with EUS and, the pancreatic margins and parenchyma could be resolved better with EUS in all sick patients. In this study, EUS findings did not alter the diagnosis in six cats with pancreatitis when compared to AUS. However, EUS may be useful in cases where AUS fails due to obesity, hyperechoic mesentery, or excessive intestinal gas.

EUS-guided injection of paclitaxel (OncoGel) provides therapeutic drug concentrations in the porcine pancreas (with video).

BACKGROUND: OncoGel (ReGel/paclitaxel) is an intralesional injectable formulation of the chemotherapeutic drug, paclitaxel, for local tumor management. OBJECTIVE: The aim of this study was to determine if a minimally invasive EUS-guided injection of paclitaxel, bound to a thermosensitive gel carrier, would lead to therapeutic tissue concentrations of the chemotherapeutic agent in the porcine pancreas. DESIGN: Eight Yorkshire breed pigs were sedated by general anesthesia and OncoGel was injected, under EUS-guidance, with a 22-gauge needle into the tail of the pancreas. MAIN OUTCOME MEASUREMENTS: During the 7-day (n = 4) or 14-day (n = 4) observational period, the animals were monitored by serum levels of amylase and lipase, and by a CT on day 4. The outcome was determined by gross and microscopic evidence of inflammation of the pancreas, clinical tolerance, and quantitation of tissue paclitaxel concentrations. RESULTS: Eight pigs underwent injection of 1, 2, 3, or 4 mL OncoGel (6 mg paclitaxel per 1 mL OncoGel) (n = 2 per group). An intrapancreatic hyperechoic focus, with an average diameter of 2.1 +/- 0.8 cm, was visible by EUS, and a hypodense area in the tail of the pancreas was visible by contrast CT. Clinically, the animals appeared to tolerate the procedure without sequelae. Blood levels of amylase and lipase were normal. At euthanasia, a depot of OncoGel, with an average diameter of 14.7 +/- 5.0 mm), was located both grossly and histologically in the pancreatic tail. After 14 days, clinically significant tissue concentrations of paclitaxel were detected at a distance of 30 to 50 mm from the depot in the animals that underwent an injection of 3 and 4 mL of the agent (n = 2). CONCLUSIONS: The EUS-guided injection of OncoGel into the pancreas of the pig provided high and sustained localized concentrations of paclitaxel. This technique is a potential minimally invasive local treatment option for unresectable pancreatic tumors.

Spontaneous intestinal melanoma in dogs.

Primary melanoma of the gastrointestinal tract is a rare, highly malignant neoplasm that is associated with an unfavorable long-term prognosis. Animal studies are needed to further characterize this tumor and to develop new and more effective protocols. A spontaneous canine intestinal melanoma is described which, because of its local aggressive behavior and advanced stage, was not treatable with conventional strategies, thus being a potential candidate for investigational trials.

Use of high-power ultrasonic shears for laparoscopic ovariectomy in mares.

A method for performing laparoscopic ovariectomy with high-power ultrasonic shears in mares is described, along with results in 10 mares. Briefly, after epidural administration of detomidine and local anesthesia with mepivacaine, 3 cannulas were placed in each paralumbar fossa. A laparoscope was placed through the most dorsal cannula, and a grasping forceps was placed through the most ventral cannula and used to grasp and manipulate the ovary. The ultrasonic shears was then placed through the middle cannula. The jaws of the ultrasonic shears were closed across a portion of the ovarian pedicle, and the instrument was discharged until tissue within the jaws was transected; the process was repeated until the entire ovarian pedicle was transected. Following removal of the right ovary, it was passed to the left side of the abdomen and both ovaries were removed through an incision in the left paralumbar fossa. No major complications were identified in any of the 10 mares. However, excessive bleeding necessitating reapplication of the ultrasonic shears (2 ovaries) or application of ligating clips (8) was encountered with 10 of the 20 ovaries. Laparoscopic ovariectomy with a high-power ultrasonic shears appears to be safe in mares.

Endoscopic ultrasonography for the diagnosis of intrathoracic lesions in two dogs.

Endoscopic ultrasound was developed initially in humans to overcome limitations of conventional ultrasound in examining certain internal organs due to intervening bone or air-filled structures. Endoscopic ultrasound has been used most widely in investigation of the gastrointestinal tract in humans, but many intrathoracic applications as well as endoscopic ultrasound-guided techniques have recently been described. Mediastinal and pulmonary structures can be examined with endoscopic ultrasound since a high frequency ultrasound probe can be brought into close contact with the areas of interest via a transesophageal approach. The purpose of this report is to describe the application of endoscopic ultrasound as an aid in the diagnosis of intrathoracic disease in the dog. Two dogs, one with a history of prior esophageal foreign body extraction, the other with apathy, weakness and dyspnea were referred for further investigation. Both dogs had caudal intrathoracic soft tissue opacities diagnosed radiographically, but their origin and nature were difficult to determine. Conventional ultrasound was limiting in both dogs due to their location and superimposition of gas-filled structures. With endosonography lesions were characterized more completely. We have found endoscopic ultrasound to be an elegant diagnostic tool for the investigation of radiographically detected intrathoracic lesions in the dog whose origins are difficult to determine or do not lend themselves to investigation by conventional ultrasound. Endoscopic ultrasound provides valuable diagnostic information complementary to that provided radiographically which aids in therapeutic planning. Endoscopic ultrasound was also more sensitive for detecting mediastinal lymphadenomegaly than radiography in one of the dogs. An additional advantage of endoscopic ultrasound is the fact that US-guided tissue sampling can be performed during the examination.

Endoscopic ultrasound instrumentation, applications in humans, and potential veterinary applications.

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.

Endoscopic and transcutaneous ultrasonographic findings and grey-scale histogram analysis in dogs with caerulein-induced pancreatitis.

Endoscopic ultrasonography (EUS), grey-scale histogram analysis of EUS images, and transcutaneous ultrasonography (TUS) were done in four dogs with caerulein-induced pancreatitis. One other dog was subjected to laparotomy and biopsy specimens were collected for histopathology. By EUS, the pancreatic lesions were first detected at 60 minutes after the start of caerulein infusion. They were detected after 120 to 150 minutes when using TUS. EUS findings included swelling, a more distinct lobular pattern, subcapsular hypoechoic areas, and anechoic stripes through the pancreatic tissue. No marked changes in the histogram analysis was seen until 30 minutes. From 30 to 60 minutes, a decrease in the mean brightness of the pancreatic tissue was observed. These changes in mean brightness reflected histopathological findings showing vacuolization of acinar cells and interstitial oedema of the pancreas. These findings indicated that EUS can detect slight and diffuse changes in pancreatic tissue. Furthermore, grey-scale histogram analysis detects histopathological changes more sensitively than endoscopic ultrasound images.