ULTRASONOGRAPHIC FEATURES OF GRASS AWN MIGRATION IN THE DOG

The aim of this study was to describe the ultrasonographic features of grass awns in soft tissue. A 10 MHz linear transducer was used. Ultrasound images from 25 dogs (27 awns) were collected and compared with the results from water bath studies using wild oat seeds (Avena spp.) collected in the field. Wild oat seeds were the most common grass awn found in soft tissue of dogs. Ultrasonographically grass awns appeared as a double/triple spindle-shaped echogenic interface within soft tissue. The same appearance was observed in water bath studies. In four dogs, the grass awn was removed surgically with a clamp introduced into a fistulous tract, using sonographic guidance. The grass awn was not found surgically in only three dogs, suggesting more attention during surgery. Ultrasonography is a useful diagnostic imaging technique to identify grass awns within soft tissue.     

Imaging diagnosis: pneumothorax and focal peritonitis in a dog due to migration of an inhaled grass awn

A 1-year-old working Kelpie developed pneumothorax and focal peritonitis after inhalation of a grass awn that migrated from the lung, through the diaphragm, into the peritoneal cavity. Radiographic evidence of sternal lymph node enlargement was fundamental in the diagnosis of intraperitoneal disease and prompted abdominal ultrasound leading to definitive diagnosis.     

Ultrasound-guided retrieval of plant awns

In dogs, surgical removal of plant awns causing a foreign body granuloma or abscess may be challenging. The inability to localize the foreign body during surgical removal often leads to abscess recurrence. In this report, we describe ultrasound-guided retrieval as an alternative to standard surgical retrieval in animals where the plant awn can be identified sonographically. This procedure was used in six dogs with a superficial abscess due to a plant awn, and in all dogs the foreign body was successfully retrieved with Hartmann forceps. No complication was observed and no abscess recurred. Minimally invasive ultrasound-guided plant awn retrieval appears to be a safe effective method of retrieving superficially located plant awns in the dog.     

BIPLANE TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN THE DOG: TECHNIQUE, ANATOMY AND IMAGING PLANES

To determine the feasibility of transesophageal echocardiography (TEE) in dogs, biplane TEE was performed in 6 normal, anesthetized dogs, using a 10 mm × 110 cm endoscopic TEE transducer. Positioning was confirmed by fluoroscopy, and imaging planes were confirmed by necropsy examination.
A transgastric position provided only a limited view of the left ventricular apex. Three TEE positions over the base of the heart were identified. A caudal position provided excellent images in both transverse and longitudinal planes, but alignment with flow for Doppler examination was poor. A middle position provided long axis views of the left ventricular inflow region and mitral valve suitable for Doppler examination. A cranial position provided excellent views for both anatomic and Doppler examination of right and left ventricular outflow and associated great vessels.
We conclude that biplane TEE provides unique views of the heart in dogs which are complementary to, and often superior to, transthoracic views for evaluation of structures at the heart base.     

ULTRASONOGRAPHIC FEATURES OF GRASS AWNS IN THE URINARY BLADDER

Grass awns are a common cause of foreign body disease in animals, but little is known about their presence in the lower urinary tract. The ultrasonographic features of grass awns in vivo and in vitro have been described in detail. The purpose of this report is to describe the clinical and sonographic features of grass awns in the urinary bladder of dogs and cats. Three male Yorkshire terriers (one of which was examined twice) and one female domestic short‐haired cat were evaluated for signs of lower urinary tract disease, and an intravesicular grass awn was suspected based on ultrasound examination. The grass awn appeared ultrasonographically as a bladder stone (n=1) or a linear hyperechoic structure (n=4) with or without acoustic shadowing that was easy to identify due to contrast with surrounding urine. The presence of a grass awn within the urinary bladder was confirmed during exploratory surgery. In all patients, the route of entry of the grass awn was thought to have been retrograde migration from the urethral opening. The ultrasonographic appearance of grass awns in the bladder is consistent with that in other tissues.     

Retroperitoneal Abscess Associated With a Migrating Grass Awn in a Cat: Treatment With Omentalization and Grass Awn Removal

An 18-month-old domestic short hair male castrated cat presented with a history of fever of unknown origin of 1-year duration. Abdominal ultrasound revealed a mixed echogenicity mass. Cytological examination of the fluid obtained through fine needle aspiration was consistent with a retroperitoneal abscess. The cat underwent a midline celiotomy and the abscess was opened, lavaged, and omentalized. Antibiotics were also administered. Two months after surgery, the cat represented with a fluctuant swelling in the right flank region at the lumbodorsal triangle. Abdominal and mass ultrasound showed a mixed echogenicity swelling in the right flank. Under gas anesthesia, the swelling was surgically explored and a 0.4 cm long grass awn was found and removed. Telephone communication with the owners 6 months after surgery found the cat to be free of clinical signs.     

ULTRASOUND EVALUATION OF SMALL BOWEL THICKNESS COMPARED TO WEIGHT IN NORMAL DOGS

The use of ultrasound to measure small bowel thickness is an important part of any ultrasound examination of the abdomen. Increased thickness of the intestinal wall is a hallmark for the detection of diseases ranging from inflammatory bowel disease to neoplasia. Our subjective impression has been that dogs with no clinical signs of gastrointestinal disease often have sonographic measurements greater than published norms. The purpose of this study was to prospectively reevaluate these norms. The clinical history on all dogs receiving an abdominal ultrasound examination was evaluated for signs of gastrointestinal disease. Those without clinical signs were entered into this study. The documentation of body weight, breed, jejunal thickness, and duodenal thickness was made in 231 dogs. Dogs were placed into five groups based on their weight. Sixty-nine breeds were represented with weight ranging from 2.1 to 64 kg. A statistically significant (P < or = 0.05) correlation between body weight and both jejunal and duodenal thickness was observed. We also found that the maximum thickness in both jejunum and duodenum in healthy dogs was larger than previously reported. These data indicate norms for the jejunum of < or = 4.1 mm for dogs up to 20 kg, < or = 4.4 mm for dogs between 20 and 39.9 kg, and < or = 4.7 mm for dogs over 40 kg. The data indicate norms for the duodenum < or = 5.1 mm for dogs up to 20 kg, < or = 5.3 kg for dogs between 20 and 29.9 kg, and < or = 6.0 mm for dogs over 30 kg.     

ENDOSCOPIC ULTRASOUND OF THE CANINE ABDOMEN

The aim of this study was to develop a standardized procedure for examination of the canine abdomen using endoscopic ultrasound and to describe the organs and structures that could be identified transgastrically. The abdomen of four healthy dogs and two cadavers were examined with endoscopic ultrasound. Five anatomic landmarks were used for standardized imaging of the cranial abdomen. These were the portal vein, splenic head and body, duodenum, left kidney, and aorta. High-resolution images of the following organs and structures could be made: distal esophagus, gastric wall from the cardia to the pylorus, liver, caudal vena cava, hepatic lymph nodes, liver hilus, and associated vessels, trifurcation of the celiac artery as well as the path of its branches and the left pancreatic limb and body. Structures that were more difficult to image were the distal duodenum and right pancreatic limb, the entire jejunum, ileum, and cecum as well as the tail of the spleen. Endoscopic ultrasound allowed excellent visualization of the gastric wall and regional structures without interference with gas artefacts. Centrally located organs such as the pancreas could be well examined transgastrically with endoscopic ultrasound without interference by overlying intestinal segments as is common with transabdominal ultrasound.     

LESIONS OF THE RENAL PELVIS AND PROXIMAL URETER IN VARIOUS NEPHRO-UROLOGICAL CONDITIONS: AN ULTRASONOGRAPHIC STUDY

The applicability of ultrasonography was studied in the diagnosis of lesions of the renal pelvis and ureter in 10 dogs. Ultrasonographic findings of processes associated with dilatation and concretion formation in the renal pelvis were described and the differential diagnosis of the lesions was discussed. The authors propose a new classification system for judging processes characterized by dilatation of the renal pelvis. Experience suggests that ultrasonography is an effective procedure in the diagnosis of certain diseases of the upper urinary tract in dogs.     

QUANTITATIVE EVALUATION OF IMAGENT® AS AN ABDOMINAL ULTRASOUND CONTRAST MEDIUM IN DOGS

Diagnostic ultrasound currently provides a noninvasive, economical means to evaluate internal organ structure. Methods to increase the amount of diagnostic information obtained from the sonographic examination are being explored. A new area of research has recently focused on the ability of microbubble contrast agents to help provide additional information. A prospective study was undertaken to quantitatively evaluate the amount of gray scale enhancement of ultrasound images of six canine livers, spleens, and left kidneys that occurs after intravenous injection of Imagent. Computerized analysis was used to assess the percent change in brightness of these images. A transient decrease in the percent change in brightness was seen to occur after injection of higher doses of Imagent. This effect was more pronounced in the deeper portions of the organs of interest. Imagent provides a measurable change in the brightness of the organs of interest and would be potentially useful in a clinical setting.     

TRANSESOPHAGEAL ULTRASONOGRAPHY OF THE NORMAL CANINE MEDIASTINUM

The mediastinum of eight normal research dogs was examined by transesophageal ultrasonography with a 5MHz frequency transducer to establish a baseline for future use of this new imaging modality as a diagnostic tool. Each examination consisted of 360 degree scans in both transverse and sagittal planes from the thoracic inlet to the esophageal hiatus. Dissections of four of these research dogs were then performed to confirm transesophageal ultrasonography findings. Transesophageal ultrasonography of the mediastinum was a good imaging modality for the evaluation of the heartbase, the major cranial mediastinal vessels, the descending aorta, and occasionally part of the azygos vein. Anatomic orientation was best obtained by beginning the examination at the heart base. Lymph nodes and smaller caliber vessels could not be distinguished from surrounding tissues; however, Doppler ultrasound was useful for identifying the smaller vessels. Although a 5 MHz frequency transducer is preferred for transesophageal echocardiography, a higher frequency transducer would improve the resolution of the images of small near-field structures and may be more appropriate for mediastinal imaging.     

Alternating one lung ventilation using a double lumen endobronchial tube and providing CPAP to the non-ventilated lung in a dog

Introduction This case report describes the anaesthetic management of exploratory thoracoscopy and alternating one lung ventilation (OLV) in a dog with a pulmonary bulla, and the application of continuous positive airway pressure (CPAP) to the non‐ventilated lung for preventing and treating hypoxia. Case history A 6‐year‐old, male castrated Border collie was scheduled for exploratory thoracoscopy to investigate spontaneous pnemothorax that had not resolved with repeated suction. Specific requirements for the thoracoscopy were alternating OLV to allow the surgical access to the right middle lobe and its removal, and the examination of the left hemithorax to rule out the presence of other lesions. Diagnosis and management Selective lung ventilation was performed with a double lumen endobronchial tube (DLT), inserted under endoscopic guidance. After a short period of two lung ventilation during preparation of the surgical field, alternating OLV was performed, combining CPAP, provided to the non‐ventilated lung via a Mapleson D breathing system, and positive end‐expiratory pressure (PEEP) applied to the ventilated lung. Left OLV occurred first and resection of the right middle pulmonary lobe was successfully performed; right OLV followed to allow the examination of the left hemithorax. Discussion and conclusions The combination of CPAP and PEEP resulted in a satisfactory intra‐operative management of hypoxemia. Alternating OLV can be performed successfully by using a DLT. CPAP, commonly employed in human medicine, should be considered an important tool in the anaesthetic management of OLV in small animals.