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1.
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.  相似文献   

2.
ENDOSCOPIC ULTRASONOGRAPHY OF THE PANCREAS IN THE DOG   总被引：1，自引：0，他引：1  
Endoscopic ultrasonography was done in 12 normal adult dogs to investigate its efficacy in visualization of the pancreas. The endoscopic ultrasonographic device used in the present study had a curved-array ultrasound transducer mounted in front of the objective lens. The tip of the ultrasonic endoscope was inserted into the stomach, and all examinations of the pancreas were performed from within the stomach. Endoscopic ultrasonography provided good images of most parts of the pancreas except for the ends of each lobe. Useful information about the pancreatic parenchyma, including pancreatic lobular structure, pancreatic duct, and vessels of the pancreas was obtained by endoscopic ultrasonography. Blood flow within vessels was detected using color Doppler and pulsed-wave Doppler examination. These results suggest that endoscopic ultrasonography is available as an effective diagnostic modality in small animal practice.  相似文献   

3.
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.  相似文献   

4.
Ultrasound scanners have the potential of becoming as important for examination of the reproductive tract of mares, as x-ray machines are for examination of the legs. The principles of ultrasonography are based on the abilities of various tissues and fluid-filled structures to either reflect or propagate high frequency sound waves. A sound beam is emitted from an intrarectal, hand-held transducer. The proportion of the beam that is reflected (echoed) is received by the transducer, converted to electrical impulses, and displayed on a screen as moving images. Liquid-filled structures do not reflect sound waves and appear black on the screen. At the other extreme, dense tissues reflect much of the beam and appear white. Other tissues are seen in various shades of the gray-scale, depending upon their echogenicity (ability to reflect sound waves). Certain tissue formations may cause the sound waves to bend (refract), bounce back and forth (reverberate), or to become weakened (attenuated) or entirely blocked. Therefore artifacts may appear on the screen and must be appreciated by the ultrasonographer. The resolving power of the equipment is dependent upon the frequency of the sound waves measured in megahertz (MHz) units. A 5 MHz transducer is more suitable for examining the reproductive tract of mares than the generally available 3 or 3.5 MHz transducer.

Preparation for intrarectal ultrasound examination is similar to preparation for rectal examination, but there are other considerations, such as protection of the equipment and management of external lighting. A linear-array transducer is hand-held and is generally oriented in the sagittal plane with respect to the mare's body. The images of the cervix and uterine body are therefore longitudinally oriented, and those of the uterine horns are cross-sectional. With sector scanners, however, the sound beam generally travels transversely with respect to the mare's body and images of the cervix and uterine body are cross-sectional and images of the horns are longitudinal or oblique. The availability of ultrasound instruments for examination of the reproductive tract should provide additional encouragement for veterinarians to be as knowledgeable as possible about reproductive anatomy and pathology. The ability to study “living,” detailed, sequential, sectional views of the organs demands a more detailed working knowledge of anatomy than that required for rectal palpation.  相似文献   


5.
A procedure for imaging the canine tympanic bulla, external ear canal and adjacent structures using currently available ultrasound equipment was established. Lateral and ventral transducer positions were identified for this purpose and a 6.5 MHz curvilinear transducer was considered to be optimal. The sonographic appearance of these structures in cadavers and live dogs unaffected by ear disease is documented. Fluid was introduced into the tympanic bullae of the cadavers and its presence could be identified through the bony wall of the bulla. The ability of ultrasound to differentiate between gas and fluid within the bulla has important clinical implications as this is a common occurrence in dogs with middle ear disease. Ultrasound has several advantages over other imaging modalities and the examination procedure was well tolerated by unsedated dogs.  相似文献   

6.
The assessment of an early and reliable pregnancy diagnosis in sows is very important for limiting the number of non-productive days in sow herds. The aim of the present study was to investigate the accuracy of trans-abdominal ultrasound detection for early pregnancy diagnosis in sows under field conditions. Particular attention was paid to the time when a reliable diagnosis can be made, and to possible differences between two commonly used types of scanners. In total, 202 sows from two herds were tested daily with scanners A (linear transducer of 5 MHz) and B (sector transducer of 3.5 MHz) from day 16 until 25 after insemination. Ninety-three percentage of the sows were pregnant 36 days after insemination. Using ultrasound, the first pregnancy could be detected already 18 days after insemination. The sensitivity, specificity and overall accuracy were higher than 95% from day 24 (scanner A) or day 23 (scanner B) post-insemination onwards. The positive predictive values from day 19 onwards were consistently higher than 95% with both types of scanners, whereas the negative predictive values were consistently low for both scanners during the entire period. The sensitivity of testing tended to be slightly lower in sows with a litter size of <10 total born piglets, compared to sows with 10 or more piglets. In conclusion, pregnancy diagnosis in sows using trans-abdominal ultrasound testing can be assessed quickly and reliably under field conditions from day 23 of gestation onwards. Predictive values of positive test results were high in these herds, whereas those of negative test results were low. This implies that sows with a negative test result early in pregnancy should be retested later.  相似文献   

7.
Diagnostic ultrasound, a non-invasive mode for imaging soft tissues, requires for its use an understanding of sound and sound-tissue interaction physics. Ultrasound frequencies from 1.0 to 10.0 MHz are created by electrical stimulation of piezoelectric crystals. These crystals are housed within transducers, which, when applied to the body surface with a coupling agent will produce sound waves, referred to as the sound beam, which are propagated through the soft tissues of the body. When the sound beam encounters tissue interfaces of differing acoustic impedance, a portion of the sound beam is reflected back to the transducer which also acts as a receiver. Echoes returning from soft tissue acoustic interfaces are converted to electrical impulses and displayed on an oscilloscope screen as a cross section of the tissue. Lower frequency sound beams penetrate further into soft tissue, but have poorer resolving capabilities, than higher frequency sound beams. A, B, and M-modes are the three basic forms of ultrasound used in soft tissue imaging. A-mode ultrasonic imaging is a one-dimensional display of echo amplitudes versus distance. B-mode ultrasonic imaging produces an accurate two-dimensional cross sectional image of soft tissues. M-mode ultrasonic imaging is an adaptation of B-mode to evaluate moving structures of the heart. Fluid-filled cystic structures have characteristic clear (anechoic) central areas with acoustic enhancement of the back wall of the cyst and deeper structures. Solid masses have echoes in their central portion with resultant poor accentuation of deeper structures. Application of ultrasound to animals requires hair removal since trapped air is a barrier to transmission of the sound beam. Gas-filled bowel and bone are effective barriers to ultrasonic imaging because of their large acoustic impedance differences compared to soft tissues. The position of the focal point of a focused transducer relative to tissue interfaces is important to accurately depict tissue character. For example, the focal point of the transducer should be superficial to the back wall when scanning cystic structures. When solid lesions, such as liver metastases, are scanned a focal point that lies deep to the lesion should be selected in order to accentuate sound beam attenuation. Time-gain compensation (TGC) settings are important to produce a balanced scan with equal echo production within like tissues throughout the depth of ultrasound tissue penetration. Initial TGC settings can be made from knowledge of the focal point of the particular transducer, but may have to be adjusted during scanning to produce a balanced image. Ultrasound is an attractive imaging modality in animals since it is noninvasive and presents no known hazard to the operator or patient.  相似文献   

8.
Transesophageal echocardiography (TEE) is a recent ultrasound technique using an endoscopic transducer to image the heart from within the esophagus. TEE avoids the anatomical structures that may affect the quality of the conventional transthoracic echocardiography. The quality of cardiovascular images obtained with TEE is therefore superior to transthoracic views. The potential indications of TEE in veterinary medicine include analysis of specific abnormalities (thrombosis, aneurism, cardiac tumors), cardiac monitoring during anesthesia or catheterization, and evaluation of cardiovascular surgical procedures.  相似文献   

9.
Diagnostic ultrasound is an easy, accurate method of locating both kidneys and liver in the horse. Good contact between the transducer and body wall is essential for clear, precise images. The greatest limitation to ultrasonic organ localization and biopsy guidance is the inability of ultrasound to transmit through gas-filled structures and bone. These structures act as barriers to sound-beam penetration and prevent visualization of soft-tissue structures deep to them. Organ parenchyma can be evaluated with ultrasonography. Focal and/or diffuse lesions can alter the normal parenchymal pattern and result in an increased or decreased echogenicity of the diseased area. Under ultrasound guidance, the biopsy instrument can be directed into these areas to insure that the sample is representative of the disease process within that organ. Biopsy-associated complications can be identified early and monitored until resolution. Equine renal and hepatic biopsies are not innocuous procedures, but ultrasonographic guidance has helped to reduce the risks involved with the biopsy techniques.  相似文献   

10.
TRANSESOPHAGEAL ULTRASONOGRAPHY OF THE NORMAL CANINE MEDIASTINUM   总被引：1，自引：0，他引：1  
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.  相似文献   

11.
Anechoic, spherical cystic lesions are important findings on ultrasound examination. In polycystic renal disease of cats, they may be the only ultrasonographic sign of disease. This study assesses the accuracy of ultrasound, as used in a veterinary setting, for the detection of cysts. Using a spherical lesion ultrasound imaging phantom and 7.5- to 8-MHz linear array transducers, images of cysts of 2- and 4-mm diameter were created at various imaging depths from 0 to 6 cm. These were digitized and given to a panel of readers for interpretation. Area under receiver operating characteristic curves were used to evaluate test accuracy. It was shown that test accuracy was different at different imaging depths and differed with machines of differing price category. It is suggested that when setting standards for quality control in ultrasound, criteria used might be better related to imaging outcome studies rather than to aspects of machine specification.  相似文献   

12.
A retrospective study was performed to evaluate the sonographic features of gastrointestinal (GI) perforation in dogs and cats. Sonographic findings in 19 animals (14 dogs and 5 cats) included regional bright mesenteric fat (19), peritoneal effusion (16), fluid-filled stomach or intestines (12), GI wall thickening (11), presence of free air (9), loss of GI wall layering (9), regional lymphadenopathy (8), reduced GI motility (7), pancreatic changes (4), corrugated intestines (4), presence of a mass (3), presence of a foreign body (3), and mineralization of the gastric wall (1). In 14 patients, "perforation" was listed as a differential diagnosis by the sonographer. Abdominal radiographs and radiographic reports were available for 14 patients. Radiographic findings were decreased serosal detail (12), free air (8), peritoneal contrast medium (1), and suspected foreign body (1). GI perforation was listed as radiographic diagnosis in eight patients, seven of which had evidence of pneumoperitoneum, and one had leakage of contrast material on an upper GI study. In 9/14 patients with radiography, "GI perforation" was listed as a sonographic diagnosis. In three patients in which free air was diagnosed sonographically, radiographs were either not available (2) or the presence of free air was not detected at presentation (1). Peritoneal fluid analysis was performed in nine patients, five of which were identified as septic inflammation, and the remaining four were classified as neutrophilic inflammation with no etiologic agent identified. The histologic or surgical diagnoses were as follows: three intestinal surgical dehiscence; one percutaneous endoscopic gastrostomy tube site leakage; one duodenal adenocarcinoma; one ileocolic lymphoma; one trichobezoar; one ascarid impaction; and one bobby pin foreign body. In the remaining 10 patients, a focal area of gastric/intestinal ulceration or transmural necrosis with perforation was identified without evidence of an underlying cause.  相似文献   

13.
Upper GI endoscopy is a frequently performed endoscopic procedure that is particularly suited for the diagnosis of upper GI diseases with a luminal or mucosal location. Contraindications are few and complications are rare. Procedures that can be performed during upper GI endoscopy include mucosal biopsy, brush cytology, aspiration of duodenal fluid for culture and cytology, foreign body retrieval, bougienage of strictures, and endoscopic placement of gastrostomy tubes. Unresolved issues that face veterinary endoscopists include the interrelationship between contrast radiology and endoscopy, the advisability of routine combination of upper and lower GI endoscopy, the reasons for discordance among clinical signs, endoscopic appearance, and biopsy findings, and the role of post-treatment biopsies.  相似文献   

14.
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.  相似文献   

15.
Otitis media is a relatively common condition in the rabbit although it can be difficult to evaluate clinically. Diagnostic imaging of the rabbit has traditionally involved radiography and there are few reports regarding the use of ultrasound. The aim of this study was to determine if the tympanic bulla (TB) and associated structures could be evaluated in the rabbit using currently available ultrasound equipment. The normal anatomy of the region was established using gross dissection and emascerated specimens and compared with the dog and cat. Ten New Zealand white rabbit cadavers were examined using two ultrasound machines and four transducers from a variety of locations. A 12 MHz linear transducer was found to be most appropriate. From a lateral approach the external ear canal could be visualized to the level of the external acoustic meatus while the TB itself could only be visualized from a ventral approach. The jugular and mastoid processes in the rabbit are very prominent and interfered with imaging of the TB from all approaches. Water-soluble lubricant introduced into the TB could be identified through the ventral bone wall of the TB and allowed the lumen and far wall to be visualised. Further work is required to determine whether ultrasound examination of the TB can be performed in live rabbits and to evaluate its benefits in the evaluation of clinical cases of otitis media.  相似文献   

16.
Paul  Y  Barthez  DVM  René  Léveillé  DVM  Peter  V  Scrivani  DVM 《Veterinary radiology & ultrasound》1997,38(5):387-393
Side lobes and grating lobes are both unwanted parts of the ultrasound beam emitted off axis that produce image artifacts due to error in positioning the returning echo. The purpose of this study was to reproduce artifacts associated with side lobes and grating lobes in vitro using different transducer types and recognize these artifacts in vivo. A phantom, composed of a water bath, a metallic wire, and a wooden tongue depressor, was imaged using a linear array, a curved linear array, a vector array, and a sector mechanical transducer. When imaging the metallic wire in a transverse plane, an echogenic artifact was constantly seen on each side of the wire, with a shape and intensity variable with the transducer type. The artifact was curvilinear and concave (linear and curved linear arrays), or curvilinear and convex (vector array and the mechanical transducer). When the tongue depressor was imaged in a longitudinal plane, the artifact was a straight line (linear array), a curved convex line(curved array), a series of convex curvilinear echo (vector array) or a small convex curvilinear echo (mechanical transducer). In vivo situations similar to the phantom experiment were investigated using clinical patients. Artifacts produced in vitro were recognized in vivo when a highly reflective object (urinary bladder wall) was imaged adjacent to an anechoic region (urine). These artifacts corresponded to the principle of secondary ultrasound lobes, and were therefore interpreted as such.  相似文献   

17.
Routine examination of the digestive system relevant to purchase includes gross examination of the feces, auscultation of the abdomen, and examination of the oral cavity and teeth for verification of age and identification of any gross abnormality. Further examination is indicated only when there is a history of diseases such as colic, especially colic surgery, or esophageal obstruction. Special procedures that might be indicated, depending upon the history and findings on the routine physical examination, include rectal palpation of the abdominal viscera; endoscopic examination of the esophagus; abdominal paracentesis; radiographs of the teeth, esophagus, or abdomen; and transabdominal or transrectal ultrasound.  相似文献   

18.
Endoscopic examination of the upper gastrointestinal (GI) tract in dogs and cats is a relatively recent development. It was just over 20 years ago, in 1978, that the first series report of GI endoscopy in dogs and cats was presented. In those initial days, endoscopy was truly a novelty, and the primary uses for endoscopes were to retrieve foreign objects or visualize the esophagus and stomach. It was not until the mid-1980s that technology and training made gastroduodenoscopy standard practice. The evolution in endoscopic technology has also mirrored the evolution in computers and imaging modalities. The original fiberoptic endoscopes, although still available, are giving way to video endoscopy and digital imaging capabilities that provide spectacular images and an ability to generate hard copy images for medical records, teaching purposes, and research data that was previously not possible.  相似文献   

19.
The recent development of a 20-MHz, high-frequency ultrasound probe has allowed tissue to be visualized at resolutions of 20 to 80 microm, which is similar to a low-power histologic view. This high degree of resolution, however, limits tissue penetration to 5 to 10 mm, which is ideal for examination of the anterior segment of the eye. The detail provided by high-resolution ultrasound readily permits the clinician to distinguish between various anterior segment entities that may appear similar but are treated quite differently, such as anterior uveal tumors, iridociliary cysts, and iris bombé. High-frequency ultrasound is also a valuable aid in creating a surgical plan for treatment of ocular disorders in which the cornea is opaque, such as feline corneal sequestrum and tumor invasion into the cornea. Other applications of this technology include elucidation of the pathogenesis of glaucoma in veterinary patients and evaluation of regions of the lens that are difficult to examine directly.  相似文献   

20.
Functional imaging using positron emission tomography (PET) plays an important role in the diagnosis, staging, image‐guided treatment planning and monitoring of malignant diseases. PET imaging complements conventional anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI). The strength of CT scanning lies in its high spatial resolution, allowing for anatomical characterization of disease. PET imaging, however, moves beyond anatomy and characterizes tissue based on functions such as metabolic rate. Combined PET/CT scanners were introduced commercially in 2001 and a number of technological advancements have since occurred. Radiolabelled tracers such as 18F‐fluorodeoxyglucose (FDG) and 18F‐fluorothymidine (FLT) allow visualization of various metabolic processes within cancer cells. Many studies in human oncology evaluating the utility of PET/CT have demonstrated clinical benefits. Few veterinary studies have been performed, but initial studies show promise for improved detection of malignancy, more thorough staging of canine cancer and determination of early response and disease recrudescence.  相似文献   

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