ULTRASONOGRAPHIC DIAGNOSIS OF OVINE CYSTIC ECHINOCOCCOSIS

The sanitary and economic impact of cystic echinococcosis is serious in those countries where it becomes endemic. Ultrasonography is one technique that may be used to diagnose this disease in endemic areas. In parasitized sheep, hydatid cysts appear sonographically as a round hypoechoic structure. Twenty two sheep destined for slaughter were studied sonographically and imaging findings compared to post-mortem findings. Three sheep with hydatid cysts were identified. Eighty additional sheep not destined for slaughter were also studied. Echinococcus granulosus cysts were detected in three animals. Forty sheep from a non-endemic area had no hepatic cysts. The in vivo sonographic study of sheep provides a useful screening tool for echinococcosis.     

COMPUTED TOMOGRAPHY OF HEREDITARY MULTIFOCAL RENAL CYSTADENOCARCINOMAS IN GERMAN SHEPHERD DOGS

the purpose of the study was to characterize the renal lesions of hereditary renal cystadenocarcinomas in the German shepherd dog using computed tomography (CT), Fourteen dogs with renal cystadenocarcinomas and nodular dermatofibrosis, and two unaffected dogs were studied. There were nine dogs with spontaneous disease and seven dogs from a test mating. The characteristic renal CT findings of renal cystadenocarcinomas were bilateral multiple cysts and tumor masses of various sizes. The earliest change were detected between 4 and 5 years of age and the smallest cysts measured 2-3 mm in diameter. Abdominal CT examination gives a wide field view and excellent anatomic images of the kidneys. It is easy to differentiate between cysts and solid tumors. CT examination is useful for the early detection of renal cystadenocarcinomas and for screening suspected carrier dogs before breeding.     

DETERMINATION OF FISH GENDER USING FRACTAL ANALYSIS OF ULTRASOUND IMAGES

The gender of cod Gadus morhua can be determined by considering the complexity in their gonadal ultrasonographic appearance. The fractal dimension ( D _B) can be used to describe this feature in images. B-mode gonadal ultrasound images in 32 cod, where gender was known, were collected. Fractal analysis was performed on these images and D _B was determined using the box counting method. A receiver–operating curve (ROC) was drawn for D _B as a test for male fish. Using a range of D _B values, the maximum accuracy for this test was calculated and compared with the accuracy for identifying male fish by subjective analysis alone. The mean (and standard deviation) of the fractal dimension D _B for male fish was 1.554 (0.073) while for female fish it was 1.468 (0.061); the difference was statistically significant ( P =0.001). The area under the ROC curve was 0.84 indicating the value of fractal analysis in gender determination in cod. Maximum accuracy (0.84) for D _B as a test for male fish was obtained using the threshold value D _B=1.5058 compared with an accuracy of 0.78 for subjective image evaluation. The use of two thresholds, D _B<1.4475 (females) and D _B>1.5054 (males) gives an 80% certainty in the classification result. Fractal analysis is useful for gender determination in cod. This or a similar form of analysis may have wide application in veterinary imaging as a tool for quantification of complexity in images.     

CONTRAST HARMONIC ULTRASOUND OF SPONTANEOUS LIVER NODULES IN 32 DOGS

Thirty-two dogs with spontaneous hepatic nodules were given intravenous ultrasound contrast medium (Definity or Sonovue) and imaged with contrast harmonic software on a conventional ultrasound machine system. Digital video images were initially reviewed to describe the perfusion pattern of malignant nodules. The images were reviewed again to test this pattern against all individual nodules. Subjectively, there was improved conspicuity of malignant nodules after contrast enhancement compared with conventional imaging and increased numbers of malignant nodules were often noted. There was decreased conspicuity of benign nodules and no additional nodules were seen after contrast enhancement. There was a highly significant (P < 0.0001) association of malignancy with a hypoechoic nodule at surrounding normal liver peak contrast enhancement. Benign nodules were isoechoic to the surrounding normal liver at peak contrast enhancement. Only one benign nodule (hepatoma) had regions of hypoechogenicity compared with the surrounding normal liver at peak liver contrast enhancement. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were highly significant (P < 0.0001) (100%, 94.1%, 93.8%, 100%, and 96.9%, respectively). No complications or morbidity was noted throughout the course of the study. Contrast harmonic ultrasound appears to be accurate at discriminating between naturally occurring benign and malignant nodules in the liver of dogs.     

EFFECT OF ULTRASOUND BEAM ANGLE ON EQUINE ARTICULAR CARTILAGE THICKNESS MEASUREMENT

The purpose of this study was to determine if variation in the ultrasound beam angle would affect cartilage thickness measurement performed with B-mode ultrasonography. Transverse sections of six fresh equine middle phalanges were obtained from necropsy. Ultrasonographic images of the proximal articular cartilage were obtained in a water bath, in a plane parallel and adjacent to the section plane using a 5-10 MHz linear transducer. Static images were acquired for all six bone specimens with an ultrasound beam angle of 0 degree, 30 degrees, 45 degrees, and 60 degrees. Proximal articular cartilage thickness was measured on ultrasonographic images and on the bone specimen at the same level. A linear mixed-effects model was used to compare articular cartilage thickness measured on specimen and on ultrasonographic images using different ultrasound beam angle. Mean +/- SD cartilage thickness was 1.82 +/- 0.35 mm on bone specimens, 1.72 +/- 0.29 with a 0 degrees angle, 1.99 +/- 0.34 with 30 degrees, 2.06 +/- 0.34 with 45 degrees, and 2.3 +/- 0.38 with 60 degrees. There was a significant difference between macroscopic measurements and ultrasonographic measurements performed with ultrasound angles at 30 degrees, 45 degrees, and 60 degrees. There was a significant increase in cartilage thickness when the ultrasound beam angle decreased (P = 0.0157; R2 = 0.969). Cartilage thickeness measured on ultrasonographic images varies with the ultrasound beam angle and may not be accurate because ultrasound speed in cartilage may be different than the speed used by the ultrasonographic unit for distance calculation.     

Ultrasonographic screening for cystic echinococcosis in sheep in Tunisia

Sheep from the areas of Fondouk-Jeddid, Bir Mchergua and El Fahs, located in the Northeast of Tunisia, were examined by ultrasonography between 2001 and 2004 in order to assess their infection with Echinococcus granulosus, the agent of hydatid disease, and to evaluate this method as an efficient aire for hydatid cysts. A total of 1039 sheep, aged between 1 and 14 years was examined. The highest prevalence was found in sheep aged more than 8 years. The least infected animals were aged between 1 and 2 years. All hydatid cysts detected by ultrasound were located in the liver. In all age-groups, the dead cysts were more numerous than viable cysts. Eighteen positive sheep were autopsied and a comparison between ultrasound and autopsy results was performed. The results showed a prevalence of about 40% for the three areas. Ultrasonography allowed the cysts, deep or superficial to localize in the central or left part in relation to the caudal vena cava of the animals. Consequently, all the cysts were not detected with this technique. This work shows that ultrasonography confirms the importance of ovine hydatid cyst in Tunisia and that its use as a mass screening approach for cystic echinococcosis in sheep could be helpful for the monitoring of this disease in a hydatid control program without great stress for the animals.     

A PATHOLOGICAL AND BACTERIOLOGICAL ABATTOIR SURVEY OF THE REPRODUCTIVE TRACTS OF MERINO EWES IN WESTERN AUSTRALIA

Macroscopic examination of 487 ewe reproductive tracts from 18 different sources was made at Perth abattoirs. Of these, 194 were examined microscopically and 217 bacteriologically. Observations were made during March to May, when ewes were not grazing oestrogenic pasture. Significant lesions in ovaries or oviducts were rare. Macroscopic cysts were found in the uterus or cervix of 159 ewes (32.7%). Microscopic lesions, including uterine or cervical cysts and squamous metaplasia or goblet cell hyperplasia of the epithelium, were observed in 76% of ewes studied. Bacteria were isolated from 59 ewes, the most common genera being Corynebacterium, Escherichia, Streptococcus and Bacillus. Escherichia coli and streptococci appeared to be the most commonly associated with endometritis. Presence of bacteria was closely associated with endometritis and with cysts in the cervix. Endometritis was observed microscopically in 48 ewes (24%) and was significantly associated with the presence of cysts in the uterus or cervix. These results suggest that there is a high incidence of clover disease lesions in West Australian ewes, and that under commercial conditions clover disease may cause functional damage to the cervix, allowing passage of bacteria and resulting in endometritis.     

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.     

USE OF CONTRAST HARMONIC ULTRASOUND FOR THE DIAGNOSIS OF CONGENITAL PORTOSYSTEMIC SHUNTS IN THREE DOGS

Contrast harmonic ultrasound was used to determine macrovascular and perfusion patterns in three dogs with congenital extrahepatic solitary portosystemic shunts (PSS). With coded harmonic angiographic ultrasound, the size and tortuosity of the hepatic arteries were subjectively increased. Single pulse intermittent low-amplitude harmonic perfusion imaging provided contrast enhancement time-intensity curves from regions of interest in the liver. Mean (+/- standard deviation) peak perfusion times of dogs with PSS were significantly shorter (p = 0.01; 7.0 +/- 2.0 s) than reported in normal dogs (22.8 +/- 6.8 s). The contrast inflow slope for the dogs with PSS (14.6 +/- 3.7 pixel intensity units [PIU] was significantly (p = 0.05) larger than reported for normal dogs (3.6 +/- 1.4 PIU/s). These results indicate that combined coded harmonic angiographic and contrast harmonic perfusion sonography can be used to detect increased hepatic arterial blood flow as an indicator of PSS in dogs.     

Extradural spinal juxtafacet (synovial) cysts in three dogs

Three dogs were presented for investigation of spinal disease and were diagnosed with extradural spinal juxtafacet cysts of synovial origin. Two dogs that were presented with clinical signs consistent with pain in the lumbosacral region associated with bilateral hindlimb paresis were diagnosed using magnetic resonance imaging. Both cysts were solitary and associated with the L6-7 dorsal articulations; both the dogs had a transitional vertebra in the lumbosacral region. A third dog that was presented with progressive paraparesis localised to T3-L3 spinal cord segments and compression of the spinal cord at T13-L1 was diagnosed using myelography. A solitary multiloculated cyst was found at surgery. Decompressive surgery resulted in resolution of the clinical signs in all three dogs. Immunohistological findings indicated that one to two layers of vimentin-positive cells consistent with synovial origin lined the cysts.     

Comparison of different methods to assess the composition of pig bellies in progeny testing

The objective of the study was to validate methods that assess the belly composition of stationary tested progenies of Piétrain boars. In German performance test stations, there are currently three methods of determining belly compositon in use: 1) a regression equation that contains different carcass characteristics, such as fat thickness and muscle area; 2) planimetric analysis of video or digital images acquired at the cut between the 13th and 14th ribs; and 3) estimation of the belly composition using ultrasound data from a three-dimensional ultrasound image produced an online carcass-grading system. Validation of these techniques was performed on 400 carcasses of stationary-tested Piétrain and Piétrain-sired crossbred pigs, which were slaughtered at a mean carcass weight of 85 and 97 kg. Magnetic resonance imaging (MRI) served as a reference to determine the lean content of the bellies. The correlation to MRI lean content ranged from 0.71 to 0.81, and corresponding correlation values were 0.62 to 0.64 for the digital imaging technique, and 0.53 to 0.59 for the AutoFOM online carcass-grading system. An increase in precision was achieved when information from digital imaging and linear carcass measures were included in the regression equation. Accuracy of the AutoFOM system does not seem to be sufficient to assess the belly composition for the special breeds in performance testing. However, extracting and combining 127 AutoFOM-base recordings into modified equations using partial least squares techniques yielded an improvement in the prediction accuracy for all tested breed and/or weight groups.     

COMPARATIVE ULTRASONOGRAPHIC INVESTIGATIONS OF THE GASTROINTESTINAL TRACT AND THE LIVER IN HEALTHY AND DISEASED PIGEONS

The use of ultrasound as a diagnostic tool in birds has been documented for cardiac, urogenital, and liver disease. However, its use in gastrointestinal tract disease is not defined. Therefore, the purpose of this study was to compare the ultrasonographic findings of the intestine and liver of six healthy racing pigeons with those of six racing pigeons with gastrointestinal disease. The echogenicity of the liver was significantly different between the two groups. Pigeons with gastrointestinal disease had less homogeneous liver echogenicity with focal heterogeneous areas and the hepatic blood vessels were visible and dilated. The duodenum was visualized and its mean diameter of 7.2 +/- 0.3 mm in the diseased pigeons was significantly wider (P < or = 0.001) than the 5.7 +/- 0.2 mm in healthy birds. The thickness of the duodenal wall in healthy and diseased pigeons was 1.6 +/- 0.1 and 2.4 +/- 0.1 mm, respectively, and they were significantly different (P < or = 0.001). We defined baseline measurements for the duodenal loop in pigeons and provided evidence that ultrasound can be a useful diagnostic tool for investigating intestinal disease in pigeons.     

DEVELOPING A TECHNIQUE FOR ULTRASOUND‐GUIDED INJECTION OF THE ADULT CANINE HIP

An accurate method for guiding injections into the canine hip would facilitate diagnostic localization of lameness and targeted treatments. Ultrasound‐guided hip injections are commonly used in humans and large animals. Aims of this prospective study were to describe ultrasound (US) anatomy of the adult canine hip and determine the feasibility and accuracy of intra‐articular placement of injectate using US‐guidance. Seven adult dogs were used to describe US anatomy, five dog cadavers were used to assess the feasibility of the injection technique and 11 dog cadavers were used to assess accuracy of injections. For the accuracy test, 22 joints were injected with iodinated contrast medium by three operators with different experience. With dogs in lateral recumbency, the hyperechoic femoral head surface was identified by following the femoral neck from the greater trochanter or the acetabular rim was localized by following caudally the ilium from the iliac wing.  An anechoic gap between the femoral head and acetabular surface represented the joint. The capsule was visible as a triangular echoic structure and the femoral head articular cartilage appeared as an anechoic band. The needle was inserted axial to the greater trochanter and directed in a dorsolateral–ventromedial direction toward the joint space and then pushed through the capsule. Based on postinjection radiography, accuracy was 81.8% at first attempt and 100% at second attempt. This study indicated that US‐guided injection is a feasible and accurate technique for injecting the adult canine hip. Future studies in live dogs are needed to assess safety and efficacy.     

A REVIEW OF NONCONVENTIONAL ULTRASOUND TECHNIQUES AND CONTRAST-ENHANCED ULTRASONOGRAPHY OF NONCARDIAC CANINE DISORDERS

Modern ultrasound contrast media are gas-containing stabilized microbubbles that remain intact in the circulating blood for several minutes after intravenous injection and increase the intensity of the backscattered ultrasound. When the microbubbles disappear from the blood, they can be detected in the parenchyma of the liver and the spleen for about 30 more minutes (late liver- and spleen-specific phase). The insonated microbubbles produce second harmonic ultrasound frequencies, whose detection requires nonconventional ultrasound modalities such as pulsed inversion imaging. Nonconventional ultrasound techniques can also be used without microbubbles because second harmonics can be generated by ultrasound in tissues as well. The physical principles and advantages of nonconventional ultrasound techniques are described. The circulating microbubbles can be used not only to enhance weak Doppler signals, but also to perform dynamic contrast studies. Contrast-enhanced dynamic ultrasound studies--similar to contrast-enhanced CT and MRI examinations--have been used in humans to characterize lesions noninvasively (i.e., without biopsies) found during conventional ultrasound examinations. To map the distribution of contrast medium in a nodule or in an organ, specific scanning techniques such as stimulated acoustic emission have been developed. Stimulated acoustic emission occurs when high acoustic pressure ultrasonic waves disrupt the stationary or slowly moving microbubbles. This results in the release of a large amount of harmonic ultrasound frequencies. When the stimulated acoustic emission technique is used for dynamic studies, scanning must be interrupted several times to allow the microvasculature of the lesion to refill with microbubbles (interval delay imaging). The contrast patterns of malignant and benign hepatic nodules in humans have been the most intensively studied. Another type of dynamic study in humans measures the transit time of the contrast medium; that is, how fast the peripherally injected microbubbles reach the hepatic veins. Hepatic cirrhosis can be differentiated from other diffuse parenchymal liver diseases by a shorter transit time. Introducing nonconventional ultrasound techniques and ultrasound contrast media in veterinary diagnostic imaging may have potential value; however, intensive research should be carried out before ultrasound contrast agents can routinely be used in clinical practice.     

3种食蟹猴早孕诊断方法的比较

本试验旨在对3种食蟹猴早孕诊断方法进行比较,找出比较准确、可靠的诊断方法。在食蟹猴怀孕第20天时用直肠触诊、B超检查和孕酮值检测3种方法进行早孕诊断,在怀孕第30天时B超确诊是否怀孕。结果表明,B超检查的准确率为96.4%;直肠触诊的准确率为92.9%;孕酮值检测的准确率为64.3%。因此B超检查准确率高,是食蟹猴怀孕诊断的金标法;直肠触诊准确率较高且方便、经济,适合基层生产中进行大批量诊断;孕酮值检测确诊率较低,但可作为早孕诊断的辅助方法。     

RADIOLOGIC DETECTION OF OVINE HYDATIDOSIS

Unilocular hydatid disease in humans is of world-wide importance. While surgical removal is the usual treatment, the drug mebendazole has been reported as being active against the cyst wall; other potentially valuable drugs are likely to become available. Naturally infected sheep would be a suitable model for testing drugs against hydatid disease, and a method for selecting infected animals from flocks in areas with a high incidence of this condition would be valuable. To determine whether radiographic examinaiton of the thorax would be a satisfactory method of identifying cysts, the authors radiographed and then killed 93 cull ewes. At necropsy, the lungs were examined, and the nature and distribution of cysts were noted and compared with the findings obtained separately by radiology. A similar study was made on a sheep infected experimentally with a large number of Echinococcus granulosus ova. The technique of thoracic radiography in sheep is described. These studies indicate that there are four different morphologic manifestations of ovine hydatid cyst that may be reliably identified by radiologic examination. They also show that thoracic radiology provides a method for detecting active hydatid infection in sheep and for following the progress of individual cysts.     

Maximum-likelihood estimation of sensitivity and specificity of ELISAs and faecal culture for diagnosis of paratuberculosis

The accuracy of three diagnostic tests for paratuberculosis was evaluated using maximum-likelihood estimation of sensitivity and specificity. We also explored the variety of estimates that can be obtained if the tests are to be used in populations of different composition with regard to infection and disease states. Two enzyme-linked immunosorbent assays (ELISAs) were evaluated separately with the faecal culture (FC). The study was carried out as a cross-sectional field study to cover all likely states of infection with Mycobacterium avium subsp. paratuberculosis.The three basic assumptions for the maximum-likelihood technique were evaluated to validate the results. Our accuracy estimates for the ELISAs were not very different from those previously published, but those for faecal culture differed if a different cut-off value was chosen for the ELISA. If faecal culture was used for screening in a Danish dairy region where the median ELISA reading was a measure of the general disease situation, the sensitivity of the faecal culture was 20-25%. If faecal culture was used as a confirmatory test on cows with a high ELISA reading (and thus high level of antibodies), the sensitivity of the faecal culture would be in the range 60-70%. These results emphasise the importance of the composition of a target population before selecting a specific diagnostic test for a given purpose. We concluded that faecal culture is useful for confirmation but not for screening purposes.     

EVALUATION OF SURVEY RADIOGRAPHY, LINEAR TOMOGRAPHY AND COMPUTED TOMOGRAPHY FOR DETECTING EXPERIMENTAL LESIONS OF THE CRIBRIFORM PLATE IN DOGS

Survey radiography, linear tomography, and computed tomography were used to image cribriform plate lesions that were created experimentally using intramedullary pins in 18 dog cadaver skulls. Computed and linear tomographic images were taken along the dorsal imaging plane. Studies were independently reviewed by five observers. Results were combined so that the relative sensitivity, specificity, and accuracy of each imaging technique could be compared using chi-square analysis. Computed tomography proved to be significantly more sensitive and accurate (p<0.05) than either linear tomography or survey radiography. Computed tomographic images were consistently of good to excellent quality for imaging the cribriform plate. It was concluded that computed tomography of the skull using a dorsal imaging plane was the best available imaging modality for detecting 3-mm and 5-mm experimentally created cribriform plate defects.     

THE USE OF MAGNETIC RESONANCE IMAGING IN EVALUATING HORSES WITH SPINAL ATAXIA

To determine the accuracy of magnetic resonance imaging for diagnosing cervical stenotic myelopathy in horses, 39 horses with spinal ataxia and 20 control horses underwent clinical and neurologic examinations, cervical radiographs, euthanasia, magnetic resonance (MR) imaging of the cervical spine and necropsy. Twenty‐four horses were diagnosed with cervical stenotic myelopathy, 5 with cervical vertebral stenosis, 7 with idiopathic ataxia, 3 horses had other causes of ataxia, and 20 were controls. The MR images were assessed for spinal cord intensity changes, presence of spinal cord compression, spinal cord compression direction, shape of spinal cord, and the presence of synovial cysts, joint mice, and degenerative joint disease. The height, width, and area of the spinal cord, dural tube and vertebral canal were measured. The identification of spinal cord compression on MR images was significantly different in horses with cervical stenotic myelopathy (P < 0.02), but in the cervical stenotic myelopathy group the identification of spinal cord compression on MR images had poor to slight agreement with histopathologic evidence of compression (κ = 0.05). Horses with cervical stenotic myelopathy were more likely to have a T2 hyperintensity in the spinal cord (P < 0.05). Horses with cervical stenotic myelopathy or cervical vertebral stenosis were more likely to have degenerative joint disease than control horses or horses with other or idiopathic ataxia.