EFFECT OF PERINEURAL ANESTHESIA ON THE ULTRASONOGRAPHIC APPEARANCE OF EQUINE PALMAR METACARPAL STRUCTURES

The purpose of this study was to describe ultrasonographic changes of the equine palmar metacarpal area attributed to the infiltration of local anesthetic solution and to determine whether these changes were noted immediately or at 24 h. The palmar metacarpal region of one forelimb in each of six horses was examined ultrasonographically with a 10-MHz linear array transducer and a 7.5-MHz curvilinear transducer. Transverse and longitudinal images were recorded at 5-cm intervals distal to the accessory carpal bone. High and low palmar and palmar metacarpal nerve blocks were performed with a 2% mepivacaine hydrochloride solution. Ultrasonographic examinations similar to the initial examination then were performed immediately, 1 h and 24 h postinjection. Cross-sectional area and mean pixel value were determined for the superficial and deep digital flexor tendons, the accessory ligament of the deep digital flexor tendon, the suspensory ligament, and the suspensory branches at each level and time period. Subjective ultrasonographic changes also were noted. No significant difference was noted in the cross-sectional area or mean pixel value of any structure at any level or time period compared to baseline. Subjective changes in the tendons and ligaments were not noted. There was mild hypoechoic swelling of the surrounding soft tissues and gas in the region of the injections. Gas could interfere with the evaluation of the origin of the suspensory ligament and the proximal portion of the accessory ligament of the deep digital flexor tendon within the first hour but was not detectable ultrasonographically at 24 h. Based on these findings, if gas interferes with an ultrasonographic examination performed temporally close to perineural anesthesia, a repeat examination at 24 h is recommended.     

ULTRASONOGRAPHIC APPEARANCE AND ETIOLOGY OF CORRUGATED SMALL INTESTINE

An ultrasound pattern of corrugated, and sometimes thickened, bowel wall has been associated with pancreatitis and small intestinal lymphangiectasia. In a retrospective study, records of dogs and cats with an ultrasound diagnosis of corrugated bowel were examined for age, breed, gender, presenting complaint, abdominal radiographic results, and final diagnosis. Eighteen dogs and six cats had an ultrasound diagnosis of corrugated bowel. The final diagnosis was pancreatitis (12 of 24), peritonitis (4 of 24), enteritis (2 of 24), pancreatic neoplasia (2 of 24), diffuse abdominal neoplasia (1 of 24), lymphocytic-plasmacytic enteritis (1 of 24), thrombosis/infarction (1 of 24), and protein-losing enteropathy and acute renal failure (1 of 24). The presence of bowel wall corrugation, although a nonspecific finding, should alert one-to the possibility of pancreatitis, enteritis, peritonitis, neoplasia, or bowel wall ischemia.     

ULTRASONOGRAPHIC EVALUATION OF IATROGENIC INJURIES OF THE EQUINE ACCESSORY (CARPAL CHECK) LIGAMENT AND SUPERFICIAL DIGITAL FLEXOR TENDON

Iatrogenic lesions to the accessory ligament (carpal check or inferior check) and to the superficial digital flexor tendon of five ponies were monitored utilizing diagnostic ultrasound for a period of 6–24 weeks post-injury. The opposite limb was used as a non-surgical control. Sonographic differences from control limbs were recorded and correlated with the gross and microscopic post-mortem lesions. Early post-surgical sonographic findings included thickening with discrete hypoechoic areas within the injured tissues which corresponded to regions of hemorrhage, edema, and tissue disruption at necropsy. The linear hyperechoic pattern seen in normal tendons was disorganized in the injured portion of the tendons or ligaments. Disruption of the margins of the incised tissues was observed. The initial hypoechoic areas disappeared or decreased in size and became more echoic as healing progressed. The increasing echoic pattern in these areas corresponded to regions of fibrous tissues invasion and collagen deposition. As post-injury time increased, the size of the tendon or ligament decreased, the margins became more distinct, and the internal structure again became more organized (linear). It was concluded that diagnostic ultrasound can be useful in evaluating injury and healing of the accessory ligament and the superficial digital flexor tendon of horses.     

QUANTITATIVE PERTECHNETATE THYROID SCINTIGRAPHY AND THE ULTRASONOGRAPHIC APPEARANCE OF THE THYROID GLAND IN CLINICALLY NORMAL HORSES

We characterized the scintigraphic and sonographic appearance of the thyroid gland in clinically normal horses to establish the value of these modalities for assessment of the thyroid gland in this species. Horses were divided into two age groups. One group consisted of eight horses between 3 and 10 years of age and the other of seven horses between 11 and 20 years of age. Total T₄ concentrations were within the laboratory reference interval in all horses. Thyroid to salivary (T/S) ratio, percent dose uptake of pertechnetate (Na^99mTcO₄) and thyroid lobe volume were calculated. The echogenicity of thyroid lobes and presence of nodules was documented. The two groups were compared using appropriate parametric and nonparametric statistics. Mean total T₄ concentration was lower in older horses. Sixty minute mean±standard deviation (SD) T/S ratios for old vs. young horses were 5.8±3.0 and 5.3±2.2, respectively. Sixty‐minute median and interquartile ranges for percent dose uptake of pertechnetate for old vs. young horses were 3.64% (1.5–3.98%) and 2.55% (2.33–2.90%), respectively. Mean±SD thyroid lobe volume for old vs. young horses were 18.93±5.16 cm ³ and 13.55±3.56 cm³, respectively. Differences between groups were not significant. Most thyroid lobes were hyper or isoechoic to the sternocephalicus muscle. Prevalence of thyroid nodules did not differ between groups. Further study is needed to determine if thyroidal percent dose uptake is significantly different in horses with thyroid dysfunction and if it is clinically useful.     

THE EFFECT OF XYLAZINE HYDROCHLORIDE ON THE RADIOGRAPHIC APPEARANCE OF THE STOMACH AND INTESTINE IN THE DOG

Twelve dogs of various breeds, age and weight were injected with xylazine hydrochloride by intravenous and intramuscular routes at various doses. Radiographs of the abdomen were made prior to and at 30, 60 and 90 minutes after injection. The drug produced dilatation of the stomach and the intestines. Radiographic changes were consistent with gastric dilatation and paralytic ileus     

TRANSCUTANEOUS ULTRASONOGRAPHIC EVALUATION OF THE AIR-FILLED EQUINE STOMACH AND DUODENUM FOLLOWING GASTROSCOPY

Gastroscopy with air insufflation was performed in 10 ponies, after which a transcutaneous ultrasound examination of the stomach and duodenum was performed immediately and at 1, 2, and 4 h postgastroscopy, and 24 h after feeding. Stomach measurements included the dorsoventral and craniocaudal dimensions, as well as the stomach depth from the skin surface and stomach wall thickness at the different time periods. Gastric wall folding was observed in one pony, becoming most distinct 2–4 h postgastroscopy. An undulating stomach wall was noted in eight other ponies postgastroscopy. These observations appeared to be a response to the deflation of the stomach as the insufflated air was released gradually. Gas was detected in the duodenum after the gastroscopy. The parameters measured were noted to be useful to evaluate the extent of stomach distension due to air or feed. The ultrasonographic appearance of the stomach can, therefore, be altered by gastroscopy and this should be borne in mind when examining horses with suspected gastric disease.     

ULTRASONOGRAPHY OF THE EQUINE LARYNX

Nasopharyngeal and laryngeal evaluation is important when examining horses with upper airway signs for poor performance. Currently endoscopy is the most common method to evaluate the equine upper airway. Ultrasonography of the equine larynx has not previously been described. Using six cadaveric specimens and four standing horses, the ultrasonographic appearance of the equine larynx was established. A scanning technique, including useful acoustic windows and the normal ultrasonographic appearance at each site, is described. Ultrasound allowed visualization of portions of the hyoid apparatus, laryngeal cartilages, associated soft tissues, and intrinsic and extrinsic laryngeal musculature, that are not seen using endoscopy. Additionally, real-time ultrasound allowed observation of the movement of the vocal folds and the arytenoid cartilages during respiration. In three horses with arytenoid chondritis, ultrasonography aided in the diagnosis and localization of arytenoid abcessation and perilaryngeal inflammation. The establishment of this technique will serve as the basis for future investigations in the evaluation of clinical patients with upper airway abnormalities.     

REPEATABILITY AND REPRODUCIBILITY OF TRANSABDOMINAL ULTRASONOGRAPHIC INTESTINAL WALL THICKNESS MEASUREMENTS IN THOROUGHBRED HORSES

The aims of this study were to assess the repeatability and reproducibility of transabdominal ultrasonography to assess intestinal wall thickness in adult Thoroughbred horses (n=8). Ultrasonographic cineloops were captured by one examiner from each horse for five consecutive days. During each examination at least three cineloops were obtained for five different intestinal tract locations. Measurements were performed by three separate observers to assess reproducibility and measured on three separate occasions by three observers to evaluate short‐term repeatability. The repeatability of measurements from the duodenum (0.3 ± 0.04 cm), jejunum (0.29 ± 0.05 cm), ventral colon (0.37 ± 0.01 cm), and cecum (0.42 ± 0.03 cm) were good ( P >0.291). The reproducibility of measurements from the duodenum, jejunum, and ventral colon were good ( P >0.394). Reproducibility of measurement of the cecal wall was inadequate ( P =0.01), although the maximum difference between observers was 0.07 cm. It was possible to image all areas on all days, with the exception of the duodenum, which could not be imaged in one horse, on 1 day. Equine intestinal wall measurements are therefore repeatable and reproducible with the exception of reproducibility of the measurements of cecal wall. Although an accepted clinical technique, measurement of cecal wall thickness from intestinal ultrasound images in a clinical setting must be interpreted with care.     

COMPARISON BETWEEN STANDARD ULTRASONOGRAPHY,ANGLE CONTRAST ULTRASONOGRAPHY,AND MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF THE NORMAL EQUINE PROXIMAL SUSPENSORY LIGAMENT

Previous studies have proposed that standard ultrasonography may not adequately represent the pertinent anatomic characteristics of the equine proximal suspensory ligament. The purpose of the study was to compare the use of standard ultrasonography, angle contrast ultrasonography, MRI, and histology for identification of the anatomic characteristics of the normal equine suspensory ligament in the forelimb. Horses free from forelimb lameness with no palpable abnormalities in the region of the suspensory ligament were included in the study. The proximal suspensory ligaments in 20 forelimbs were examined using the standard ultrasound technique, angle contrast ultrasound technique, and MRI, followed by histologic evaluation. Total transverse (cross‐sectional) area of the proximal suspensory ligament was estimated using the standard ultrasound and the angle contrast ultrasound techniques, MRI, and histologic sections for the following parameters: total area of the ligament, ligament fibers, muscle, and fat. The proximal suspensory ligament lobe size and tissue distribution were compared and subjectively graded (0–4) for asymmetry. Subjectively, angle contrast ultrasound technique improved differentiation of fibers from the remaining tissue types and allowed identification of the peripheral ligament margin. There was no significant difference in asymmetry scores between modalities. The asymmetry scores of the right and left forelimbs were significantly different with both ultrasound and MRI, based on the level of measurement. The angle contrast ultrasound technique has limitations compared to MRI. However, it provides additional diagnostic information that is not available with the standard ultrasound technique.     

不同粗精比日粮对绵羊小肠中瘤胃微生物蛋白质利用的影响

用4只装有瘤胃瘘管、十二肠瘘管和回肠瘘管的去势(公母各半)萨福克羊体重平均为(45.5±5.2)kg,在不同粗精比日粮条件下 ,研究瘤胃细菌、纤毛虫体蛋白质在小肠内的利用率。结果表明 :到达十二指肠的瘤胃细菌和纤毛虫的量 ,随日粮中精饲料水平的提高而显著减少(P<0.05)。与此相反 ,过瘤胃饲料蛋白质的量则显著增加(P<0.05)。小肠内的细菌利用率显著受日粮变化的影响 ,而纤毛虫利用率则不易受日粮影响且显著地高于细菌的利用率(P<0.05)。小肠内被吸收的细菌和纤毛虫对微生物氮的贡献率在全试验组中平均为50 %。     

EFFECTS OF TWO CONTRAST INJECTION PROTOCOLS ON FELINE AORTIC AND HEPATIC ENHANCEMENT USING DYNAMIC COMPUTED TOMOGRAPHY

This prospective study compared aortic and hepatic enhancement achieved using a contrast injection protocol with a fixed rate of 5 ml/s vs. that achieved using a protocol with fixed injection duration of 20 s in eight cats. Cats were assigned into two groups (Group 1, rate 5 ml/s; Group 2, duration 20 s). The dose of contrast was the same in both groups (740 mgI/kg). Regions of interest (ROI) were drawn in the aorta and liver for transverse scans acquired at the hepatic hilus. Time to peak aortic enhancement occurred significantly earlier in Group 1 (M = 11s, SD = 1.63) than in Group 2 (M = 25.5 s, SD = 2.51). Peak aortic enhancement was significantly higher in Group 1 (M = 1906.51 HU, SD = 368.64) than in Group 2 (M = 745.08 HU, SD = 201.84). Duration of aortic enhancement equal to or above 300 HU was statistically longer in Group 2 (M = 24.5 s, SD = 8.39) than in Group 1 (M = 10 s, SD = 1.63). There were no significant differences in time to peak liver enhancement, peak liver enhancement, or duration of hepatic arterial phase between groups. Findings supported the hypothesis that longer injection duration results in a broader bolus geometry with a longer time to peak and a lower peak aortic enhancement in cat. This strong influence of injection duration on timing of aortic enhancement may help future users optimize protocols for CT angiography of the aorta and multiphasic evaluation of the liver, pancreas, and small intestine.     

EFFECTS OF A DIGITAL FILTER ON DETECTABILITY OF A PHANTOM LESION IN A SCINTIGRAM OF THE EQUINE TARSUS

The aim of this study was to examine the effects of a digital filter on the detectability of a phantom lesion in a scintigram of the equine tarsus. Lateral images containing 50, 100, 150, 500, or 1000 kcounts were acquired. A created phantom lesion of 0 (normal), 10, 15, 20, or 30% increased intensity relative to local background was placed in the centrodistal tarsal joint area in the images of different count levels. Duplicate images were filtered with a Metz filter. The complete set of filtered and unfiltered images totaling 180 images was projected as slides to a group of 9 observers. The sensitivity in 50 and 100 kcount images was improved by applying the filter. Digital filtering increased the false positive fraction at all count levels but this effect was most pronounced in 500 and 1000 kcount images. Based on receiver operating characteristic analysis, filtering of a 50 kcount image improved image quality to that of a 150 kcount image.     

ULTRASONIC ANATOMY OF THE TENDONS AND LIGAMENTS IN THE DISTAL METACARPAL-METATARSAL REGION OF THE EQUINE LIMB

In a two-phase study, ultrasound was used to delineate the normal sonographic anatomy of soft tissues of the equine distal limb. The study was limited to the soft tissues of the palmar surface of the limb just proximal to the fetlock joint. In the first phase, cadavers were evaluated with a B-mode ultrasound machine, † Then the limbs were radiographed and dissected to compare their gross, radiographic, and ultrasonographic appearances. In the second phase, nine normal adult horses were ultrasonographically scanned. The sonographic appearance of the normal animals was compared with that of the cadavers. Front and rear limbs of all horses had similar ultrasonographic appearances. Flexor tendons and the suspensory ligament were easily identified as having linear, uniformly intense ecogenicity. The borders of the digital sheath and of the proximal palmar pouch of the fetlock joint had a less organized and less intense ecogenic appearance than the flexor tendons and suspensory ligament, and they were poorly delineated unless distended with fluid. Ultrasonography was used in three lame horses and aided the diagnoses of synovial proliferation in the fetlock joint, tendosynovitis, and bowed tendon. Diagnostic ultrasonography was effective in identifying and characterizing soft-tissue structures of the distal equine limb. It is a valuable, noninvasive diagnostic aid.     

ELASTOGRAPHIC EVALUATION OF NATURALLY OCCURING TENDON AND LIGAMENT INJURIES OF THE EQUINE DISTAL LIMB

Compression elastography is an ultrasonographic technique that estimates tissue strain and may have utility in diagnosing and monitoring soft tissue injuries in the equine athlete. Recently, elastography has been proven to be a feasible and repeatable imaging modality for evaluating normal tendons and ligaments of the equine distal forelimb. The purposes of this prospective study were to investigate the ability of elastography to detect spontaneously occurring lesions of equine tendons and ligaments diagnosed with magnetic resonance imaging (MRI) and gray‐scale ultrasound (US) and to characterize the differences in the elastographic appearance of acute vs. chronic injuries. Fifty seven horses with a total of 65 lesions were evaluated. Images were assessed quantitatively and qualitatively. Acute lesions were found to be significantly softer (P < 0.0001) than chronic lesions (P < 0.0001) and the stiffness of lesions increased with progression of healing (P = 0.0138). A negative correlation between lesion hypoechogenicity and softness was appreciated with more hypoechoic lesions appearing softer (P = 0.0087) and more hyperechoic regions harder (P = 0.0002). A similar finding occurred with increased signal intensity on short tau inversion recovery (STIR) and proton density (PD) MRI sequences correlating with increased softness on elastography (P = 0.0164). Using US and MRI as references, commonly encountered soft tissue injuries of the equine distal limb could be detected with elastography. However, elastography was limited for detecting small, proximal injuries of the hindlimb proximal suspensory ligament. Elastographic evaluation of equine tendons and ligaments may allow better characterization of lesion chronicity and severity, and sequential examinations may optimize lesion management, rehabilitation, and return to training.     

EVALUATION OF THE EQUINE DIGITAL FLEXOR TENDON SHEATH USING DIAGNOSTIC ULTRASOUND AND CONTRAST RADIOGRAPHY

This study was designed to evaluate the normal anatomy of the digital flexor tendon sheath using contrast radiography and diagnostic ultrasound. Iodinated contrast medium was injected into eight cadaver limbs and the limbs immediately frozen. Lateromedial and dorsopalmar/plantar radiographs were made. These limps were then cut transversely and proximal to distal radiographs of each slab were made. This cross sectional contrast methodology allowed the visualization of the relative size and shape of the superficial and deep digital flexor tendons as well as the potential space taken by effusions of the digital flexor tendon sheath.
The second part of the study used twelve live animals with normal digital flexor tendon sheaths. Ultrasonographic measurement of the structures of the digital flexor tendon sheath at each level were compiled. This documented the ability of diagnostic ultrasound to image: 1) the superficial and deep digital flexor tendons, 2) the proximal and distal ring of the manica flexoria , 3) the straight and oblique sesamoidean ligaments, and 4) the mesotendinous attachments to the superficial and deep flexor tendons. Iodinated contrast medium was then injected into the digital flexor tendon sheath and the ultrasonography repeated. These images were compared with those obtained from contrast radiography and prosections of twenty normal limbs. The iodinated contrast medium enhanced sonographic imaging of the structures of the digital tendon sheath, particularly the abaxial borders of the superficial digital flexor tendon branches and the mesotendinous attachments to the superficial and deep digital flexor tendons.     

ULTRASONOGRAPHIC MEASUREMENT OF PALMAR METACARPAL TENDON AND LIGAMENT STRUCTURES IN THE HORSE

An ultrasonographic study was made at several levels of the palmar metacarpal region of 23 horses (Anglo-Arabian-Andalusian) aged over three years. Lateromedial and palmodorsal measurements were made of tendons and ligaments, following clinical examination to confirm the absence of pathology in this region. Dissection was performed on 23 forelimbs, and these were measured at the same levels to establish a base of reference for the study. These measurements should prove useful in the evaluation of possible pathology in this region.     

COMPUTED TOMOGRAPHIC APPEARANCE OF MELANOMAS IN THE EQUINE HEAD: 13 CASES

Melanomas are one of the most common neoplasms in the horse and are frequently found in the head region. There is a genetic predisposition in horses with a gray hair coat. Computed tomography (CT) is frequently used in referral practice to evaluate the equine head but there are few reports describing the CT appearance of melanomas in this location. The aim of this retrospective, case series study was to describe characteristics in a group of horses with confirmed disease. Case records from two referral hospitals were reviewed, and 13 horses were identified that had undergone CT of the head, with a diagnosis of melanoma based on cytology, histopathology, or visual assessment of black (melanotic) tissue. A median of 11 melanomas was identified per horse (range 3–60), with a total of 216 masses. Melanomas were found most frequently in the parotid salivary gland, guttural pouches, surrounding the larynx and pharynx and adjacent to the hyoid apparatus. In noncontrast CT images, all melanomas were hyperattenuating (median; 113.5 Hounsfield units (HU), IQR; 26 HU) compared to masseter musculature (median; 69 HU, IQR; 5.5 HU). Fifty‐six (25.9%) masses were partially mineralized and 41 (19.4%) included hypoattenuating areas. Histopathological assessment of these melanomas suggested that the hyperattenuation identified was most likely a result of abundant intracytoplasmic melanin pigment. Melanomas of the equine head appeared to have consistent CT features that aided detection of mass lesions and their distribution, although histopathological analysis or visual confirmation should still be obtained for definitive diagnosis .     

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.