Validation of Ultrasonography for Assessment of Gastric Emptying Time in Healthy Cats by Radionuclide Scintigraphy.

BACKGROUND: The prevalence of gastric emptying (GE) disorders in cats is unknown due to lack of clinically applicable diagnostic tests. OBJECTIVES: The principal aim of this study was to assess correlation between scintigraphic and ultrasonographic measurements of GE time (GET) in healthy cats. Additionally, variability of ultrasonographic GET, and correlation between scintigraphy and ultrasonographic parameters of gastric motility were evaluated. ANIMALS: Eight healthy domestic shorthair cats. METHODS: Prospective study. Scintigraphic GET was determined using a solid test meal containing 4 mCi 99m Tc-mebrofenin. Each cat had 3 separate ultrasonographic assessments of GE, performed independent of scintigraphic assessment, after solid test meal consumption. The motility index (MI) of antral contractions was plotted against time and time for each fraction of the area under the MI curve determined. Ultrasonographic GET and MI were correlated to scintigraphic GET. RESULTS: Scintigraphic GET (mean ± SD) for 25, 50, and 75% GE was 103 ± 32 minutes, 196 ± 45 minutes, and 288 ± 62 minutes, whereas sonographic GET for 25, 50, and 75% GE was 106 ± 13 minutes, 203 ± 19 minutes, and 305 ± 27 minutes. There was good correlation between scintigraphic and sonographic GET (r = 0.72-0.82) at 45-90% fractional GE and between scintigraphic GET and time of corresponding MI curve fraction (r = 0.78-0.86) at 40-90% fraction of the MI curve. There was moderate intraindividual variability for sonographic GET and MI curve fraction times as well as significant variation among individuals. CONCLUSIONS AND CLINICAL IMPORTANCE: Ultrasonography is a valid alternative to scintigraphy for assessment of solid-phase GE and allows assessment of postprandial gastric motility in healthy cats.

Diagnostic imaging and endoscopic finding in dogs and cats with gastric tumors: a review.

Medical imaging is an essential part of the diagnostic workup of many gastrointestinal disorders. This paper reviews imaging and endoscopy of gastric tumors in dogs and cats and the techniques used. The appearance of the normal as well as the various aspects of gastric tumors are described for these different modalities. Plain radiography is widely available but has limited diagnostic value. Contrast radiography has higher sensitivity but is laborious and time-consuming. Ultrasonography (if an adequate acoustic window is available), endosonography and endoscopy are the most appropriate modalities for diagnosing gastric tumors. They are especially useful when obtaining samples for cytologic or histopathologic examination, because the imaging modalities do not always differentiate between inflammatory or infectious conditions and neoplastic disorders. Hydro-helical CT was found helpful for evaluating the location and local invasiveness of the lesion. Ultrasonography and endoscopy are useful modalities for taking adequate biopsies.

L'imagerie diagnostique est un élément important du diagnostic de nombreuses affections gastro-intestinales. Cet article donne un aperçu des diverses techniques d'imagerie qui peuvent être utilisées pour identifier des tumeurs gastriques chez le chien et le chat. On décrit aussi bien les aspects physiologiques que les altérations pathologiques. Des clichés radiographiques sont en général facilement disponibles, ils n'ont toutefois qu'une valeur diagnostique limitée. Les études utilisant des moyens de contraste ont une meilleure valeur diagnostique mais nécessitent du temps et de travail. L'échographie (pour autant qu'on dispose d'une fenêtre acoustique adéquate), l'endosonographie et l'endoscopie sont les techniques diagnostiques les plus sûres pour identifier les tumeurs gastriques. Comme les techniques d'imagerie ne permettent pas toujours de différencier entre inflammation et tumeur, elles sont particulièrement utiles pour prélever des échantillons pour la cytologie ou l'histopathologie. Le scanner hydro-hélical est utile pour définir la localisation et l'extension d'une lésion, alors que l'échographie et l'endoscopie servent avant tout à effectuer des biopsies adéquates.

Magnetic resonance imaging of the ligamentous structures of the occipitoatlantoaxial region in the dog.

Our objectives were to establish a magnetic resonance (MR) protocol for the examination of, and then describe, the normal ligaments and the supporting structures of the occipitoatlantoaxial region. This was done in 10 cadaver dogs. In addition, MR images of three patients with cervical pain localized to the occipitoatlantoaxial region are included to provide examples of ligamentous abnormalities. All ligaments were hypointense in all pulse sequences. The apical, dorsal atlantoaxial, and dorsal longitudinal vertebral ligaments were seen best in the sagittal T1W and PD-weighted images. The transverse ligament was best visualized in the transverse plane in all pulse sequences and appeared to be confluent with the dorsal longitudinal vertebral ligament dorsal to the dens in the sagittal plane. A 20° dorsal plane reconstructed image in 0.6-mm slice thickness was necessary to visualize the alar ligaments, which were visible in 9/10 dogs. The dorsal longitudinal vertebral ligament appeared continuous with the apical ligament and tectorial membrane. Abnormalities in clinically affected dogs included thickening of the alar ligaments, absence of transverse ligament and elongation, and irregularity of the apical ligament.

Evaluation of a wireless ambulatory capsule (SmartPill®) to measure gastrointestinal tract pH, luminal pressure and temperature, and transit time in ponies.

REASONS FOR PERFORMING STUDY: This study investigated the use of a wireless ambulatory capsule (WAC; SmartPill(®) pH.p GI Monitoring System) to determine WAC-gastric emptying time (GET) in ponies. OBJECTIVES: To measure WAC-GET and compare it to those findings with GET assessed by nuclear scintigraphy (S-GET). HYPOTHESIS: WAC-GET will be slower than S-GET, but will be significantly correlated. METHODS: Seven healthy adult mixed-breed pony mares were used in this study. Feed was withheld for 12 h prior to the WAC administration. After administration, a complete-feed diet was fed to allow the WAC to pass into the stomach. Luminal pH, temperature and pressure were collected by a modified receiver secured to the pony. Once the pH reached a value of ≥ 8.0, it was determined that gastric emptying had occurred, and ponies were fed grass hay. After 5 days, data were downloaded and analysed using proprietary software. During the second period of the study, after at least 2 weeks, 4 of the ponies underwent a standard S-GET test. RESULTS: The WAC was successfully administered, and data were collected from all ponies. The mean percentage of data packets collected by the receiver was 84.9 ± 3.51% (range 66.8-95.1%). Mean WAC-GET was 7.38 h (range 0.15-46.65 h). Mean gastric pH was 4.75 (range 2.07-6.99). Mean small intestinal transit time was 4.6 h. The mean pH for the small intestine was 8.0. The mean S-GET time (in hours) when 10% of the radioactive feed is present in the stomach (T-90%) was 2.3 h. The S-GET did not correlate significantly with the WAC-GET. CONCLUSIONS AND POTENTIAL RELEVANCE: The WAC was safely administered to ponies, and data were collected using a modified receiver. The WAC-GET varied considerably between ponies, but was ≤ 3 h in 5 of the 6 ponies. The WAC used in this study provided a noninvasive technique that produced novel information about the pony gastrointestinal tract, but owing to the substantial variability in GET values and long transit time it may not be a reliable clinical tool at this time.

Doppler sonography of the medial arterial blood supply to the coxofemoral joints of 36 medium to large breed dogs and its relationship with radiographic signs of joint disease.

The medial arterial supply to 68 of the 72 coxofemoral joints of 36 medium to large breed dogs was examined ultrasonographically. The medial circumflex femoral artery and three branches were identified; the artery and its transverse branch were identified in all 68 joints, and the deep branch was identified in 61 joints, and the ascending branch was identified in 63. However, the acetabular and obturator branches were not identified. The pulsatility index, the mean velocity and the peak systolic velocity of the medial circumflex femoral artery were determined and associated with a radiographic score of degenerative coxofemoral joint disease and a lath distraction index (LDI). In joints with a LDI greater than 0.35, the pulsatility index was significantly lower (P=0.023) and its mean velocity was higher (P=0.005). However, no significant associations were observed in individual dogs when the measurements in both joints were taken into account.

Influence of food composition on splanchnic blood flow during digestion in unsedated normal dogs: a Doppler study.

The effect of dietary components in gastrointestinal blood flow was investigated non-invasively in dogs. Doppler ultrasound (US) waveform analysis of the celiac artery (CA) and the cranial mesenteric artery (CMA) of eight healthy dogs was performed both in the fasting state and at 20, 40, 60 and 90 min after feeding maintenance, high protein, high carbohydrate and high fat diets. Resistive index (RI), pulsatility index (PI) and the percentage differences between measurements were calculated. In fasted dogs, the CA showed significantly (p<0.05) lower resistance than the CMA. With all diets, post-prandial RI and PI values decreased significantly in both vessels (CA: RI=-12-13%; PI=-25-29%; CMA: RI=-13-15%; PI=-27-29% [p<0.05]), and in all cases significantly earlier in the CA than in the CMA (p<0.05). With all diets except high fat the maximum decrease in RI and PI was reached in the CA at 40 min and in the CMA at 60 min. High fat diets were unique in that the maximum decrease in RI and PI in the CMA occurred earlier (at 20 min) and values were slower to return to normal (p<0.05). We conclude that Doppler US can be used in dogs to quantify significant differences in the response of splanchnic blood flow to different dietary components.

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.

Ultrasound detection of non-Hodgkin's lymphoma in three cynomolgus monkeys after renal transplantation and cyclosporine immunosuppression.

PURPOSE: To describe the early detection of non-Hodgkin's lymphoma (NHL) with ultrasound in three clinically normal cynomolgus monkeys post-renal transplantation and immunosuppression with cyclosporine. MATERIALS AND METHODS: The monkeys in this report were treated with cyclosporine (Neoral) after receiving renal transplants. In addition to clinical and laboratory (hematology, serum chemistry) monitoring, renal allografts were monitored every 2 weeks with ultrasound and ultrasound-guided allograft biopsies were performed. RESULTS: Enlarged renal hilar and mesenteric lymph nodes were detected with ultrasound in three monkeys on days 36, 49 and 134 post-transplantation. Sonographically the lymph nodes were inhomogeneous, of low echogenity and rounded. In two animals, the spleen was sonographically enlarged and inhomogeneous. All three monkeys were symptom-free at the time of ultrasound detection and NHL was diagnosed histologically. CONCLUSION: Ultrasound provides a rapid, non-invasive means of early detection of NHL in animal transplantation models prior to the onset of clinical symptoms of disease.

Renal allograft vasculopathy: ultrasound findings in a non-human primate model of chronic rejection.

The purpose was to determine whether decreased cortical flow detected with power Doppler (PD) ultrasound in renal allografts in cynomolgus monkeys marks the presence or onset of chronic renal allograft vasculopathy. The 2D grey scale and PD ultrasound findings of 24 consecutively implanted non-life-supporting renal allografts in cynomolgus monkeys that underwent either 24 h (n=15) or 48 h (n=9) cold ischaemia times were recorded and compared with the results of histology performed every 2 weeks post-operatively. 13 allografts developed vasculopathies, 10 of which had PD scores equal to 1 (severe reduction of cortical flow). A PD score of 1 occurred in only one instance in the group of allografts without vasculopathies and this was due to necrosis. Allografts without vasculopathies otherwise had either PD scores of 3 (normal flow; n=2) or 2 (reduced flow; n=4). Allografts subjected to 48 h cold ischaemia times were smaller than those with 24 h cold ischaemia times (significant at weeks 5-11, p<0.05), but a reduction in graft size associated with vasculopathies occurred infrequently. In conclusion, the finding of reduced renal cortical flow detected by PD ultrasound during serial examination of non-life-supporting renal allografts is highly supportive of a diagnosis of graft vasculopathy due to arteriolar intimal proliferation, and illustrates an excellent method of monitoring changes in cortical perfusion in allografts in animal models. The combination of findings of reduced or absent cortical flow together with severe graft enlargement is highly suggestive of the presence of not only vasculopathies but also tissue damage and degeneration.

Safety of percutaneous ultrasound-guided biopsy of renal allografts in the cynomolgus monkey: results of 348 consecutive biopsies.

The safety of a technique for ultrasound-guided biopsy of renal allografts was evaluated based on 348 consecutive procedures in cynomolgus monkeys. A spring-loaded biopsy device with an 18G tru-cut biopsy needle was used to biopsy renal allografts in 139 cynomolgus monkeys performed either on clinical indication (n = 95 animals) or as serial protocol biopsies (n = 44 animals) for a total of 348 biopsies. Monkeys having serial biopsies received between 3-9 biopsies per animal. All others received non-protocol biopsies that were performed on clinical indication, and the range was 1-15 biopsies per animal. No life-threatening complications or deaths occurred and there were no clinically detectable minor complications such as macrohematuria. Self-limiting complications such as small arteriovenous fistulas (n = 4, 3-5 mm large) were detected with Doppler ultrasound and resolved hemodynamically after 2-4 weeks. Three animals developed hematomas ranging 4 mm-2 cm in diameter and were no longer sonographically evident 2-4 weeks later. Ultrasound-guided biopsy of renal allografts can be performed with a high degree of safety in small (3-5 kg) laboratory animals such as the cynomolgus monkey and provides a valuable tool for renal transplantation research. Even when cores were taken at two week intervals no major complications occurred and only rarely were clinically irrelevant complications detected. Experience with diagnostic ultrasound, both gray scale and Doppler, is important for both safety and the recognition of complications that may arise.

Contribution of power Doppler sonography to the detection of renal allograft rejection in the cynomolgus monkey.

RATIONALE AND OBJECTIVES: To evaluate whether a change in the power Doppler (PD) flow signals produced by the renal cortical interlobular vasculature of allografts in cynomolgus monkey transplant models is useful for the detection of cellular rejection and vasculopathies. METHODS: Seventy-three monkeys with life-supporting allografts (bilateral native kidney nephrectomy) and 20 monkeys with allografts implanted with only unilateral native kidney nephrectomy were examined with ultrasound that included an examination with PD. Each graft received a PD score of 3 (normal cortical blush), 2 (reduced flow, no blush), or 1 (absence of cortical flow), and the results were compared with histology either from ultrasound-guided biopsy or at necropsy. RESULTS: One hundred seventy-one allograft examinations (histological and PD) were compared. Histologically normal grafts were statistically more likely to have normal PD findings than were those with reduced flow or absent flow. Allografts with reduced flow had statistically more severe cellular rejection than those with normal flow. Also, vasculopathies were present in all three PD groups. CONCLUSIONS: Reduced renal cortical flow in the cynomolgus monkey renal allograft indicates that more severe degrees of cellular rejection are present compared with allografts with normal flow. Overlap in the histological diagnoses of allografts with normal and reduced flow exists, and the finding of reduced flow with PD may be prognostically important and indicates the need for tissue sampling.

Ultrasonographic findings of functioning renal allografts in the cynomolgus monkey (Macaca fascicularis).

PURPOSE: The purpose of this study was to describe the findings of serial ultrasound investigations of functioning and histologically normal renal allografts in the cynomolgus monkey. METHODS: Ten cyclosporine (Neoral) treated cynomolgus monkeys underwent renal allograft transplantation with bilateral nephrectomy, seven of which were examined serially with ultrasound. Ultrasound findings were compared to serum creatinine, and the results of histology from allograft biopsy on day 150 post-transplantation. RESULTS: Allografts increased in volume up to one and a half to twice that of their original volume and appeared morphologically similar to native kidneys. Allograft ureters were dilated postoperatively but decreased in size with time. Other than in two cases of ureter complications, the resistive index (RI) was normal in functioning grafts. CONCLUSIONS: Elevations in RI, as well as graft enlargement and increased cortical thickness, were related to graft pathology, but not necessarily to rejection histologically. The ultrasound findings of functioning grafts and of surgical complications after renal allograft transplantation in the cynomolgus monkey were similar to those in humans.

MRI and ultrasonographic detection of morphologic and hemodynamic changes in chronic renal allograft rejection in the rat.

PURPOSE: The purpose of this study is to describe the sonographic, MRI, and histopathologic findings in a rat model of chronic renal allograft rejection. MATERIALS AND METHODS: Allogeneic renal grafts (male DA kidney into male Lewis rat with unilateral nephrectomy, N = 27) and syngeneic renal grafts (male Lewis kidney into male Lewis rat, N = 19) were examined serially with ultrasound, MRI, and histology. RESULTS: Nonparametric Spearman rank correlation showed significance between the histologic score and the following parameters: the MRI score (r(s) = 0.91, P < 0.01, N = 46), the ultrasound score (r(s) = 0.9, P < 0.01, N = 46), the power Doppler score (r(s) = 0.86, P < 0.01, N = 46), and the MRI perfusion (r(s) = -0.80, P < 0.01, N = 45). Positive correlations were also found between the MRI volume estimations (graft r(s) = 0.49, P < 0.01, N = 46; native r(s) = 0.59, P < 0.01, N = 46), and the ultrasound volume estimations (graft r(s) = 0.39, P < 0.01, N = 45; native r(s) = 0.64, P < 0.01, N = 46) as well as with actual graft weight. CONCLUSIONS: This study shows that both MRI and ultrasound can provide complementary, accurate information compared to histology in regard to the alterations in anatomy and hemodynamic changes associated with chronic allograft nephropathy.

Ultrasonography of the normal kidney in the cynomolgus monkey (Macaca fascicularis): morphologic and Doppler findings.

The purpose of this study was to obtain sonographic measures of normal kidneys in cynomolgus monkeys (Macaca fascicularis). The kidneys of 27 healthy female cynomolgus monkeys were examined with two-dimensional, duplex and power Doppler under sedation or general anesthesia. Except for shape and sinus echogenicity, the kidneys of the cynomolgus monkey are morphologically similar to those of humans. Left kidney volume estimations (mean, 5.1 cm3) were significantly smaller (P<0.001) than those of the right (mean, 5.9 cm3), and both increased significantly with increasing body weight (P<0.05, r = 0.408). The mean resistive index (RI) of ketamine-sedated monkeys was 0.54, with an upper limit of 0.74 for the renal artery. The mean RI under general anesthesia was 0.65, with an upper limit of 0.77. Morphologic and Doppler ultrasound assessments of the kidneys can be consistently performed in the conscious cynomolgus monkey, and anesthesia can have hemodynamic effects that alter the Doppler arterial waveform.

Cardiomyopathy in dystrophin-deficient hypertrophic feline muscular dystrophy.

A colony of cats affected with hypertrophic feline muscular dystrophy was used to study the occurrence of cardiomyopathy associated with dystrophin deficiency. Affected male and female cats, obligate carrier females, and unaffected healthy littermates were followed from 12 weeks of age into adulthood. Thoracic radiography, 2-D echocardiography, and 2-D-derived M-mode echocardiography were performed at 3-month intervals until 12 months of age and regularly thereafter. From 9 months of age, all affected cats had larger hearts than normal and carrier animals. Left ventricular wall thickness in systole and in diastole and interventricular septal thickness in systole were greater in affected cats 12 months and older when compared with normal or heterozygous animals (P < .05). The myocardium of affected cats was diffusely hypoechoic and thickened. Multiple hyperechoic foci were in the myocardium and papillary musculature. Shortening fraction was normal in all cats. Changes seen in carrier females included enlargement and hyperechogenicity of the papillary musculature after the age of 2 years. Gross and light microscopic examination revealed left ventricular wall thickening with multiple foci of mineralization in 2 of 5 hearts from dystrophin-deficient cats. Although approximately 10% of the normal dystrophin amount was present in the skeletal muscle, dystrophin could not be detected in the myocardium. Early onset concentric myocardial hypertrophy was present in all adult cats. Lesions were mainly localized in the myocardium of the left ventricular free wall and interventricular septum, papillary musculature, and the endocardium. Clinical signs of heart failure developed only infrequently in cats with hypertrophic feline muscular dystrophy.

Ultrasonographic comparison of adhesions induced by two different methods of gastropexy in the dog.

Ultrasonography was used to compare adhesions induced by two different methods of gastropexy in 16 dogs. An incisional gastropexy technique was used in eight dogs (group 1) and a 'modified' gastropexy technique in the remaining eight (group 2). The length and thickness of the gastropexy and the peristaltic activity of the stomach were measured ultrasonographically and compared between groups. Measurements for the two groups were taken in the early postoperative interval (two to four days), intermediate postoperative interval (eight to 20 days) and late postoperative interval (57 to 79 days). Both techniques were equally successful in forming permanent adhesions at two months postoperatively and there was no recurrence of gastric dilatation and volvulus. The length and thickness of the gastropexy were similar for both groups at two months postoperatively and there were no surgical complications with either technique. The modified gastropexy provides a technique that can easily be performed by a single surgeon, with no increased operative time or duration of anaesthesia, and with the formation of a permanent adhesion.

Lethal peracute rhabdomyolysis associated with stress and general anesthesia in three dystrophin-deficient cats.

Three cats affected with dystrophin deficiency and hypertrophic muscular dystrophy developed peracute rhabdomyolysis with a fatal outcome. Two cats were anesthetized with isoflurane for routine procedures and did not recover properly from the anesthetic procedure. One cat was manually restrained for an echographic examination and started staggering after a short struggle; its condition worsened, and it died. Blood chemistry findings included severe hyperkalemia, hyperphosphatemia, hypocalcemia, massive increases in creatine kinase, aspartate aminotransferase, and alanine aminotransferase concentrations, and high ion gap metabolic acidosis. Light microscopic evaluation of skeletal muscle revealed severe acute rhabdomyolysis with marked extensive necrosis of large groups of fibers and endomysial edema. These lesions were observed in many skeletal muscles but particularly in the masseter and supraspinatus muscles and in the diaphragm. Typical changes associated with dystrophin deficiency in cats were also noted. Histochemical analysis revealed that the dystrophin deficiency was associated with a decrease in the percentage of type 1 myofibers in all three cats. This change was marked in the 20-month-old cat and milder in the younger cats (6.5 and 8.5 months of age). Percentages of type 2A fibers were markedly decreased and percentages of type 2X fibers were markedly increased in the younger cats. Rhabdomyolysis has been reported in dystrophinopathic humans but not in other animal models of dystrophin deficiency. An increased sensitivity of the dystrophin-deficient sarcolemmal membrane to volatile anesthetic agents, stress, or intense muscular activity is suspected.