Elastography of the normal canine liver, spleen and kidneys.

Elastography is a simple, expedient and noninvasive technique that may be used to assess the elasticity or stiffness of a tissue, in conjunction with traditional B-mode ultrasonography. Quantitative assessment of tissue stiffness can be made which involves measurement of the shear wave velocity within the tissue of interest. The goal of this study was to assess the feasibility of elastography for clinical use in the abdomen of conscious small animals and to investigate factors that affect shear wave velocity measurement. Elastography was performed on the liver, spleen, and kidneys of 15 dogs at predefined depths within the parenchyma. Breed, age, gender, neuter status, and weight were documented for each animal. Depth at which measurements were taken had a significant negative relationship with the shear wave velocity value obtained. Individual dog effects, such as weight and gender, also appeared to have a significant effect on the shear wave velocity measurement for specific organs; weight had a significant positive effect on the shear wave velocity for each of the organs examined, whereas the effect of gender was inconsistent between organs (having a positive effect for the liver and a negative effect for the spleen). It is hoped that these results may act as a baseline to guide further work into the field of elastography in companion animals.

Computed tomographic characteristics of the cisterna chyli in dogs.

Previous lymphangiographic studies have investigated the use of computed tomography (CT) for characterizing the thoracic duct and its tributaries in dogs. However, there is limited published information on the appearance of the canine cisterna chyli using CT. The objective of this retrospective study was to describe the features of the canine cisterna chyli in pre- and post-contrast abdominal CT studies. The presence, location, shape, maximum width, size compared with the aortic diameter (Ao:cisterna chyli ratio) and mean attenuation of the cisterna chyli were recorded from archived abdominal CT scans of 30 dogs. Breed, age, sex and neutering status were also noted. A cisterna chyli was identified in 26 of the dogs (87%). In 22 cases a cisterna chyli could be reliably identified prior to intravenous contrast administration and in all 26 cases in postcontrast images. The cisterna chyli was most commonly located right dorsolateral to the abdominal aorta between L1 and L4. Shape varied on transverse images from crescent-like to globular and maximum diameters ranged from 5 to 9 mm. The Ao:cisterna chyli ratio varied between 0.29 and 0.71 (mean value-males: 0.32; females: 0.38). On pre-contrast images the mean Hounsfield units were 21.3HU (range: -3.8 to 64.25). Mild enhancement of the cisterna chyli post-contrast was observed in 24 dogs (80%). Findings supported the use of pre- and post-contrast abdominal CT as a non-invasive method for assessing qualitative and quantitative characteristics of the canine cisterna chyli.

Evaluation of a manual biopsy device, the 'Spirotome', on fresh canine organs: liver, spleen, and kidneys, and first clinical experiences in animals.

Several methods for obtaining specimens from abdominal organs have been described. Imaging-guided biopsy, particularly ultrasound-guided biopsy, is the most frequently used in clinical trials. The aim of this study was to evaluate the diagnostic quality of histological samples obtained with a manual biopsy device (Spirotome) on biopsies of the liver, spleen, and kidney, in fresh canine organs and in live animals in a clinical trial. The study was divided into two different parts, one using normal fresh canine organs with a total of 60 biopsies, 20 of liver, spleen, and kidney, respectively; and one on clinical patients, including 35 biopsied lesions in 28 animals (25 dogs and three cats) for a total of 95 biopsies. All the biopsy samples were considered satisfactory from canine cadavers, and all specimens were diagnostic in clinical cases. The technique was accurate and safe and no major complications were noted.

Intra- and interobserver variability of ultrasonographic measurements of the adrenal glands in healthy Beagles.

The aim of the present study was to establish which adrenal gland measurement was characterized by the least variations. To do this, we quantified the variability of seven different size measurements of the canine adrenal gland (maximal length, maximal height at the cranial and caudal poles on longitudinal and transverse images, and maximal width of the cranial and caudal poles) within observer, between observer, and between dogs based on three different measurements made by each of the three observers in six healthy Beagle dogs. The height of the caudal pole of both adrenal glands measured on longitudinal images had the lowest intra- and interobserver variability, while measurements of the length had the highest intra- and interobserver variability. Other measurements that were characterized by low intra- and interobserver variability were: height and width of the caudal pole on transverse images and height of the cranial pole on longitudinal images only. These results provide a basis for further study of the changes in adrenal gland size in dogs with pituitary-dependent hyperadrenocorticism.

Pre- and posttreatment ultrasonography of the thyroid gland in hyperthyroid cats.

Ultrasonography is useful for assessing the morphology of the thyroid gland in hyperthyroid cats. Our aim was to describe the ultrasonographic changes of the thyroid gland in hyperthyroid cats after 131I therapy. Ultrasonography was performed in 15 hyperthyroid cats at initial presentation and 6 months after 131I using a multifrequency linear transducer set at 12 MHz. The following criteria were evaluated: length, width, height, volume, shape, homogeneity, and vascularity, using Power Doppler. Pretreatment, 10 cats had bilaterally abnormal thyroid lobes, four cats one abnormal lobe with the contralateral lobe being normal or reduced in size, and one cat with one normal lobe and one lobe not visible. Six months after 131I therapy, there was a reduction in median volume from 819 to 210 mm3, reduced rounding, reduced heterogeneity, and decreased vascularity. In conclusion, ultrasonography may be used to monitor thyroid changes in order to assess 131I treatment response. Further studies are necessary to determine whether ultrasonography could contribute to the detection of a relapsing course of hyperthyroidism.

Quantification of the effect of various patient and image factors on ultrasonographic detection of select canine abdominal organs.

We assessed factors that affected ultrasonographic visualization of the pylorus, duodenal papilla, pancreas, adrenal glands, and jejunal and medial iliac lymph nodes in the dog. An abdominal ultrasonographic examination was performed on 100 canine patients, equally divided between two facilities. The pylorus was visible in 64% of the dogs, the major duodenal papilla in 42%, the left pancreatic lobe in 56%, the body of the pancreas in 60%, the right pancreatic lobe in 87%, the left adrenal gland in 91%, the right adrenal gland in 86%, the medial iliac lymph nodes in 54%, and the jejunal lymph nodes in 51%. The parameters that negatively influenced the visibility of these organs were the presence of air or food in the gastrointestinal tract (pancreas, duodenal papilla), age (lymph nodes), and body weight (pancreas, duodenal papilla). The parameters that positively influenced their visibility were the presence of air or food in the gastrointestinal tract (lymph nodes), body weight (lymph nodes), body condition score (right adrenal gland), and inherent image quality (left pancreatic lobe). There was a significant difference between the two institutes for the visualization of the pylorus, pancreas, and lymph nodes, which was probably related to different body positions used for scanning in each institution.

Computed tomographic features of the normal canine thyroid gland.

The computed tomographic (CT) features of the normal thyroid gland were compiled from images acquired in 25 client-owned dogs without thyroid gland disease. The mean pre- and postcontrast attenuation values were 107.5 and 169.0 Hounsfield Units, respectively. After injection of intravenous contrast medium (600 mg iodine/kg), the apparent thyroid gland volume (both lobes combined) increased from a mean value of 1148.0 nm3 to a mean value of 1188.9 mm3. All thyroid lobes were homogeneous on pre- and postcontrast images. In a craniocaudal direction, the gland spanned a region from the 1st to the 8th tracheal ring and the right lobe was often more cranial than the left. On transverse images the lobe shape was ovoid in 72%, and its location was dorsolateral to the trachea in 90% of dogs. Parathyroid glands could not be identified and an isthmus connecting both thyroid lobes was only seen in one dog. Considering the excellent visibility of the normal canine thyroid gland, CT can be beneficial in the differentiation of thyroidal versus nonthyroidal neck masses. CT also yields potential in the staging of thyroid carcinomas.

Ultrasonographic anatomy of abdominal lymph nodes in the normal cat.

Lymph nodes are essential structures to be evaluated in an ultrasonographic examination of the feline abdomen. It was hypothesized that current technical proficiency would allow all feline abdominal lymph nodes to be identified ultrasonographically. Ten clinically normal, adult, domestic shorthair cats were examined using real-time compound ultrasonographic imaging. The medial iliac lymph nodes were visible in 100% of the cats, the jejunal lymph nodes in 90%, the hepatic lymph nodes in 70%, the aortic lumbar, the splenic, and the pancreaticoduodenal lymph nodes in 60% each, the ileocecal and the colic lymph nodes in 50% each, and the renal, the gastric, the sacral and the caudal mesenteric lymph nodes in 40%, 30%, 20%, and 10% of the cats, respectively. The inconsistent presence of lymph nodes, their poor echocontrast and interposed gas of the gastrointestinal tract explain the lower percentages of identification. The ultrasonographic length and diameter of the lymph nodes were determined. The majority of these measurements corresponded to those in the literature. We conclude that ultrasonography is a valuable tool for the identification and evaluation of most abdominal lymph nodes in the normal cat. Average ultrasonographic measurements are presented as a preliminary guideline for normal feline abdominal lymph nodes. ete