Multicentric nerve sheath fibrosarcomas of multiple cranial nerve roots in two dogs

Nerve sheath fibrosarcomas of the left 5th through 8th cranial nerve roots were diagnosed in 1 dog and of the left 4th through 8th cranial nerve roots in another dog. Clinical signs in both dogs included head tilt to the left, circling to the left, left hemiparesis and proprioception deficits, rotary nystagmus, left-sided atrophy of masticatory muscles, and cutaneous hypalgesia of the left side of the face. Cranial nerve roots from both dogs were incorporated in discrete, firm, encapsulated, lobulated, tan masses of various sizes that compressed adjacent brain stem and cranial nerves. There were no regional or distant metastases; however, there was enlargement of nerve roots adjacent to the masses. The masses were composed of bundles and sheets of anaplastic, polymorphic to spindle-shaped cells that infiltrated cranial nerves and ganglia and extended into the brain along nerve roots. Masses contained various amounts of collagen and reticulin fibers, but no mucopolysaccharide ground substance. There was no myelin or S-100 protein associated with neoplastic cells. The tumors appeared to have a multicentric origin from cranial nerve sheaths.     

Comparison of intraocular pressure and pupil diameter after sedation with either acepromazine or dexmedetomidine in healthy dogs

Objective

To compare intraocular pressure (IOP) and pupillary diameter (PD) following intravenous (IV) administration of dexmedetomidine and acepromazine in dogs.

Evaluating the correlation between adrenal gland dimensions and aortic diameter in healthy dogs

In the present study, the relationship of normal adrenal dimensions with weight, aortic diameter, age and sex was evaluated. Moreover, a formula for estimating the normal dimensions of adrenal gland was provided. Thirty‐two intact adult dogs that were considered healthy based on history, physical examination, routine blood works and specific adrenal tests as well as absence of any abnormal ultrasonographic findings were included. Adrenal glands and abdominal aorta were imaged in the sagittal plane by ultrasound. Length, maximal height of the cranial and caudal poles, area and circumference of the left and right adrenal glands and also the internal diameter of the abdominal aorta were measured. Analysis showed that there is a positive correlation between the adrenal gland dimensions and weight and aortic diameter. The ratio of adrenal gland dimensions and the aortic diameter was calculated, but this ratio showed a great amount of variability in tandem with a significant correlation to the weight; Meaning that the ratio of the adrenal gland dimensions to the aortic diameter was not a reliable index for evaluating the size of the normal adrenal gland in animals with different weights. Therefore, we used the weight along with adrenal measurements in a linear regression model, and then, we were able to estimate the adrenal gland dimensions in different weights. Knowing the relationship of normal adrenal dimensions with the indices such as weight, age, sex and diameter of abdominal aorta can help the clinicians to diagnose the adrenal gland diseases.     

Scanning electron microscopy of corrosion casts of the optic nerve microcirculation in dogs

Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pillars around the scleral canal. The central retinal artery was not present in the dog. Differences between the casts in normal and glaucomatous dogs were not detected.     

Ultrasound-guided fine needle aspiration in the diagnosis of peripheral nerve sheath tumors in 4 dogs

Ultrasound-guided fine needle aspiration was used in establishing the diagnosis in 4 cases of malignant peripheral nerve sheath tumor. Sonographic and cytologic characteristics are discussed. Because of its availability and ease of use, axillary ultrasonography with fine needle aspiration can be an initial diagnostic step for suspected brachial plexus tumors.     

Qualitative and quantitative comparison of renal vs. hepatic ultrasonographic intensity in healthy dogs

A prospective, cross-sectional study was performed to qualitatively and quantitatively compare the echogenicity of the renal cortex relative to the liver in healthy dogs. Twenty-five normal adult dogs were examined ultrasonographically. Three standard B-mode images (8.0 MHz) and three tissue harmonic images of the cranial pole of the right kidney adjacent to the caudate lobe of the liver were obtained. Renal and hepatic echogenicities were qualitatively compared by two observers. Subsequently, regions of interest (ROIs) were drawn in the renal cortex and the adjacent liver parenchyma at equal depths on each image, using two different ROI geometries: deep adjacent half-annular ROIs centered at the focal zone and small superficial adjacent squares placed in the near field. Renal and hepatic mean pixel intensities were quantified and averaged for individual subjects. Qualitatively, the right renal cortex was more commonly hyperechoic to liver. Quantitatively, the renal cortical mean pixel intensity was significantly higher than that of liver using deep half-annular ROIs, but not superficial square ROIs, for both standard (P = 0.0007) and harmonic (P = 0.0107) tissue imaging. These findings suggest that the renal cortex can be slightly hyperechoic to adjacent liver. The framework within which the canine renal cortical parenchyma is routinely evaluated in abdominal ultrasonography should be reconsidered, and mild hyperechogenicity relative to the liver (at 8.0 MHz) interpreted as a normal finding.     

Anatomical and ultrasonographic study of the femoral nerve within the iliopsoas muscle in beagle dogs and cats

ObjectivesAn ultrasound (US)-guided ventral suprainguinal approach to block the femoral nerve (FN) within the iliopsoas muscle (IPM) has recently been described in dogs. The goal of the present study was to provide the operator with additional information to locate the FN within the IPM in dogs and cats using US.Study designThe study was carried out in three phases: a dissection of the FN (phase 1); an in vivoUS-assisted nerve study (phase 2), and an anatomical cross-sectional study (phase 3).AnimalsNine healthy adult beagle dogs and nine healthy adult cats.MethodsDissections were performed to investigate the anatomical characteristics of the FN and its related structures in one dog and one cat. Ultrasound scans of the left and right FN were performed in eight dogs and eight cats. The FN diameter and the distance between the FN and the external iliac artery (EIA) in US images and in anatomical cryosections were measured.ResultsThe median FN diameter did not differ significantly between cats and dogs (1.1 mm versus 1.0 mm) or between the two techniques (US versus anatomical cross-sectional study) (1.1 mm versus 1.1 mm in dogs; 1.0 mm versus 1.1 mm in cats). The US and anatomical measurements of the median distances between the FN and EIA differed significantly between dogs and cats (8.2 mm versus 5.8 mm by US; 5.7 mm versus 4.8 mm in the anatomical study).Conclusions and clinical relevanceThe distance between the EIA and FN is reproducible in beagle dogs and cats and can be used in locating the FN within the IPM.     

Pulsed-wave Doppler ultrasonographic evaluation of hepatic veins during variable hemodynamic states in healthy anesthetized dogs

OBJECTIVES: To quantify direction and velocity of blood flow in hepatic veins in dogs under different hemodynamic conditions by use of pulsed-wave Doppler ultrasonography. ANIMALS: 10 healthy dogs. PROCEDURE: Dogs were anesthetized, and venous flow velocities in the quadrate lobe were measured. Arterial blood pressure, right atrial pressure, pulmonary artery pressure, and cardiac output were measured simultaneously. The timing of each waveform during the cardiac cycle was used to identify velocity profiles. Peak waveform velocities were measured during conditions of light anesthesia with isoflurane (baseline; period 1), cardiovascular depression following administration of high-dose isoflurane and esmolol i.v. (period 2), cardiovascular depression with crystalloid volume expansion (period 3), and high cardiac output induced with dobutamine (period 4). Hemodynamic measurements and maximum waveform velocities were compared among the 4 periods by use of an ANOVA and univariate and multivariate linear regression. RESULTS: During each study period, 4 distinct, low-velocity waves were identified. Mean velocities recorded during period 1 were as follows: retrograde atrial contraction a-wave, 7.3 cm/s; antegrade systolic S-wave, 15.0 cm/s; retrograde venous return v-wave, 2.7 cm/s; and antegrade diastolic D-wave, 11.4 cm/s. Mean S:D ratio was 1.27. During periods 3 and 4, S-wave velocity increased; D-wave velocity was highest during period 4. CONCLUSIONS AND CLINICAL RELEVANCE: Consistent hepatic venous velocity profiles were observed in healthy dogs under different hemodynamic conditions. These findings provide baseline values that may be useful in evaluating clinical cases, but further study involving healthy, awake dogs and dogs with cardiac and hepatic diseases is required.     

Comparison of ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs

OBJECTIVE: To determine ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs and evaluate the relationships of thyroid gland size and volume with body weight and body surface area (BSA). ANIMALS: 72 dogs of small (6 Toy and 6 Miniature Poodles), medium (12 Beagles), and large breeds (12 Akitas and 36 Golden Retrievers). PROCEDURE: Each dog's thyroid gland was examined ultrasonographically with a 10- to 5-MHz multifrequency linear-array transducer. Size, shape, echogenicity, and homogeneity of thyroid lobes were evaluated on longitudinal and transverse images. Thyroid lobe volume was estimated by use of the equation for an ellipsoid (pi/6 [length x height x width]). RESULTS: Thyroid lobes appeared fusiform or elliptical on longitudinal images and triangular or round to oval on transverse images. In most dogs, thyroid lobes were hyperechoic or isoechoic, compared with surrounding musculature, and had a homogeneous echogenic pattern. Mean length, width, height, and volume of thyroid lobes were significantly greater in Akitas and Golden Retrievers, compared with findings in Beagles or Poodles; mean length, width, and height were significantly greater in Beagles, compared with findings in Poodles. Total thyroid gland volume correlated with body weight (r = 0.73) and BSA (r = 0.74). CONCLUSIONS AND CLINICAL RELEVANCE: Among the dog breeds examined ultrasonographically, thyroid lobe size and volume were more variable than shape, echogenicity, and homogeneity. The correlation of thyroid gland volume with BSA suggests that size of the dog, rather than breed, should be considered when assessing thyroid glands ultrasonographically.     

Ultrasonographic measurement of gastrointestinal wall thickness and the ultrasonographic appearance of the ileocolic region in healthy cats

Ultrasound evaluation was performed on 11 healthy cats to determine wall thickness measurements for the stomach, duodenum, jejunum, ileum, and colon and to characterize the appearance of the ileocolic region. The terminal ileum had a characteristic "wagon wheel" appearance on cross-sectional images. Gastrointestinal wall thickness measurements were as follows: gastric fundus (mean, 2.0 mm; 95% confidence interval [CI], 1.7 to 2.2 mm), pylorus (mean, 2.1 mm; 95% CI, 1.9 to 2.4 mm), duodenum (mean, 2.2 mm; 95% CI, 2.0 to 2.4 mm), jejunum (mean, 2.3 mm; 95% CI, 2.1 to 2.5 mm), ileum (mean, 2.8 mm; 95% CI, 2.5 to 3.2 mm), and colon (mean, 1.5 mm; 95% CI, 1.4 to 1.7 mm).     

Arterial blood pressure measurement in a population of healthy geriatric dogs

The purpose of this study was to evaluate healthy geriatric dogs for the presence of systemic hypertension. Thirty-three geriatric dogs (i.e., dogs exceeding the geriatric age range for their weight group) and 22 control dogs (i.e., dogs less than six years of age) were evaluated by measuring blood pressure with an oscillometric monitor. Five consecutive blood pressure measurements were taken in each dog, averaged, and compared. Diastolic and mean blood pressure measurements were significantly lower in the geriatric group as compared to the control group. Systolic blood pressure measurements were not significantly different between the two groups. Systemic hypertension does not appear to be a common clinical problem in the healthy geriatric dog.