Patricia A. Walter

Evaluation of urine gamma-glutamyl transpeptidase-to-creatinine ratio as a diagnostic tool in an experimental model of aminoglycoside-induced acute renal failure in the dog

The potential diagnostic utility of the urine gamma-glutamyl transpeptidase (GGT)-to-creatinine ratio was evaluated in an experimental canine model of aminoglycoside-induced nephrotoxicity. A therapeutic dosage of gentamicin resulted in a twofold increase in the mean urine GGT-to-creatinine ratio that was not associated with clinically significant nephrotoxicity. In dogs each given a nephrotoxic dosage of gentamicin, an increase in mean urine GGT-to-creatinine ratios approximately three times baseline values preceded clinically significant abnormalities in serum creatinine, urine specific gravity, and urine protein-to-creatinine ratio. The urine GGT-to-creatinine ratio appears superior as an early indicator of aminoglycoside-induced nephrotoxicity. Further studies in canine clinical cases are warranted.

Duplex Doppler estimation of resistive index in arcuate arteries of sedated, normal female dogs: implications for use in the diagnosis of renal failure.

The resistive index (RI), an ultrasonographic method of evaluating intrarenal resistance to blood flow, may be used to aid in diagnosis of renal failure. Values for arcuate artery RI, expressed as mean +/- two standard deviations, were obtained in clinically normal female dogs sedated with atropine, acepromazine maleate, diazepam, and ketamine hydrochloride. No statistically significant differences were noted between the values for the right kidney (0.33 to 0.57) versus the left kidney (0.32 to 0.56); however, the values were statistically significantly lower than values reported for nonsedated, normal dogs.

Canine gastric neoplasia: utility of ultrasonography in diagnosis.

The utility of ultrasonography in the diagnosis of canine gastric neoplasia was evaluated prospectively in a series of six cases subsequently confirmed as having adenocarcinoma by cytological or histological examination or both. Gastric neoplasia was associated with mural thickening with loss of normal wall sonographic layers and decreased or absent local motility. Sonographic findings were consistent with tumor localization obtained by other diagnostic methods employed. Ultrasonographic-guided, percutaneous, fine-needle aspirations biopsies were successful in two of the three cases in which they were performed. Ultrasonography appears useful in the diagnostic of canine gastric neoplasia.

Ultrasonographic-guided, percutaneous antegrade pyelography: technique and clinical application in the dog and cat.

Fluoroscopically guided, percutaneous antegrade pyelography in canine patients has been described previously in the veterinary literature. This report describes the technique with ultrasonographic guidance and its clinical application in the diagnosis of four cases (two dogs, two cats) of obstructive uropathy. The technique provided successful diagnosis of ureteral obstruction in all four cases. No complications were observed in three cases. In one feline case, ureteral obstruction with a blood clot occurred following the procedure; however, it could not be ascertained whether this event represented a complication of the technique.

Acalculous cholecystitis in four canine cases: ultrasonographic findings and use of ultrasonographic-guided, percutaneous cholecystocentesis in diagnosis

Canine cholecystitis is diagnosed infrequently. Clinical signs, physical examination findings, and clinicopathological abnormalities are nonspecific. Few reports exist of associated ultrasonographic findings which also are nonspecific for the disorder. Ultrasonographic-guided, percutaneous cholecystocentesis has been suggested for diagnostic confirmation. The present report further documents ultrasonographic findings associated with canine acalculous cholecystitis and demonstrates the utility of ultrasonographic-guided, percutaneous cholecystocentesis in confirmation of the diagnosis in a prospectively acquired clinical case series.

Diagnostic Imaging of the Male Canine Reproductive Organs: Methods and Limitations

Survey radiographic, contrast radiographic, and ultrasonographic techniques for evaluation of the male canine reproductive organs are reviewed. The applications and limitations of these technique as they apply to reproductive diseases involving the prostate gland and testicles are illustrated.

Gray-scale sonographic characterization of aminoglycoside-induced nephrotoxicosis in a canine model

RATIONALE AND OBJECTIVES The diagnostic usefulness of gray-scale sonography was evaluated in a canine model of aminoglycoside-induced nephrotoxicosis. METHODS Sonography was performed before and during the onset and progression of nephrotoxicosis induced by administration of a toxic dosage of gentamicin. Subjective visualization of increased renal cortex echogenicity (IRCE) was objectified with digital image analysis methods. Results of both subjective and objective evaluation were correlated with clinicopathologic tests and renal cortex biopsy obtained concurrently. RESULTS Subjective visualization of IRCE was associated with significant nephrotoxicosis and was superior to serum creatinine elevation in nephrotoxicity detection. Objective detection of IRCE improved nephrotoxicity detection sensitivity to that of increased urine enzymuria. CONCLUSIONS Based on the above results, subjective visualization of IRCE in patients with aminoglycoside-induced nephrotoxicity may occur before azotemia and is suggestive of significant renal dysfunction; application of digital image analysis methods may lead to earlier sonographic recognition of nephrotoxicity.

Two-dimensional, gray-scale abdominal ultrasonography. General interpretation and abdominal masses.

The techniques of and general interpretive principles of gray-scale, two-dimensional abdominal ultrasonography in small animals are described. Using case examples, commonly encountered imaging artifacts and categories of disease are integrated with a description of what was obtained by radiography. Tissue echogenicity as a basis for general assessment of organ abnormalities as well as the expectations (interpretive and prognostic) one should have of abdominal ultrasonography are presented.