REPEATABILITY AND RELIABILITY OF GLOMERULAR FILTRATION RATE DETERMINATION VIA GAMMA CAMERA UPTAKE OF TC-99M-DTPA IN CATS WITH CHRONIC KIDNEY DISEASE.

Measurement of glomerular filtration rate (GFR) via gamma camera uptake of 99mTc-diethylenetriaminepentaacetic acid is a standard method for quantifying renal function. Aims of this retrospective, observer agreement study were to determine intra- and interobserver variation in GFR values for cats with chronic kidney disease and to determine whether renal insufficiency classification changed between observers. Guideline cut-points were established for the difference in repeated GFRs to differentiate changes caused by therapeutic effect vs. inherent variation. Included cats had a diagnosis of chronic kidney disease and had undergone GFR examinations between the years of 2010 and 2013. Twenty-nine GFR studies were sampled. Each study was read twice, 6 months apart, by two veterinary radiologists and one radiology resident. Modified Bland-Altman plots were used to investigate differences between readings 1 and 2 by observer and between pairs of observers by reading. Reliability of clinical classification was assessed through comparisons between readings and observers. Measurements were not systematically different between readings for the experienced observers but were higher in reading 1 than reading 2 for the inexperienced observer. Measurements were not systematically different between the experienced observers in reading 1 or between any two observers in reading 2. Reliability for GFR measurements was high among experienced observers; variations in GFR measurements rarely led to differences in clinical classification. Results suggested that, for experienced observers, changes in GFR values following treatment in cats with chronic kidney disease between -0.4 and 0.4 mL/min/kg may be due to inherent variability rather than treatment effect.

Use of ultrasound to locate retained testes in dogs and cats.

Ultrasound was used to locate undescended testes in 30 dogs and 4 cats where the final testicular location was determined surgically. Time between ultrasound and surgery ranged between 0 and 17 days. Forty-three testes (63.2%) were retained and 42/43 (97.7%) were detected ultrasonographically. Retained testes were located in the abdomen (n = 28) and inguinal region (n = 14). One retained testis could not be identified with use of ultrasound. Locations of retained testes ranged from the caudal pole of the kidney to the inguinal region. Descriptions of testicular echogenicity and size were not available for all testes. A 100% positive predictive value was found for all testes with use of ultrasound in both abdominal and inguinal regions. The sensitivity of ultrasound was 96.6% for abdominal and 100% for inguinal testes. Ultrasound is a sensitive test for location of retained testes, and supports the opinion that preoperative ultrasound can help facilitate location of retained testes prior to surgical exploration or laparoscopy. © 2012 Veterinary Radiology & Ultrasound.