Evaluierung der lokalen kontrastmittelgestützten Sonographie zur Messung der renalen Perfusion bei gesunden, unsedierten Hunden ; Evaluation of renal local perfusion using contrast-enhanced ultrasound in healthy unsedated dogs

Renal insufficiency is one of the most common diseases in dogs, especially in the geriatric patient. With progression of the disease, the perfusion of the kidney decreases which leads to a reduction of renal function. Contrast-enhanced ultrasound (CEUS) offers the possibility to evaluate local renal perfusion of the dog with few side effects. An interesting question is the assessment of the potential of CEUS as a local early diagnostic tool for renal insufficiency before global changes, like decrease of the glomerular filtration rate (GFR), appear. CEUS bases on the measurement of contrast enhancement in selective regions of interest (ROI) from which time intensity curves (TIC) can be created. Following perfusion parameters can be determined from the TIC: Arrival time (AT), time to peak (TTP), peak enhancement (PE), wash in- and wash out-gradient (WiGrad and WoGrad) and the area under the wash in-curve (WiAUC). Aim of this study was to create a standardized method for the assessment of local renal perfusion in healthy unsedated dogs. Furthermore, the influence of different ROI-sizes and -locations, of two different ultrasound probes and of two analysis programs on the evaluability of TICs were to be examined. For this purpose, a five stage ranking system was developed. Another aim was to assess reference values for the CEUS-perfusion parameters of healthy unsedated dogs and to examine the influence of age on these parameters. The correlation between perfusion and clinical parameters (specific urine gravity, GFR, serum creatinine and blood urea) served as a prognostic tool for clinical applicability of CEUS. In the first section of the study the amount of evaluable TICs in different regions of the kidney, examined with two different probes (convex and linear) and analyzed with the internal software of the ultrasound device GE Logiq E9. was compared. There were three ROIs compared with each other in the following locations: the cortex close to the probe (near field cortex), the cortex distant to the probe (far ...