Figure 1.
The gamma-variate function represents a suitable curve fit approximation of the time-intensity curve (TIC).
With the formula for the gamma-variate function, quantitative perfusion parameters such as the slope rate of ascending curve (A), the slope rate of descending curve (α), area under curve (AUC), derived peak intensity (DPI), time to peak (TTP) were measured to estimate renal blood flow.
Figure 2.
CEUS renal perfusion images were converted into a time-intensity curve (TIC) by Q-LAB quantification software, which was generated from the region of interest (ROI). (a) TIC of dog’s right kidney before operation. (b) TIC of dog’s right kidney 5 weeks after the placement of AC. (c) TIC of dog’s right kidney 7 weeks after the placement of AC. TIC showed weekly delayed enhancement and perfusion in the renal perfusion curve. The slope rate of ascending curve was lower and descending curve was higher. It took more time to reach the peak intensity.
Figure 3.
Changes of quantitative indexes in dogs’ CIRD models (1∼12 weeks after operation).
With the progress of CIRD, area under curve (AUC), time to peak (TTP), derived peak intensity (DPI) and the slope rate of descending curve (α) gradually increased, however the slope rate of ascending curve (A)decreased.
Table 1.
Changes of quantitative indexes in dogs’ CIRD model.
Table 2.
Changes of PSV and RI of right renal interlobular arteries in dogs’ CIRD model.
Figure 4.
Pathologic changes of vessel inside and outside AC.
(a) Vessel outside AC: slight hyperplasia of the vascular smooth muscle. (b) Vessel inside AC: Obvious hyperplasia of the vascular smooth muscle, narrowing of the renal artery with wall thickening. (hematoxylin and eosin, original magnification ×40).