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New hemodynamic approach to angiogenesis: color and pulsed Doppler ultrasonography.

RATIONALE AND OBJECTIVES
To determine the capacity of color and spectral Doppler ultrasonography (US) to quantify angiogenesis in vivo and to characterize low-resistance intratumor blood flow.


METHODS
Thirty-two tumors, xenografted into mice, were studied with Doppler US. The number of intratumor vessels visualized with color Doppler US was compared with the density of microvessels and the number of vessels >100 microm determined by histologic examination. The resistance index and the peak systolic velocities were evaluated.


RESULTS
The number of intratumor vessels visualized by color Doppler US was correlated with the number of vessels >100 microm (P<0.001) determined histologically. When vessel density was >30, intratumor vessels were always detected by color Dopper US. The resistance index and peak systolic velocities were significantly lower in intratumor than in peritumor vessels.


CONCLUSIONS
Color Doppler US evaluated tumor angiogenesis accurately. Spectral analysis confirmed the low resistance of intratumor blood flow.