INTRATUMORAL VASCULARITY OF EXPERIMENTALLY-INDUCED VX2 CARCINOMA - COMPARISON OF COLOR DOPPLER SONOGRAPHY, POWER DOPPLER SONOGRAPHY, AND MICROANGIOGRAPHY

RATIONALE AND OBJECTIVES. Tumor vascularity is useful for characterizi ng tumors and determining tumor management. The recent development of power Doppler sonography has enhanced the sensitivity of color Doppler imaging in the detection of blood flow because of low power noise and less angle dependence. The purpose of this study was to compare the c apability of color and power Doppler sonography with that of microangi ography for showing tumor vascularity of VX2 carcinoma. METHODS. Color and power Doppler sonography was performed on VX2 carcinomas in the r abbit thighs, and their findings were correlated with those of microan giography. For qualitative analysis, tumor vascularity was categorized into four items including distribution of tumor vessels, crowdedness of vessels, small vessels, (greater than or equal to 0.1 mm), and micr o-vessels (< 0.1 mm). Tumor blood flow signals of color Doppler sonogr aphy and power Doppler sonography were graded as 3, 2, 1, and 0 and we re compared with tumor vascularity on microangiography. For quantitati ve analysis, percentages of tumor vascular area per tumor area on each study were compared. RESULTS. The mean scores of tumor vascularity on power Doppler sonography were 2.87, 2.73, 2.93, and 2.73 in tumor vas cular distribution, crowdedness of vessels, small vessels, and micro-v essels, respectively. Those on color Doppler sonography were 2.4, 2.2, 2.8, and 1.67, respectively. Power Doppler sonography was statistical ly superior to color Doppler sonography in displaying tumor vascular d istribution (P < 0.05) and micro-vessels (P < 0.01). The means and med ians of percentages of tumor vascular area per tumor area were 22.7% a nd 23.5% on microangiography, 17.9% and 21.4% on color Doppler sonogra phy, and 36.4% and 34.7% on power Doppler sonography, respectively. Pe rcentages of tumor vascular area per tumor area on both color Doppler sonography (r = 0.70) and power Doppler sonography (r = 0.84) were wel l correlated with those on microangiography. CONCLUSIONS. Power Dopple r sonography can demonstrate the tumor vascularity on microangiography relatively well, however, it tends to overestimate the blood flow sig nals. Color Doppler sonography may have some limitations in imaging tu mor vascular distribution and micro-vessels and tends to underestimate tumor vascularity, but can display the blood flow direction. Therefor e, power Doppler and color Doppler sonography could complement each ot her in demonstrating the tumor vascularity.