Evaluation of soft-tissue masses using segmented color Doppler velocity images: preliminary observations

OBJECTIVE: We report our initial experience with segmented color Doppler velocity-based estimates of tumor vascularity for various histogically proven soft-tissue masses. SUBJECTS AND METHODS: Color Doppler sonography of 23 histologically proven masses in 22 patients was performed. Digital color Doppler images were acquired directly off the scanner output or from video recordings and stored on a personal computer as 24-bit gray-scale and color composite images. A color Doppler velocity segmentation and analysis algorithm was applied to the digital images, from which we calculated the normalized percentage of color Doppler area. Normalization was determined by expressing color Doppler area as a percentage of the area enclosed by a preselected region of interest. We also calculated mean percentage, SD, and cumulative distribution of color Doppler area, relative to a fixed threshold, for the acquired image data sets. RESULTS: Estimates of mean percentage of color Doppler area showed a dynamic range of at least two or three orders of magnitude between lowest and highest values obtained. A scatterplot of mean percentage of color Doppler area versus SD of percentage of color Doppler area showed a linear monotonic relationship (r2 = .92), illustrating increasing vascular heterogeneity with mean vascularity. Preliminary data also suggest the presence of at least two distinct groups of masses (p < .0001) based on these vascularity estimates. One group corresponds to high-grade lesions in which tumor angiogenesis is expected to be important in predicting biologic behavior. The second group appeared to have little or no relationship to tumor vascularity or was of an intermediate (or lower) histologic grade. CONCLUSION: Quantitative color Doppler estimates of tumor vascularity can be obtained over a wide dynamic range. Such estimates provide a mechanism to assess vascular heterogeneity of soft-tissue tumors. Preliminary data suggest that two biologically distinct groups of masses may be separable on the basis of quantitative velocity-based estimates of tumor vascularity as obtained from color Doppler sonography.