[Evaluating tumor vascularization with Doppler ultrasound]

Tumor vessels are structurally and functionally abnormal. The degree of vascularity determines a tumor's aggressiveness, as well as its radiosensitivity and chemosensitivity. Assessing tumor vascularity may help in differential diagnosis and assist therapy monitoring. Together with other imaging methods, Doppler sonography has been evaluated for the assessment of tumor vascularity but has proven to be difficult to evaluate. Using quantitative analysis methods, Doppler sonography was shown to carry differential diagnostic and prognostic information as well as to reflect vascular changes during radiotherapy. Its clinical role, however, remains to be determined. With current technology neither blood volume flow nor microvessel density can be reliably assessed in a tumor using Doppler sonography, because it is insensitive to capillary blood flow. Upcoming developments such as harmonic imaging and contrast media that generate stimulated acoustic emissions are expected to significantly improve sensitivity.