[Ultrasonic angiography: principles and clinical use]

A new technique for detecting blood flow called Colour Doppler Energy (CDE), Power Doppler or Ultrasound Angio, is based on the integrated power spectrum of the standard Doppler signal used for Colour Flow Mapping (CFM). CDE is independent of the insonation angle, has no aliasing artefacts and improves the sensitivity with respect to detection of the presence or absence of flow compared to CFM. However, CDE provides no directional or quantitative information about the flow. CDE is superior to CFM in detection of low velocity flow, perfusion in small vessels, flow in torsioned vessels and flow in multiple vessels in the same image plane. The clinical applications are reviewed. Complicated stenosis, renal perfusion, penile Doppler and scanning of the vessels of the extremities are examples where CDE improves sensitivity in detecting flow compared to CFM.