Two-dimensional Doppler echocardiographic flow imaging--exploration of clinical impact and problems.

Recent advances in electronic engineering have allowed Doppler echocardiography to be presented in the form of a real-time two-dimensional image. The resulting image of blood flow has been described as a 'non-invasive angiogram', but the analogy with angiography should not be pushed too far since the technical determinants of these images are entirely different. Nevertheless, the colour flow map does allow rapid and direct exclusion, detection and quantitation of regurgitant and stenotic lesions, and semi-quantitative assessment of valvular regurgitation and shunts. To achieve optimum results, it is necessary to standardise recording procedure, to take account of patient variables which influence the image appearance and quality and to be aware of the possibility of artefact. As for all investigations, results which are not coherent with other echocardiographic data, with other investigations and with the clinical assessment should be subjected to particular scrutiny with the possibility of false diagnosis in mind.