Presentation of colour flow maps of the peripheral circulation

The use of continuous wave Doppler ultrasound for lower limb arterial assessment is a well established technique in most district hospitals. Patients found to have disturbances in blood flow attributable to arterial plaques are often referred for arteriographic visualization of the disease with its inherent risks and complications. The availability of colour flow mapping on modern ultrasound scanners provides a non-invasive way of detecting the size and extent of these plaques and, in some institutions, is replacing arteriography. One possible disadvantage of the use of colour flow mapping is that it does not provide a permanent record showing the relationship of the plaques to the patient's gross anatomy in the same way as arteriography. This may limit the acceptability of this technique. At Lincoln work was undertaken to develop a system for presenting images of a whole segment of a limb simultaneously along with the associated blood velocity spectrum. This was performed first by hand and then a suite of computer software was developed to automate the process. Comparisons were made between the ultrasound based images and arteriography, showing the techniques to be of similar diagnostic value. The technique provides composite images showing anatomical detail, blood flow and velocity spectra for ease of interpretation. Further studies will be undertaken in order to define patient groups where diagnostic arteriography can be avoided.