Lower limb colour flow imaging: a comparison with ankle: brachial measurements and angiography.

Peripheral lower limb vascular disease represents a substantial health problem. Arteriography is currently the 'gold standard' imaging modality. However, much effort is presently being channeled towards alternative non-invasive techniques. To date, this involves mainly the interpretation of ankle: brachial pressure indices and segmental pressure measurements. A prospective pilot study of 20 patients (40 limbs) comparing these two techniques with colour Doppler ultrasound was carried out. Although ankle: brachial indices could accurately predict disease (sensitivity 100%, accuracy 92.5%), it failed to localize it; neither a high thigh: brachial index nor segmental drop could localize disease to the iliac (accuracy 70%) or femoro-popliteal (accuracy 55%) vessels respectively. Colour Doppler ultrasound correctly differentiated iliac from femoro-popliteal disease. It had an overall diagnostic accuracy of 90% in the femoral and popliteal vessels for both occlusion and stenosis and diagnosed 10 of 11 iliac lesions. Colour Doppler ultrasound has many advantages over pressure measurements in that it can both diagnose and localize arterial lesions accurately. We feel that using both techniques prior to angiography can accurately separate patients into either a surgical or angioplasty group. This may help utilize angiographic resources and radiologists' time more efficiently as well as reducing radiation dose to both patients and staff.