OBSERVER VARIABILITY IN VOLUMETRIC BLOOD-FLOW MEASUREMENTS IN LEG ARTERIES USING DUPLEX ULTRASOUND

Duplex ultrasound volumetric flow measurements have not found a major clinical use because of variability caused by errors in estimating cro ss-sectional area (CSA) and in measuring time averaged mean velocity ( TAMeV). We determined inter- and intraobserver variation in volumetric blood flow measured at rest in the common femoral artery (CFA) and it s main branches, the superficial femoral (SFA) and profunda femoris (P FA) arteries, in 20 normal subjects. The product of TAMeV and CSA was taken as volumetric flow. The coefficient of variation of TAMeV was co nsistently greater than that of CSA. Interobserver variation for blood flow (16.2%, 20.2% and 40.3% for CFA, SFA and PFA, respectively) was larger than intraobserver variation (13.0%, 15.1%, 21.2%). In conclusi on, these data define the minimum changes in VQ that can be realistica lly detected and indicate that, with modern duplex Doppler equipment, volumetric flow can be used as a reliable haemodynamic measure for mon itoring patients before and after surgical or radiological interventio n.