VOLUMETRIC FLOW ESTIMATION IN-VIVO AND IN-VITRO USING PULSED-DOPPLER ULTRASOUND

The measurement of volumetric blood flow in small vessels in vitro and in vivo poses a significant technological challenge. In this study, t wo pulsatile how models were developed, one with a 3.2-mm lumen diamet er and one with a 12.7-mm lumen diameter, to assess the accuracy of vo lumetric flow estimation of two pulsed-Doppler devices, a Crystal Biot ech VF1 20-MHz system with either a cuff-mounted or a needle-mounted p robe and an Advanced Technology Laboratories Ultramark 9 High Definiti on Imaging(R) system with a 5-MHz linear array transducer. The VF1 vol umetric flow error was measured in the 3.2-mm phantom over a variety o f pulsatile and continuous waveforms. The accuracy of the VF1 was also tested in porcine femoral and renal arteries. VF1 volumetric flow err or ranged from 4.8% to 54.3% in the in vivo studies. The ATL demonstra ted similar volumetric flow errors in the porcine femoral artery(simil ar to 3.2 mm diameter), but these errors were reduced to less than or equal to 17.4% in the 12.7-mm-diameter in vitro flow model.