Oliver D. Kripfgans PhD, Abstract Co-Author: Nothing to Disclose

Jonathan Matthew Rubin MD, PhD, Abstract Co-Author: Consultant, Koninklijke Philips Electronics NV Consultant, Siemens AG Consultant, General Electric Company

Anne L Hall, Abstract Co-Author: Employee, General Electric Company

Michael B. Gordon MD, Abstract Co-Author: Nothing to Disclose

Jeffrey Brian Fowlkes PhD, Presenter: Equipment support, General Electric Company Equipment support, Toshiba Corporation

To evaluate a 3-D ultrasound method for the measurement of volumetric flow under conditions of known flow rates and Doppler angles.

A GE/Kretz Voluson 730 (GE Medical Systems, Milwaukee, WI) and RAB2-5 probe was used to acquire 3D Doppler measurements in a custom flow phantom (CIRS, Norfolk, VA) containing a thin-walled (0.38 mm) natural rubber tube (9.5 mm lumen diameter). Blood mimicking fluid circulated by a CompuFlow 1000 System pump (both from Shelly Medical Imaging Technologies, London, Ontario) provided a range of flow velocities (2-15 ml/sec). A six axis positioning system maneuvered the ultrasound probe through a range of angles (40-70° and 110-140°) with respect to the tube (US beam was orthogonal to the tube at 90°). Volume data sets were obtained spanning 29° lateral and 20° elevational angles encompassing the flow tube in a scanning time of <10 s. Flow estimates are derived by directly integrating the flux across a surface passing through the tube. Power Doppler data was used to correct for partial volume effects.

Direct comparisons of volume flow rates estimated using 3D (volumetric) ultrasound and known flow rates showed that the method has good accuracy. Using a single angle (110°) with respect to the flow tube, the agreement between measured and actual volume flow rates was within +/-20% over the full range of flow rates with only 2 exceptions in 20 estimations. At flow rates of 5 and 10 ml/sec, the measured rates were all within +/-20% of actual values (all but 2 measurements within +/-10%) for the range of angles tested.

The technique appears highly robust, being independent of angle and should not depend on vessel shape, flow profile or integration surface selected. Real-time 3D acquisitions should make time-dependent flow monitoring feasible. Subsequent comparisons under pulsatile and in vivo conditions will be needed to verify this performance for clinical applications. This work is supported by 1RO1 HL67921.

Volumetric scanning using mechanical or electronic steering will make volume flow measurements easy to implement and diagnoses, i.e. fetal blood flow and cardiac output measurements, are inevitable.

Kripfgans, O, Rubin, J, Hall, A, Gordon, M, Fowlkes, J, Measurement of Volumetric Flow Using Current 3-D Ultrasound Imaging Methods—A Direct Comparison with Known Flow.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4441181.html