VALIDATION OF VOLUME BLOOD-FLOW MEASUREMENTS USING 3-DIMENSIONAL DISTANCE-CONCENTRATION FUNCTIONS DERIVED FROM DIGITAL X-RAY ANGIOGRAMS

RATIONALE AND OBJECTIVES. The authors present phantom validation of a method for computing pulsatile flow waveforms in arterial vessels from high-frame-rate biplane x-ray angiograms. METHODS. The three-dimensional course of a blood vessel is constructed from biplane digital x-ray angiograms. A parametric image of contrast mass versus time and true three-dimensional path length is generated. Adjacent contrast mass-distance profiles are matched to compute instantaneous velocity, which is multiplied by cross-sectional area to yield volume flow. An electromagnetic flowmeter was used to validate flow estimates in a phantom consisting of 150-mm tubes 3, 4, and 6 mm in diameter, orientated 15 degrees, 30 degrees, and 35 degrees to the imaging plane, with now rates and waveforms expected in vivo. RESULTS. Mean and peak flows were accurate to within 9% and 10%, respectively, for velocities of less than 1 meter/ second at a frame rate of 25 frames per second. CONCLUSIONS. A practical method for computing highly pulsatile flow waveforms in vivo in tortuous vessels is presented.