Validation of volume blood flow measurements using three-dimensional distance-concentration functions derived from digital x-ray angiograms.
OBJECTIVE
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 flow 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.
Division of Radiological Sciences, UMDS, Guy's Hospital, London, United Kingdom.
D J
DJ
Hawkes
A M
AM
Seifalian
A C
AC
Colchester
N
N
Iqbal
C R
CR
Hardingham
C F
CF
Bladin
K E
KE
Hobbs
D000465:Algorithms; D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity / Q000502:physiology; D001808:Blood Vessels; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008955:Models, Cardiovascular; D008961:Models, Structural; D011673:Pulsatile Flow / Q000502:physiology