MR flow mapping in coronary artery bypass grafts: a validation study with Doppler flow measurements.
OBJECTIVE
To validate fast magnetic resonance (MR) flow mapping with intravascular Doppler flow measurements in vitro and in patients with nonstenotic and stenotic coronary artery bypass grafts.


METHODS
MR and Doppler flow measurements were performed in a small-diameter flow phantom with physiologic flow conditions and at baseline and during adenosine stress in 27 grafts in 23 patients, who were scheduled for cardiac catheterization. At invasive analysis, the grafts were divided into those with stenosis of less than 50% (nonstenotic) and those with stenosis greater than or equal to 50% (stenotic). In vitro velocity values and velocity values in nonstenotic and stenotic grafts were compared with linear regression analysis, and the in vitro interstudy variability was determined.


RESULTS
Excellent correlations in average peak velocity (r = 0.99, P <.001) and diastolic peak velocity (r = 0.99, P <.001) were demonstrated in vitro between MR and Doppler flow measurements, with less than 5% interstudy variability. MR and Doppler flow measurements revealed good correlations in peak velocity and velocity reserve both in nonstenotic (n = 20) (average peak velocity: r = 0.81, P <.001; diastolic peak velocity: r = 0.83, P <.001; velocity reserve: r = 0.56, P =.010) and stenotic (n = 7) (average peak velocity: r = 0.83, P <.001; diastolic peak velocity: r = 0.78, P =.001; velocity reserve: r = 0.70, P =.078) grafts.


CONCLUSIONS
Fast MR flow mapping provides noninvasive measures of peak velocity and velocity reserve, which closely correlate with Doppler values both in vitro and in nonstenotic and stenotic grafts.
Langerak
Susan E
SE
Dept of Cardiology, Leiden Univ Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands.
Kunz
Patrik
P
Vliegen
Hubert W
HW
Jukema
J Wouter
JW
Zwinderman
Aeilko H
AH
Steendijk
Paul
P
Lamb
Hildo J
HJ
van der Wall
Ernst E
EE
de Roos
Albert
A
D000241:Adenosine; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001026:Coronary Artery Bypass; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000502:physiology*; D015150:Echocardiography, Doppler; D005260:Female; D006083:Graft Occlusion, Vascular / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D014654:Vascular Patency
D000241:Adenosine