Improved MR flow mapping in coronary artery bypass grafts during adenosine-induced stress.
OBJECTIVE
To validate a recently developed fast high-temporal-resolution magnetic resonance (MR) flow sequence and use it to assess coronary artery bypass graft function during pharmacologic stress.


METHODS
Aortic and internal mammary artery flow was measured in 11 healthy volunteers by using conventional cine gradient-echo imaging as a reference standard method and turbo-field echo-planar imaging (TFEPI). By using TFEPI, breath-hold flow mapping with a spatial and temporal resolution of 0.8 mm(2) and 23 msec, respectively, can be performed. This sequence was applied in 20 angiographically normal grafts, and total blood flow at rest and during adenosine infusion (140 microgram/kg/min) was measured.


RESULTS
Good agreement in aortic and internal mammary artery flow values between conventional fast-field echo and TFEPI techniques was found. The mean bypass graft total flow (+/- SD), as assessed with TFEPI, increased from 30.8 mL/min +/- 13.5 to 76.7 mL/min +/- 36.5 (P <.05) to yield a flow reserve of 2.7. Furthermore, this sequence revealed a difference in total flow between single and sequential grafts at rest (25.4 mL/min vs 40.9 mL/min; P <.05) and during stress (65.2 mL/min vs 98.3 mL/min; P <.05).


CONCLUSIONS
Breath-hold TFEPI provides fast accurate flow measurements with high temporal resolution and allows motion-compensated flow quantification in multiple coronary artery bypass grafts during one 6-minute adenosine infusion.
Langerak
S E
SE
Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands.
Kunz
P
P
Vliegen
H W
HW
Lamb
H J
HJ
Jukema
J W
JW
van Der Wall
E E
EE
de Roos
A
A
D000241:Adenosine; D000328:Adult; D000368:Aged; D001026:Coronary Artery Bypass; D003326:Coronary Circulation; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D013997:Time Factors; D014665:Vasodilator Agents
D014665:Vasodilator Agents; D000241:Adenosine