A Comparison of Theory-Based and Experimentally Determined Myocardial Signal Intensity Correction Methods in First-Pass Perfusion Magnetic Resonance Imaging.
OBJECTIVE
To evaluate the impact of correcting myocardial signal saturation on the accuracy of absolute myocardial blood flow (MBF) measurements.


METHODS
We performed 15 dual bolus first-pass perfusion studies in 7 dogs during global coronary vasodilation and variable degrees of coronary artery stenosis. We compared microsphere MBF to MBF calculated from uncorrected and corrected MRI signal. Four correction methods were tested, two theoretical methods (Th1 and Th2) and two empirical methods (Em1 and Em2).


RESULTS
The correlations with microsphere MBF (n = 90 segments) were: uncorrected (y = 0.47x + 1.1, r = 0.70), Th1 (y = 0.53x + 1.0, r = 0.71), Th2 (y = 0.62x + 0.86, r = 0.73), Em1 (y = 0.82x + 0.86, r = 0.77), and Em2 (y = 0.72x + 0.84, r = 0.75). All corrected methods were not significantly different from microspheres, while uncorrected MBF values were significantly lower. For the top 50% of microsphere MBF values, flows were significantly underestimated by uncorrected SI (31%), Th1 (25%), and Th2 (19%), while Em1 (1%), and Em2 (9%) were similar to microsphere MBF.


CONCLUSIONS
Myocardial signal saturation should be corrected prior to flow modeling to avoid underestimation of MBF by MR perfusion imaging.
Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Jacob U
JU
Fluckiger
Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Brandon C
BC
Benefield
Division of Cardiology, Department of Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153, USA.
Lara
L
Bakhos
Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Kathleen R
KR
Harris
Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA ; Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA ; Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Daniel C
DC
Lee
D000818:Animals; D001783:Blood Flow Velocity; D003198:Computer Simulation; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology*; D023921:Coronary Stenosis / Q000175:diagnosis; D004285:Dogs; D019786:Gadolinium DTPA; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000706:statistics & numerical data; D008863:Microspheres; D008955:Models, Cardiovascular; D014664:Vasodilation
D003287:Contrast Media; D019786:Gadolinium DTPA