Comparison of MRI and positron emission tomography for measuring myocardial perfusion reserve in healthy humans.
Myocardial perfusion reserve (MPR, defined as the ratio of the maximum myocardial blood flow (MBF) to the baseline) is an indicator of coronary artery disease and myocardial microvascular abnormalities. First-pass contrast-enhanced magnetic resonance imaging (CE-MRI) using gadolinium (Gd)-DTPA as a contrast agent (CA) has been used to assess MPR. Tracer kinetic models based on compartmental analysis of the CA uptake have been developed to provide quantitative measures of MBF by MRI. To study the accuracy of Gd-DTPA first-pass MRI and kinetic modeling for quantitative analysis of myocardial perfusion and MPR during dipyridamole infusion, we conducted a comparison with positron emission tomography (PET) in 18 healthy males (age = 40 +/- 14 years). Five planes were acquired at every second heartbeat with a 1.5T scanner using a saturation recovery turboFLASH sequence. A perfusion-related parameter, the unidirectional influx constant (Ki), was computed in three coronary artery territories. There was a significant correlation for both dipyridamole-induced flow (0.70, P = 0.001) and MPR (0.48, P = 0.04) between MRI and PET. However, we noticed that MRI provided lower MPR values compared to PET (2.5 +/- 1.0 vs. 4.3 +/- 1.8). We conclude that MRI supplemented with tracer kinetic modeling can be used to quantify myocardial perfusion.
Pärkkä
Jussi P
JP
Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku, Finland. jussi.parkka@utu.fi
Niemi
Pekka
P
Saraste
Antti
A
Koskenvuo
Juha W
JW
Komu
Markku
M
Oikonen
Vesa
V
Toikka
Jyri O
JO
Kiviniemi
Tuomas O
TO
Knuuti
Juhani
J
Sakuma
Hajime
H
Hartiala
Jaakko J
JJ
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003287:Contrast Media / Q000493:pharmacokinetics; D003326:Coronary Circulation / Q000502:physiology*; D004176:Dipyridamole / Q000008:administration & dosage; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D014665:Vasodilator Agents / Q000008:administration & dosage
D003287:Contrast Media; D014665:Vasodilator Agents; D004176:Dipyridamole; D019786:Gadolinium DTPA