title: Comparison of MRI and positron emission tomography for measuring myocardial perfusion reserve in healthy humans.
abstract: 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.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku, Finland. jussi.parkka@utu.fi
authors.forename: Jussi P
authors.initials: JP
authors.lastname: Pärkkä
authors.forename: Pekka
authors.initials: P
authors.lastname: Niemi
authors.forename: Antti
authors.initials: A
authors.lastname: Saraste
authors.forename: Juha W
authors.initials: JW
authors.lastname: Koskenvuo
authors.forename: Markku
authors.initials: M
authors.lastname: Komu
authors.forename: Vesa
authors.initials: V
authors.lastname: Oikonen
authors.forename: Jyri O
authors.initials: JO
authors.lastname: Toikka
authors.forename: Tuomas O
authors.initials: TO
authors.lastname: Kiviniemi
authors.forename: Juhani
authors.initials: J
authors.lastname: Knuuti
authors.forename: Hajime
authors.initials: H
authors.lastname: Sakuma
authors.forename: Jaakko J
authors.initials: JJ
authors.lastname: Hartiala
mesh_terms: 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
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D004176:Dipyridamole; D019786:Gadolinium DTPA