title: A refined method for quantification of myocardial oxygen consumption rate using mean transit time with carbon-11-acetate and dynamic PET.
abstract: The utility of the mean transit time equation was investigated for estimation of the myocardial clearance rate constant of 11C-acetate, which is proportional to myocardial oxygen consumption rates. The mean transit time approach was also employed to generate parametric images of the clearance rate constant of 11C-acetate with dynamic PET imaging in 20 normal human studies. Input function delays and cutoff errors due to the truncation of the myocardial tissue time-activity curve at a finite time were corrected. The clearance rate constants estimated by mean transit time correlated well with the estimates by conventional monoexponential fitting (15 min (truncation time): Y = 0.01 + 0.94X, correlated coefficient (r) = 0.99; 16 min: Y = 0.03 + 0.94X, r = 0.98; 20 min: Y = 0.03 + 0.84X, r = 0.99). The clearance rate constants estimated by the mean transit time approach also correlated well (r = 0.94) with the measured rate-pressure products. The quality and noise level of parametric images of the clearance rate constants generated by mean transit time are improved over those generated by monoexponential fitting. Additional advantages of the mean transit time approach compared to the standard monoexponential fitting method for estimating myocardial clearance rate constant of 11C-acetate include ease of input function delay correction, less sensitivity to the shape of the input function and elimination of subjective data selection of the linear portion of the clearance data on a semilog plot. Thus, this approach is expected to facilitate objective quantitative analysis of indices of myocardial oxygen consumption.
authors.affiliation: Department of Molecular and Medical Pharmacology, University of California, Los Angeles.
authors.forename: Y
authors.initials: Y
authors.lastname: Choi
authors.forename: S C
authors.initials: SC
authors.lastname: Huang
authors.forename: R A
authors.initials: RA
authors.lastname: Hawkins
authors.forename: C K
authors.initials: CK
authors.lastname: Hoh
authors.forename: J
authors.initials: J
authors.lastname: Krivokapich
authors.forename: D B
authors.initials: DB
authors.lastname: Buxton
authors.forename: J J
authors.initials: JJ
authors.lastname: Armbrecht
authors.forename: K T
authors.initials: KT
authors.lastname: Sun
authors.forename: M E
authors.initials: ME
authors.lastname: Phelps
authors.forename: H R
authors.initials: HR
authors.lastname: Schelbert
mesh_terms: D000085:Acetates; D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D002250:Carbon Radioisotopes; D006339:Heart Rate; D006801:Humans; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes