title: Triggered replenishment imaging reduces variability of quantitative myocardial contrast echocardiography and allows assessment of myocardial blood flow reserve.
abstract: Assessment of replenishment kinetics (RK) following ultrasound-induced destruction of contrast microbubbles allows quantification of myocardial blood flow reserve (MBFR) applying the model f (t) = A (1 - e(-betat)), with parameter beta describing mean flow velocity and parameter A representing blood volume. However, few data on the variability and reproducibility of RK in a clinical setting are available. Therefore, we examined 30 patients in a rest-adenosine protocol in one center. Off-line quantification of real-time perfusion imaging (RTPI) and triggered replenishment imaging (TRI) was performed at two sites and compared with coronary angiography and flow reserve measurements. Parameter A was found to be robust in all investigated segments (coefficient of variation (CV) < 7.2%+/- 5.1). Variability was lowest for parameter beta using TRI in apical segments (CV 6.5%+/- 5.2, P < 0.01). Highest CV was found with RTPI in lateral segments (CV : 39.8%+/- 40.6). Concerning day-to-day reproducibility both methods revealed similar results within range of heterogeneity of myocardial blood flow. Both sites obtained significantly lower MBFR in patients with flow-limiting CAD, compared to subjects without (P < 0.01). Correlation of both sites showed close relationship (y = 0.88x + 0.45, r = 0.83, P < 0.0001), without systematic bias. TRI significantly reduces variability of RK in quantitative MCE. Assessment of MBFR allows investigator-independent evaluation of CAD.
authors.affiliation: Department of Medicine-Cardiology, University of Bonn, Bonn, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ghanem
authors.forename: Anthony N
authors.initials: AN
authors.lastname: DeMaria
authors.forename: Stefan
authors.initials: S
authors.lastname: Lohmaier
authors.forename: Mona A
authors.initials: MA
authors.lastname: El-Sayed
authors.forename: Monet
authors.initials: M
authors.lastname: Strachan
authors.forename: Torsten
authors.initials: T
authors.lastname: Sommer
authors.forename: Jörg
authors.initials: J
authors.lastname: Stypmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Tiemann
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000502:physiology; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D015588:Observer Variation; D010743:Phospholipids; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013459:Sulfur Hexafluoride
chemical_list: D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride