title: Measurement of coronary blood flow and flow reserve using magnetic resonance imaging.
abstract: OBJECTIVE
  It was the purpose of this study to demonstrate the feasibility of performing coronary artery flow and coronary flow reserve (CFR) measurements in normal human volunteers using a magnetic resonance (MR) phase contrast technique.
  
  
  METHODS
  Coronary flow rate, flow velocity, peak flow and CFR were determined at rest and during pharmacologically induced hyperemia in 10 healthy volunteers. The flow measurements were obtained during a single breath-hold by using a fast, prospectively gated, segmented k-space gradient-echo phase contrast acquisition with view sharing (FASTCARD PC) that was modified to improve sampling of the diastolic flow. Data were processed using the standard phase difference (PD) processing techniques as well as a new complex difference (CD) flow measurement method intended to improve the accuracy of flow measurements in small vessels.
  
  
  RESULTS
  Mean hyperemic flow velocity (40 +/- 16 cm/s) and blood flow (3.9 +/- 1.5 ml/s) rates differed significantly from resting velocity (13 +/- 6.6 cm/s) and flow (1.1 +/- 0.4 ml/s) measurements (p < 0.0001). PD methods consistently measured larger flow rates at rest (24% larger, p < 0.0005) and stress (29% larger, p < 0.0001). CFR, calculated as the ratio of the mean PD flows (4.7 +/- 2.8), was higher than CFR calculated as the ratio of mean CD flows (4.2 +/- 1.8); however, the differences did not reach statistical significance (p = 0.07). Flow measurements performed in adjacent slices of the same vessel correlated well (r = 0.88).
  
  
  CONCLUSIONS
  Coronary flow and CFR measurements using the MR techniques are feasible and are similar to those reported in the literature for healthy volunteers.
authors.affiliation: Department of Radiology, University of Wisconsin Medical School, Madison 53792-3252, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Grist
authors.forename: J A
authors.initials: JA
authors.lastname: Polzin
authors.forename: J A
authors.initials: JA
authors.lastname: Bianco
authors.forename: T K
authors.initials: TK
authors.lastname: Foo
authors.forename: M A
authors.initials: MA
authors.lastname: Bernstein
authors.forename: C M
authors.initials: CM
authors.lastname: Mistretta
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D003331:Coronary Vessels / Q000502:physiology*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results