title: Accelerated cardiac MR stress perfusion with radial sampling after physical exercise with an MR-compatible supine bicycle ergometer.
abstract: OBJECTIVE
  To evaluate the feasibility of accelerated cardiac MR (CMR) perfusion with radial sampling using nonlinear image reconstruction after exercise on an MR-compatible supine bike ergometer.
  
  
  METHODS
  Eight healthy subjects were scanned on two separate days using radial and Cartesian CMR perfusion sequences in rest and exercise stress perfusion. Four different methods (standard gridding, conjugate gradient SENSE [CG-SENSE], nonlinear inversion with joint estimation of coil-sensitivity profiles [NLINV] and compressed sensing with a total variation constraint [TV]) were compared for the reconstruction of radial data. Cartesian data were reconstructed using SENSE. All images were assessed by two blinded readers in terms of image quality and diagnostic value.
  
  
  RESULTS
  CG-SENSE and NLINV were scored more favorably than TV (in both rest and stress perfusion cases, P < 0.05) and gridding (for rest perfusion cases, P < 0.05). TV images showed patchy artifacts, which negatively influenced image quality especially in the stress perfusion images acquired with a low number of radial spokes. Although CG-SENSE and NLINV received better scores than Cartesian sampling in both rest and exercise stress perfusion cases, these differences were not statistically significant (P > 0.05).
  
  
  CONCLUSIONS
  We have demonstrated the feasibility of accelerated CMR perfusion using radial sampling after physical exercise using a supine bicycle ergometer in healthy subjects. For reconstruction of undersampled radial perfusion, CG-SENSE and NLINV resulted in better image quality than standard gridding or TV reconstruction. Further technical improvements and clinical assessment are needed before using this approach in patients with suspected coronary artery disease.
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.|Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
authors.forename: Silvio
authors.initials: S
authors.lastname: Pflugi
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Roujol
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Akçakaya
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Keigo
authors.initials: K
authors.lastname: Kawaji
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Murilo
authors.initials: M
authors.lastname: Foppa
authors.affiliation: Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Bobby
authors.initials: B
authors.lastname: Heydari
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Goddu
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Kraig
authors.initials: K
authors.lastname: Kissinger
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Sophie
authors.initials: S
authors.lastname: Berg
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.|Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Nezafat
mesh_terms: D000328:Adult; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005080:Exercise Test / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D016683:Supine Position
keywords: compressed sensing; myocardial perfusion imaging; radial sampling