title: Free-breathing cardiac MR stress perfusion with real-time slice tracking.
abstract: OBJECTIVE
  To develop a free-breathing cardiac MR perfusion sequence with slice tracking for use after physical exercise.
  
  
  METHODS
  We propose to use a leading navigator, placed immediately before each 2D slice acquisition, for tracking the respiratory motion and updating the slice location in real-time. The proposed sequence was used to acquire CMR perfusion datasets in 12 healthy adult subjects and 8 patients. Images were compared with the conventional perfusion (i.e., without slice tracking) results from the same subjects. The location and geometry of the myocardium were quantitatively analyzed, and the perfusion signal curves were calculated from both sequences to show the efficacy of the proposed sequence.
  
  
  RESULTS
  The proposed sequence was significantly better compared with the conventional perfusion sequence in terms of qualitative image scores. Changes in the myocardial location and geometry decreased by 50% in the slice tracking sequence. Furthermore, the proposed sequence had signal curves that are smoother and less noisy.
  
  
  CONCLUSIONS
  The proposed sequence significantly reduces the effect of the respiratory motion on the image acquisition in both rest and stress perfusion scans.
authors.affiliation: Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Tamer A
authors.initials: TA
authors.lastname: Basha
authors.forename: Sébastien
authors.initials: S
authors.lastname: Roujol
authors.forename: Kraig V
authors.initials: KV
authors.lastname: Kissinger
authors.forename: Beth
authors.initials: B
authors.lastname: Goddu
authors.forename: Sophie
authors.initials: S
authors.lastname: Berg
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.forename: Reza
authors.initials: R
authors.lastname: Nezafat
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000503:physiopathology*; D003287:Contrast Media; D015444:Exercise / Q000502:physiology*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D015656:Respiratory Mechanics; D055425:Respiratory-Gated Imaging Techniques
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: localized 2D restore pulses; motion correction; navigator; real-time slice tracking; stress-perfusion