title: Quantification of left ventricular functional parameter values using 3D spiral bSSFP and through-time non-Cartesian GRAPPA.
abstract: BACKGROUND
  The standard clinical acquisition for left ventricular functional parameter analysis with cardiovascular magnetic resonance (CMR) uses a multi-breathhold multi-slice segmented balanced SSFP sequence. Performing multiple long breathholds in quick succession for ventricular coverage in the short-axis orientation can lead to fatigue and is challenging in patients with severe cardiac or respiratory disorders. This study combines the encoding efficiency of a six-fold undersampled 3D stack of spirals balanced SSFP sequence with 3D through-time spiral GRAPPA parallel imaging reconstruction. This 3D spiral method requires only one breathhold to collect the dynamic data.
  
  
  METHODS
  Ten healthy volunteers were recruited for imaging at 3 T. The 3D spiral technique was compared against 2D imaging in terms of systolic left ventricular functional parameter values (Bland-Altman plots), total scan time (Welch's t-test) and qualitative image rating scores (Wilcoxon signed-rank test).
  
  
  RESULTS
  Systolic left ventricular functional values were not significantly different (i.e. 3D-2D) between the methods. The 95% confidence interval for ejection fraction was -0.1 ± 1.6% (mean ± 1.96*SD). The total scan time for the 3D spiral technique was 48 s, which included one breathhold with an average duration of 14 s for the dynamic scan, plus 34 s to collect the calibration data under free-breathing conditions. The 2D method required an average of 5 min 40s for the same coverage of the left ventricle. The difference between 3D and 2D image rating scores was significantly different from zero (Wilcoxon signed-rank test, p < 0.05); however, the scores were at least 3 (i.e. average) or higher for 3D spiral imaging.
  
  
  CONCLUSIONS
  The 3D through-time spiral GRAPPA method demonstrated equivalent systolic left ventricular functional parameter values, required significantly less total scan time and yielded acceptable image quality with respect to the 2D segmented multi-breathhold standard in this study. Moreover, the 3D spiral technique used just one breathhold for dynamic imaging, which is anticipated to reduce patient fatigue as part of the complete cardiac examination in future studies that include patients.
authors.forename: Kestutis J
authors.initials: KJ
authors.lastname: Barkauskas
authors.forename: Prabhakar
authors.initials: P
authors.lastname: Rajiah
authors.forename: Ravi
authors.initials: R
authors.lastname: Ashwath
authors.forename: Jesse I
authors.initials: JI
authors.lastname: Hamilton
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Dan
authors.initials: D
authors.lastname: Ma
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Wright
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulani
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
authors.forename: Nicole
authors.initials: N
authors.lastname: Seiberlich
mesh_terms: D062485:Breath Holding; D055424:Cardiac-Gated Imaging Techniques; D004562:Electrocardiography; D064368:Healthy Volunteers; D006339:Heart Rate; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D011237:Predictive Value of Tests; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D016277:Ventricular Function, Left