title: Fast assessment of long axis strain with standard cardiovascular magnetic resonance: a validation study of a novel parameter with reference values.
abstract: BACKGROUND
  Assessment of longitudinal function with cardiovascular magnetic resonance (CMR) is limited to measurement of systolic excursion of the mitral annulus (MAPSE) or elaborate strain imaging modalities. The aim of this study was to develop a fast assessable parameter for the measurement of long axis strain (LAS) with CMR.
  
  
  METHODS
  40 healthy volunteers and 125 patients with different forms of cardiomyopathy were retrospectively analyzed. Four different approaches for the assessment of LAS with CMR measuring the distance between the LV apex and a line connecting the origins of the mitral valve leaflets in enddiastole and endsystole were evaluated. Values for LAS were calculated according to the strain formula.
  
  
  RESULTS
  LAS derived from the distance of the epicardial apical border to the midpoint of the line connecting the mitral valve insertion points (LAS-epi/mid) proved to be the most reliable parameter for the assessment of LAS among the different approaches. LAS-epi/mid displayed the highest sensitivity (81.6 %) and specificity (97.5 %), furthermore showing the best correlation with feature tracking (FTI) derived transmural longitudinal strain (r = 0.85). Moreover, LAS-epi/mid was non-inferior to FTI in discriminating controls from patients (Area under the curve (AUC) = 0.95 vs. 0.94, p = NS). The time required for analysis of LAS-epi/mid was significantly shorter than for FTI (67 ± 8 s vs. 180 ± 14 s, p < 0.0001). Additionally, LAS-epi/mid performed significantly better than MAPSE (Delta AUC = 0.09; p < 0.005) and the ejection fraction (Delta AUC = 0.11; p = 0.0002). Reference values were derived from 234 selected healthy volunteers. Mean value for LAS-epi/mid was -17.1 ± 2.3 %. Mean values for men were significantly lower compared to women (-16.5 ± 2.2 vs. -17.9 ± 2.1 %; p < 0.0001), while LAS decreased with age.
  
  
  CONCLUSIONS
  LAS-epi/mid is a novel and fast assessable parameter for the analysis of global longitudinal function with non-inferiority compared to transmural longitudinal strain.
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. johannes.riffel@med.uni-heidelberg.de.
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Riffel
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. florian.andre@med.uni-heidelberg.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Andre
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. m-maertens@gmx.de.
authors.forename: Malte
authors.initials: M
authors.lastname: Maertens
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. franzi.rost@gmx.net.
authors.forename: Franziska
authors.initials: F
authors.lastname: Rost
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. mariuskeller@gmail.com.
authors.forename: Marius G P
authors.initials: MG
authors.lastname: Keller
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. sorin.giusca@med.uni-heidelberg.de.
authors.forename: Sorin
authors.initials: S
authors.lastname: Giusca
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. sebastian.seitz@med.uni-heidelberg.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Seitz
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. Arnt.Kristen@med.uni-heidelberg.de.
authors.forename: Arnt V
authors.initials: AV
authors.lastname: Kristen
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. Matthias.muller@med.uni-heidelberg.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. Evangelos.Giannitsis@med.uni-heidelberg.de.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Giannitsis
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. grigorios.korosoglou@med.uni-heidelberg.de.
authors.forename: Grigorios
authors.initials: G
authors.lastname: Korosoglou
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. hugo.katus@med.uni-heidelberg.de.|DZHK (German Centre for Cardiovascular Research), Heidelberg, Germany. hugo.katus@med.uni-heidelberg.de.
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.affiliation: Department of Cardiology, Angiology and Pneumology, University of Heidelberg, INF 410, 69120, Heidelberg, Germany. sebastian.buss@med.uni-heidelberg.de.
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Buss
mesh_terms: D000328:Adult; D000367:Age Factors; D019540:Area Under Curve; D001696:Biomechanical Phenomena; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards*; D019028:Magnetic Resonance Imaging, Cine / Q000592:standards*; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012737:Sex Factors; D013314:Stress, Mechanical; D013997:Time Factors; D016277:Ventricular Function, Left