title: Comparison of left ventricular manual versus automated derived longitudinal strain: implications for clinical practice and research.
abstract: Systolic global longitudinal strain (GLS) is emerging as a useful metric of ventricular function in heart failure and usually assessed using post-processing software. The purpose of this study was to investigate whether longitudinal strain (LS) derived using manual-tracings of ventricular lengths (manual-LS) can be reliable and time efficient when compared to LS obtained by post-processing software (software-LS). Apical 4-chamber view images were retrospectively examined in 50 healthy controls, 100 patients with dilated cardiomyopathy (DCM), and 100 with hypertrophic cardiomyopathy (HCM). We measured endocardial and mid-wall manual-LS and software-LS, using peak of average regional curve [software-LS(a)] and global ventricular lengths [software-LS(l)] according to definition of Lagragian strain. We compared manual-LS and software-LS by using Bland-Altman plot and coefficient of variation (COV). In addition, test-retest was also performed for further assessment of variability in measurements. While manual-LS was obtained in all subjects, software-LS could be obtained in 238 subjects (95%). The time spent for obtaining manual-LS was significantly shorter than for the software-LS (94 ± 39 s vs. 141 ± 79 s, P < 0.001). Overall, manual-LS had an excellent correlation with both software-LS (a) (R(2) = 0.93, P < 0.001) and software-LS(l) (R(2) = 0.84, P < 0.001). The bias (95%CI) between endocardial manual-LS and software-LS(a) was 0.4% [-2.8, 3.6%] in absolute and 3.5% [-17.0, 24.0%] in relative difference while it was 0.4% [-2.5, 3.3%] and 3.4% [-16.2, 23.1%], respectively with software-LS(l). Mid-wall manual-LS and mid-wall software-LS(a) also had good agreement [a bias (95% CI) for absolute value of 0.1% [-2.1, 2.5%] in HCM, and 0.2% [-2.2, 2.6%] in controls]. The COV for manual and software derived LS were below 6%. Test-retest showed good variability for both methods (COVs were 5.8 and 4.7 for endocardial and mid-wall manual-LS, and 4.6 and 4.9 for endocardial and mid-wall software-LS(a), respectively. Manual-LS appears to be as reproducible as software-LS; this may be of value especially when global strain is the metric of interest.
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA. yukariko@stanford.edu.|Stanford Cardiovascular Institute, Stanford, CA, USA. yukariko@stanford.edu.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Ariyama
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Giraldeau
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Dominik
authors.initials: D
authors.lastname: Fleischman
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Mirta
authors.initials: M
authors.lastname: Kozelj
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Bojan
authors.initials: B
authors.lastname: Vrtovec
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Euan
authors.initials: E
authors.lastname: Ashley
authors.affiliation: Stanford Cardiovascular Institute, Stanford, CA, USA.|Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Louvain, Belgium.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuznetsova
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Ingela
authors.initials: I
authors.lastname: Schnittger
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Liang
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive Room H2170, Stanford, CA, 94305, USA.|Stanford Cardiovascular Institute, Stanford, CA, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Haddad
mesh_terms: D000328:Adult; D000368:Aged; D001331:Automation; D001696:Biomechanical Phenomena; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D013314:Stress, Mechanical; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: Dilated cardiomyopathy; Echocardiography; Global longitudinal strain; Heart failure; Hypertrophic cardiomyopathy; Post-processing software; Strain imaging; Vendor-independent; Ventricular function