title: Left atrial structure and functional quantitation using cardiovascular magnetic resonance and multimodality tissue tracking: validation and reproducibility assessment.
abstract: BACKGROUND
  Left atrium (LA) strain, volume and function are important markers of cardiovascular disease and myocardial impairment. We aimed to assess the accuracy of LA biplane volume and function measured by Multimodality Tissue Tracking (MTT). Also we assessed the inter-study reproducibility for cardiovascular magnetic resonance (CMR) derived LA volume and function parameters.
  
  
  METHODS
  Thirty subjects (mean age: 71.3 ± 8.7, 87% male) including twenty subjects with cardiovascular events and ten healthy subjects, with CMR were evaluated in the Multi-Ethnic Study of Atherosclerosis (MESA). LA volumes were computed by the modified biplane method from 2- and 4-chamber projections and the Simpson's method from short-axis slices using both methods - manual and semi-automated delineation using MTT. LA total, active and passive ejection fractions were calculated. Pearson's correlation and Bland-Altman analysis were used to compare the measurements. In a second sample of 25 subjects (age: 65.7 ± 7.1, 72% males) inter study, intra and inter reader reliability analysis was performed. The intra-class correlation coefficient (ICC) was evaluated.
  
  
  RESULTS
  Left atrial MTT structural and functional parameters were not different from manual delineation, yet image analysis was only half as time consuming on average with MTT. Maximal volume MTT was not different between the Simpson's and Biplane methods, functional parameters, however were different. MTT allowed us to measure multiple LA parameters with good-excellent (ICC; 0.88- 0.98, p < 0.001) intra-and inter reader reproducibility and fair-good (ICC; 0.44-0.82, p < 0.05-0.001) inter study reproducibility.
  
  
  CONCLUSIONS
  MTT derived LA biplane volume and function is accurate and reproducible and is suited for use in longitudinal studies.
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. mytra_z@hotmail.com.
authors.forename: Mytra
authors.initials: M
authors.lastname: Zareian
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. iallem@hotmail.com.
authors.forename: Luisa
authors.initials: L
authors.lastname: Ciuffo
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. mahabibi@gmail.com.
authors.forename: Mohammadali
authors.initials: M
authors.lastname: Habibi
authors.affiliation: Oslo University Hospital and University of Oslo, Oslo, Norway. a.opdahl@gmail.com.
authors.forename: Anders
authors.initials: A
authors.lastname: Opdahl
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. echamer1@jhmi.edu.
authors.forename: Elzbieta H
authors.initials: EH
authors.lastname: Chamera
authors.affiliation: National Institutes of Health, Bethesda, MD, USA. wuc@nhlbi.nih.gov.
authors.forename: Colin O
authors.initials: CO
authors.lastname: Wu
authors.affiliation: National Institutes of Health, Bethesda, MD, USA. bluemked@cc.nih.gov.
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. jlima@jhmi.edu.
authors.forename: João A C
authors.initials: JA
authors.lastname: Lima
authors.affiliation: MR 110, Radiology, Johns Hopkins University, Baltimore, MD, 21287, USA. bambale1@jhmi.edu.
authors.forename: Bharath Ambale
authors.initials: BA
authors.lastname: Venkatesh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016279:Atrial Function, Left; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology; D006331:Heart Diseases / Q000175:diagnosis* / Q000208:ethnology / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013997:Time Factors; D014481:United States / Q000453:epidemiology