title: Accurate and reproducible measurement of left ventricular volume and ejection fraction by contrast echocardiography: a comparison with magnetic resonance imaging.
abstract: OBJECTIVE
  We evaluated the accuracy and reproducibility of contrast echocardiography versus tissue harmonic imaging for measurements of left ventricular (LV) volumes and ejection fraction (EF) compared to magnetic resonance imaging (MRI).
  
  
  METHODS
  Digital echo recordings of apical LV views before and after intravenous contrast were collected from 110 consecutive patients. Magnetic resonance imaging of multiple short-axis LV sections was performed with a 1.5-T scanner. Left ventricular volumes and EF were calculated offline by method of discs. Thirty randomly selected patients were reanalyzed for intraobserver and interobserver variability.
  
  
  RESULTS
  Compared with baseline, contrast echo increased feasibility for single-plane and biplane volume analysis from 87% to 100% and from 79% to 95%, respectively. The Bland-Altman analysis demonstrated volume underestimation by echo, but much less pronounced with contrast. Limits of agreement between echo and MRI narrowed significantly with contrast: from -18.1% to 8.3% to -7.7% to 4.1% (EF), from -98.2 to -11.7 ml to -59.0 to 10.7 ml (end-diastolic volume), and from -58.8 to 21.8 ml to -38.6 to 23.9 ml (end-systolic volume). Ejection fraction from precontrast echo and MRI differed by > or =10% (EF units) in 23 patients versus 0 after contrast (p < 0.001). At intraobserver and interobserver analysis, limits of agreement for EF narrowed significantly with contrast.
  
  
  CONCLUSIONS
  The two-dimensional echocardiographic evaluation of LV volumes and EF in non-selected cardiac patients was found to be more accurate and reproducible when adding an intravenous contrast agent.
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim.
authors.forename: Siri
authors.initials: S
authors.lastname: Malm
authors.forename: Sigmund
authors.initials: S
authors.lastname: Frigstad
authors.forename: Einar
authors.initials: E
authors.lastname: Sagberg
authors.forename: Henrik
authors.initials: H
authors.lastname: Larsson
authors.forename: Terje
authors.initials: T
authors.lastname: Skjaerpe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005466:Fluorocarbons; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D010743:Phospholipids; D015203:Reproducibility of Results; D013318:Stroke Volume; D013459:Sulfur Hexafluoride; D016277:Ventricular Function, Left
chemical_list: D005466:Fluorocarbons; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride; C042852:perflutren