title: Determination of Right Ventricular Volume by Combining Echocardiographic Distance Measurements.
abstract: BACKGROUND
  The position of the right ventricle (RV), often partly behind the sternum, implies difficulties to image the RV free wall using transthoracic echocardiography (TTE) and consequently limits the possibilities of stroke volume calculations. The aim of this study was to evaluate whether the volume of the right ventricle (RV) can be determined by combining TTE distance measurements that do not need the RV free wall to be fully visualized.
  
  
  METHODS
  The RV volume was approximated by an ellipsoid composed of three distances. Distance measurements, modeled RV stroke volumes (RVSV), and RV ejection fraction (RVEF) were compared to reference values obtained from cardiac magnetic resonance (CMR) imaging for 12 healthy volunteers.
  
  
  RESULTS
  Inter-modality comparisons showed that distance measurements were significantly underestimated in TTE compared to CMR. The modeled RV volumes using TTE distance measurements were underestimated compared to reference CMR volumes. There was, however, for TTE an agreement between modeled RVSV and left ventricular stroke volumes determined by biplane Simpson's rule. Similar agreement was shown between modeled RVSV based on CMR distance measurements and the CMR reference. Regarding RVEF, further studies including patients with a wider range of RVEF are needed to evaluate the method.
  
  
  CONCLUSIONS
  In conclusion, the ellipsoid model of the RV provides good estimates of RVSVs, but volumes based on distance measurements from different modalities cannot be used interchangeably.
authors: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors: Stina
authors: S
authors: Jorstig
authors: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.|Department of Clinical Physiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors: Micael
authors: M
authors: Waldenborg
authors: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.|Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors: Mats
authors: M
authors: Lidén
authors: Department of Clinical Physiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors: Maciej
authors: M
authors: Wodecki
authors: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.|Department of Medical Physics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors: Per
authors: P
authors: Thunberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059925:Anatomic Landmarks / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D055815:Young Adult
keywords: cardiac magnetic resonance imaging; echocardiography; ejection fraction; right ventricle; right ventricular volume