title: Compared with 3-dimensional analysis, 2-dimensional gated SPECT analysis overestimates left ventricular ejection fraction in patients with regional dyssynchrony.
abstract: BACKGROUND
  Left ventricular (LV) ejection fraction (EF) is a powerful prognostic predictor in patients with heart disease. However, LVEF calculated by 2-dimensional (2D) modalities such as echocardiography by use of the "modified" Simpson's rule may be incorrect in patients with regional dyssynchrony, presumably because regions of dyssynchrony are excluded from analysis.
  
  
  RESULTS
  To elucidate the difference between 2D and 3-dimensional (3D) methods with regard to LVEF calculation in patients with regional dyssynchrony, we compared LVEF derived from 8-frame gated technetium 99m sestamibi stress perfusion tomograms using commercially available 2D single photon emission computed tomography (SPECTEF) software that uses the modified Simpson's rule, 3D QGS, and investigational 3D p-FAST software in 136 left bundle branch block patients. Twenty-four patients had normal wall motion, whereas one hundred twelve showed septal dyssynchrony. Bland-Altman plots demonstrated that compared with QGS and p-FAST, SPECTEF overestimated LVEF in patients with septal dyssynchrony systemically by 8.6% and 11.3%, respectively.
  
  
  CONCLUSIONS
  We conclude that compared with 3D modalities, 2D modalities that use the modified Simpson's rule, such as SPECT EF, overestimate LVEF in patients with dyssynchronous septal wall motion. Therefore 3D modalities are preferred to evaluate patients with regional dyssynchrony.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, St. Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY, USA. tkkasai@jikei.ac.jp
authors.forename: Tokuo
authors.initials: T
authors.lastname: Kasai
authors.forename: E Gordon
authors.initials: EG
authors.lastname: Depuey
authors.forename: Arshad Ali
authors.initials: AA
authors.lastname: Shah
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology