title: The exactness of left ventricular segmentation in cine magnetic resonance imaging and its impact on systolic function values.
abstract: OBJECTIVE
  To evaluate the impact of exactness of the segmentation of the left ventricle (LV), using cine magnetic resonance imaging (MRI).
  
  
  METHODS
  Steady-state free-precession cine MRI was performed on 100 randomly selected subjects. Myocardial borders were outlined on short-axis images using three methods: method 1 was computer assisted, excluding papillary muscles from the left ventricular mass (LVM); method 2 was similar but included papillary muscles; and method 3 was manually traced including papillary muscles. LV end-systolic (ES) and end-diastolic (ED) masses and volumes, ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were calculated from these measurements. The difference between the ES and ED LVM was used to estimate the exactness of the methods.
  
  
  RESULTS
  Method 3 was the most exact, and method 1 was the least exact. The three methods generated differing EF, SV, and CO measurements. With an ES-ED LVM difference exceeding 20 g, the mean SV measurement error was 8.8+/-3.6 ml.
  
  
  CONCLUSIONS
  Manual tracing proved more exact than computer-assisted quantification. Exactness had an impact on EF, SV, and CO measurements, and the ES-ED LVM difference can be used to identify assessments that would benefit from more exact segmentation.
authors: Department of Radiology, Uppsala University Hospital, Uppsala, Sweden. charlotte.ebeling_barbier@radiol.uu.se
authors: C Ebeling
authors: CE
authors: Barbier
authors: L
authors: L
authors: Johansson
authors: L
authors: L
authors: Lind
authors: H
authors: H
authors: Ahlström
authors: T
authors: T
authors: Bjerner
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis; D016277:Ventricular Function, Left