title: Quantification of left ventricular trabeculae using fractal analysis.
abstract: BACKGROUND
  Left ventricular noncompaction (LVNC) is a myocardial disorder characterized by excessive left ventricular (LV) trabeculae. Current methods for quantification of LV trabeculae have limitations. The aim of this study is to describe a novel technique for quantifying LV trabeculation using cardiovascular magnetic resonance (CMR) and fractal geometry. Observing that trabeculae appear complex and irregular, we hypothesize that measuring the fractal dimension (FD) of the endocardial border provides a quantitative parameter that can be used to distinguish normal from abnormal trabecular patterns.
  
  
  METHODS
  Fractal analysis is a method of quantifying complex geometric patterns in biological structures. The resulting FD is a unitless measure index of how completely the object fills space. FD increases with increased structural complexity. LV FD was measured using a box-counting method on CMR short-axis cine stacks. Three groups were studied: LVNC (defined by Jenni criteria), n=30(age 41±13; men, 16); healthy whites, n=75(age, 46±16; men, 36); healthy blacks, n=30(age, 40±11; men, 15).
  
  
  RESULTS
  In healthy volunteers FD varied in a characteristic pattern from base to apex along the LV. This pattern was altered in LVNC where apical FD were abnormally elevated. In healthy volunteers, blacks had higher FD than whites in the apical third of the LV (maximal apical FD: 1.253±0.005 vs. 1.235±0.004, p<0.01) (mean±s.e.m.). Comparing LVNC with healthy volunteers, maximal apical FD was higher in LVNC (1.392±0.010, p<0.00001). The fractal method was more accurate and reproducible (ICC, 0.97 and 0.96 for intra and inter-observer readings) than two other CMR criteria for LVNC (Petersen and Jacquier).
  
  
  CONCLUSIONS
  FD is higher in LVNC patients compared to healthy volunteers and is higher in healthy blacks than in whites. Fractal analysis provides a quantitative measure of trabeculation and has high reproducibility and accuracy for LVNC diagnosis when compared to current CMR criteria.
authors.affiliation: Division of Cardiovascular Imaging, The Heart Hospital, part of University College London NHS Foundation Trust, 16-18 Westmoreland Street, London, W1G 8PH, UK.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Captur
authors.forename: Vivek
authors.initials: V
authors.lastname: Muthurangu
authors.forename: Christopher
authors.initials: C
authors.lastname: Cook
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Flett
authors.forename: Robert
authors.initials: R
authors.lastname: Wilson
authors.forename: Andrea
authors.initials: A
authors.lastname: Barison
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sado
authors.forename: Sarah
authors.initials: S
authors.lastname: Anderson
authors.forename: William J
authors.initials: WJ
authors.lastname: McKenna
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Mohun
authors.forename: Perry M
authors.initials: PM
authors.lastname: Elliott
authors.forename: James C
authors.initials: JC
authors.lastname: Moon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044383:Black People / Q000706:statistics & numerical data; D016009:Chi-Square Distribution; D004452:Echocardiography; D017709:Fractals; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D056830:Isolated Noncompaction of the Ventricular Myocardium / Q000208:ethnology / Q000473:pathology*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000208:ethnology / Q000473:pathology*; D044465:White People / Q000706:statistics & numerical data