Quantification of left ventricular trabeculae using fractal analysis

Abstract

BackgroundLeft 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.MethodsFractal 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).ResultsIn 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).ConclusionsFD 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.

Fractal Analysis of Myocardial Trabeculations in 2547 Study Participants: Multi-Ethnic Study of Atherosclerosis

“…FD MaxApical are in arbitrary units. FD MaxApical reference ranges for BMI 30 kg/m 2 or greater (n = 163), 25 kg/m 2 or greater to less than 30 kg/m 2 (n = 206), and less than 25 kg/m 2 (n = 235) were 1.203 6 0.06 (95% confidence interval: 1.194, 1.212), 1.194 6 0.06 (95% confidence interval: 1.186, 1.202), and 1.169 6 0.05 (95% confidence interval: 1.162, 1.176), respectively. In the entire cohort, adjusted for anthropometrics, trabeculation was higher in African American participants (standardized b [sb] = 0.09; P  .001) and Hispanic participants (sb = 0.05; P = .013) compared with white participants and was also higher in African American participants compared with Chinese American participants (sb = 0.08; P = .01), and this persisted after adjustment for hypertension and LV size.…”

“…Validation experiments for the fractal method were Recent work by Zemrak et al (8) revealed statistically significant differences in BMI between quintiles of noncompacted severity measured by using the noncompacted-to-compacted ratio method. For this reason, all participants from within the entire cohort who did not have hypertension or LV hypertrophy, diabetes or impaired fasting glucose (11), and known cardiac disease or atrial fibrillation were further stratified by BMI into the following three reference groups: a reference group for BMI 30 kg/m 2 …”

“…; and manuscript editing, G.C., F.Z., V.M., S.E.P., P.B., N.K.B., W.J.M., P.M.E., J.A.C.L., D.A.B., J.C.M. A bnormal trabecular patterns of the ventricular myocardium coexist with established cardiac disease (1)(2)(3)(4)(5), and a spectrum of so-called normal trabeculation with interethnic differences has also been observed in healthy hearts (2,6). Because of this large variability, trabecular phenotypes are hard to measure, but the recently described (3) fractal method applied to cardiac magnetic resonance (MR) imaging provides a sensitive mathematical solution.…”

Noncompaction Cardiomyopathy

“…[87], по сравне-нию с обычными критериями магнитно-резонанс-ной томографии фрактальный анализ, обеспечивая количественную оценку трабекулярности, имеет более высокую воспроизводимость и точность при постановке диагноза НМЛЖ. Фрактальные разме-ры трабекулярности более высокие у пациентов с НМЛЖ по сравнению со здоровыми волонтерами.…”

“…Фрактальные разме-ры трабекулярности более высокие у пациентов с НМЛЖ по сравнению со здоровыми волонтерами. Они также более высокие у здоровых чернокожих, чем у белых волонтеров [87].…”