Premium
Automated T 2 * measurements using supplementary field mapping to assess cardiac iron content
Author(s) -
Taylor Brian A.,
Loeffler Ralf B.,
Song Ruitian,
McCarville Mary E.,
Hankins Jane S.,
Hillenbrand Claudia M.
Publication year - 2013
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.23990
Subject(s) - ventricle , voxel , coefficient of variation , nuclear medicine , autoregressive–moving average model , medicine , mathematics , autoregressive model , nuclear magnetic resonance , cardiology , statistics , physics , radiology
Purpose To develop and evaluate an algorithm that automatically identifies high‐susceptibility areas and excludes them from T 2 * measurements in the left ventricle (LV) for myocardial iron measurements. Materials and Methods An autoregressive moving average (ARMA) model was implemented on multigradient echo scans of 24 patients (age range 3–45 years, 10 male/14 female). Voxels with relatively high susceptibility (>3 Hz/mm) were flagged and deselected from the T 2 * calculations for iron quantification. The mean, standard deviation, and coefficient of variation (CoV) of the ARMA‐defined region were compared to the CoV of four distinct regions of the LV and the entire LV using a Student's t ‐test (α = 0.05). Results The CoV of T 2 * values obtained by the ARMA method are comparable with that in the interventricular septum (IS), where susceptibility was the lowest (CoV = 0.31). The ARMA method provides a greater area (51.9 ± 13.7% of the LV) to measure T 2 * than that using the IS alone (21.1 ± 3.4%, P < 0.0001). Areas where low susceptibility are measured corroborate with areas reported in previous studies that investigated T 2 * variations throughout the LV. Conclusion An automated method to measure T 2 * relaxation in the LV with minimal effects from susceptibility has been developed. Variability is reduced while covering more regions for cardiac T 2 * calculation. J. Magn. Reson. Imaging 2013;38:441–447. © 2012 Wiley Periodicals, Inc.