MRI T2* imaging for assessment of liver iron overload: study of different data analysis approaches. Acta Radiol 2016 Dec;57(12):1453-1459
Date
02/11/2016Pubmed ID
26861202DOI
10.1177/0284185116628337Scopus ID
2-s2.0-84995553841 (requires institutional sign-in at Scopus site) 8 CitationsAbstract
Background Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2* in the liver. Purpose To investigate the effects of various factors associated with T2* calculation on the resulting measurement and to determine the analysis criterion that provides the most accurate T2* measurements. Material and Methods Both phantom and in vivo MRI experiments were conducted to study the effects of the selected region of interest (ROI) location and size, signal-averaging method, exponential-fitting model, echo truncation, iron-overload severity, and inter-/intra-observer variabilities on T2* measurements. The results were compared to reference values from the scanner processing software. Results The pixel-by-pixel calculation method provided results in better agreement with the reference values from the MRI scanner than the average or median methods. The choice of the exponential fitting model affected the results, depending on signal-to-noise ratio, number of echoes, minimum and maximum echo times, and tissue composition inside the selected ROI. The single-exponential model resulted in smaller error than the bi-exponential or exponential-plus-constant models, where the latter two models showed similar results. The relative performance of the different models and methods was not affected by the degree of iron-overload. Conclusion Various factors associated with the adopted T2* calculation method affect the resulting measurement. In this study, the pixel-by-pixel calculation method and single-exponential model provided the most accurate results based on the conducted phantom and in vivo MRI experiments.
Author List
Ibrahim EH, Khalifa AM, Eldaly AKMESH terms used to index this publication - Major topics in bold
AdultFemale
Humans
Iron Overload
Liver
Magnetic Resonance Imaging
Male
Observer Variation
Phantoms, Imaging
Reproducibility of Results
Severity of Illness Index
Signal-To-Noise Ratio