| Autor: |
Bidhult, Sebastian, Xanthis, Christos G., Liljekvist, Love Lindau, Greil, Gerald, Nagel, Eike, Aletras, Anthony H., Heiberg, Einar, Hedström, Erik |
| Zdroj: |
Magnetic Resonance in Medicine; Apr2016, Vol. 75 Issue 4, p1717-1729, 13p |
| Abstrakt: |
Purpose: To validate an automatic algorithm for offline T2* measurements, providing robust, vendor-independent T2*, and uncertainty estimates for iron load quantification in the heart and liver using clinically available imaging sequences. Methods: A T2* region of interest (ROI)-based algorithm was developed for robustness in an offline setting. Phantom imaging was performed on a 1.5 Tesla system, with clinically available multiecho gradient-recalled-echo (GRE) sequences for cardiac and liver imaging. A T2* single-echo GRE sequence was used as reference. Simulations were performed to assess accuracy and precision from 2000 measurements. Interand intraobserver variability was obtained in a patient study (n=23). Results: Simulations: Accuracy, in terms of the mean differences between the proposed method and true T2* ranged from 0-0.73 ms. Precision, in terms of confidence intervals of repeated measurements, was 0.06-4.74 ms showing agreement between the proposed uncertainty estimate and simulations. Phantom study: Bias and variability were 0.2664.23 ms (cardiac sequence) and -0.23±1.69 ms (liver sequence). Patient study: Intraobserver variability was similar for experienced and inexperienced observers (0.03±1.44 ms versus 0.16±2.33 ms). Interobserver variability was 1.0±3.77 ms for the heart and -0.52±2.75 ms for the liver. Conclusion: The proposed algorithm was shown to provide robust T2* measurements and uncertainty estimates over the range of clinically relevant T2* values. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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