On using T2 to assess extrinsic magnetic field inhomogeneity effects on T2* measurements in myocardial siderosis in thalassemia
✍ Scribed by Taigang He; Gillian C. Smith; Peter D. Gatehouse; Raad H. Mohiaddin; David N. Firmin; Dudley J. Pennell
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 353 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
Magnetic resonance T~2~* has been validated as a noninvasive means of assessing myocardial iron overload. However, the effect on myocardial T~2~* of factors such as shimming, variations in capillary geometry, and susceptibility in relation to the effects of iron has not been fully clarified. Since T~2~ is not affected by extrinsic magnetic field inhomogeneity and has different sensitivity to capillary geometry, investigation into the in vivo relationship between myocardial T~2~* and T~2~ measurements can shed light on this important issue. This study was performed in 136 thalassemia patients. The myocardial T~2~ and T~2~* thresholds for normality created identical no‐iron‐overload and iron‐overloaded patient groups. In the no‐iron group, there was no correlation between myocardial T~2~ and T~2~*. In the iron‐overloaded patients, there was a linear correlation (R^2^ = 0.89) between myocardial T~2~* and T~2~ measurements, which indicates that the iron deposition is the dominant factor in determining these two relaxation values in this scenario. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.