Volume 13 Supplement 1

Abstracts of the 2011 SCMR/Euro CMR Joint Scientific Sessions

Open Access

Cardiac T2* measurements in patients with iron overload: a comparison of imaging parameters and analysis techniques

  • Phalla Ou1,
  • Yansong Zhao2,
  • Sara El Fawal1,
  • Puja Banka1 and
  • Andrew J Powell1
Journal of Cardiovascular Magnetic Resonance201113(Suppl 1):P302

https://doi.org/10.1186/1532-429X-13-S1-P302

Published: 2 February 2011

Introduction

In patients at risk for iron overload, measurement of myocardial T2* has emerged as an important non-invasive tool to detect preclinical evidence of toxic levels and titrate chelation therapy. Nevertheless, there exists some variation among practitioners in cardiac T2* calculation methods.

Purpose

To examine the impact of different imaging parameters and data analysis techniques on the calculated cardiac R2* (1/T2*) in patients at risk for cardiac siderosis.

Methods

The study group consisted of 36 patients with thalassemia syndromes who had undergone clinical MRI assessment of cardiac siderosis using a standardized protocol and who were selected to yield a broad range of cardiac R2* values. Cardiac R2* measurements were performed on a 1.5 Tesla scanner using a ECG-gated, segmented, multiecho gradient echo sequence obtained in a single breath-hold. R2* was calculated from the signal intensity versus echo time data in the ventricular septum on a single mid-ventricular short-axis slice.

Results

There was excellent agreement between R2* measured with a blood suppression pre-pulse (black blood technique) and without (mean difference 6.0±10.7 Hz). The black blood technique had superior within study reproducibility (R2* mean difference 1.6±8.6 Hz versus 2.7±14.6 Hz) and better interobserver agreement (R2* mean difference 3.4±8.2 Hz versus 8.3±16.5 Hz). Using the same minimum TE, the use of small (1.0 ms) versus large (2.2 ms) echo spacing had minimal impact on cardiac R2* (mean difference 0.3±8.7 Hz). The application of a region of interest versus a pixel-based data analysis had little effect on cardiac R2* calculation (mean difference 8.4±6.9 Hz). With black blood images, fitting the signal curve to a monoexponetial decay or to a monoexponential decay with a constant offset yielded similar R2* values (mean difference 3.4±8.1 Hz). Figure 1.
Figure 1

Typical short-axis mid-ventricular cardiac T2* images from the first echo (TE 2.0 ms) without and with a blood suppression pre-pulse in the same patient. Below, signal intensity versus TE is plotted for a region of interest encompassing the ventricular septum (outlined in red) along with the decay curve fit to a monoexponential with a constant offset model.

Conclusions

The addition of a blood suppression pre-pulse for cardiac R2* measurement yields similar R2* values, and improves reproducibility and interoberver agreement. The findings regarding other variations may be helpful in establishing a broadly accepted imaging and analysis technique for cardiac R2* calculation.

Authors’ Affiliations

(1)
Children's Hospital Boston
(2)
Philips Healthcare

Copyright

© Powell et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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