Quantitative T2* imaging of iron overload in a non-dedicated center – Normal variation, repeatability and reader variation

Abstract

Background: Patients with transfusion dependent anemia are at risk of complications from iron overload. Quantitative T2* magnetic resonance imaging (MRI) is the best non-invasive method to assess iron deposition in the liver and heart and to guide chelation therapy. Purpose: To investigate the image quality and inter-observer variations in T2* measurements of the myocardium and the liver, and to obtain the lower limit of cardiac and hepatic quantitative T2* values in patients without suspicion of iron overload. Material and methods: Thirty-eight patients referred for cardiac MRI were prospectively included in the study. Three patients were referred with, and 35 without suspicion of iron overload. Quantitative T2* parametric maps were obtained on a 1.5 T MRI system in the cardiac short axis and liver axial view. Two readers independently assessed the image quality and the representative and the lowest T2* value in the myocardium and the liver. Results: The normal range of representative T2* values in the myocardium and liver was 24−45 ms and 14−37 ms, respectively. None of the 35 participants (0 %, 95 % confidence interval 0–11 %) in the normal reference group demonstrated representative T2* values below previously reported lower limits in the myocardium (20 ms) or the liver (8 ms). Focal myocardial areas with T2* values near the lower normal range, 19−20 ms, were seen in two patients. The readers generally reported good image quality. Conclusion: T2* imaging for assessing iron overload can be performed in a non-dedicated center with sufficient image quality.

Keywords

• Quantitative MRI
• Iron overload
• T2 star
• Heart
• Liver
• Thalassemia