Reduced transverse relaxation rate (RR2) for improved sensitivity in monitoring myocardial iron in thalassemia

Jerry S. Cheung, Wing Yan Au, Shau Yin Ha, Daniel Kim, Jens H. Jensen, Iris Y. Zhou, Matthew M. Cheung, Yin Wu, Hua Guo, Pek Lan Khong, Truman R. Brown, Gary M. Brittenham, Ed X. Wu

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Purpose: To evaluate the reduced transverse relaxation rate (RR2), a new relaxation index which has been shown recently to be primarily sensitive to intracellular ferritin iron, as a means of detecting short-term changes in myocardial storage iron produced by iron-chelating therapy in transfusion-dependent thalassemia patients. Materials and Methods: A single-breathhold multi-echo fast spin-echo sequence was implemented at 3 Tesla (T) to estimate RR2 by acquiring signal decays with interecho times of 5, 9 and 13 ms. Transfusion-dependent thalassemia patients (N = 8) were examined immediately before suspending iron-chelating therapy for 1 week (Day 0), after a 1-week suspension of chelation (Day 7), and after a 1-week resumption of chelation (Day 14). Results: The mean percent changes in RR2, R2, and R2* off chelation (between Day 0 and 7) were 11.9 ± 8.9%, 5.4 ± 7.7% and -4.4 ± 25.0%; and, after resuming chelation (between Day 7 and 14), -10.6 ± 13.9%, -8.9 ± 8.0% and -8.5 ± 24.3%, respectively. Significant differences in R2 and RR2 were observed between Day 0 and 7, and between Day 7 and 14, with the greatest proportional changes in RR2. No significant differences in R2* were found. Conclusion: These initial results demonstrate that significant differences in RR2 are detectable after a single week of changes in iron-chelating therapy, likely as a result of superior sensitivity to soluble ferritin iron, which is in close equilibrium with the chelatable cytosolic iron pool. RR2 measurement may provide a new means of monitoring the short-term effectiveness of iron-chelating agents in patients with myocardial iron overload.

Original languageEnglish (US)
Pages (from-to)1510-1516
Number of pages7
JournalJournal of Magnetic Resonance Imaging
Volume33
Issue number6
DOIs
StatePublished - Jun 2011

Keywords

  • MRI
  • RR2
  • cardiac MR
  • chelation therapy
  • ferritin
  • heart
  • hemosiderin
  • iron overload
  • thalassemia

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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