Rapid monitoring of iron‐chelating therapy in thalassemia major by a new cardiovascular MR measure: the reduced transverse relaxation rate
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| Title: | Rapid monitoring of iron‐chelating therapy in thalassemia major by a new cardiovascular MR measure: the reduced transverse relaxation rate |
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| Authors: | Feng, L, Au, WY, Cheung, JS, Ha, SY, Sheth, SS, Brittenham, GM, Wu, EX, Jensen, JH, Kim, D |
| Source: | NMR in Biomedicine. 24:771-777 |
| Publisher Information: | Wiley, 2010. |
| Publication Year: | 2010 |
| Subject Terms: | Chelation Therapy - Methods, Adult, Male, Adolescent, Myocardium, beta-Thalassemia, Myocardium - Metabolism, Hemosiderin, Iron Chelating Agents, Magnetic Resonance Imaging, Chelation Therapy, Beta-Thalassemia - Therapy, Hemosiderin - Metabolism, Young Adult, 03 medical and health sciences, Iron Chelating Agents - Therapeutic Use, Treatment Outcome, 0302 clinical medicine, Ferritins - Metabolism, Magnetic Resonance Imaging - Methods, Ferritins, Humans, Female |
| Description: | In iron overload, almost all the excess iron is stored intracellularly as rapidly mobilizable ferritin iron and slowly exchangeable hemosiderin iron. Increases in cytosolic iron may produce oxidative damage that ultimately results in cardiomyocyte dysfunction. Because intracellular ferritin iron is evidently in equilibrium with the low‐molecular‐weight cytosolic iron pool, measurements of ferritin iron potentially provide a clinically useful indicator of changes in cytosolic iron. The cardiovascular magnetic resonance (CMR) index of cardiac iron used clinically, the effective transverse relaxation rate (R 2*), is principally influenced by hemosiderin iron and changes only slowly over several months, even with intensive iron‐chelating therapy. Another conventional CMR index of cardiac iron, the transverse relaxation rate (R 2), is sensitive to both hemosiderin iron and ferritin iron. We have developed a new MRI measure, the ‘reduced transverse relaxation rate’ (RR 2), and have proposed in previous studies that this measure is primarily sensitive to ferritin iron and largely independent of hemosiderin iron in phantoms mimicking ferritin iron and human liver explants. We hypothesized that RR 2 could detect changes produced by 1 week of iron‐chelating therapy in patients with transfusion‐dependent thalassemia. We imaged 10 patients with thalassemia major at 1.5 T in mid‐ventricular short‐axis planes of the heart, initially after suspending iron‐chelating therapy for 1 week and subsequently after resuming oral deferasirox. After resuming iron‐chelating therapy, significant decreases were observed in the mean myocardial RR 2 (7.8%, p R 2 (5.5%, p R 2* (1.7%, p > 0.90). Although the difference between changes in RR 2 and R 2 was not significant (p > 0.3), RR 2 was consistently more sensitive than R 2 (and R 2*) to the resumption of iron‐chelating therapy, as judged by the effect sizes of relaxation rate differences detected. Although further studies are needed, myocardial RR 2 may be a promising investigational method for the rapid assessment of the effects of iron‐chelating therapy in the heart. Copyright © 2010 John Wiley & Sons, Ltd. |
| Document Type: | Article |
| Language: | English |
| ISSN: | 1099-1492 0952-3480 |
| DOI: | 10.1002/nbm.1639 |
| Access URL: | https://europepmc.org/articles/pmc3138893?pdf=render https://pubmed.ncbi.nlm.nih.gov/21190261 https://www.onlinelibrary.wiley.com/doi/full/10.1002/nbm.1639 https://europepmc.org/articles/PMC3138893 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3138893 https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/pdf/10.1002/nbm.1639 https://www.scholars.northwestern.edu/en/publications/rapid-monitoring-of-iron-chelating-therapy-in-thalassemia-major-b https://hub.hku.hk/handle/10722/155640 http://hdl.handle.net/10722/155640 |
| Rights: | Wiley Online Library User Agreement |
| Accession Number: | edsair.doi.dedup.....23f8101b7c9651c2ddbbde33d9d116c2 |
| Database: | OpenAIRE |
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Nájsť tento článok vo Web of Science | Abstract: | In iron overload, almost all the excess iron is stored intracellularly as rapidly mobilizable ferritin iron and slowly exchangeable hemosiderin iron. Increases in cytosolic iron may produce oxidative damage that ultimately results in cardiomyocyte dysfunction. Because intracellular ferritin iron is evidently in equilibrium with the low‐molecular‐weight cytosolic iron pool, measurements of ferritin iron potentially provide a clinically useful indicator of changes in cytosolic iron. The cardiovascular magnetic resonance (CMR) index of cardiac iron used clinically, the effective transverse relaxation rate (R 2*), is principally influenced by hemosiderin iron and changes only slowly over several months, even with intensive iron‐chelating therapy. Another conventional CMR index of cardiac iron, the transverse relaxation rate (R 2), is sensitive to both hemosiderin iron and ferritin iron. We have developed a new MRI measure, the ‘reduced transverse relaxation rate’ (RR 2), and have proposed in previous studies that this measure is primarily sensitive to ferritin iron and largely independent of hemosiderin iron in phantoms mimicking ferritin iron and human liver explants. We hypothesized that RR 2 could detect changes produced by 1 week of iron‐chelating therapy in patients with transfusion‐dependent thalassemia. We imaged 10 patients with thalassemia major at 1.5 T in mid‐ventricular short‐axis planes of the heart, initially after suspending iron‐chelating therapy for 1 week and subsequently after resuming oral deferasirox. After resuming iron‐chelating therapy, significant decreases were observed in the mean myocardial RR 2 (7.8%, p R 2 (5.5%, p R 2* (1.7%, p > 0.90). Although the difference between changes in RR 2 and R 2 was not significant (p > 0.3), RR 2 was consistently more sensitive than R 2 (and R 2*) to the resumption of iron‐chelating therapy, as judged by the effect sizes of relaxation rate differences detected. Although further studies are needed, myocardial RR 2 may be a promising investigational method for the rapid assessment of the effects of iron‐chelating therapy in the heart. Copyright © 2010 John Wiley & Sons, Ltd. |
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| ISSN: | 10991492 09523480 |
| DOI: | 10.1002/nbm.1639 |