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Article: Rapid monitoring of iron-chelating therapy in thalassemia major by a new cardiovascular MR measure: The reduced transverse relaxation rate

TitleRapid monitoring of iron-chelating therapy in thalassemia major by a new cardiovascular MR measure: The reduced transverse relaxation rate
Authors
Issue Date2011
PublisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/13087
Citation
NMR in Biomedicine, 2011, v. 24 n. 7, p. 771-777 How to Cite?
AbstractIn 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<0.01) and R 2 (5.5%, p<0.05), but not in 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. © 2010 John Wiley & Sons, Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/155640
ISSN
2015 Impact Factor: 2.983
2015 SCImago Journal Rankings: 1.533
PubMed Central ID
ISI Accession Number ID
Funding AgencyGrant Number
National Institutes of HealthR01 DK069373
R01 DK066251
R37 DK049108
American Heart Association0730143N
Hong Kong Research Grant CouncilGRF7794/07M
Hong Kong Children Thalassaemia Foundation2007/02
Funding Information:

The following organizations provided grant support: National Institutes of Health (R01 DK069373, R01 DK066251, R37 DK049108); American Heart Association (0730143N); Hong Kong Research Grant Council (GRF7794/07M); Hong Kong Children Thalassaemia Foundation (2007/02).

References

 

DC FieldValueLanguage
dc.contributor.authorKim, Den_US
dc.contributor.authorJensen, JHen_US
dc.contributor.authorWu, EXen_US
dc.contributor.authorFeng, Len_US
dc.contributor.authorAu, WYen_US
dc.contributor.authorCheung, JSen_US
dc.contributor.authorHa, SYen_US
dc.contributor.authorSheth, SSen_US
dc.contributor.authorBrittenham, GMen_US
dc.date.accessioned2012-08-08T08:34:37Z-
dc.date.available2012-08-08T08:34:37Z-
dc.date.issued2011en_US
dc.identifier.citationNMR in Biomedicine, 2011, v. 24 n. 7, p. 771-777en_US
dc.identifier.issn0952-3480en_US
dc.identifier.urihttp://hdl.handle.net/10722/155640-
dc.description.abstractIn 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<0.01) and R 2 (5.5%, p<0.05), but not in 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. © 2010 John Wiley & Sons, Ltd.en_US
dc.languageengen_US
dc.publisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/13087en_US
dc.relation.ispartofNMR in Biomedicineen_US
dc.subject.meshAdolescenten_US
dc.subject.meshAdulten_US
dc.subject.meshChelation Therapy - Methodsen_US
dc.subject.meshFemaleen_US
dc.subject.meshFerritins - Metabolismen_US
dc.subject.meshHemosiderin - Metabolismen_US
dc.subject.meshHumansen_US
dc.subject.meshIron Chelating Agents - Therapeutic Useen_US
dc.subject.meshMagnetic Resonance Imaging - Methodsen_US
dc.subject.meshMaleen_US
dc.subject.meshMyocardium - Metabolismen_US
dc.subject.meshTreatment Outcomeen_US
dc.subject.meshYoung Adulten_US
dc.subject.meshBeta-Thalassemia - Therapyen_US
dc.titleRapid monitoring of iron-chelating therapy in thalassemia major by a new cardiovascular MR measure: The reduced transverse relaxation rateen_US
dc.typeArticleen_US
dc.identifier.emailWu, EX:ewu1@hkucc.hku.hken_US
dc.identifier.authorityWu, EX=rp00193en_US
dc.description.naturelink_to_OA_fulltexten_US
dc.identifier.doi10.1002/nbm.1639en_US
dc.identifier.pmid21190261-
dc.identifier.pmcidPMC3138893-
dc.identifier.scopuseid_2-s2.0-80051583462en_US
dc.identifier.hkuros206806-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-80051583462&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume24en_US
dc.identifier.issue7en_US
dc.identifier.spage771en_US
dc.identifier.epage777en_US
dc.identifier.isiWOS:000294686900002-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridKim, D=8524290700en_US
dc.identifier.scopusauthoridJensen, JH=7404521984en_US
dc.identifier.scopusauthoridWu, EX=7202128034en_US
dc.identifier.scopusauthoridFeng, L=41761336100en_US
dc.identifier.scopusauthoridAu, WY=7202383089en_US
dc.identifier.scopusauthoridCheung, JS=16174280400en_US
dc.identifier.scopusauthoridHa, SY=7202501115en_US
dc.identifier.scopusauthoridSheth, SS=7102603512en_US
dc.identifier.scopusauthoridBrittenham, GM=36155186400en_US

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