T1 at 1.5T and 3T compared with conventional T2*at 1.5T for cardiac siderosis
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Author(s)
Type
Journal Article
Abstract
Background: Myocardial black blood (BB) T2* relaxometry at 1.5T provides robust, reproducible and calibrated
non-invasive assessment of cardiac iron burden. In vitro data has shown that like T2*, novel native Modified
Look-Locker Inversion recovery (MOLLI) T1 shortens with increasing tissue iron. The relative merits of T1 and
T2* are largely unexplored. We compared the established 1.5T BB T2* technique against native T1 values at
1.5T and 3T in iron overload patients and in normal volunteers.
Methods: A total of 73 subjects (42 male) were recruited, comprising 20 healthy volunteers (controls) and 53 patients
(thalassemia major 22, sickle cell disease 9, hereditary hemochromatosis 9, other iron overload conditions 13). Single
mid-ventricular short axis slices were acquired for BB T2* at 1.5T and MOLLI T1 quantification at 1.5T and 3T.
Results: In healthy volunteers, median T1 was 1014 ms (full range 939–1059 ms) at 1.5T and modestly increased to
1165ms (full range 1056–1224 ms) at 3T. All patients with significant cardiac iron overload (1.5T T2* values <20 ms) had
T1 values <939 ms at 1.5T, and <1056 ms at 3T. Associations between T2* and T1 were found to be moderate
with y =377 · x0.282 at 1.5T (R2 = 0.717), and y =406 · x0.294 at 3T (R2 = 0.715). Measures of reproducibility of T1
appeared superior to T2*.
Conclusions: T1 mapping at 1.5T and at 3T can identify individuals with significant iron loading as defined by
the current gold standard T2* at 1.5T. However, there is significant scatter between results which may reflect
measurement error, but it is also possible that T1 interacts with T2*, or is differentially sensitive to aspects of iron
chemistry or other biology. Hurdles to clinical implementation of T1 include the lack of calibration against human
myocardial iron concentration, no demonstrated relation to cardiac outcomes, and variation in absolute T1 values
between scanners, which makes inter-centre comparisons difficult. The relative merits of T1 at 3T versus T2* at 3T
require further consideration.
non-invasive assessment of cardiac iron burden. In vitro data has shown that like T2*, novel native Modified
Look-Locker Inversion recovery (MOLLI) T1 shortens with increasing tissue iron. The relative merits of T1 and
T2* are largely unexplored. We compared the established 1.5T BB T2* technique against native T1 values at
1.5T and 3T in iron overload patients and in normal volunteers.
Methods: A total of 73 subjects (42 male) were recruited, comprising 20 healthy volunteers (controls) and 53 patients
(thalassemia major 22, sickle cell disease 9, hereditary hemochromatosis 9, other iron overload conditions 13). Single
mid-ventricular short axis slices were acquired for BB T2* at 1.5T and MOLLI T1 quantification at 1.5T and 3T.
Results: In healthy volunteers, median T1 was 1014 ms (full range 939–1059 ms) at 1.5T and modestly increased to
1165ms (full range 1056–1224 ms) at 3T. All patients with significant cardiac iron overload (1.5T T2* values <20 ms) had
T1 values <939 ms at 1.5T, and <1056 ms at 3T. Associations between T2* and T1 were found to be moderate
with y =377 · x0.282 at 1.5T (R2 = 0.717), and y =406 · x0.294 at 3T (R2 = 0.715). Measures of reproducibility of T1
appeared superior to T2*.
Conclusions: T1 mapping at 1.5T and at 3T can identify individuals with significant iron loading as defined by
the current gold standard T2* at 1.5T. However, there is significant scatter between results which may reflect
measurement error, but it is also possible that T1 interacts with T2*, or is differentially sensitive to aspects of iron
chemistry or other biology. Hurdles to clinical implementation of T1 include the lack of calibration against human
myocardial iron concentration, no demonstrated relation to cardiac outcomes, and variation in absolute T1 values
between scanners, which makes inter-centre comparisons difficult. The relative merits of T1 at 3T versus T2* at 3T
require further consideration.
Date Issued
2015-11-24
Date Acceptance
2015-11-16
Citation
Journal of Cardiovascular Magnetic Resonance, 2015, 17
ISSN
1532-429X
Publisher
BioMed Central
Journal / Book Title
Journal of Cardiovascular Magnetic Resonance
Volume
17
Copyright Statement
© 2015 Alam et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
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Subjects
Science & Technology
Life Sciences & Biomedicine
Cardiac & Cardiovascular Systems
Radiology, Nuclear Medicine & Medical Imaging
Cardiovascular System & Cardiology
Cardiac siderosis
3 Tesla
T1 mapping
MOLLI
T2*
Cardiovascular magnetic resonance
CARDIOVASCULAR MAGNETIC-RESONANCE
BETA-THALASSEMIA MAJOR
IRON OVERLOAD
MYOCARDIAL IRON
CONSENSUS STATEMENT
TISSUE IRON
HEART
T2
REPRODUCIBILITY
FIBROSIS
Publication Status
Published
Article Number
102