Evaluation of Hepatic Iron Overload Using a Contemporary 0.55 T MRI System.
MRI
R2*
T2*
iron overload
low field
Journal
Journal of magnetic resonance imaging : JMRI
ISSN: 1522-2586
Titre abrégé: J Magn Reson Imaging
Pays: United States
ID NLM: 9105850
Informations de publication
Date de publication:
06 2022
06 2022
Historique:
revised:
19
09
2021
received:
13
07
2021
accepted:
23
09
2021
pubmed:
21
10
2021
medline:
18
5
2022
entrez:
20
10
2021
Statut:
ppublish
Résumé
MRI T2* and R2* mapping have gained clinical acceptance for noninvasive assessment of iron overload. Lower field MRI may offer increased measurement dynamic range in patients with high iron concentration and may potentially increase MRI accessibility, but it is compromised by lower signal-to-noise ratio that reduces measurement precision. To characterize a high-performance 0.55 T MRI system for evaluating patients with liver iron overload. Prospective. Forty patients with known or suspected iron overload (sickle cell anemia [n = 5], ß-thalassemia [n = 3], and hereditary spherocytosis [n = 2]) and a liver iron phantom. A breath-held multiecho gradient echo sequence at 0.55 T and 1.5 T. Patients were imaged with T2*/R2* mapping 0.55 T and 1.5 T within 24 hours, and 16 patients returned for follow-up exams within 6-16 months, resulting in 56 paired studies. Liver T2* and R2* measurements and standard deviations were compared between 0.55 T and 1.5 T and used to validate a predictive model between field strengths. The model was then used to classify iron overload at 0.55 T. Linear regression and Bland-Altman analysis were used for comparisons, and measurement precision was assessed using the coefficient of variation. A P-value < 0.05 was considered statistically significant. R2* was significantly lower at 0.55 T in our cohort (488 ± 449 s We demonstrated that 0.55 T provides T2* and R2* maps that can be used for the assessment of liver iron overload in patients. 2 TECHNICAL EFFICACY: Stage 2.
Sections du résumé
BACKGROUND
MRI T2* and R2* mapping have gained clinical acceptance for noninvasive assessment of iron overload. Lower field MRI may offer increased measurement dynamic range in patients with high iron concentration and may potentially increase MRI accessibility, but it is compromised by lower signal-to-noise ratio that reduces measurement precision.
PURPOSE
To characterize a high-performance 0.55 T MRI system for evaluating patients with liver iron overload.
STUDY TYPE
Prospective.
POPULATION
Forty patients with known or suspected iron overload (sickle cell anemia [n = 5], ß-thalassemia [n = 3], and hereditary spherocytosis [n = 2]) and a liver iron phantom.
FIELD STRENGTH/SEQUENCE
A breath-held multiecho gradient echo sequence at 0.55 T and 1.5 T.
ASSESSMENT
Patients were imaged with T2*/R2* mapping 0.55 T and 1.5 T within 24 hours, and 16 patients returned for follow-up exams within 6-16 months, resulting in 56 paired studies. Liver T2* and R2* measurements and standard deviations were compared between 0.55 T and 1.5 T and used to validate a predictive model between field strengths. The model was then used to classify iron overload at 0.55 T.
STATISTICAL TESTS
Linear regression and Bland-Altman analysis were used for comparisons, and measurement precision was assessed using the coefficient of variation. A P-value < 0.05 was considered statistically significant.
RESULTS
R2* was significantly lower at 0.55 T in our cohort (488 ± 449 s
DATA CONCLUSION
We demonstrated that 0.55 T provides T2* and R2* maps that can be used for the assessment of liver iron overload in patients.
EVIDENCE LEVEL
2 TECHNICAL EFFICACY: Stage 2.
Identifiants
pubmed: 34668604
doi: 10.1002/jmri.27950
pmc: PMC9018883
mid: NIHMS1770763
doi:
Substances chimiques
Iron
E1UOL152H7
Types de publication
Journal Article
Research Support, N.I.H., Intramural
Langues
eng
Sous-ensembles de citation
IM
Pagination
1855-1863Subventions
Organisme : Intramural NIH HHS
ID : ZIA HL006214
Pays : United States
Organisme : Intramural NIH HHS
ID : ZIA HL006257
Pays : United States
Informations de copyright
© 2021 International Society for Magnetic Resonance in Medicine. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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