Comparison of 3 T and 1.5 T for T2∗magnetic resonance of tissue iron

Background: t2∗magnetic resonance of tissue iron concentration has improved the outcome of transfusion dependant anaemia patients. clinical evaluation is performed at 1.5 t but scanners operating at 3 t are increasing in numbers. there is a paucity of data on the relative merits of iron quantification at 3 t vs 1.5 t. methods: a total of 104 transfusion dependent anaemia patients and 20 normal volunteers were prospectively recruited to undergo cardiac and liver t2∗assessment at both 1.5 t and 3 t. intra-observer,inter-observer and inter-study reproducibility analysis were performed on 20 randomly selected patients for cardiac and liver t2∗. results: association between heart and liver t2∗at 1.5 t and 3 t was non-linear with good fit (r 2 = 0.954,p < 0.001 for heart white-blood (wb) imaging; r 2 = 0.931,p < 0.001 for heart black-blood (bb) imaging; r 2 = 0.993,p < 0.001 for liver imaging). r2∗approximately doubled between 1.5 t and 3 t with linear fits for both heart and liver (94,94 and 105 % respectively). coefficients of variation for intra- and inter-observer reproducibility,as well as inter-study reproducibility trended to be less good at 3 t (3.5 to 6.5 %) than at 1.5 t (1.4 to 5.7 %) for both heart and liver t2∗. artefact scores for the heart were significantly worse with the 3 t bb sequence (median 4,iqr 2-5) compared with the 1.5 t bb sequence (4 [3-5],p = 0.007). conclusion: heart and liver t2∗and r2∗at 3 t show close association with 1.5 t values,but there were more artefacts at 3 t and trends to lower reproducibility causing difficulty in quantifying low t2∗values with high tissue iron. therefore t2∗imaging at 1.5 t remains the gold standard for clinical practice. however,in centres where only 3 t is available,equivalent values at 1.5 t may be approximated by halving the 3 t tissue r2∗with subsequent conversion to t2∗. © 2016 the author(s).