Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls

Abstract

Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* < 20 ms) in comparison with those without had significantly lower mean myocardial T1 times (868.9 ± 120.2 vs. 1170.3 ± 25.0 ms P = 0.005 respectively) and T2 times (34.9 ± 4.7 vs. 45.1 ± 2.0 ms P = 0.007 respectively). 3 T T1 and T2 times strongly correlated with 1.5 T, T2* times (Pearson's r = 0.95 and 0.91 respectively). T1 and T2 measures presented less variability than T2* in inter- and intra-observer analysis. Native myocardial T1 and T2 times at 3 T correlate closely with T2* times at 1.5 T and may be useful for myocardial iron overload quantification.

Native T1 reference values for nonischemic cardiomyopathies and populations with increased cardiovascular risk: A systematic review and meta‐analysis

“…T 1 mapping has numerous MRI-dependent and methodological factors that can influence the final T 1 values. 58 The field strength and sequence are two of these factors, but this meta-analysis shows that they do not influence the SMD, even though the T 1 values at 3T are overall 100msec higher than at 1.5T. More research towards understanding the effect on accuracy, precision, and reproducibility of T 1 mapping is needed.…”

“…. A total of ten studies were included for the HCM group, nine for DCM, twelve in MC, five in iron overload, six in amyloidosis, two in Fabry disease, ten in HT, four in DM, and one in obesity (Table ). The field strength is known to influence the T 1 values significantly; therefore, results from studies performed on a 1.5T or 3T are shown separately, but used as covariant in the meta‐regression analysis.…”

“…In addition, the postprocessing of the T 1 map can also introduce bias, errors, and loss of precision, particularly in protocols using regional regions of interest (ROIs), image segmentation, variable slice orientations . Almost half of the included studies used ROIs to determine the T 1 . Conversely, Moon et al recommended global myocardial T 1 measurements.…”

“…21 Almost half of the included studies used ROIs to determine the T 1 . 32,35,[38][39][40][41][42]45,49,51,[53][54][55][57][58][59][60][61][62]66,[68][69][70][71] Conversely, Moon et al 21 recommended global myocardial T 1 measurements. Puntmann et al clearly showed the importance of this in their studies on DCM patients.…”

T1 mapping in cardiac MRI

“…T 1 mapping has potential here as well and can serve as a complementary tool [76]. Native myocardial T 1 correlates well with T 2 * but has the added advantage of greater reproducibility and sensitivity, and it can detect lower myocardial iron levels potentially missed by T 2 * [34, 42, 77–79]. In thalassemia major, for example, native T 1 detected cardiac iron overload in a third of cases missed by T 2 * [76].…”