Wideband myocardial T2 mapping with implantable cardiac device: A preliminary evaluation in healthy volunteers at 1.5 T
Author Block: P. Gut1, D. Kim2, H. Cochet3, F. Sacher3, P. Jais3, M. Stuber1, A. Bustin4; 1Lausanne/CH, 2Northwestern/US, 3Pessac/FR, 4Bordeaux/FR
Purpose: Myocardial T2 mapping allows assessment of myocardial inflammation and edema, but is impacted by artefacts related to implantable cardioverter defibrillators (ICDs), leading to image artifacts and inacurate T2 values. This study aimed to integrate a wideband T2 preparation into a T2 mapping sequence and evaluate its performance against conventional T2 mapping in healthy subjects with and without ICDs.
Methods or Background: Three short-axis slices covering the heart at the basal, mid-ventricular, and apical levels were acquired in eight healthy volunteers (2 females, age: 26±6y) at 1.5T (MAGNETOM Aera, Siemens) during end-expiration in mid-diastole using both conventional and wideband T2 mapping, with and without an ICD taped below the left clavicle (~10 cm from the heart).
The T2 preparation module (duration=0, 27, 55ms) included two adiabatic hyperbolic secant refocusing pulses of 1.6 kHz (conventional) and 5.0 kHz (wideband). Common parameters included: resolution=1.4mmx1.4mm, slice thickness=8mm, FA=15°, GRAPPA x2, partial Fourier phase 6/8, TE/TR=2.09/3.95ms, readout bandwidth=1221Hz/pixel, FOV=360mmx287mm, and gradient recalled-echo (GRE) readout.
T2 maps were reconstructed using a 2-parameter (M0 and T2) fitting model. Myocardial T2 values were manually extracted in 16 heart segments. Statistical analyses were performed using repeated measures ANOVA and Bonferroni correction.
Results or Findings: Without ICD, T2 values were not significantly different between conventional (mean: mean: 43.5, SD: 2.21) and wideband sequences (mean: 44.0, SD: 2.15) (P=0.111). With ICD, conventional T2 values significantly decreased (mean: 36.4, SD: 5.91) (P<0.01), especially in apical anterior, apical inferior, mid-ventricular anterior, and basal anterior segments. Wideband T2 values remained unchanged (mean: 42.7, SD: 1.91) (P=0.377).
Conclusion: Wideband T2 mapping effectively reduces ICD-related artifacts, providing more accurate myocardial T2 values than conventional T2 mapping.
Limitations: The study was conducted solely on healthy individuals. Validation in clinical populations is warrented.
Funding for this study: This research was supported by funding from the French National Research Agency under grant agreements Equipex MUSIC ANR-11-EQPX-0030, ANR-22-CPJ2-0009-01, ANR-21-CE17-0034-01, and Programme d’Investissements d’Avenir ANR-10-IAHU04-LIRYC, and from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement 101076351).
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: The study was approved by the Biomedical Research Ethics Committee and all participants provided informed consent for participation.