- Poster presentation
- Open Access
High-resolution modified look-locker inversion recovery (HR-MOLLI) for RV extracellular volume fraction at 3T and 1.5T: A feasibility study
© Semaan et al.; licensee BioMed Central Ltd. 2014
- Published: 16 January 2014
- Interobserver Variance
- Gadobenate Dimeglumine
- Extracellular Volume Fraction
- MOLLI Sequence
- Motion Corrected Image
Cardiac MR (CMR) is the reference standard for assessing macroscopic myocardial scar. Determination of the extracellular volume fraction (ECV) by T1 estimation using the modified Look-Locker inversion recovery (MOLLI) correction enables quantitation of diffuse fibrosis. The purpose of this study is to evaluate the feasibility and reproducibility of an optimized high-resolution MOLLI (HR-MOLLI) technique at 3T and 1.5T for RV ECV calculation in healthy volunteers.
25 healthy volunteers (16 males, 41 ± 14.3 yrs) were scanned at 3T (MAGNETOM Skyra, Siemens AG, Healthcare Sector, Erlangen, Germany) and 15 (11 males, 46.4 ± 13.5 yrs) were scanned at 1.5T (MAGNETOM Aera). T1 mapping was performed in the axial orientation using an investigational HR-MOLLI technique with a 1 × 1 mm 2 in-plane resolution that applies motion correction with synthetic image estimation. Motion corrected images were used to generate parametric maps with (T1) and without (T1*) the MOLLI correction. The MOLLI sequence uses a 5 heart-beat (HB) acquisition, 3 HB recovery, 3 HB acquisition scheme with a single shot bSSFP diastolic readout. Images were acquired pre- and 10-25 minutes post- administration of 0.2 mmol/kg gadobenate dimeglumine (Multihance, Bracco Diagnostics, Monroe, NJ). T1 and T1* parametric maps were used to quantify the T1 of tissue and blood, respectively. Two reviewers quantified basal and mid RV free wall, interventricular septal, and lateral LV wall T1 values on T1 parametric maps. RV and LV ECV ranges were calculated assuming normal hematocrit values (women: 0.38-0.46, men: 0.42-0.54). Global ventricular ECV values were compared using the student's t-test. Intra and inter-observer variance was measured by the intraclass correlation coefficient (ICC).
Global RV and LV ECV ranges at 3T and 1.5T as determined using T1 BP values from either the RV or LV on T1 and T1* parametric maps.
T1 BP Estimate
This feasibility study demonstrates that HR-MOLLI can quantitate the global RV ECV fraction at both 1.5 and 3T with good intra- and interobserver variance. Our results demonstrated a field-strength influence on RV and LV ECV values, and showed that ECV calculations using blood pool extimates without a look-locker correction are necessary at 3T.
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