Browsing by Author "Jaubert, Olivier"
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- Item3D Cartesian fast interrupted steady-state (FISS) imaging(2019) Küstner, Thomas; Bustin, Aurélien; Jaubert, Olivier; Neji, Radhouene; Prieto Vásquez, Claudia; Botnar, René Michael
- Item3D whole-heart isotropic-resolution motion-compensated joint T-1/T(2)mapping and water/fat imaging(2020) Milotta, Giorgia; Bustin, Aurelien; Jaubert, Olivier; Neji, Radhouene; Prieto Vásquez, Claudia; Botnar, René MichaelPurpose To develop a free-breathing isotropic-resolution whole-heart joint T1 and T2 mapping sequence with Dixon-encoding that provides coregistered 3D T1 and T2 maps and complementary 3D anatomical water and fat images in a single ~9 min scan. Methods Four interleaved dual-echo Dixon gradient echo volumes are acquired with a variable density Cartesian trajectory and different preparation pulses: 1) inversion recovery-preparation, 2) and 3) no preparations, and 4) T2 preparation. Image navigators are acquired to correct each echo for 2D translational respiratory motion; the 8 echoes are jointly reconstructed with a low-rank patch-based reconstruction. A water/fat separation algorithm is used to obtain water and fat images for each acquired volume. T1 and T2 maps are generated by matching the signal evolution of the water images to a simulated dictionary. Complementary bright-blood and fat volumes for anatomical visualization are obtained from the T2-prepared dataset. The proposed sequence was tested in phantom experiments and 10 healthy subjects and compared to standard 2D MOLLI T1 mapping, 2D balance steady-state free precession T2 mapping, and 3D T2-prepared Dixon coronary MR angiography. Results High linear correlation was found between T1 and T2 quantification with the proposed approach and phantom spin echo measurements (y = 1.1 × −11.68, R2 = 0.98; and y = 0.85 × +5.7, R2 = 0.99). Mean myocardial values of T1/T2 = 1116 ± 30.5 ms/45.1 ± 2.38 ms were measured in vivo. Biases of T1/T2 = 101.8 ms/−0.77 ms were obtained compared to standard 2D techniques. Conclusion The proposed joint T1/T2 sequence permitted the acquisition of motion-compensated isotropic-resolution 3D T1 and T2 maps and complementary coronary MR angiography and fat volumes, showing promising results in terms of T1 and T2 quantification and visualization of cardiac anatomy and pericardial fat.
- ItemFree-running 3D whole heart myocardial T-1 mapping with isotropic spatial resolution(2019) Qi, Haikun; Jaubert, Olivier; Bustin, Aurélien; Cruz, Gastao; Chen, Huijun; Botnar, René Michael; Prieto Vásquez, Claudia
- ItemFree-running simultaneous myocardial T1/T2 mapping and cine imaging with 3D whole-heart coverage and isotropic spatial resolution(2019) Qi, Haikun; Bustin, Aurélien; Cruz, Gastao; Jaubert, Olivier; Chen, Huijun; Botnar, René Michael; Prieto Vásquez, Claudia
- ItemFully self-gated free-running 3D Cartesian cardiac CINE with isotropic whole-heart coverage in less than 2 min(2021) Küstner, Thomas; Bustin, Aurelien; Jaubert, Olivier; Hajhosseiny, Reza; Masci, Pier Giorgio; Neji, Radhouene; Botnar, René Michael; Prieto Vásquez, Claudia
- ItemGeneralized low-rank nonrigid motion-corrected reconstruction for MR fingerprinting(WILEY, 2021) Cruz, Gastao; Qi, Haikun; Jaubert, Olivier; Kuestner, Thomas; Schneider, Torben; Michael Botnar, Rene; Prieto, ClaudiaPurpose: Develop a novel low-rank motion-corrected (LRMC) reconstruction for nonrigid motion-corrected MR fingerprinting (MRF).
- ItemHigh-Spatial-Resolution 3D Whole-Heart MRI T2 Mapping for Assessment of Myocarditis(2021) Bustin, Aurélien; Hua, Alina; Milotta, Giorgia; Jaubert, Olivier; Hajhosseiny, Reza; Ismail, Tevfik F.; Botnar, René Michael; Prieto Vásquez, ClaudiaBackground: Clinical guidelines recommend the use of established T2 mapping sequences to detect and quantify myocarditis and edema, but T2 mapping is performed in two dimensions with limited coverage and repetitive breath holds.Purpose:To assess the reproducibility of an accelerated free-breathing three-dimensional (3D) whole-heart T2 MRI mapping se-quence in phantoms and participants without a history of cardiac disease and to investigate its clinical performance in participants with suspected myocarditis.Materials and Methods: Eight participants (three women, mean age, 31 years 6 4 [standard deviation]; cohort 1) without a history of cardiac disease and 25 participants (nine women, mean age, 45 years 6 17; cohort 2) with clinically suspected myocarditis underwent accelerated free-breathing 3D whole-heart T2 mapping with 100% respiratory scanning efficiency at 1.5 T. The participants were enrolled from November 2018 to August 2020. Three repeated scans were performed on 2 separate days in cohort 1. Segmental variations in T2 relaxation times of the left ventricular myocardium were assessed, and intrasession and intersession reproducibility were measured. In cohort 2, segmental myocardial T2 values, detection of focal inflammation, and map quality were compared with those obtained from clinical breath-hold two-dimensional (2D) T2 mapping. Statistical differences were assessed using the nonparametric Mann-Whitney and Kruskal-Wallis tests, whereas the paired Wilcoxon signed-rank test was used to assess subjective scores.Results: Whole-heart T2 maps were acquired in a mean time of 6 minutes 53 seconds 6 1 minute 5 seconds at 1.5 mm3 resolution. Breath-hold 2D and free-breathing 3D T2 mapping had similar intrasession (mean T2 change of 3.2% and 2.3% for 2D and 3D, respectively) and intersession (4.8% and 4.9%, respectively) reproducibility. The two T2 mapping sequences showed similar map quality (P = .23, cohort 2). Abnormal myocardial segments were identified with confidence (score 3) in 14 of 25 participants (56%) with 3D T2 mapping and only in 10 of 25 participants (40%) with 2D T2 mapping.Conclusion: High-spatial-resolution three-dimensional (3D) whole-heart T2 mapping shows high intrasession and intersession repro-ducibility and helps provide T2 myocardial characterization in agreement with clinical two-dimensional reference, while enabling 3D assessment of focal disease with higher confidence.
- ItemMyocardial T1, T2, T2*, and fat fraction quantification via low-rank motion-corrected cardiac MR fingerprinting(WILEY, 2022) da Cruz, Gastao Jose Lima; Velasco, Carlos; Lavin, Begona; Jaubert, Olivier; Michael Botnar, Rene; Prieto, ClaudiaPurpose Develop a novel 2D cardiac MR fingerprinting (MRF) approach to enable simultaneous T1, T2, T2*, and fat fraction (FF) myocardial tissue characterization in a single breath-hold scan. Methods Simultaneous, co-registered, multi-parametric mapping of T1, T2, and FF has been recently achieved with cardiac MRF. Here, we further incorporate T2* quantification within this approach, enabling simultaneous T1, T2, T2*, and FF myocardial tissue characterization in a single breath-hold scan. T2* quantification is achieved with an eight-echo readout that requires a long cardiac acquisition window. A novel low-rank motion-corrected (LRMC) reconstruction is exploited to correct for cardiac motion within the long acquisition window. The proposed T1/T2/T2*/FF cardiac MRF was evaluated in phantom and in 10 healthy subjects in comparison to conventional mapping techniques. Results The proposed approach achieved high quality parametric mapping of T1, T2, T2*, and FF with corresponding normalized RMS error (RMSE) T1 = 5.9%, T2 = 9.6% (T2 values <100 ms), T2* = 3.3% (T2* values <100 ms), and FF = 0.8% observed in phantom scans. In vivo, the proposed approach produced higher left-ventricular myocardial T1 values than MOLLI (1148 vs 1056 ms), lower T2 values than T2-GraSE (42.8 vs 50.6 ms), lower T2* values than eight-echo gradient echo (GRE) (35.0 vs 39.4 ms), and higher FF values than six-echo GRE (0.8 vs 0.3 %) reference techniques. The proposed approach achieved considerable reduction in motion artifacts compared to cardiac MRF without motion correction, improved spatial uniformity, and statistically higher apparent precision relative to conventional mapping for all parameters. Conclusion The proposed cardiac MRF approach enables simultaneous, co-registered mapping of T1, T2, T2*, and FF in a single breath-hold for comprehensive myocardial tissue characterization, achieving higher apparent precision than conventional methods.
- ItemSimultaneous comprehensive liver T1, T2, , T1ρ, and fat fraction characterization with MR fingerprinting(2022) Velasco, Carlos; Cruz, Gastão; Jaubert, Olivier; Lavin, Begoña; Botnar, René Michael; Prieto Vásquez, ClaudiaPurpose: To develop a novel simultaneous co-registered T1, T2, urn:x-wiley:07403194:media:mrm29089:mrm29089-math-0811, T1ρ, and fat fraction abdominal MR fingerprinting (MRF) approach for fully comprehensive liver-tissue characterization in a single breath-hold scan. Methods: A gradient-echo liver MRF sequence with low fixed flip angle, multi-echo radial readout, and varying magnetization preparation pulses for multiparametric encoding is performed at 1.5 T. The urn:x-wiley:07403194:media:mrm29089:mrm29089-math-0011 and fat fraction are estimated from a graph/cut water/fat separation method using a six-peak fat model. Water/fat singular images obtained are then matched to an MRF dictionary, estimating water-specific T1, T2, and T1ρ. The proposed approach was tested in phantoms and 10 healthy subjects and compared against conventional sequences. Results: For the phantom studies, linear fits show excellent coefficients of determination (r2 > 0.9) for every parametric map. For in vivo studies, the average values measured within regions of interest drawn on liver, spleen, muscle, and fat are statistically different from the reference scans (p < 0.05) for T1, T2, and T1⍴ but not for urn:x-wiley:07403194:media:mrm29089:mrm29089-math-0012 and fat fraction, whereas correlation between MRF and reference scans is excellent for each parameter (r2 > 0.92 for every parameter). Conclusion: The proposed multi-echo inversion-recovery, T2, and T1⍴ prepared liver MRF sequence presented in this work allows for quantitative T1, T2, urn:x-wiley:07403194:media:mrm29089:mrm29089-math-0013, T1⍴, and fat fraction liver-tissue characterization in a single breath-hold scan of 18 seconds. The approach showed good agreement and correlation with respect to reference clinical maps.