Myocardial T1, T2, T2*, and fat fraction quantification via low‐rank motion‐corrected cardiac MR fingerprinting

Abstract

Purpose 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.

Free‐breathing, non‐ECG, simultaneous myocardial T1, T2, T2*, and fat‐fraction mapping with motion‐resolved cardiovascular MR multitasking

“…Conventional single parametric cardiac mapping requires multiple breath-hold scans, [16][17][18] leading to long scan times, potential image misregistration, and patient fatigue. Advanced techniques including 2D T 1 /T 2 /FF mapping 43 and T 1 /T 2 /T 2 */FF mapping 49 with a single breath-hold and free-breathing multiparametric mapping techniques such as 3D T 1 /T 2 mapping 23 and 2D T 1 /T 2 /T 2 * mapping 21 have been developed. However, ECG signal is still required to deal with cardiac motion, which is prone to noise and errors particularly at high field strengths 26 and may fail in arrhythmia patients.…”

Cardiac MRF using rosette trajectories for simultaneous myocardial T1, T2, and proton density fat fraction mapping

“…Given the multi-echo acquisition nature of rosette trajectories, quantification in the heart and liver has been shown feasible using rosette trajectories ( 33 ). Even though the current study did not aim at quantification and thus used a relatively short rosette readout, future work will explore the quantification of T 1 , T 2 , and PDFF simultaneously using either a long rosette readout ( 34 ) or multi-echo radial readout ( 35 ) in the MRF framework.…”

Quantitative MRI in cardiometabolic disease: From conventional cardiac and liver tissue mapping techniques to multi-parametric approaches

“…Hamilton et al (131) proposed for the first time the application of the MRF framework for an ECG-trigged scan for simultaneous T 1 , T 2 and M 0 characterization of myocardial tissue. However, given the high flexibility that MRF provides for the extension of the sequence to encode additional parameters, several works have been proposed to extend cardiac MRF to multiparametric assessment, including simultaneous cardiac T 1 /T 2 maps and PDFF, simultaneous T 1 , T 2 and T1ρ cardiac MRF and simultaneous T 1 , T 2 , PDFF and T 2 * acquisition (132) (133,134). Some of these approaches have been evaluated in healthy subjects (135,136) and small patient cohorts (137) (138) (139).…”