Simultaneous comprehensive liver T₁, T₂, , T_1ρ, and fat fraction characterization with MR fingerprinting

Abstract

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, multiecho radial readout, and varying magnetization preparation pulses for multiparametric encoding is performed at 1.5 T. The T * 2 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 T 1 , T 2 , and T 1ρ . 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 (r 2 > 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

Imaging Methods: Magnetic Resonance Imaging

“…The "fingerprint" of every voxel is then compared against all entries included in the dictionary by pattern matching (eg, dot product or least square), to estimate the parameter combination that best represents the measured signal evolution. 49 Magnetic resonance multitasking is an alternative paradigm that can also provide multiparametric imaging. This technique captures cardiac motion, respiratory motion and relaxation parameters continuously, and can resolve the overlapping dynamics without the use of ECG triggering or breath holds.…”

“…The “fingerprint” of every voxel is then compared against all entries included in the dictionary by pattern matching (eg, dot product or least square), to estimate the parameter combination that best represents the measured signal evolution. 49…”

Magnetic Resonance Fingerprinting

“…111 This framework was later expanded to also include simultaneous T1rho mapping, given evidence that T1rho can play a role in liver fibrosis assessment. 117,118 Velasco et al 112 found that simultaneous mapping of T1, T2, T2*, T1rho, and FF again provided comparable measurements to conventional techniques in phantoms and was feasible in vivo with excellent output of high-quality reconstructed maps. More recently, Fujita et al 13 validated MRF-derived simultaneous T1, T2, T2*, and FF maps by comparing to reference maps and to biopsy histopathology.…”

“…Image acquisition variability and reader experience remain sources for inhomogeneity in the care received by patients in centers around the world. There is evidence that quantitative parameters can be measured for various imaging findings in the abdomen, can be used in characterization of liver disease, and can be used for therapeutic response assessment 13,104–115 . Magnetic resonance fingerprinting provides a simultaneous multiparametric rapid quantitative analysis that could be highly valuable to abdominal organ assessment.…”

Efficient performance analysis and optimization of transient‐state sequences for multiparametric magnetic resonance imaging

“…By combining multiple steady‐state acquisitions, quantitative information regarding several tissue properties can be extracted. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 However, these steady‐state approaches require a multiplicity of scans or scan‐segments, leading to scan times that are too long for clinical practice. Transient‐state sequences may overcome this downside.…”