Magnetic Resonance Fingerprinting with Combined Gradient- and Spin-echo Echo-planar Imaging: Simultaneous Estimation of T1, T2 and T2* with integrated-B1 Correction

Abstract

Purpose: To introduce a novel magnetic-resonance fingerprinting (MRF) framework with single-shot echo-planar imaging (EPI) readout to simultaneously estimate tissue T2, T1 and T2*, and integrate B1 correction.Methods: Spin-echo EPI is combined with gradient-echo EPI to achieve T2 estimation as well as T1 and T2* quantification. In the dictionary matching step, the GE-EPI data segment provides estimates of tissue T1 and T2* with additional B1 information, which are then incorporated into the T2-matching step that uses the SE-EPI data segment. In this way, biases in T2 and T2* estimates do not affect each other.Results: An excellent correspondence was found between our T1, T2, and T2* estimates and results obtained from standard approaches in both phantom and human scans. In the phantom scan, a linear relationship with R 2 >0.96 was found for all parameter estimates. The maximum error in the T2 estimate was found to be below 6%. In the in-vivo scan, similar contrast was noted between MRF and standard approaches, and values found in a small region of interest (ROI) located in the grey matter (GM) were in line with previous measurements (T2 MRF =88±7ms vs T2 Ref =89±11ms, T1 MRF =1153±154ms vs T1 Ref =1122±52ms, T2* MRF =56±4ms vs T2* Ref =53±3ms).Conclusion: Adding a spin echo data segment to EPI based MRF allows accurate and robust measurements of T2, T1 and T2* relaxation times. This MRF framework is easier to implement than spiral-based MRF. It doesn't suffer from undersampling artifacts and seems to require a smaller dictionary size that can fasten the reconstruction process.

Analysing the effects of metallic biomaterial design and imaging sequences on MRI interpretation challenges due to image artefacts

“…An MRI sequence is a group of specified RF pulses that forms the k-space matrix and the image appearance. The imaging sequences which are called Spin Echo and Gradient Echo are commonly used in MRI scans to generate T1-weighted and T2weighted images [20,21]. While the T1-weighted image is based on the longitudinal relaxation time differences, the T2weighted image is based on the transverse relaxation time differences of the magnetic vector between the tissues and structures.…”

Magnetic resonance fingerprinting for simultaneous renal T1 and T2* mapping in a single breath‐hold

“…Imaging of the relaxation times , , has been achieved simultaneously with different acquisition and readout schemes. Its application is increasingly gaining clinical relevance . In MRF, unique fingerprints are generated by a pseudo‐random pulse design with varying flip angles, echo (TE), and repetition times (TR) to generate different sets of contrast weightings.…”

“…Its application is increasingly gaining clinical relevance. [1][2][3][4][5][6][7] In MRF, unique fingerprints are | 1941…”

Lesion probability mapping in MS patients using a regression network on MR Fingerprinting

“…[10,11] Rieger et al proposed an MRF method to quantify T 1 and T 2 * with an echo-planar imaging (EPI) readout, [12] which showed promising results in renal and neural applications. [13][14][15][16] The fact that only conventional undersampling factors lead to only slightly corrupted magnitude data reduces the time for reconstruction and increases its robustness. However, a major drawback of MRF is the tradeoff between reconstruction time and accuracy.…”