F. Szczepankiewicz, W. S. Hoge, and C. - F. Westin, “
Linear, planar and spherical tensor-valued diffusion MRI data by free waveform encoding in healthy brain, water, oil and liquid crystals,”
Data in Brief, vol. 25, pp. 104208, 2019.
Publisher's VersionAbstractPurpose
Quantitative parameter maps, as opposed to qualitative grayscale images, may represent the future of diagnostic MRI. A new quantitative MRI method is introduced here that requires a single 3D acquisition, allowing good spatial coverage to be achieved in relatively short scan times.
Methods
A multipathway multi‐echo sequence was developed, and at least 3 pathways with 2 TEs were needed to generate T1, T2, T2*, B1+, and B0 maps. The method required the central k‐space region to be sampled twice, with the same sequence but with 2 very different nominal flip angle settings. Consequently, scan time was only slightly longer than that of a single scan. The multipathway multi‐echo data were reconstructed into parameter maps, for phantom as well as brain acquisitions, in 5 healthy volunteers at 3 T. Spatial resolution, matrix size, and FOV were 1.2 × 1.0 × 1.2 mm3, 160 × 192 × 160, and 19.2 × 19.2 × 19.2 cm3 (whole brain), acquired in 11.5 minutes with minimal acceleration. Validation was performed against T1, T2, and T2* maps calculated from gradient‐echo and spin‐echo data.
Results
In Bland‐Altman plots, bias and limits of agreement for T1 and T2 results in vivo and in phantom were −2.9/±125.5 ms (T1 in vivo), −4.8/±20.8 ms (T2 in vivo), −1.5/±18.1 ms (T1 in phantom), and −5.3/±7.4 ms (T2 in phantom), for regions of interest including given brain structures or phantom compartments. Due to relatively high noise levels, the current implementation of the approach may prove more useful for region of interest–based as opposed to pixel‐based interpretation.
Conclusions
We proposed a novel approach to quantitatively map MR parameters based on a multipathway multi‐echo acquisition.
C. - C. Cheng, W. S. Hoge, T. - H. Kuo, and B. Madore, “
Multi-Pathway Multi-Echo (MPME) imaging: all main MR parameters mapped based on a single 3D scan,”
Magn Reson Med, vol. 81, no. 3, pp. 1699-1713, 2019.
Publisher's VersionAbstractPurpose: Quantitative parameter maps, as opposed to qualitative grayscale images, may
represent the future of diagnostic MRI. A new quantitative MRI method is introduced here that requires little more than a single 3D acquisition, allowing good spatial coverage to be achieved in relatively short scan times.
Methods: A multi-pathway multi-echo (MPME) sequence was developed, and at least three pathways with two echo times were needed to generate T1, T2, T2*, B1 and B0 maps. The method required the central k-space region to be sampled twice, with the same sequence but with two very different nominal flip angle settings. Consequently, scan time was only slightly longer than that of a single scan. MPME data were reconstructed into parameter maps, for phantom as well as brain acquisitions, in five healthy volunteers at 3T. Spatial resolution, matrix size and FOV were 1.2×1.0×1.2 mm3, 160×192×160 and 19.2×19.2×19.2 cm3 (whole brain), acquired in 11.5 min with minimal acceleration. Validation was performed against T1, T2 and T2* maps calculated from gradient-echo and spin-echo data.
Results: In Bland-Altman plots, bias and limits of agreement for T1 and T2 results in vivo and in phantom were: -2.9/±125.5ms (T1 in vivo), -4.8/±20.8ms (T2 in vivo), -1.5/±18.1ms (T1 in phantom), and -5.3/±7.4ms (T2 in phantom), for ROIs including given brain structures or phantom compartments.
Conclusions: We proposed a novel approach to quantitatively map MR parameters based on an MPME acquisition.