Spin and Gradient Multiple Overlapping-Echo Detachment Imaging (SAGE-MOLED): Highly Efficient T2, T 2 * $$ {T}_2^{\ast } $$ , and M0 Mapping for Simultaneous Perfusion and Permeability Measurements.

Journal: Magnetic resonance in medicine
Published Date: Nov 2, 2025

Abstract

PURPOSE: Combined spin- and gradient-echo EPI (SAGE-EPI) offers advantages in tissue quantification and dynamic imaging but suffers from low spatial resolution and geometric distortions. This study aims to develop a multiple overlapping-echo detachment-based SAGE acquisition (SAGE-MOLED) to enable efficient, distortion-corrected T2, T 2 * $$ {T}_2^{\ast } $$ , and M0 mapping for perfusion MRI. METHODS: SAGE-MOLED was designed as an optimized MOLED variant by refining echo time sampling and integrating multi-train blip-reversed EPI to enhance distortion correction and temporal SNR, enabling reliable extraction of subject-specific arterial input functions (AIFs). To support dynamic imaging, a steady-state Bloch simulation-based synthetic data framework was developed to simultaneously model T1, T2, and T 2 * $$ {T}_2^{\ast } $$ -related effects, providing training data for an end-to-end deep learning model that enables efficient multiparametric quantification. In addition, a signal-to-concentration model tailored for dynamic MOLED signals was formulated for accurate estimation of permeability and leakage-corrected perfusion parameters. The proposed technique was validated in water phantom experiments, healthy volunteers, and a pilot clinical study. RESULTS: Single-shot SAGE-MOLED demonstrated high consistency with standard methods in both phantom and in vivo experiments, with Pearson correlation coefficient = 0.991 for T2 and 0.988 for T 2 * $$ {T}_2^{\ast } $$ mapping in the brain. Compared to conventional SAGE-EPI, SAGE-MOLED mitigated geometric distortions and intravoxel dephasing-related signal loss. In perfusion MRI, dynamic SAGE-MOLED enabled simultaneous permeability and leakage-corrected perfusion parameter estimation with a single-dose contrast injection. CONCLUSION: SAGE-MOLED overcomes key limitations of SAGE-EPI, providing high-fidelity, distortion-corrected T2, T 2 * $$ {T}_2^{\ast } $$ , and M0 maps for simultaneous quantification of permeability and perfusion parameters.

Authors

  • Qinqin Yang
    Institute of Laser and Optoelectronics Technology, Fujian Provincial Key Laboratory for Photonics Technology, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Normal University, Fuzhou, China.
  • Jianfeng Bao
    Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China. [email protected].
  • Lu Wang
    Department of Laboratory, Akesu Center of Disease Control and Prevention, Akesu, China.
  • Nuowei Ge
    Department of Electronic Science, Xiamen University, Xiamen, China.
  • Xiaoyue Ma
    Department of Radiology, New York-Presbyterian Hospital and Weill Cornell Medicine, New York, NY, USA.
  • Shuhui Cai
    Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.
  • Zhong Chen
    Institute of HIV/AIDS The First Hospital of Changsha, Changsha, China.
  • Yong Zhang
    Outpatient Department of Hepatitis, The Sixth Affiliated People's Hospital of Dalian Medical University, Dalian, Liaoning, China.
  • Ali Gholipour
  • Congbo Cai
    Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.

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