Accelerated 3D whole-brain T1, T2, and proton density mapping: feasibility for clinical glioma MR imaging

Carolin M Pirkl,Matteo Cencini,Benedikt Wiestler,Marion I Menzel,Lioba Grundl,Florian Kofler,Laura Nunez-Gonzalez,Pedro A Gómez,Bjoern H Menze,Juan A Hernandez-Tamames,Marion Smits,Mohammad Golbabaee,Rolf F Schulte,Guido Buonincontri,Sebastian Endt

doi:10.1007/s00234-021-02703-0

Abstract

PurposeAdvanced MRI-based biomarkers offer comprehensive and quantitative information for the evaluation and characterization of brain tumors. In this study, we report initial clinical experience in routine glioma imaging with a novel, fully 3D multiparametric quantitative transient-state imaging (QTI) method for tissue characterization based on T1 and T2 values.MethodsTo demonstrate the viability of the proposed 3D QTI technique, nine glioma patients (grade II–IV), with a variety of disease states and treatment histories, were included in this study. First, we investigated the feasibility of 3D QTI (6:25 min scan time) for its use in clinical routine imaging, focusing on image reconstruction, parameter estimation, and contrast-weighted image synthesis. Second, for an initial assessment of 3D QTI-based quantitative MR biomarkers, we performed a ROI-based analysis to characterize T1 and T2 components in tumor and peritumoral tissue.ResultsThe 3D acquisition combined with a compressed sensing reconstruction and neural network-based parameter inference produced parametric maps with high isotropic resolution (1.125 × 1.125 × 1.125 mm3 voxel size) and whole-brain coverage (22.5 × 22.5 × 22.5 cm3 FOV), enabling the synthesis of clinically relevant T1-weighted, T2-weighted, and FLAIR contrasts without any extra scan time. Our study revealed increased T1 and T2 values in tumor and peritumoral regions compared to contralateral white matter, good agreement with healthy volunteer data, and high inter-subject consistency.Conclusion3D QTI demonstrated comprehensive tissue assessment of tumor substructures captured in T1 and T2 parameters. Aiming for fast acquisition of quantitative MR biomarkers, 3D QTI has potential to improve disease characterization in brain tumor patients under tight clinical time-constraints.

Highlights

Gliomas are the most frequent primary brain tumors in adults
We present the feasibility of a novel, fully 3D multiparametric quantitative transient-state imaging (QTI) technique [18] for simultaneous mapping of T1 and T2 relaxation times and relative proton density (PD) for use in clinical routine glioma imaging
With 3D QTI, we demonstrate a 3D acquisition with high isotropic resolution that allows us to go beyond the resolution of other recently presented quantitative MRI methods based on 2Dslice acquisitions

Summary

Introduction

Gliomas are the most frequent primary brain tumors in adults. This diverse group of brain tumors comprises glioblastomas, astrocytomas, oligodendrogliomas, and ependymomas [1]. State-of-the-art glioma treatment includes a multi-disciplinary approach, combining surgical resection, chemotherapy, and radiation therapy [3]. Treatment strategy and prognosis for each individual case depend on tumor grade, which is defined upon histopathologic appearance and molecular features according to the 2016 WHO criteria [4]. High-grade gliomas (grade IV), so called glioblastomas, are aggressive, fastgrowing tumor types that require immediate treatment. For lower-grade gliomas (grades II, III), including various types of astrocytic, oligodendroglial, and ependymal tumors, extensive treatment is often delayed as long as possible [5]

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