A fast protocol for multi-center, multi-parametric quantitative MRI studies in brain tumor patients using vendor sequences

Abstract

Multi-parametric quantitative MRI (mp-qMRI) provides non-invasive, quantitative measurements sensitive to a variety of tissue properties. In brain tumors (BTs), T1, T2*, T2, Water content (H2O) and quantitative susceptibility (χ) give valuable insights into the microenvironment. To generate large multi-center datasets, protocols need to be short and implementable on any scanner. The goal of this work was to develop and validate an 8-minute, 3T mp-qMRI protocol for BT patients solely using generalized pulse sequences (mGRE and EPI). A protocol was developed and tested on a multi-compartment phantom, five healthy subjects (mean age: 31.64 yrs), and four BT patients (mean age:39.5 yrs). Phantom and healthy subject T1 maps were compared to those obtained using two reference methods. The five healthy subjects were scanned on 3T MRI scanners at two different sites and the reproducibility between scanners assessed by computing Coefficients of Variance (COV) maps, performing Bland Altman analysis and t-tests. Clinical feasibility was tested on four BT patients. T1 values obtained using the proposed mp-qMRI protocol agree with those obtained using the reference methods in volunteers (mean error = 8.94 ms). The qMRI maps (T1, T2*, H2O and χ) of the volunteers showed good reproducibility between scanners with no significant differences for mean WM and GM qMRI values. WM and GM mean qMRI values agreed well with literature values. H2O gave the lowest COV and χ maps the highest. The proposed vendor sequence-based 3T mp-qMRI protocol gives high resolution (1 mm isotropic) T1, T2*, H2O and χ maps in 8 minutes acquisition.