VOLUMETRIC 3D MR FINGERPRINTING OF ADULT BRAIN TUMORS: INITIAL RESULTS

Magnetic Resonance Fingerprinting (MRF) is a non-invasive multi-parametric quantitative MR imaging technique, which allows rapid and simultaneous quantification of T1 and T2 relaxation times. We have already demonstrated the ability of 2D single-slice MRF-based relaxometry in identifying quantitative differences between various regions in intraaxial brain tumors. 3D volumetric MRF offers the capability to analyze the quantitative features of entire tumor volume, thereby offering the opportunity to capture the heterogeneity of tumor microenvironment. In this IRB approved ongoing study, we assess the utility of the new volumetric 3D MRF technique with whole-brain coverage to differentiate between common intra-axial brain tumors. Volumetric 3D-MRF acquisition was performed in 16 patients (F:9/M:7, mean age 53 ± 15) with untreated intra-axial brain tumors including 8 glioblastomas (GBM), 3 grade lower grade gliomas (LGG), and 6 metastases (METS). Volumetric 3D regions of interest (ROI) were drawn on the solid tumor regions on quantitative MRF maps using Matlab and T1 and T2 values were recorded (The Mathworks, Natick, MA). The statistical comparisons between mean T1 and T2 values were performed using unpaired Student’s t-test across tumor types. Mean T1 values were significantly different between the three groups. Solid tumor region mean T1 value of GBMs (1588 ± 130 ms) differed from metastases and LGGs (p=0.029 and p=0.010 respectively). Solid tumor region mean T1 values were also significantly different between metastases and LGGs (mean 1416 ± 162 ms versus 1784 ± 77 ms respectively, p=0.001). There was no significant difference between mean T2 values of various tumor types. Preliminary data with 3D volumetric MR fingerprinting demonstrates promising differences in T1 values of various tumor types. Further ongoing data collection will allow evaluating the robustness of this technique in differentiating between various tissue types in larger sample size.