Introduction: Traditional MRI acquisitions are restricted to qualitative “weighted” measurements of tissue properties where the signal intensities are dependent upon many factors, including the type and set-up of the scanner. Magnetic Resonance Fingerprinting (MRF) is a revolutionary new approach to collecting and analyzing MRI data that permits simultaneous quantification of multiple tissue properties (e.g. T1 and T2).
Methods: MRF uses a pseudorandomized acquisition that causes the signals from different materials or tissues to have a unique signal evolution or ‘fingerprint’ that is simultaneously a function of the multiple material properties under investigation. MRF processing after acquisition involves a pattern recognition algorithm to match the fingerprints to a predefined dictionary of predicted signal evolutions. These can then be translated into quantitative maps of the magnetic parameters of interest.
Results: We used MRF in a Siemens 3T scanner to collect a fully quantitative 3D image of a whole human brain within a Leksell Vantage MRI compatible stereotactic frame. T1, T2, and proton density maps were created at 1.2 mm isotropic resolution. Basic tissue clusters were then calculated using k-means analysis and used to segment anatomical structures within the subthalamic region. The whole brain MRF scan time was less than 12 min, including a B1 mapping scan to correct for inhomogeneity, making acquisition of these quantitative MRI measurements clinically plausible.
Conclusions: MRF represents a new imaging tool that can quantitatively standardize MRI-based tissue segmentation and surgical target identification.
Patient Care: Advanced methodology for improving patient-specific surgical targeting.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the new imaging concept MRF, 2) Understand the differences between T1-weighted images and quantitative T1 maps, and 3) Identify methods for using MRF in DBS targeting.