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The authors assessedthereproducibilityof2automatedsegmentationsoftwarepackages(FreeSurferandthe FMRIB Integrated Registration and Segmentation Tool) by quantifying the volume changes of deep GM structures by using back-to-back MR imaging scans from the Alzheimer Disease Neuroimaging Initiative's multicenter dataset in 562 subjects. Back-to-back differences in 1-year percentage volume change were approximately 1.5–3.5 times larger than the mean measured 1-year volume change of those structures. They conclude that longitudinal deep GM atrophy measures should be interpreted with caution and that deep GM atrophy measurement techniques require substantially improved reproducibility, specifically when aiming for personalized medicine.

Tumor stiffness properties were prospectively quantified in 18 patients with histologically proved gliomas using MR elastography. Images were acquired on a 3T MR imaging unit with a vibration frequency of 60 Hz. Tumor stiffness was compared with unaffected contralateral white matter, across tumor grade, and by IDH1-mutation status. Gliomas were softer than healthy brain parenchyma, 2.2kPa compared with 3.3kPa, with grade IV tumors softer than grade II. MR elastography demonstrated that not only were gliomas softer than normal brain but the degree of softening was directly correlated with tumor grade and IDH1-mutation status.