Murphy, Matthew C.

Abstract Background Microbleeds have been associated with Alzheimer's disease (AD), although it is unclear whether they occur in atypical presentations of AD, such as the logopenic variant of primary progressive aphasia (lvPPA). We aimed to assess the presence and clinical correlates of microbleeds in lvPPA. Methods Thirteen lvPPA subjects underwent 3T T2*‐weighted and fluid‐attenuated inversion recovery magnetic resonance imaging and Pittsburgh compound B (PiB) positron emission tomography imaging. Microbleeds were identified on manual review and assigned a regional location. Total and regional white matter hyperintensity (WMH) burden was measured. Results Microbleeds were observed in four lvPPA subjects (31%), most commonly in the frontal lobe. Subjects with microbleeds were older, more likely female, and had a greater burden of WMH than those without microbleeds. The regional distribution of microbleeds did not match the regional distribution of WMH. All cases were PiB positive. Conclusions Microbleeds occur in approximately one third of subjects with lvPPA, with older women at the highest risk.

Object The object of this study was to determine the potential of magnetic resonance elastography (MRE) to preoperatively assess the stiffness of meningiomas. Methods Thirteen patients with meningiomas underwent 3D brain MRE examination to measure stiffness in the tumor as well as in surrounding brain tissue. Blinded to the MRE results, neurosurgeons made a qualitative assessment of tumor stiffness at the time of resection. The ability of MRE to predict the surgical assessment of stiffness was tested using a Spearman rank correlation. Results One case was excluded due to a small tumor size. In the remaining 12 cases, both tumor stiffness alone (p = 0.023) and the ratio of tumor stiffness to surrounding brain tissue stiffness (p = 0.0032) significantly correlated with the surgeons' qualitative assessment of tumor stiffness. Results of the MRE examination provided a stronger correlation with the surgical assessment of stiffness compared with traditional T1- and T2-weighted imaging (p = 0.089), particularly when considering meningiomas of intermediate stiffness. Conclusions In this cohort, preoperative MRE predicted tumor consistency at the time of surgery. Tumor stiffness as measured using MRE outperformed conventional MRI because tumor appearance on T1- and T2-weighted images could only accurately predict the softest and hardest meningiomas.