Complete Evaluation of Dementia: PET and MRI Correlation and Diagnosis for the Neuroradiologist.

This article will familiarize neuroradiologists with the pathophysiology, clinical findings, and standard MR imaging and PET imaging features of multiple forms of dementia as well as new emerging techniques. Cases were compiled from multiple institutions with the goal of improved diagnostic accuracy and improved patient care as well as information about biomarkers on the horizon. Dementia topics addressed include the following: Alzheimer disease, frontotemporal dementia, cerebral amyloid angiopathy, Lewy body dementia, Parkinson disease and Parkinson disease variants, amyotrophic lateral sclerosis, multisystem atrophy, Huntington disease vascular dementia, and Creutzfeldt-Jakob disease.

Analysis of normal-appearing white matter in multiple sclerosis: comparison of diffusion tensor MR imaging and magnetization transfer imaging.

BACKGROUND AND PURPOSE: Our purpose was to compare diffusion tensor MR and magnetization transfer imaging in assessing normal-appearing white matter (WM) regions in multiple sclerosis (MS). METHODS: Diffusion tensor, magnetization transfer, and conventional MR imaging were performed in 12 patients with MS. Fractional anisotropy, apparent diffusion coefficients (ADCs), and magnetization transfer ratios (MTRs) were measured in plaques, normal-appearing periplaque WM (PWM) regions, and normal-appearing WM regions remote from plaques. Mean fractional anisotropy, ADCs, and MTRs were calculated and compared in WM regions. RESULTS: Fractional anisotropy was lower in normal-appearing PWM regions than in remote WM regions (P <.001) but higher than in plaques (P <.001). MTRs were lower (not significantly, P =.19) in normal-appearing PWM regions than in remote regions. MTRs were higher in normal-appearing PWM regions than in plaques (P <.001). ADCs were higher in normal-appearing PWM regions than in remote regions (P =.008) but lower than in plaques (P =.001). Correlation between fractional anisotropy and MTRs of individual lesions was poor (r = 0.18) and between fractional anisotropy and ADC, modest (r = -0.39). CONCLUSION: In MS, diffusion tensor MR imaging can depict differences between WM regions that are not apparent on conventional MR images. Anisotropy measurements may be more sensitive than those of MTRs in detecting subtle abnormalities in PWM.