Diffusion-derived parameters in lesions, peri-lesion and normal-appearing white matter in multiple sclerosis using tensor, kurtosis and fixel-based analysis.

Neuronal damage is the primary cause of long-term disability of multiple sclerosis (MS) patients. Assessment of axonal integrity from diffusion MRI parameters might enable better disease characterisation. 16 diffusion derived measurements from diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and fixel-based analysis (FBA) in lesions, peri-lesion and normal appearing white matter were investigated.

Repeatability of parametric methods for [F]florbetapir imaging in Alzheimer's disease and healthy controls: A test-retest study.

Accumulation of amyloid beta (Aβ) is one of the pathological hallmarks of Alzheimer's disease (AD), which can be visualized using [F]florbetapir positron emission tomography (PET). The aim of this study was to evaluate various parametric methods and to assess their test-retest (TRT) reliability. Two 90 min dynamic [F]florbetapir PET scans, including arterial sampling, were acquired ( = 8 AD patient,  = 8 controls).

Parametric methods for [F]flortaucipir PET.

[F]Flortaucipir is a PET tau tracer used to visualize tau binding in Alzheimer's disease (AD) in vivo. The present study evaluated the performance of several methods to obtain parametric images of [F]flortaucipir. One hundred and thirty minutes dynamic PET scans were performed in 10 AD patients and 10 controls.