PET/MRI tomographs represent the latest development in hybrid molecular imaging, opening
new perspectives for clinical and research applications and attracting a large interest among the
medical community. This new hybrid modality is expected to play a pivotal role in a number of clinical
applications and among these the assessment of neurodegenerative disorders. PET and MRI, acquired
separately, are already the imaging biomarkers of choice for a comprehensive assessment of
the changes occurring in dementias (major cognitive disorders) as well as in their prodromal phase.
In this paper we review the current evidence on the use of integrated PET/MRI scanners to investigate
patients with neurodegenerative conditions, and in particular major neurocognitive disorders. The
number of studies performed is still limited and shows that the use of PET/MRI gives results overall
comparable to PET/CT and MRI acquired independently. We also address the challenges for quantitative
aspects in PET/MRI, namely attenuation, partial volume and motion correction and the use of
semi-quantitative approaches for FDG PET image analysis in this framework.
The recent development of PET tracers for the in vivo differential diagnosis of dementias, able to
visualize amyloid and tau deposits, suggests that in the future PET/MRI might represent the investigation
of choice for a single session evaluation of morphological, functional and molecular markers.