Can Neuroimaging Predict Dementia in Parkinson's Disease?

Juliette H. Lanskey; Peter McColgan; Anette E. Schrag; Julio Acosta-Cabronero; Geraint Rees; Huw R. Morris; Rimona S. Weil


Brain. 2018;141(9):2545-2560. 

In This Article

Quantitative Susceptibility MRI

Selective neuronal vulnerability that predisposes to cognitive involvement in Parkinson's disease may relate to oxidative stress due in part to excessive brain iron deposition (Dias et al., 2014). Iron has the capacity to generate free-radical species that may precipitate the production of pathological α-synuclein (Li et al., 2011). Susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM) are relatively new MRI techniques that show promise as proxies for regional cellular vulnerability due to iron accumulation. Both SWI (Schwarz et al., 2014) and QSM (Murakami et al., 2015; Langkammer et al., 2016; Du et al., 2017) have shown sensitivity levels in Parkinson's disease greater than ever before with MRI. Indeed, a recent whole-brain QSM study revealed widespread cross-sectional changes across brainstem and cortex in a Parkinson's disease cohort without dementia for which no abnormalities were detected using structural or DTI measures (Acosta-Cabronero et al., 2016). In addition, a longitudinal SWI study found changes on follow-up consistent with increased iron content in several basal ganglia structures that were partly associated with cognitive decline (Rossi et al., 2014). Taken together, these studies suggest that SWI and QSM can detect processes that are highly relevant to the cognitive aspects of Parkinson's disease.