PET Imaging in Movement Disorders

Abstract

Positron emission tomography (PET) has revealed key insights into the pathophysiology of movement disorders. This paper will focus on how PET investigations of pathophysiology are particularly relevant to Parkinson disease (PD), a neurodegenerative condition usually starting later in life marked by a varying combination of motor and non-motor deficits. Various molecular imaging modalities help to determine what changes in brain herald the onset of pathology; can these changes be used to identify presymptomatic individuals who may be appropriate for to-be-developed treatments that may forestall onset of symptoms or slow disease progression; can PET act as a biomarker of disease progression; can molecular imaging help enrich homogenous cohorts for clinical studies; and what other pathophysiologic mechanisms relate to non-motor manifestations. PET methods include measurements of regional cerebral glucose metabolism and blood flow, selected receptors, specific neurotransmitter systems, post synaptic signal transducers, and abnormal protein deposition. We will review each of these methodologies and how they are relevant to important clinical issues pertaining to PD.

Spatiotemporal Progression Patterns of Dopamine Availability and Deep Gray Matter Volume in Parkinson Disease–Related Cognitive Impairment

“…48 This may be attributed to the floor effect in dopamine transporter imaging, which becomes prominent when >50% of dopaminergic neurons are lost. 49 Third, UPDRS part III score increased with cognitive decline, which might reflect a difference in striatal dopamine availability. To address this issue, we performed the analysis while controlling for UPDRS part III.…”

Spatiotemporal Progression Patterns of Dopamine Availability and Deep Gray Matter Volume in Parkinson Disease–Related Cognitive Impairment

“…48 This may be attributed to the floor effect in dopamine transporter imaging, which becomes prominent when >50% of dopaminergic neurons are lost. 49 Third, UPDRS part III score increased with cognitive decline, which might reflect a difference in striatal dopamine availability. To address this issue, we performed the analysis while controlling for UPDRS part III.…”

Obstructive Sleep Apnea and Striatal Dopamine Availability in Parkinson's Disease

“…Because estrogen also influences striatal dopamine uptake, 43 further studies on sex difference in striatal dopamine and hormonal changes in patients with OSA are needed. Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost 44 . Therefore, the correlations between the imaging parameters and other variables might be biased.…”

“…Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost. 44 Therefore, the correlations between the imaging parameters and other variables might be biased. Finally, the enrolled patients in this study had considerably lower UPDRS scores because they were in early, de novo, and drug-naive states.…”

Premorbid cancer and motor reserve in patients with Parkinson’s disease

“…First, the number of patients with neoplasia was relatively small compared to those without neoplasia. Second, the dopaminergic imaging has a flooring effect after 50% of neurons are lost 24 . Therefore, the correlation between the imaging parameters and clinical severities can be biased, especially in patients with severe motor handicap.…”

Spatiotemporal Progression Patterns of Dopamine Availability and Deep Gray Matter Volume in Parkinson Disease–Related Cognitive Impairment

“…48 This may be attributed to the floor effect in dopamine transporter imaging, which becomes prominent when >50% of dopaminergic neurons are lost. 49 Third, UPDRS part III score increased with cognitive decline, which might reflect a difference in striatal dopamine availability. To address this issue, we performed the analysis while controlling for UPDRS part III.…”

Obstructive Sleep Apnea and Striatal Dopamine Availability in Parkinson's Disease

“…Because estrogen also influences striatal dopamine uptake, 43 further studies on sex difference in striatal dopamine and hormonal changes in patients with OSA are needed. Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost 44 . Therefore, the correlations between the imaging parameters and other variables might be biased.…”

“…Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost. 44 Therefore, the correlations between the imaging parameters and other variables might be biased. Finally, the enrolled patients in this study had considerably lower UPDRS scores because they were in early, de novo, and drug-naive states.…”

Premorbid cancer and motor reserve in patients with Parkinson’s disease

“…First, the number of patients with neoplasia was relatively small compared to those without neoplasia. Second, the dopaminergic imaging has a flooring effect after 50% of neurons are lost 24 . Therefore, the correlation between the imaging parameters and clinical severities can be biased, especially in patients with severe motor handicap.…”

Spatiotemporal Progression Patterns of Dopamine Availability and Deep Gray Matter Volume in Parkinson Disease–Related Cognitive Impairment

“…48 This may be attributed to the floor effect in dopamine transporter imaging, which becomes prominent when >50% of dopaminergic neurons are lost. 49 Third, UPDRS part III score increased with cognitive decline, which might reflect a difference in striatal dopamine availability. To address this issue, we performed the analysis while controlling for UPDRS part III.…”

Obstructive Sleep Apnea and Striatal Dopamine Availability in Parkinson's Disease

“…Because estrogen also influences striatal dopamine uptake, 43 further studies on sex difference in striatal dopamine and hormonal changes in patients with OSA are needed. Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost 44 . Therefore, the correlations between the imaging parameters and other variables might be biased.…”

“…Second, dopamine transporter imaging has a floor effect in that more than 50% of dopaminergic neurons are lost. 44 Therefore, the correlations between the imaging parameters and other variables might be biased. Finally, the enrolled patients in this study had considerably lower UPDRS scores because they were in early, de novo, and drug-naive states.…”

Premorbid cancer and motor reserve in patients with Parkinson’s disease

“…First, the number of patients with neoplasia was relatively small compared to those without neoplasia. Second, the dopaminergic imaging has a flooring effect after 50% of neurons are lost 24 . Therefore, the correlation between the imaging parameters and clinical severities can be biased, especially in patients with severe motor handicap.…”