Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism

Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism.This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism.We conducted a thorough literature search using reputable databases such as PubMed and Web of Science.Selection criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical applications.The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis.Moreover,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker.This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion.In summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.

Electroacupuncture at Tianshu (ST 25) for diarrhea-predominant irritable bowel syndrome using positron emission tomography Changes in visceral sensation center

Previous studies have demonstrated that electroacupuncture therapy is effective in the treatment of irritable bowel syndrome. However, the precise mechanism of this therapy is unknown. The present study served to investigate the effects of electroacupuncture therapy on treatment of patients with diarrhea-predominant irritable bowel syndrome （IBS）. We compared brain activation maps based on the changes of cerebral glucose metabolism obtained by 18-fluorodeoxyglucose positron emission tomography scanning under three conditions： resting, rectal balloon distension and rectal balloon distension plus electroacupuncture. Under the resting condition, compared with healthy controls, IBS patients displayed an increasing regional cerebral metabolic rate of glucose over a wide range： bilateral superior temporal gyrus, right middle occipital gyrus, superior frontal gyrus and bilateral middle frontal gyrus. However, there was no significant activity in the visceral pain center. Compared with the resting condition, under the rectal balloon distension condition, patients with IBS had a greater regional cerebral metabolic rate of glucose in the prefrontal cortex, left anterior cingulate cortex, postcentral gyrus, precentral gyrus and temporal gyrus. Under the rectal balloon distension plus electroacupuncture condition, stimulation by electroacupuncture at Tianshu （ST 25） manifested a decreased regional cerebral metabolic rate of glucose in the left cingulate gyrus, right insula, right caudate nucleus, fusiform gyrus and hippocampal gyrus. Electroacupuncture therapy relieved abdominal pain, distension or discomfort by decreasing glucose metabolism in the brain.

The metabolic brain network in patients with Parkinson's disease based on ^(18)F-FDG PET imaging: evaluation of neuronal injury and regeneration

Over the past two decades, the development of functional imaging methods has greatly promoted our understanding on the changes of neurons following neurodegenerative disorders, such as Parkin- son＇s disease （PD）. The application of a spatial covariance analysis on 18F-FDG PET imaging has led to the identification of a distinc- tive disease-related metabolic pattern. This pattern has proven to be useful in clinical diagnosis, disease progression monitoring as well as assessment of the neuronal changes before and after clinical treatment. It may potentially serve as an objective biomarker on disease progression monitoring, assessment, histological and func- tional evaluation of related diseases.

International Nuclear Medicine Consensus on the Clinical Use of Amyloid Positron Emission Tomography in Alzheimer’s Disease

Alzheimer’s disease(AD)is the main cause of dementia,with its diagnosis and management remaining challenging.Amyloid positron emission tomography(PET)has become increasingly important in medical practice for patients with AD.To integrate and update previous guidelines in the field,a task group of experts of several disciplines from multiple countries was assembled,and they revised and approved the content related to the application of amyloid PET in the medical settings of cognitively impaired individuals,focusing on clinical scenarios,patient preparation,administered activities,as well as image acquisition,processing,interpretation and reporting.In addition,expert opinions,practices,and protocols of prominent research institutions performing research on amyloid PET of dementia are integrated.With the increasing availability of amyloid PET imaging,a complete and standard pipeline for the entire examination process is essential for clinical practice.This international consensus and practice guideline will help to promote proper clinical use of amyloid PET imaging in patients with AD.

Infuence of Gender on Tau Precipitation in Alzheimer’s Disease According to ATN Research Framework

Tau proteins accumulation and their spreading pattern were afected by gender in cognitive impairment patients,especially in the progression of Alzheimer’s disease(AD).However,it was unclear whether the gender efects for tau deposition infuenced by amyloid deposition.The aim of this study was to investigate gender diferences for tau depositions in Aβpositive(A^(+))subjects.In this study,tau and amyloid positron emission tomography images,structural magnetic resonance imaging images,and demographic information were collected from 179 subjects in Alzheimer’s Disease Neuroimaging Initiative(ADNI)database and 63 subjects from Huashan Hospital.Subjects were classifed as T^(+)or T^(-)according to the presence or absence of tau(T)biomarkers.We used two-sample t test and one-way analysis of variance test to analyze the efect of gender with adjusting for age,years of education,and Minimum Mental State Examination.In the ADNI cohort,we found diferences in Tau deposition in fusiform gyrus,inferior temporal gyrus,middle temporal gyrus and parahippocampal gyrus between the female T^(+)(FT^(+))and male T^(+)(MT^(+))groups(p<0.05).Tau deposition did not difer signifcantly between female T^(-)(FT^(-))and male T^(-)(MT^(-))subjects(p>0.05).In the Huashan Hospital cohort,there was no diference in Tau deposition between FT^(+)and MT^(+)(p>0.05).The results show that tau depositions signifcantly increased in females in above brain regions.Our fndings suggest that tau deposition is infuenced by gender in the A+subjects.This result has important clinical implications for the development of gender-guided early interventions for patients with both Tau and Amyloid depositions.

Head-to-head comparison of plasma and PET imaging ATN markers in subjects with cognitive complaints

Background Gaining more information about the reciprocal associations between different biomarkers within the ATN(Amyloid/Tau/Neurodegeneration)framework across the Alzheimer’s disease(AD)spectrum is clinically relevant.We aimed to conduct a comprehensive head-to-head comparison of plasma and positron emission tomography(PET)ATN biomarkers in subjects with cognitive complaints.Methods A hospital-based cohort of subjects with cognitive complaints with a concurrent blood draw and ATN PET imaging(18F-florbetapir for A,18F-Florzolotau for T,and 18F-fluorodeoxyglucose[18F-FDG]for N)was enrolled(n=137).Theβ-amyloid(Aβ)status(positive versus negative)and the severity of cognitive impairment served as the main outcome measures for assessing biomarker performances.Results Plasma phosphorylated tau 181(p-tau181)level was found to be associated with PET imaging of ATN biomarkers in the entire cohort.Plasma p-tau181 level and PET standardized uptake value ratios of AT biomarkers showed a similarly excellent diagnostic performance for distinguishing between Aβ+and Aβ−subjects.An increased tau burden and glucose hypometabolism were significantly associated with the severity of cognitive impairment in Aβ+subjects.Additionally,glucose hypometabolism-along with elevated plasma neurofilament light chain level-was related to more severe cognitive impairment in Aβ−subjects.Conclusion Plasma p-tau181,as well as 18F-florbetapir and 18F-Florzolotau PET imaging can be considered as interchangeable biomarkers in the assessment of Aβstatus in symptomatic stages of AD.18F-Florzolotau and 18F-FDG PET imaging could serve as biomarkers for the severity of cognitive impairment.Our findings have implications for establishing a roadmap to identifying the most suitable ATN biomarkers for clinical use.

Adjustment for the Age-and Gender-Related Metabolic Changes Improves the Differential Diagnosis of Parkinsonism

Age and gender are the important factors for brain metabolic declines in both normal aging and neurodegeneration,and the confounding effects may influence early and differential diagnosis of neurodegenerative diseases based on the[^(18)F]fluorodeoxyglucose positron emission tomography([^(18)F]FDG PET).We aimed to explore the potential of the adjustment of age-and gender-related confounding factors on[^(18)F]FDG PET images in differentiation of Parkinson’s disease(PD),multiple system atrophy(MSA)and progressive supra-nuclear palsy(PSP).Eight hundred and seventy-seven clinically definitely diagnosed Parkinsonian patients from a benchmark Huashan Parkinsonian PET imaging database were included.An age-and gender-adjusted Z(AGAZ)score was established based on the gender-specific longitudinal metabolic changes on healthy subjects.AGAZ scores and standardized uptake value ratio(SUVR)values were quantified at regional-level and support vector machine-based error-correcting output codes method was applied for classification.Additional references of the classifications based on metabolic pattern scores were included.The feature-based AGAZ score showed the best performance in classification(accuracy for PD,MSA,PSP:93.1%,96.3%,94.8%).In both genders,the AGAZ score con-sistently achieved the best efficiency,and the improvements compared to the conventional SUVR value for PD,MSA,and PSP mainly laid in specificity(Male:5.7%;Female:11.1%),sensitivity(Male:7.2%;Female:7.3%),and sensitivity(Male:7.3%;Female:17.2%).Female patients benefited more from the adjustment on[^(18)F]FDG PET in MSA and PSP groups(absolute net reclassification index,p<0.001).Collectively,the adjustment of age-and gender-related confounding factors may improve the differential diagnosis of Parkinsonism.Particularly,the diagnosis of female Parkinsonian population has the best improvement from this correction.