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Interplay of age-sensitive cortical vulnerability and dopaminergic degeneration in clinical manifestations of Parkinson's disease

2026-07-01T00:00:00Z

Title: Interplay of age-sensitive cortical vulnerability and dopaminergic degeneration in clinical manifestations of Parkinson's disease Authors: Kang, Sungwoo; Na, Han Kyu; Yoon, So Hoon; Kim, Han-Kyeol; Ryu, Young Hoon; Lee, Hye Sun; Yoo, Han Soo; Lyoo, Chul Hyoung; 유한수 Abstract: To identify the pattern of cortical atrophy variation in Parkinson's disease (PD) and its contribution to clinical manifestations beyond dopaminergic dysfunction, 45 healthy controls (HCs) underwent MRI, and 222 participants with PD additionally underwent dopamine transporter (DAT)-PET, Unified PD Rating Scale (UPDRS), and neuropsychological tests. Using principal component analysis in PD, a single pattern in cortical thickness (PC1PD) was identified. Linear regressions models were applied to investigate the effects of PC1PD and putaminal DAT (DAT-P) on parkinsonism, and PC1PD and caudate DAT (DAT-C) on cognition. PC1PD accounted for more than 80% of total cortical variance and showed a strong negative correlation with age. The spatial pattern of PC1PD was similar to that of PC1 derived from HCs, but its age-related association was more pronounced in PD. Independent of DAT-P, lower PC1PD was associated with higher UPDRS motor score and showed a synergistic significant interaction with DAT-P on the axial subscore. Independent of DAT-C, lower PC1PD was associated with worse performance in global cognition, language, and executive functions, with synergistic interaction with DATC on global cognition and executive function. The associations of PC1PD with UPDRS motor scores, general cognition, and executive function were stronger in older participants, indicating that aging amplifies the clinical effect of PC1PD. PC1PD represents an age-sensitive cortical vulnerability axis whose expression is amplified in PD, and its interplay with dopaminergic depletion and aging contributes to axial motor symptoms and executive dysfunction in PD.

Use of Generative Artificial Intelligence in Nuclear Medicine Research, Education, and Clinical Practice: Results from a 2025 Society-Wide Survey

2026-05-01T00:00:00Z

Title: Use of Generative Artificial Intelligence in Nuclear Medicine Research, Education, and Clinical Practice: Results from a 2025 Society-Wide Survey Authors: Chong, Ari; Lim, Chae Hong; Kim, Dong-Yeon; Yun, Mijin; Bom, Hee-Seung Henry; Lee, Suk Hyun Abstract: Purpose Generative artificial intelligence (AI) is rapidly expanding within medical practice, yet its use among nuclear medicine professionals has not been systematically evaluated. This study provides the first society-wide assessment of generative AI adoption among members of the Korean Society of Nuclear Medicine (KSNM). Methods An anonymous online survey was distributed to approximately 670 KSNM members. The questionnaire assessed AI use in two domains (research/education and clinical practice), including platforms, frequency, purposes, and perceived usefulness and trust. Descriptive statistics and chi-square tests were used. Results A total of 122 members responded (estimated response rate, 18.2%); 105 (86.1% of respondents) reported using generative AI. Among users, 51.4% used AI daily and 51.4% used paid services; paid subscriptions were more frequent among daily than non-daily users (58.9% vs. 34.4%, p = 0.021). ChatGPT was the most commonly used platform (89.5%), followed by Gemini (55.2%) and Perplexity (26.7%). Perceived usefulness was higher in research/education (n = 96) than in clinical practice (n = 60): 85.4% vs. 41.7% rated AI as helpful/very helpful (p < 0.001). In research/education, translation/ language editing showed high prevalence and high utility, whereas code generation had lower prevalence but high perceived utility. Conclusion Generative AI showed a high adoption rate among the survey respondents, with higher perceived usefulness in research/education than in clinical practice. Given the widespread real-world use of third-party generative AI tools, our findings underscore the need for institutional guidance and privacy-aware governance to ensure safe clinical adoption.

Functional Reorganization of Corticostriatal Connectivity Across the Degree of Nigrostriatal Degeneration in Parkinson Disease

2026-05-01T00:00:00Z

Title: Functional Reorganization of Corticostriatal Connectivity Across the Degree of Nigrostriatal Degeneration in Parkinson Disease Authors: Yoo, Han Soo; Kim, Han-Kyeol; Park, Mina; Ahn, Sung Jun; Lee, Jae-Hoon; Ryu, Young Hoon; Lyoo, Chul Hyoung; 유한수 Abstract: Background and ObjectivesIn Parkinson disease (PD), deafferentation of nigral dopaminergic neurons to the striatum leads to striatal dopamine depletion and impaired direct and indirect basal ganglia pathways, which in turn reduce thalamocortical excitation and ultimately lead to parkinsonism. Therefore, understanding the manifestation of motor deficits requires the evaluation of degree of striatal dopamine depletion and the related changes in striatal functional connectivity (FC) as the nigrostriatal system degenerates.MethodsIn this cross-sectional study, we recruited 326 patients with PD and 29 patients with idiopathic REM sleep behavior disorder who underwent brain resting-state functional MRI, N-(3-[18F]fluoropropyl)-2 beta-carbomethoxy-3 beta-(4-iodophenyl) nortropane PET, and the Unified Parkinson's Disease Rating Scale assessment. A total of 40 healthy controls (HCs) were recruited to determine the extent of striatal dopamine depletion in patients with PD spectrum, and another 40 HCs were recruited to compare corticostriatal FC with that of the patient group. Using a sliding window method, we examined changes in FC with seed regions in the anterior and posterior caudate and putamen on both the more affected and less affected sides as the mean putaminal dopamine declined from 70% to 20%.ResultsThe more affected side of the posterior caudate showed elevated FC with the primary motor cortex and paracentral lobule, which was present before approximately 50% putaminal dopamine depletion, peaked around this depletion level, and disappeared when caudate dopamine was abnormally reduced. The more affected side of the posterior putamen showed reduced FC with the superior parietal cortex, precuneus, and cuneus when putaminal dopamine depletion reached approximately 50%, after which the motor symptoms deteriorated linearly.DiscussionIn summary, our study demonstrated that the FC between the posterior caudate and primary motor cortex was elevated from the prodromal to early stages of PD, a period in which motor symptom progression remained relatively slow. The FC between the posterior putamen and motor cortex remained unchanged, while its connectivity with the posterior cortical regions declined from the onset of motor symptoms, coinciding with the accelerated progression of motor deterioration. Collectively, our study demonstrated that corticostriatal connectivity undergoes functional reorganization across the different stages of PD, which is associated with motor symptoms.

Sarcopenia Predicts Outcome After Chemoimmunotherapy, Not Chemotherapy, in Advanced Lung Cancer: Single-Centre Retrospective Study

2026-04-01T00:00:00Z

Title: Sarcopenia Predicts Outcome After Chemoimmunotherapy, Not Chemotherapy, in Advanced Lung Cancer: Single-Centre Retrospective Study Authors: Lee, Hyojin; Kim, Chang Gon; Han, Sookyeong; Park, Su Kyoung; Yoon, Hong In; Kim, Kyung Hwan; Shim, Hyo Sup; Hong, Min Hee; Yeo, Ja Hyun; Kim, Sangwoo; Hwang, Sang Hyun; Kim, Hye Ryun; Hong, Namki; 여자현; 여자현 Abstract: Background Sarcopenia, characterized by progressive loss of skeletal muscle mass, is prevalent in patients with non-small cell lung cancer (NSCLC). While sarcopenia has been associated with poor prognosis in multiple types of cancer, its predictive role in the context of first-line treatment combining PD-(L)1 inhibitors with platinum-based chemotherapy (CITx) remains unclear in advanced NSCLC.Methods In a single-centre retrospective cohort, patients with advanced NSCLC without actionable genomic alterations who received either CITx (n = 552) or platinum-doublet chemotherapy alone (CTx; n = 622) were analysed. Sarcopenia was defined on the Martin's computed tomography-derived skeletal muscle index definition. Progression-free survival (PFS) and overall survival (OS) were assessed. Interaction between sarcopenia and treatment modality was explored.Results Sarcopenia was observed in 49.5% of patients. The presence of sarcopenia was associated with worse outcomes in overall patients (median OS: 9.4 vs. 11.4 months; HR 1.22, 95% CI 1.08-1.39). When stratified by treatment groups, sarcopenia was significantly associated with higher risk of progression (adjusted HR 1.23, 95% CI 1.01-1.49) and death (adjusted HR 1.42, 95% CI 1.16-1.74) in CITx-treated patients, whereas no such association was observed in the CTx group. The interaction between sarcopenia and treatment type was significant for both PFS (p = 0.041) and OS (p = 0.022).Conclusions Sarcopenia is a predictive biomarker for inferior outcomes in patients with advanced NSCLC treated with CITx, but not with CTx. Assessment of skeletal muscle mass can help identify patients at risk for suboptimal response to CITx. This study provides grounds for future exploration in interventions targeting sarcopenia and cachexia to enhance clinical outcomes in advanced cancer patients.