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Igor Sibon

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YNICL Journal 2025 Journal Article

A comparison of clinical, lesion-based and connectome-based models of post-stroke depression: a prospective longitudinal study

  • Nicolas Borderies
  • Suhrit Duttagupta
  • Thomas Tourdias
  • Sylvie Berthoz
  • Michel Thiebaut de Schotten
  • Igor Sibon

Post-stroke depression (PSD) is a frequent and disabling complication of ischemic stroke. Although clinical risk factors of PSD are well-established, the added predictive value of lesion and connectome-based brain-symptom mapping methods remains unclear. This study aimed to compare the predictive performance of clinical, lesion based, and network-based models of 3-months PSD in patients with minor ischemic stroke. We conducted a prospective longitudinal study including 263 patients with recent ischemic stroke. Clinical, radiological, and psychometric data were collected at baseline and at 3-month follow-up. Structural lesions were segmented on acute MRI and used to generate disconnectome maps and compute graph-theory metrics. Depressive symptoms severity at 3 months were measured using the CES-D scale. We developed six predictive models (clinical, radiological, gray-matter lesion, white matter disconnection, functional network disconnection, and topological graph features) using LASSO regression. Models performances were compared using the coefficient of determination (R2) and their combinations further examined through hierarchical regression. The clinical model demonstrated the best individual predictive performance (R2 = 23 %), identifying female sex, low cognitive status, poor functional outcome, and socioeconomic deprivation as significant predictors. Imaging-based models alone showed limited predictive power (R2 < 6 %), but identified significant associations for frontal and cerebellar lesions, somatomotor network disconnections, and altered network topology. A hierarchical model combining clinical, anatomical, and topological features significantly improved prediction (R2 = 31. 6 %, p < 0. 001), outperforming all individual models. In patients with minor ischemic stroke, PSD is most accurately predicted by clinical factors. However, combining lesion and network level neuroimaging features with clinical variables significantly enhances predictive accuracy. This multimodal approach supports the development of integrative, personalized models for PSD risk stratification and early intervention.

YNICL Journal 2013 Journal Article

[123I]-IBVM SPECT imaging of cholinergic systems in multiple system atrophy: A specific alteration of the ponto-thalamic cholinergic pathways (Ch5–Ch6)

  • Joachim Mazere
  • Wassilios. G. Meissner
  • Igor Sibon
  • Frédéric Lamare
  • François Tison
  • Michèle Allard
  • Willy Mayo

UNLABELLED: We evaluated in vivo the integrity of brain cholinergic pathways in Multiple System Atrophy (MSA) and the relationship between cholinergic dysfunction and motor disturbances, by measuring the vesicular acetylcholine transporter (VAChT) expression using Single Photon Emission Computed Tomography (SPECT) and [(123)I]-iodobenzovesamicol ([(123)I]-IBVM). METHODS: Nine patients with probable MSA and 12 healthy volunteers underwent a dynamic [(123)I]-IBVM SPECT-CT scan and a magnetic resonance imaging (MRI) scan. All patients were examined with the Unified MSA Rating Scale (UMSARS; subscale I = activities of daily living (ADL), II = motor and IV = disability). CT and MRI images were used to register the dynamic SPECT image to the Montreal Neurological Institute brain template, which includes the regions of interest (ROI) of striatum and Ch1 (medial septum nucleus-hippocampus), Ch4 (nucleus basalis of Meynert-cortex) and Ch5-Ch6 (pedunculopontine and laterodorsal tegmental nuclei-thalamus) cholinergic pathways. For each ROI, pharmacokinetic modeling of regional time activity curves led to the calculation of [(123)I]-IBVM to VAChT binding potential (BPND) value, proportional to VAChT expression. RESULTS: When compared to controls, BPND values for MSA in Ch5-Ch6 were significantly decreased in both the pedunculopontine-laterodorsal nuclei and the thalamus (p = 0.004 and p = 0.006, respectively). Additionally, thalamus BPND values were correlated with UMSARS ADL (p = 0.006), motor (p = 0.002) and disability (p = 0.02) sub-scores. UMSARS motor subscale items 13 (postural instability) and 14 (gait) were also correlated with thalamus BPND values (p = 0.04). CONCLUSION: Ch5-Ch6 are the most affected cholinergic pathways in MSA at both cell bodies and thalamic cholinergic terminals. These results underscore the relevant role of [(123)I]-IBVM SPECT for improving our understanding of the pathophysiology in MSA.