Integrated PET/MR Assessment of Brain Recovery After Recanalization of Non-Acute Atherosclerotic MCA Occlusion
Middle Cerebral Artery Occlusion · Intracranial Atherosclerosis · Cerebrovascular Disease
What this study involves
The registry says this study is recruiting. Individual locations may have different availability.
- Study type
- Observational
- Phase
- Not applicable / not listed
- Age range
- 18 years - 80 years
- Sex eligible
- All sexes
- Healthy volunteers
- Not reported
- Participants
- 15 Estimated
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
Restoration of arterial patency following recanalization of non-acute atherosclerotic middle cerebral artery (MCA) occlusion may improve cerebral blood supply. However, the extent to which restored perfusion is accompanied by changes in cerebral metabolism and functional brain network organization remains incompletely understood.
This prospective observational study, RESTORE, aims to characterize cerebral perfusion-metabolism recoupling and functional network recovery in patients with non-acute atherosclerotic MCA occlusion who undergo clinically indicated recanalization.
Integrated positron emission tomography/magnetic resonance imaging (PET/MR) will be used to assess cerebral perfusion, metabolic activity, and brain functional connectivity at protocol-defined time points. Imaging measurements will be evaluated in relation to vascular characteristics, recanalization status, and neurological and cognitive outcomes, as applicable.
The study seeks to clarify the temporal and spatial relationships among reperfusion, metabolic changes, and functional network reorganization, and to explore imaging markers associated with clinical recovery after recanalization.
The decision to perform recanalization and the selection of treatment strategies will be based on routine clinical care and will not be assigned by the observational study protocol.
Read the full description
Background and Rationale: Non-acute atherosclerotic MCA occlusion can result in persistent cerebral hypoperfusion, altered metabolic activity, and disruption of functional brain networks. Although recanalization can restore arterial patency in selected patients, anatomical reopening of an occluded artery does not necessarily indicate complete restoration of tissue-level perfusion, cerebral metabolism, or neuronal network function.
Cerebral perfusion and metabolism are closely related under physiological conditions. Chronic hypoperfusion may disrupt this relationship, while successful revascularization may facilitate subsequent physiological adaptation. The timing, magnitude, and distribution of perfusion-metabolism recoupling after recanalization remain uncertain.
Integrated PET/MR allows complementary evaluation of cerebral hemodynamics, tissue metabolic activity, structural abnormalities, and functional connectivity. Its multimodal capabilities may provide a more comprehensive assessment of cerebral recovery than vascular imaging alone.
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria:
1. Aged 18-80 years, regardless of sex.
2. Symptomatic non-acute middle cerebral artery (MCA) occlusion, with an interval of ≥4 weeks between the most recent ischemic event or imaging confirmation of occlusion and the recanalization procedure.
3. Occlusion involving the M1 segment of the MCA, confirmed by computed tomography angiography (CTA), magnetic resonance angiography (MRA), or digital subtraction angiography (DSA).
4. Occlusion presumed to be of atherosclerotic origin.
5. Persistence of at least one of the following despite guideline-directed medical therapy: recurrent transient ischemic attacks (TIAs), minor ischemic stroke, symptoms attributable to cerebral hypoperfusion, watershed infarction, or imaging evidence of cerebral hypoperfusion or metabolic abnormalities.
6. Preoperative PET/MR images of sufficient quality for quantitative analysis.
7. Clinically scheduled to undergo endovascular recanalization.
8. Provision of written informed consent by the patient or their legally authorized representative.
Exclusion Criteria:
1. Acute large-territory cerebral infarction involving more than one-third of the MCA territory.
2. Extensive encephalomalacia within the affected vascular territory that precludes reliable assessment of cortical regions of interest (ROIs).
3. Non-atherosclerotic causes of MCA occlusion, including moyamoya disease, arterial dissection, central nervous system vasculitis, or cardioembolism.
4. Severe bilateral intracranial arterial occlusive disease that precludes reliable calculation of hemispheric asymmetry indices.
5. Structural lesions involving the cerebellum or brainstem that may interfere with metabolic analysis using the cerebellum as a reference region.
6. Contraindications to MRI (e.g., incompatible cardiac pacemakers, metallic foreign bodies, or severe claustrophobia) or PET imaging.
7. Severe head motion or imaging artifacts that render PET/MR, arterial spin labeling (ASL), or blood oxygen level-dependent (BOLD) imaging data unsuitable for analysis.
8. Poor glycemic control (fasting blood glucose \>11.1 mmol/L) that may compromise the quality of 18F-fluorodeoxyglucose (18F-FDG) PET imaging.
Study population
The study population will consist of patients with non-acute atherosclerotic MCA occlusion who are evaluated for recanalization at participating clinical centers.
Eligible patients undergoing clinically indicated recanalization will be invited to participate in prospective PET/MR imaging assessments and clinical follow-up.
Understand screeningTreatment, groups and participation
The registry may describe treatments and study duration without a complete visit calendar. Ask the study team for the exact schedule, procedures, risks, costs and alternatives. Keep your usual care plan unless your treating clinician tells you otherwise.
- Assignment
- Not reported
- Masking
- Not reported
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Change in Perfusion-Metabolism Abnormality Burden in the Affected Hemisphere From Baseline to 1 Month After Recanalization (ΔPMB)
Time frame: Baseline and 1 Month After Recanalization;
The cerebral perfusion-metabolism coupling index will be derived from spatially corresponding cerebral perfusion and PET-based metabolic measurements within prespecified regions of interest in the affected MCA territory. The exact coupling metric, its calculation, normalization, and interpretation will be defined in the prespecified imaging analysis protocol. The primary measure will be the within-participant change in this index between baseline and the specified follow-up visit.
Secondary measures
Change in Regional Cerebral Blood Flow From Baseline to 1 Month After Recanalization;
Time frame: Preoperative baseline and 1 month after recanalization.
Cerebral blood flow (CBF) in the affected hemisphere will be quantified using arterial spin labeling (ASL) MRI, expressed in mL/100 g/min. The change in CBF will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in Arterial Cerebral Blood Volume in the Affected Hemisphere
Time frame: Baseline and 1 Month After Recanalization;
Arterial cerebral blood volume (aCBV) in the affected hemisphere will be quantified using the prespecified ASL-derived imaging method. The change in aCBV will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in Arterial Transit Time in the Affected Hemisphere
Time frame: Baseline and 1 Month After Recanalization;
Arterial transit time (ATT) will be quantified using the prespecified ASL MRI technique and expressed in milliseconds. The change in ATT will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in 18F-FDG Standardized Uptake Value Ratio in the Affected Hemisphere
Time frame: Baseline and 1 Month After Recanalization;
Cerebral glucose metabolism will be assessed using 18F-fluorodeoxyglucose (18F-FDG) PET. The standardized uptake value ratio (SUVR) will be calculated using the prespecified reference region and expressed as a dimensionless ratio. The change in SUVR will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in Hemispheric Asymmetry Index of Cerebral Blood Flow
Time frame: Baseline and 1 Month After Recanalization;
The hemispheric asymmetry index of cerebral blood flow (CBF-AI) will be calculated from corresponding CBF measurements in the affected and contralateral hemispheres using the prespecified asymmetry formula. The change will be calculated as the index at 1 month after recanalization minus the baseline index.
Change in Hemispheric Asymmetry Index of Arterial Cerebral Blood Volume
Time frame: Baseline and 1 Month After Recanalization;
The hemispheric asymmetry index of arterial cerebral blood volume (aCBV-AI) will be derived from aCBV measurements in the affected and contralateral hemispheres using the prespecified asymmetry formula. The change will be calculated as the index at 1 month after recanalization minus the baseline index.
Change in Hemispheric Asymmetry Index of Arterial Transit Time
Time frame: Baseline and 1 Month After Recanalization;
The hemispheric asymmetry index of arterial transit time (ATT-AI) will be calculated from ATT measurements in the affected and contralateral hemispheres using the prespecified asymmetry formula. The change will be calculated as the index at 1 month after recanalization minus the baseline index.
Change in Hemispheric Asymmetry Index of 18F-FDG Standardized Uptake Value Ratio
Time frame: Baseline and 1 Month After Recanalization;
Change in Hemispheric Asymmetry Index of 18F-FDG Standardized Uptake Value Ratio
Proportion of Brain Regions Showing Spatially Concordant Perfusion and Metabolic Improvement After Recanalization
Time frame: Baseline and 1 Month After Recanalization;
Integrated PET/MR will be used to identify regions of interest (ROIs) exhibiting both perfusion improvement and metabolic improvement at 1 month after recanalization compared with preoperative baseline. Spatial coupling will be quantified as the percentage of evaluable ROIs demonstrating concordant improvement in both parameters, according to prespecified quantitative thresholds and spatial matching criteria.
Change in Global Efficiency of Resting-State Functional Brain Networks
Time frame: Baseline and 1 Month After Recanalization;
Resting-state functional MRI will be used to construct whole-brain functional connectivity networks. Global efficiency will be calculated using graph-theoretical analysis as a quantitative measure of network-wide information integration. The change in global efficiency will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in Interhemispheric Functional Connectivity Strength
Time frame: Baseline and 1 Month After Recanalization;
Interhemispheric functional connectivity will be assessed using resting-state blood oxygen level-dependent (BOLD) MRI. Connectivity strength between prespecified corresponding regions in the two hemispheres will be quantified using Fisher z-transformed correlation coefficients. The change will be calculated as the value at 1 month after recanalization minus the preoperative baseline value.
Change in Nodal Efficiency of Prespecified Brain Network Hubs
Time frame: Preoperative baseline and 1 month after recanalization.
Nodal efficiency of prespecified key brain regions will be calculated from resting-state functional connectivity networks using graph-theoretical analysis. Changes in nodal efficiency will be evaluated by comparing measurements obtained before recanalization and at 1 month after recanalization. The regions of interest and the summary metric will be defined in the prespecified imaging analysis protocol.
Correlation Between 1-Month Change in Perfusion-Metabolism Abnormality Burden and Modified Rankin Scale Score at 90 Days
Time frame: Preoperative baseline and 1 month after recanalization.
The association between the change in perfusion-metabolism abnormality burden (ΔPMB) from baseline to 1 month after recanalization and functional disability at 90 days will be assessed. Functional disability will be measured using the modified Rankin Scale (mRS), ranging from 0 (no symptoms) to 6 (death), with higher scores indicating greater disability. The association will be quantified using a prespecified correlation coefficient.
Correlation Between 1-Month Change in Perfusion-Metabolism Abnormality Burden and Barthel Index Score at 90 Days
Time frame: Preoperative baseline, 1 month after recanalization (ΔPMB), and 90 days after recanalization (Barthel Index).
The association between ΔPMB from baseline to 1 month after recanalization and activities of daily living at 90 days will be assessed. Functional independence will be measured using the Barthel Index (BI), ranging from 0 to 100, with higher scores indicating greater independence in activities of daily living. The association will be quantified using a prespecified correlation coefficient.
Correlation Between 1-Month Change in Perfusion-Metabolism Abnormality Burden and EQ-5D Health Utility Index at 90 Days
Time frame: Preoperative baseline, 1 month after recanalization (ΔPMB), and 90 days after recanalization (EQ-5D).
The association between ΔPMB from baseline to 1 month after recanalization and health-related quality of life at 90 days will be assessed using the EuroQol 5-Dimension (EQ-5D) questionnaire. EQ-5D responses will be converted into a health utility index using the prespecified instrument version and population-specific value set. Higher utility scores generally indicate better health-related quality of life. The association will be quantified using a prespecified correlation coefficient.
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (1)
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1 locations
The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan HospitalJinan, Shandong, ChinaRecruiting
Study team and timeline
- Lead sponsor
- Qianfoshan Hospital
- Study start
- Mar 21, 2024 Actual
- Primary completion
- Jan 1, 2027 Estimated
- Study completion
- Jan 1, 2027 Estimated
- First posted
- Nov 10, 2026 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
Official study title
RESTORE: A Prospective Observational Study of Perfusion-Metabolism Recoupling and Functional Network Recovery After Recanalization of Non-Acute Atherosclerotic Middle Cerebral Artery Occlusion Using Integrated PET/MR
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Source: ClinicalTrials.gov API v2. Information is submitted by sponsors and investigators. NLM does not approve the safety or science of all listed studies. Registry disclaimer.
Retrieved: Nov 12, 2026 · Last registry update: Nov 10, 2026