Insights Into the Pathophysiology of Neurovascular Uncoupling in Patients With Brain Lesions.

Condition(s) studied

Investigational drug(s) / intervention(s)

Functional MRI: 11 minutes of Functional MRI alternating breathing Air-Room and gaz mix (5%CO2 21%O2 74%N2). All procedure are acquired simultaneously on a single acquisition on the PET/MRI camera in the institution.

FDG-PET: Some patients who did not benefit from a FDG-PET in their clinical evaluation or more than 1 month before the inclusion in the present study will be ask to also undergo a brain FDG-PET , the dose is set at 2 Mega becquerel per Kg. All procedure are acquired simultaneously on a single acquisition on the PET/MRI camera in the institution.

Structural MRI: Patient will benefit Different anatomical sequence of acquisition listed here : T1 , T1 with contrast agent (gadovist) , T2 flair , T2 and DSC (Dynamic susceptibility contrast) , and Time Of Flight . All procedure are acquired simultaneously on a single acquisition on the PET/MRI camera in the institution.

Study summary

Neurovascular uncoupling (NVU) represents a major source of potential bias for the identification of eloquent brain regions through activation procedures in blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI).

Same region shows proper pattern in glucose metabolism in victiny of brain lesions, investigated with positron emitted tomography with radiolabeled glucose (PET-FDG) This research project aims at investigating the mechanisms of NVU by using a multimodal noninvasive imaging approach in neurosurgical patients.

Eligibility

Primary outcome measure(s)

• Effects of Hypercapnia administration on fMRI data — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  For brain fRMI data: BOLD signal variation (Arbitrary Unit from a percent change from baseline).
• Effects of Hypercapnia administration on PET-FDG regional standardized data. — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  For brain PET-FDG: regional SUV value (Standardized Uptake Ratio) .The SUV is a mathematically derived ratio of tissue radioactivity concentration at a point in time at a specific region of interest and the injected dose of radioactivity per kilogram of the patient's body weight
• Effects of Hypercapnia administration on PET-FDG global data — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  For brain PET-FDG: Statistical Parametric Mapping analysis (SPM) for voxel-wise comparison and multiple correlations (t-score)
• Effects of Hypercapnia administration on oxygen saturation (SpO2) — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  SpO2 Variation: Measured in percentage points (%), reflecting the change from baseline levels.
• End tidal CO2 — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  End Tidal CO2 during the experiment allow the modelisation and quantification of MRI signal among brain tissue. End tidal CO2 pressure is measured in mmHg
• Breathing Rate — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  Breathing Rate during the experiment allow the modelisation and quantification of MRI signal among brain tissue. Breathing rate is measure in respiration per minute
• Regional Cerebral Blood Volume — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  CBV represents the volume of blood present in 100 grams of brain tissue at a given time. It is used to assess the vascular capacity of the brain. unit are in mL per 100g of brain tissue .A DSC (Dynamic susceptibility contrast) -MRI is needed, the sequence involves the intravenous injection of a contrast agent, usually gadolinium-based. The contrast agent passes through the brain, and changes in the MRI signal are recorded over time.
• Regional Cerebral Blood Flow — end of acquisition ( group of 40 subject estimated at 10 months after first subjet acquisition)
  CBF measures the amount of blood flowing through 100 grams of brain tissue in one minute. This is a crucial measure for assessing cerebral perfusion and identifying areas of under- or hyperperfusion.(mL/100g/min)A DSC-MRI is needed, the sequence involves the intravenous injection of a contrast agent, usually gadolinium-based. The contrast agent passes through the brain, and changes in the MRI signal are recorded over time.

Trial sites (1)

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