Sickle Cell Anemia and Cerebral Microcirculation : Multimodal Exploration

Study Overview
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Brief Summary
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The aim of this study is to evaluate determinants of cerebral oxygenation and perfusion at the microcirculatory level in children with sickle cell anemia (SCA) using combined novel investigational tools: Arterial Spin Labeling (ASL) perfusion MR (Magnetic Resonnance) imaging, brain Near Infra-Red Spectroscopy (NIRS) and red blood cell (RBC) rheological properties.

Detailed Description
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The investigators hypothesize that brain perfusion and/or oxygenation modifications may be evidenced in SCA children who have no microarteriopathy and may correlate with hemorheological abnormalities and impaired vasomotion. A multimodal approach designed to study a. cerebral perfusion and oxygenation, b. flow motion properties and c. blood rheological parameters might help to describe the different processes involved in cerebral ischemia.

Official Title
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Determinants of Cerebral Oxygenation and Perfusion in SCA Children Based on Combined ASL MRI, NIRS and Hemorheological Investigation

Conditions
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Sickle Cell Disease

Intervention / Treatment
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* Procedure: Physical exams and blood analyzes


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: SS or S-beta° genotype; age 6-16 years; steady state; normal TCD (Transcranial Doppler); parental study approval and written informed consent. Exclusion Criteria: SC, Sbeta+, SD Punjab genotype history of overt stroke, intracranial or cervical arterial stenosis, abnormal TCD at the time of the study.

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sickle cell disease patients<br>Physical exams and blood analyzes | Procedure: Physical exams and blood analyzes<br>* Blood samples collection (for DNA, plasma and cells analyzes) ; Hemorheologic analyzes ; ASL sequence on MRI ; Near Infra Red Spectroscopy (NIRS) and associated cardiofrequency analyze.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of patients on which we detect default of cerebral perfusion (in order to correlate them with other clinical or biological parameters) | ASL sequence (duration 4 min) : Regional brain tissue perfusion (expressed in mL/min/100g of tissue) will be measured in different lobes in both hemispheres and in the cerebellum. Pattern of perfusion will be analysed and measured. | 1.5 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bifrontal cerebral hemoglobin oxygen saturation | Bifrontal cerebral hemoglobin oxygen saturation monitored by NIRS (15 min). Spectral analyses (Fourrier transform) will be used to analyze the brain microvascular oxygen variability and calculate the flowmotion and vasomotion activities. | 1.5 years | 
| Description of the global assessment of RBC deformability | The description of the global assessment of RBC deformability will be done via a global association of several biological parameters : RBC deformability at several shear stresses by ektacytometry, RBC aggregation properties by syllectometry and blood viscosity by cone-plate viscosimetry. Measurements will be made according to the international guidelines for standardisation in hemorheology and within 4/5 hrs of sampling | 1.5 years |