SC#2 – Quantitative and UHF SC MRI

Research Works

The project, initially based on small animal MR investigations , now largely relies on developments directed toward human explorations.

This particularly includes: morphology, structure, perfusion, metabolism and function assessments using  quantitative and Ultra-High Field MR methods.

Investigations performed at both high field (3T) and ultra-high field (7T) are directed toward spinal cord tissue characterization in normal and pathological conditions .

Main achievements and current activities:

• Morphometric characteristics of the spinal cord (CSA, WM/GM area, AP/RL diameters, shape..) have been investigated along the entire spinal cord, leading to a normative morphometric database (age, gender) and to the identification of SC invariants. Database available upon request. Such results allowed building the first SC probabilistic atlases of the white and gray matter (AMU15, AMU40) now included in the Spinal Cord Toolbox . This database was also used to feed the Spine Model for Safety and Surgery (SM2S) used for biomechanical simulations (cf. iLab-Spine activities) .
• Developments directed toward the microstructural description of the spinal cord have also been achieved. Recent results especially concern MP2RAGE optimization for SC WM/GM and MS lesion delineation as well as ihMT methods for whole cervical spinal cord imaging.
• Researches also focus on perfusion assessment using different endogenous (ASL, IVIM) and exogeneous (DSC, DCE) strategies. Given the challenges related to SC blood flow measurements, especially sensitivity, current investigations are conducted at both 3T and 7T.
• Further investigations directed toward very high resolution and new contrasts are  concurrently conducted on our whole-body 7T MR system using a dedicated 8Tx/8Rx SC coil. Multimodal methodologies are developed and optimized to overcome the challenges related to ultra-high field. Quantitative MR protocols now include very high-resolution T2*, T1 and Diffusion Imaging. A new SC template has also been proposed (7T AMU) and further improvements are under investigation.
• Different clinical research protocols focusing in MS and ALS are on-going.
• Multicentric studies are conducted as well. If interested by our protocols, please contact us.
• Parallel transmission (pTx) developments are now also on-going in order to overcome some of the limitations encountered when imaging the cord at 7T (SAR, RF inhomogeneities, ..).

Key-words : Morphometry, inhomogeneous Magnetization Transfer (ihMT), MP2RAGE, T1 relaxometry, Perfusion, Intra Voxel Incoherent Motion (IVIM), Dynamic Susceptibility Contrast (DSC), Dynamic Contrast Enhancement (DCE), 7T, Diffusion, White Matter, Gray Matter, parallel transmission (pTx)

Acknowledgments : we strongly acknowledge grant supports from Fondation ARSEP, Fondation Latran, Institut CARNOT Star, Institut Marseille Imaging, DOC2AMU, NeuroAMU and ANR.