[Functional MRI 2.0. ²³Na and CEST imaging].

Area of Science:

• Radiology and Medical Imaging
• Biophysics
• Biomedical Engineering

Background:

• Morphological magnetic resonance imaging (MRI) is complemented by functional imaging techniques like diffusion-weighted imaging (DWI) for enhanced diagnostic information.
• Emerging MRI techniques offer novel ways to visualize physiological processes, moving beyond conventional structural imaging.

Purpose of the Study:

• To review two advanced functional MRI techniques: X-nuclei imaging (specifically sodium-23 MRI) and chemical exchange saturation transfer (CEST) imaging.
• To introduce the technical principles, challenges, benefits, and drawbacks of these novel MRI methods.
• To highlight the potential clinical applications of sodium-23 MRI and CEST imaging across various medical specialties.

Main Methods:

• X-nuclei imaging utilizes the spin of nuclei other than hydrogen, such as sodium-23 (23Na), for image acquisition, providing unique physiological data.
• Chemical exchange saturation transfer (CEST) imaging detects proton exchange processes between metabolites and free water, revealing biochemical information.
• A comprehensive review of the technical underpinnings and comparative advantages/disadvantages of these advanced MRI techniques.

Main Results:

• Sodium-23 MRI offers a distinct imaging modality by leveraging the magnetic properties of sodium ions.
• CEST imaging provides insights into metabolic processes by quantifying the exchange of protons between water and other molecules.
• Potential applications span neuroimaging (stroke, tumors), musculoskeletal imaging (osteoarthritis), and abdominal imaging (kidney function, hypertension).

Conclusions:

• X-nuclei (sodium-23) MRI and CEST imaging represent significant advancements in functional MRI, offering new physiological insights.
• These techniques hold considerable promise for future clinical diagnostics but are currently under extensive evaluation in academic centers.
• Further research and validation are needed to fully integrate these powerful imaging tools into routine clinical practice.