Biomedical applications of sodium MRI in vivo

Abstract

In this article, we present an up-to-date overview of the potential biomedical applications of sodium MRI in vivo. Sodium MRI is a subject of increasing interest in translational imaging research as it can give some direct and quantitative biochemical information on the tissue viability, cell integrity and function, and therefore not only help the diagnosis but also the prognosis of diseases and treatment outcomes. It has already been applied in vivo in most of human tissues, such as brain for stroke or tumor detection and therapeutic response, in breast cancer, in articular cartilage, in muscle and in kidney, and it was shown in some studies that it could provide very useful new information not available through standard proton MRI. However, this technique is still very challenging due to the low detectable sodium signal in biological tissue with MRI and hardware/software limitations of the clinical scanners. The article is divided in three parts: (1) the role of sodium in biological tissues, (2) a short review on sodium magnetic resonance, and (3) a review of some studies on sodium MRI on different organs/diseases to date.

Acute changes in extracellular volume fraction in skeletal muscle monitored by23Na NMR spectroscopy

“…2010). Depending on the organ, sensitivity of 23 Na‐NMR is 3000–20,000 times smaller than the one of 1 H (Madelin and Regatte 2013). For a sufficient SNR, long acquisition times are generally needed for sodium imaging.…”

Improved Differentiation of Benign and Malignant Breast Tumors with Multiparametric 18Fluorodeoxyglucose Positron Emission Tomography Magnetic Resonance Imaging: A Feasibility Study

“…Initial results of MP MRI with 3 parameters demonstrated a further increase in diagnostic accuracy compared with various combinations of 2 parameters (38). A further improvement in the differentiation of benign and malignant breast lesions with MP MRI can be expected by the addition or replacement of new and more sensitive parameters, such as sodium imaging (39), chemical exchange saturation transfer (CEST) imaging (40), or hyperpolarized MRSI (41). This also highlights the potential of supplemental information provided by 18 FDG-PET with hybrid imaging systems (42,43).…”

Sodium-23 Magnetic Resonance Imaging Has Potential for Improving Penumbra Detection but Not for Estimating Stroke Onset Time

“…At 8.5 T, the intracellular longitudinal relaxation time, T 1i has been determined to be monoexponential with a value of 23 ms 30 and T 1e is assumed to be similar to measured brain cerebrospinal fluid of 50 ms. 31 For further computational purposes, the following sequence parameters were extracted from the current study: TR = 23 ms, TE = 2.6 ms, and flip angle = 60°.…”