We measure sodium in breast lesions, which allows us to monitor cell viability that is characterized by ion homeostasis maintained by the Na+/K+ pump.

Our unique hardware, pulse sequences and processing pipeline allow us to measure intracellular sodium concentration (C1) and extracellular volume fraction (α2) that can indicate loss of ion homeostasis and/or inflammation. These parameters provide direct insight on breast tumor metabolism, which may serve as an early predictor of patient response to chemotherapy. We aim to identify non-responders early in the treatment process so that they avoid ineffective toxic treatment and are guided to alternative options.

Traditional MR images illustrate a 2.9 cm invasive adenocarcinoma (bottom left). The quantitative sodium maps (bottom right, 5mm isotropic resolution) show a significant local C1 increase in the tumor and α2 in the tumor and adjacent tissue, indicating a malignant tumor with inflammation. C1 and α2 values are within the expected range for healthy tissue (top row).

 

We build sodium MRI coils to quantify the glycosaminoglycan content in knee cartilage, which may allow early osteoarthritis detection

Sodium is difficult to measure because it is not abundant in cartilage (~250 mmol/L) and  the sodium nuclei has inherently low receptivity (associated with a low gyromagnetic ratio that causes both reduced polarization and lower coil sensitivity). These factors result in a sodium MRI signal that is approximately 4,000 times lower than the proton signal. We alleviate this fundamental disadvantage by implementing custom multi-channel dual-nuclei coils that exploit the improved signal strength available at high-field and utilize a new wideband matching technique that reduces preamplifier noise coupling, which is particularly relevant in sodium MRI that operates at low frequencies. Our developments enable us to acquire proton and sodium cartilage measurements in a single examination.