Liver pH imaging for diagnosis and prognosis

Motivation: Extracellular acidosis is a unique feature of the tumor microenvironment (TME). The low pHe can reduce the cytotoxic activity of immune T-cells and enhance the tumor-promoting phenotype of macrophages, supporting an immunosuppressive TME. Goal(s): To accurately correlate pHe with density of immune cells, imaging pHe at submillimeter resolution is necessary Approach: pHe imaging at submillimeter resolution was achieved using a special k-space sampling strategy, called REduced Spherical Encoding with GAussian Weighting (RESEGAW) Results: We demonstrate the feasibility of pHe imaging with RESEGAW at isotropic 0.6mm resolution in a mouse liver tumor model. The pHe with RESEGAW was validated using 31P MRSI with 3-APP. Impact: This study validates high-resolution pHe imaging in mouse liver tumors using RESEGAW, enabling precise, noninvasive metabolic characterization. By mapping pHe at 0.6 mm isotropic resolution, it advances understanding of TME acidity and immune dynamics, potentially guiding liver cancer therapies.