Toward Noninvasive High-Resolution In Vivo pH Mapping in Brain Tumors by 31P-Informed deepCEST MRI

Schüre JR, Rajput JR, Shrestha M, Deichmann R, Hattingen E, Maier A, Nagel AM, Dörfler A, Steidl E, Zaiß M (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Book Volume: 38

Article Number: e70060

Journal Issue: 6

DOI: 10.1002/nbm.70060

Abstract

The intracellular pH (pHi) is critical for understanding various pathologies, including brain tumors. While conventional pHi measurement through ³¹P-MRS suffers from low spatial resolution and long scan times, ¹H-based APT-CEST imaging offers higher resolution with shorter scan times. This study aims to directly predict ³¹P-pHi maps from CEST data by using a fully connected neuronal network. Fifteen tumor patients were scanned on a 3-T Siemens PRISMA scanner and received ¹H-based CEST and T1 measurement, as well as ³¹P-MRS. A neural network was trained voxel-wise on CEST and T1 data to predict ³¹P-pHi values, using data from 11 patients for training and 4 for testing. The predicted pHi maps were additionally down-sampled to the original the ³¹P-pHi resolution, to be able to calculate the RMSE and analyze the correlation, while higher resolved predictions were compared with conventional CEST metrics. The results demonstrated a general correspondence between the predicted deepCEST pHi maps and the measured ³¹P-pHi in test patients. However, slight discrepancies were also observed, with a RMSE of 0.04 pH units in tumor regions. High-resolution predictions revealed tumor heterogeneity and features not visible in conventional CEST data, suggesting the model captures unique pH information and is not simply a T1 segmentation. The deepCEST pHi neural network enables the APT-CEST hidden pH-sensitivity and offers pHi maps with higher spatial resolution in shorter scan time compared with ³¹P-MRS. Although this approach is constrained by the limitations of the acquired data, it can be extended with additional CEST features for future studies, thereby offering a promising approach for 3D pH imaging in a clinical environment.

Authors with CRIS profile

Involved external institutions

Goethe-Universität Frankfurt am Main Germany (DE) Universitätsklinikum Frankfurt am Main (KGU) Germany (DE)

How to cite

APA:

Schüre, J.-R., Rajput, J.R., Shrestha, M., Deichmann, R., Hattingen, E., Maier, A.,... Zaiß, M. (2025). Toward Noninvasive High-Resolution In Vivo pH Mapping in Brain Tumors by 31P-Informed deepCEST MRI. NMR in Biomedicine, 38(6). https://doi.org/10.1002/nbm.70060

MLA:

Schüre, Jan-Rüdiger, et al. "Toward Noninvasive High-Resolution In Vivo pH Mapping in Brain Tumors by 31P-Informed deepCEST MRI." NMR in Biomedicine 38.6 (2025).

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