Towards applying NMR relaxometry as a diagnostic tool for bone and soft tissue sarcomas: a pilot study

Elzbieta Masiewicz,Danuta Kruk,George P Ashcroft,Sinclair R Dundas,David Boddie,Lionel M Broche

doi:10.1038/s41598-020-71067-x

Abstract

This work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients. We present the results of an ex vivo pilot study involving 10 cases of biopsy-proven sarcoma and we propose a quantitative method to analyse 1H NMR relaxation dispersion profiles based on a model-free approach describing the main dynamical processes in the tissues and assessing the amplitude of the Quadrupole Relaxation Enhancement effects due to 14N. This approach showed five distinct groups of dispersion profiles indicating five discrete categories of sarcoma, with differences attributable to microstructure and rigidity. Data from tissues surrounding sarcomas indicated very significant variations with the proximity to tumour, which may be attributed to varying water content but also to tissue remodelling processes due to the sarcoma. This pilot study illustrates the potential of FFC relaxometry for the detection and characterisation of sarcoma.

Highlights

This work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients
This profile is a quantitative measurement of molecular dynamics occurring on timescales of ms to ns within the material under study, providing unique insights on tissue structure non-invasively
This in turn should affect the overall dynamics of water and proteins, which should be quantifiable by R1 relaxometry

Summary

Introduction

This work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients. We present the results of an ex vivo pilot study involving 10 cases of biopsy-proven sarcoma and we propose a quantitative method to analyse 1H NMR relaxation dispersion profiles based on a model-free approach describing the main dynamical processes in the tissues and assessing the amplitude of the Quadrupole Relaxation Enhancement effects due to 14N. FFC methods repeat the measurement of R1 over a range of magnetic field strengths to obtain a profile of R1 variations as a function of the proton NMR resonant frequency ( ωH ), referred to as a relaxation dispersion profile This profile is a quantitative measurement of molecular dynamics occurring on timescales of ms to ns within the material under study, providing unique insights on tissue structure non-invasively. QRE effects have been observed for tissues and its amplitude has been correlated with the fraction of immobilized p roteins[34,35,36]

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Discussion

Conclusion