Imaging Metabolico Al Carbonio 13 Iperpolarizzato: Stato Dell'arte

TL;DR

This paper reviews the state of the art in hyperpolarized 13C MRI imaging, highlighting recent techniques to enhance substrate polarization for improved diagnostic imaging.

Contribution

It provides a comprehensive overview of current methods and advancements in hyperpolarized 13C MRI imaging techniques and contrast agents.

Findings

Hyperpolarized agents significantly increase MRI signal strength.

Recent techniques extend the lifetime of hyperpolarized states.

Enhanced contrast agents improve diagnostic accuracy.

Abstract

Magnetic Resonance Imaging (MRI) can be considered one of the most effective techniques in both clinical diagnostic medical field and biomedicine, as it allows to obtain images anatomy of the body and its various parts and information functional, such as flow, perfusion, diffusion, motion, etc.. It is based on the interaction of nuclei with magnetic spin number different from zero with the magnetic field outside and, in theory, could be used for the analysis of different nuclei, such as 1H, 13C, 31P (endogenous) or 129 Xe, 3He (Exogenous). In practice, however, the clinical use of MRI is limited analysis of 1H that, compared to the others, manifest the highest concentration in the human body. The use of contrast media usually lengthens the execution time of an examination of MRI. These, however, would greatly directly reduce by increasing the intensity of the substrate signal. This can be achieved through an increase in the substrate polarization via the creation of an equilibrium state where the population difference between levels is increased. This state is called hyperpolarized. In recent years have been designed and developed several techniques for achieving this goal. Hyperpolarized contrast agents therefore act very differently from classical ones, because, instead of modifying the signal due the protons surrounding themselves, become themselves a source of signal. In order to be functional such contrast agents should be characterized by a high longitudinal relaxation time T1, because the hyperpolarized state must remain as long as possible after injection into the circulatory system of the patient.