Long Lived NMR Signal in Bone

TL;DR

This paper demonstrates the excitation of long-lived NMR signals in bone tissue, challenging previous beliefs and opening new possibilities for high-resolution MRI of rigid tissues.

Contribution

It reveals that dipolar coupling networks are essential for long-lived NMR signals in bone, enabling improved MRI imaging of rigid tissues.

Findings

Long-lived NMR signals can be excited in cortical bone.

Dipolar coupling networks are crucial for these signals.

Potential for enhanced MRI of rigid tissues.

Abstract

Solids and rigid tissues such as bone, ligaments, and tendons, typically appear dark in magnetic resonance imaging (MRI), which is due to the extremely short-lived proton nuclear magnetic resonance (NMR) signals. This short lifetime is due to strong dipolar interactions between immobilized proton spins, which render it challenging to detect these signals with sufficient resolution and sensitivity. Here we show the possibility of exciting long-lived signals in cortical bone tissue with a signature consistent with that of bound water signals. Contrary to long-standing belief, it is further shown that dipolar coupling networks are an integral requirement for the excitation of these long-lived signals. The use of these signals could enhance the ability to visualize rigid tissues and solid samples with high sensitivity, resolution, and specificity via MRI.