[Basics of MRI technique and MRI image interpretation]

Area of Science:

• Medical Imaging
• Biophysics

Background:

• Magnetic Resonance Imaging (MRI) is a cornerstone of modern diagnostic imaging in orthopaedics.
• It leverages the principle of nuclear magnetic resonance, specifically the behavior of hydrogen atoms in a magnetic field.
• Variations in tissue water content significantly influence MRI signal characteristics.

Purpose of the Study:

• To explain the fundamental principles of MRI signal generation.
• To describe how different tissue compositions and substances affect MRI image appearance.
• To outline the advantages and limitations of MRI in orthopaedics.

Main Methods:

• Explanation of the nuclear magnetic resonance phenomenon.
• Description of how hydrogen atoms interact with magnetic and electromagnetic fields.
• Analysis of factors influencing MR signal intensity, including water content, fat, proteins, and paramagnetic materials.

Main Results:

• Higher tissue water content generally results in high MR signals, indicative of conditions like blastomas, inflammation, and degenerative changes.
• Water-deficient tissues (calcified, fibrous, tendons, ligaments) exhibit low MR signals.
• Fatty tissues display high signals, while dissolved proteins alter water signals. Paramagnetic materials and flow also influence image contrast.

Conclusions:

• MRI provides detailed imaging without ionizing radiation, offering multi-planar views.
• High costs and limited availability are current drawbacks.
• Future advancements promise faster imaging and expanded applications, including MR fluoroscopy and interventions.