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How is spectroscopy used in magnetic resonance imaging of soft tissue?

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It is important to clarify that while magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) utilize the same underlying technology, they serve different diagnostic purposes. MRI is primarily used to visualize the anatomy of soft tissues, whereas MRS is used to analyze their chemical composition.

In the context of soft tissue imaging, the process works as follows:

Mechanism: The body is placed in a strong magnetic field, and high-frequency radio waves are applied. Hydrogen nuclei (protons) in the body's water and lipids absorb and reemit these waves at specific frequencies.12
Image Construction: A computer analyzes these emissions to construct high-contrast images of anatomic structures based on the density and distribution of hydrogen nuclei.2
Differentiation: Because different tissues have varying concentrations of water and lipids, the technique effectively differentiates between normal, diseased, or damaged soft tissues, allowing for the detection of tumors, lesions, and other abnormalities.12

While MRI focuses on structural visualization, MRS measures the concentration of specific metabolites, such as neurotransmitters, to provide metabolic information about tissues.3