What Does MRI Spectroscopy Do?, Key Metabolites Analyzed in Brain MRS, How Is It Performed?,

MRI Spectroscopy (MRS) – Overview

MRI Spectroscopy (MRS), or Magnetic Resonance Spectroscopy, is an advanced MRI technique used to analyze the chemical composition of tissues, especially in the brain.

What Does MRI Spectroscopy Do?

Instead of creating detailed anatomical images like conventional MRI, MRS provides a spectrum of metabolites (biochemical markers) in tissues, helping identify abnormalities at a molecular level.

Key Metabolites Analyzed in Brain MRS:

Metabolite	Abbreviation	Significance
N-Acetylaspartate	NAA	Marker of healthy neurons. ↓ in tumors, stroke, MS.
Choline	Cho	Reflects cell membrane turnover. ↑ in tumors, demyelination.
Creatine	Cr	Energy metabolism marker. Used as internal reference.
Lactate	Lac	Sign of anaerobic metabolism. ↑ in abscess, infarct, tumor.
Myo-Inositol	mI	↑ in gliosis, Alzheimer’s disease.
Lipids	Lip	Present in necrosis or high-grade tumors.

Common Clinical Applications:

🧠 Brain

• Differentiation between tumor vs abscess

• Grading of brain tumors

• Radiation necrosis vs tumor recurrence

• Metabolic disorders (e.g., leukodystrophies)

• Epilepsy localization

• Alzheimer’s disease and other dementias

🎯 Other Organs (less common use):

• Prostate MRS: Evaluate cancer aggressiveness.

• Breast MRS: Detect malignant vs benign lesions.

How Is It Performed?

• Done after a routine MRI scan.

• A small voxel (volume of interest) is selected (e.g., in a brain lesion).

• Spectral data is acquired and plotted as peaks.

• Each peak represents a metabolite.

Sample MR Spectroscopy Graph:

(NAA ↓, Cho ↑, Lipid ↑ → suggestive of high-grade glioma)

mri spectroscopy result graf

Why Is MRS Important?

• Non-invasive metabolic biopsy

• Helps differentiate tumor types

• Guides biopsy location and treatment planning

• Adds diagnostic value to conventional MRI

SVS vs MVS in MR Spectroscopy

Feature	SVS (Single Voxel Spectroscopy)	MVS (Multi Voxel Spectroscopy) / CSI (Chemical Shift Imaging)
📍 Voxel Count	One voxel	Multiple voxels (grid of small voxels)
🧠 Coverage Area	Small, localized region	Larger area (e.g., whole lesion or hemisphere)
🕒 Scan Time	Shorter (typically 2–5 mins)	Longer (5–10+ mins)
📊 Data Output	One spectrum	Multiple spectra (spectral map)
📌 Use Case	Focused lesion (e.g., tumor core)	Tumor with edema, infiltration, or multifocal disease
🧰 Ease of Use	Simpler to plan and analyze	More complex to plan and interpret
📷 Example	One single spectrum graph	Metabolic map overlaid on MRI images

When to Use svs and mvs?

• SVS (Single Voxel Spectroscopy):

  • Small, well-localized lesion

  • Quick diagnostic answer

  • Common in clinical routine

• MVS (Multi Voxel Spectroscopy):

  • Larger or heterogeneous tumors

  • Suspected infiltration or multifocal pathology

  • Research or surgical planning