Spectroscopy Of The Breast

Spectroscopy Of The Breast

Peter Stanwell, PhD

Carolyn Mountford, D.Phil



  • Magnetic resonance spectroscopy (MRS)


  • Detectable biochemicals are distinguished by their resonance frequency, line shape, line width, phase, and peak area

Anatomy-Based Imaging Issues


  • MRS success depends on

    • Appropriate pre-acquisition set up

    • Acquisition protocol

    • Post-processing

    • Shimming for MRS acquisition is essential to overcome magnetic field inhomogeneities

  • MRS pitfalls

    • B0 inhomogeneities are often dominant factor limiting successful MRS

    • Some breast coils are not optimized for spectroscopy

    • Presence of biopsy clips may affect shimming

    • Some gadolinium-based MR agents have been shown to affect breast MRS

    • Lipids

      • Localized shimming more difficult due to abundance of adipose tissue with different susceptibility from surrounding glandular (and malignant) tissue

      • Impact of unwanted lipid signals can be reduced by decreasing amplitude of lipid signal

      • Techniques for lipid suppression exist for use in MRS

Spectroscopy Acquisition Protocols

Data Acquisition

  • Parameters set during pre-scan include power calibrations, frequency adjustment, shimming, and water suppression adjustment

    • Shimming = process by which B0 field is made as homogeneous as possible, typically using linear x-, y-, and z-gradient coils

    • Water suppression = process by which water signal is suppressed to allow detection of important metabolites

Spectroscopy Processing

Processing Steps

  • Water referencing

    • Aligns spectral resonances against water set at 4.74 ppm

    • Allows for correction of resonance distortions using water signal as reference

  • Apodization

    • In clinical application, this mathematical function is used to improve SNR

  • Zero filling

    • Method of improving spectral resolution

  • Fourier transformation

    • Converts time domain signal into frequency domain

  • Phase correction

    • Allows for correction of distortions in final spectrum

  • Baseline correction

    • Allows for correction of baseline errors in final spectrum

    • Vertical display may need to be increased to see resonances between 3.00 and 3.40 ppm

Spectra Interpretation

Malignant vs. Benign

  • Key metabolite in breast spectroscopy is choline resonance at 3.23 ppm

  • Malignant breast cancers show resonance at 3.23 ppm

  • Benign breast lesions show resonance at 3.28 ppm

    • This resonance is reported in breast tissue in lactating and other healthy women

Differential Diagnosis

Invasive Tumor

  • Early single series showed sensitivity of 100% and specificity of 88%

Ductal Carcinoma in Situ

  • Early stage DCIS (no microinvasion) has spectral characteristics of benign lesion (in vitro studies)

  • DCIS with microinvasion has same spectral profile as malignant tumor

    • These results need to be verified with larger studies

Sep 18, 2016 | Posted by in OBSTETRICS & GYNAECOLOGY IMAGING | Comments Off on Spectroscopy Of The Breast
Premium Wordpress Themes by UFO Themes