Appropriate timing of proton MR spectroscopy in breast cancer.

Proton magnetic resonance (MR) spectroscopy (MRS) of the mammary gland region has customarily been used in basic research but is now commonly performed in clinical practice as MR techniques have improved. To debate its usefulness in a variety of fields and ultimately grade the timing of its use, a symposium entitled "Clinical Application and the Latest Technology of MRS-Timing of the Addition of MRS" was presented in 2009 at the 37th Annual Meeting of the Japanese Society for Magnetic Resonance in Medicine (JSMRM). MRS timing was classified into 3 grades according to when its addition: is always better, Grade 1; will sometimes be effective, Grade 2; and can provide only supplemental information, Grade 3. We describe the content of the meeting session on "Timing of the Addition of MRS in the Breast Cancer Field," explain the reasons for the timing classifications, and review previous papers.