Volume localized in vivo proton MR spectroscopy of breast carcinoma: variation of water-fat ratio in patients receiving chemotherapy.

Results are reported on in vivo volume localized proton magnetic resonance spectroscopy (MRS) of patients (n = 44) suffering from carcinoma of the breast, using a bilateral breast surface coil. Localized proton MR spectra of the unaffected contralateral breast of these patients are dominated by resonances arising from fat and are similar to the breast tissue from normal volunteers (controls, n = 13), while in the malignant breast tissues the water resonance dominates. On the other hand, the water suppressed proton MR spectra of malignant breast tissue reveal several metabolites of low concentration including the choline peak around 3.2 ppm and other resonances attributable to purine and pyrimidine nucleotides, in the 8.5 ppm region. Elevated water- fat (W-F) ratios are measured in the malignant tissues, compared with the normal breast tissue of controls and from the contralateral unaffected breast tissue of the patients (n = 11). In the case of patients receiving chemotherapy resulting in the reduction of primary tumor size, the W-F ratio shows a statistically significant (P < 0.01) decrease compared with the pre-therapy value, thus providing a non-invasive indicator of favourable clinical outcome of neoadjuvant chemotherapy for locally advanced breast cancer. The method provides the potential for non-invasively monitoring and assessing the response of breast cancer to neoadjuvant chemotherapy.