Lesion T2 relaxation times and volumes predict the response of malignant breast lesions to neoadjuvant chemotherapy

The aim of this study was to investigate the utility of the water T2 values of malignant breast lesions in predicting response after the first and second cycles of neoadjuvant chemotherapy (NAC), both alone and in combination with lesion volumes. Thirty-five patients were scanned before the commencement of chemotherapy and again after the first, second and final treatment cycles. Two methods of obtaining lesion T2 were used: imaging, where a series of T2-weighted images was acquired (TR/TE=1000/30, 60, 90 and 120 ms), and spectroscopy, where the T2 value of unsuppressed water signal was determined with a multiecho sequence (TR=1.5 s; initial TE=35 ms; 64 steps of 2.5 ms; 2 unsuppressed acquisitions per TE). Lesion volumes were computed from contrast-enhanced 3D fat-suppressed images. The study found that, using the imaging method of obtaining T2, the ratio of the product of lesion T2 and volume after the second cycle of NAC to pretreatment value is a good predictor of ultimate lesion response, defined as a ≥65% reduction in tumor volume after the final treatment cycle, with positive and negative predictive values of 95.5% and 84.6%, respectively.