Abstract:

Objective

To analyze the values of functional MRI, including magnetic resonance spectroscopy (MRS), dynamic contrast enhancement (DCE) and diffusion weighted image (DWI) in monitoring the early response of breast cancer to neoadjuvant chemotherapy(NCT).

Methods

Twenty-one patients with breast cancer were recruited. All the patients underwent both NCT and surgery. By evaluating histopathology from surgery, patients were divided into a significant responder group (R group) and a non-significant responder group(NR group). All the patients underwent MRI twice, including MRS, DCE and DWI, (within one week before and within three weeks after the first cycle of NCT, respectively). Four parameters, including total choline (tCho) concentration on MRS, time-signal intensity curve and lesion size on DCE, apparent diffusion coefficient (ADC) on DWI and lesion size on DCE, before and after the first cycle of NCT were compared using paired sample t test or Wilcoson nonparametric test. ROC curves were drawn and their sensitivity, specificity,positive predictive value and negative predictive value were analyzed.

Results

Among the 21 cases, 18 were grouped into the R group and 3 into the NR group. In the R group, tCho concentration, DCE time-signal curve, ADC and lesion size after the 1st cycle of NCT changed significantly, compared with those before NCT(P ＜0.050), but the tCho concentration changed the earliest, followed by DCE time-signal curve and ADC and lesion size. In the NR group, the four parameters had no significant change. The areas under the ROC curves of the four parameters were 0. 98, 0. 83, 0. 72 and 0. 63, respectively. The values of tCho concentration decrease (threshold of 35.84%), DCE time-signal curve change, ADC increase(threshold of 1. 17%) and lesion size decrease (threshold of 3. 71%) in predicting the sensitivity,specificity and positive predictive value for the early response of breast cancer to NCT were 94.4%/100.0%/100.0%, 66.7%/100.0%/100.0%, 44.4%/100.0%/100.0%and 55.6%/66.7%/90.9%, respectively.

Conclusions

Functional MRI can be used in early predicting the response of tumor to NCT. tCho concentration, DCE time-signal curve, ADC and lesion size have good positive predictive value, but tCho concentration has the highest sensitivity.

Key words: magnetic resonance spectroscopy, pharmacokinetics, diffusionweighted imaging, breast neoplasms, chemotherapy