Dynamic contrast-enhanced MRI texture analysis for pretreatment prediction of clinical and pathological response to neoadjuvant chemotherapy in patients with locally advanced breast cancer.

The aim of this study was to investigate the potential of texture analysis, applied to dynamic contrast-enhanced MRI (DCE-MRI), to predict the clinical and pathological response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer (LABC) before NAC is started. Fifty-eight patients with LABC were classified on the basis of their clinical response according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines after four cycles of NAC, and according to their pathological response after surgery. T1 -weighted DCE-MRI with a temporal resolution of 1 min was acquired on a 3-T Siemens Trio scanner using a dedicated four-channel breast coil before the onset of treatment. Each lesion was segmented semi-automatically using the 2-min post-contrast subtracted image. Sixteen texture features were obtained at each non-subtracted post-contrast time point using a gray level co-occurrence matrix. Appropriate statistical analyses were performed and false discovery rate-based q values were reported to correct for multiple comparisons. Statistically significant results were found at 1-3 min post-contrast for various texture features for the prediction of both the clinical and pathological response. In particular, eight texture features were found to be statistically significant at 2 min post-contrast, the most significant feature yielding an area under the curve (AUC) of 0.77 for response prediction for stable disease versus complete responders after four cycles of NAC. In addition, four texture features were found to be significant at the same time point, with an AUC of 0.69 for response prediction using the most significant feature for classification based on the pathological response. Our results suggest that texture analysis could provide clinicians with additional information to increase the accuracy of prediction of an individual response before NAC is started.

Monitoring neoadjuvant chemotherapy in breast cancer patients: improved MR assessment at 3 T?

PURPOSE: To investigate possible improvements in predicting the response to neoadjuvant chemotherapy (NAC) at 3 T for locally advanced breast cancer (LABC). MATERIALS AND METHODS: Dynamic contrast-enhanced magnetic resonance (DCE-MR) images acquired before and during NAC were retrospectively analyzed in 85 patients. Tumor volume and diameter, three volumes based on the shape of the enhancement curve, relative signal intensity, area under the curve, and the signal-to-noise ratio were extracted. Differences between responders and nonresponders at the same and between MR timepoints during treatment were evaluated. RESULTS: A higher signal-to-noise ratio was observed on 3 T images compared to 1.5 T, and 3 T revealed more significant findings related to response compared to 1.5 T. The DCE-MRI-derived volume parameters were the earliest predictors of response at both 1.5 and 3 T. CONCLUSION: Our results show that 3 T provides an improved assessment of the response to NAC in LABC patients, where the MR determined tumor volume reduction before the second cycle of NAC was the strongest and earliest predictor of a response.

Diffusion-weighted and dynamic contrast-enhanced MRI in evaluation of early treatment effects during neoadjuvant chemotherapy in breast cancer patients.

PURPOSE: To use dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI at 3 Tesla (T) for early evaluation of treatment effects in breast cancer patients undergoing neoadjuvant chemotherapy (NAC), and assess the reliability of DW-MRI. MATERIALS AND METHODS: DW- and DCE-MRI acquisitions of 15 breast cancer patients were performed before and after one cycle of NAC. MRI tumor diameter and volume, apparent diffusion coefficient (ADC) and kinetic parameters (K(trans), v(e)) were derived. The reliability of ADC before NAC was assessed. Changes in MRI parameters after NAC were analyzed, and logistic regression analysis was used to find the best predictors for pathologic response. RESULTS: The reliability for ADC values was high, with intraclass correlation coefficient of 0.84 (P = 0.001). After one cycle of NAC, MRI tumor diameter (8%, P = 0.005) and tumor volume (30%, P = 0.008) was reduced for all patients, while ADC mean values increased (0.12 mm(2)/s, P = 0.008). The best predictor for treatment response was a change in MRI tumor diameter with mean error rate of 0.167 (13% for responders, 5% for nonresponders, P = 0.291). CONCLUSION: Changes in MRI derived tumor diameter and ADC after only one cycle of NAC could provide a valuable tool for early evaluation of treatment effects in breast cancer patients.

In vivo MRS of locally advanced breast cancer: characteristics related to negative or positive choline detection and early monitoring of treatment response.

OBJECT: To explore factors determining the detection of total choline (tCho) by in vivo MR spectroscopy (MRS) in locally advanced breast cancer and to evaluate the ability of in vivo tCho to predict treatment response after one cycle of neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: Breast cancer patients (N=40) scheduled for NAC were examined with an MR protocol including in vivo single voxel proton MRS, dynamic contrast enhanced MRI and diffusion weighted MRI. tCho was quantified based on the signal-to-noise ratio. The detection was considered positive with tCho signal-to-noise ratio≥2. RESULTS: tCho was detected in 60% of the patients. Excellent reliability in tCho (ICC=0.97, P<0.001) measurements was confirmed. The water/fat-ratio, tumor volume and distribution of Type II voxels (based on contrast uptake curve) were significantly higher in patients with positive choline detection. The probability of detecting tCho was higher in ER-negative patients. A significant decrease in tChoSNR was detected after treatment, but responders could not be distinguished from non-responders. CONCLUSION: The use of in vivo MRS in breast cancer diagnosis and treatment monitoring should bring supplementary information to the standard MR imaging protocol. With the currently observed low choline detection rate, this is not the case, and technological challenges related to choline detection have to be resolved.

Prognostic value of pretreatment dynamic contrast-enhanced MR imaging in breast cancer patients receiving neoadjuvant chemotherapy: overall survival predicted from combined time course and volume analysis.

BACKGROUND: The prognostic value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in breast cancer has been explored, and the results are promising. PURPOSE: To investigate the possible correlation between pretreatment DCE-MRI and overall survival 5 years after diagnosis in breast cancer patients receiving neoadjuvant chemotherapy (NAC) using combined time course analysis and volume measurement from DCE-MRI data acquired with 1 min temporal resolution. MATERIAL AND METHODS: Pretreatment DCE-MR images of 32 female patients were examined. The total enhancing volume was calculated by including the voxels with >60% signal enhancing 1 min postcontrast. The signal intensity time course data were automatically classified on a voxel-by-voxel basis according to the enhancing characteristics: persistent (type I), plateau (type II) or washout (type III), and the resulting volumes of each enhancement type were calculated. RESULTS: A significant correlation between total enhancing volume and 5-year survival was found, P=0.05 (log-rank). The survival was 51 +/-15 months (mean +/-95% confidence intervals (CI)) and 73+/-12 months in patients with a total enhancing volume >41 cm(3) and < or =41 cm(3), respectively. A two-dimensional discriminator, taking both total enhancing volume and type III enhancing volume into account, improved the prediction of survival, resulting in a P value (log-rank) between survivors and non-survivors of <0.001. The survival was 44+/-16 months (mean +/-95% CI) and 74+/-11 months in patients with a total enhancing volume >58 cm(3) and/or a type III volume >8 cm(3), and < or =58 cm(3) and < or =8 cm(3), respectively. CONCLUSION: Pretreatment DCE-MRI might help in predicting prognosis in breast cancer patients receiving NAC.