Yuan Jiang, Presenter: Nothing to Disclose

Xiaoying Wang MD, Abstract Co-Author: Nothing to Disclose

Naishan Qin, Abstract Co-Author: Nothing to Disclose

Li Guo, Abstract Co-Author: Nothing to Disclose

To retrospectively evaluate the feasibility of time intensity curve (TIC) in dynamic contrast-enhanced MR imaging (DCE-MRI) in prediction of pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) in breast cancer.

Institutional committees on clinical research and ethics approval were obtained. Eighty-four breast lesions with pathologically confirmed locally advanced breast cancer received NAC between 2007 and 2012 were reviewed, who were imaged by 1.5T MRI pre-NAC, after the second and forth cycle of NAC, with pathologic response Grade 4 (non-pCR,n=40) and Grade 5 (pCR,n=44) according to the Miller & Payne grading system. DCE-MRI was acquired every 58s to scan 124 slices. A total of 8 time points were obtained, with a bolus of Gd-DTPA at 0.1mmol/kg and injection rate 3ml/s. Scan parameters were TR/TE=6/2.6ms, matrix=324×288, slice thickness=2.4mm and spacing=-1.2mm. TIC was obtained by placing the region of interest of 20mm2 in the mass without the obvious cystic area and necrosis. The steepest slope (Smax) of TIC and change rate (⊿S%) were calculated by the formula, Smax(%/s)=(SIend-SIprior)×100/[SI0×(Tend-Tprior)], ⊿S%=[(Smax1-Smax2&3) / Smax1]×100%. SIend and SIprior represented the two consecutive points, between which was the maximum slope in the TIC. Tend and Tprior were the corresponding time of contrast agent injection. SI0 was the signal intensity pre-enhanced. Smax1 and Smax2&3 represented the Smax pre- and post-NAC. All the Smax and ⊿S% were compared with Independent-Samples t test or Mann-Whitney U test between groups. Receiver operating characteristic(ROC) analysis of the Smax and ⊿S% were used to find out the valuable parameters in predicting the pCR after NAC.

The Smax between non-pCR and pCR were not significantly different pre-NAC. After the second and forth cycle of NAC, the Smax of TIC in pCR (1.12±0.77, 0.70±0.54, /s) were significantly lower than those in non-pCR (2.02±1.08, 1.20±0.65, /s), while the ⊿S% were significantly higher in pCR (51.98%, 70.32%) than those in non-pCR (-0.95%, 44.53%) (P<0.001). Post-NAC, the areas under ROC curve of Smax were too low. But the areas under ROC curve of ⊿S% were 0.735 and 0.734.

 TIC in DCE-MRI has the potential capability in predicting pCR after NAC in breast cancer.

 DEC-MRI can be used in breast cancer-response evaluation after NAC and can help predict pCR.

Jiang, Y, Wang, X, Qin, N, Guo, L, Dynamic Contrast-enhanced MR Imaging: A Potential Predictor to Pathologic Complete Response of Breast Cancer after Neoadjuvant Chemotherapy.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13021047.html