Monitoring Response to Neoadjuvant Chemotherapy in HER2 Negative Breast Cancer Using High-speed MR Spectroscopic Imaging

The primary objective of the study is to assess the correlation of serial high-speed MRSI of \[tCho\] with pCR following NAC in women with HNBC. The endpoint is the pCR. Hypothesis 1: Changes in \[tCho\] early during NAC (from 24 hours after the start of the first cycle until the start of the 2nd cycle of NAC) are predictive of pathologic response (using quantitative metrics of Residual Cancer Burden (RCB)1 and/or CPS+EG score 2 and radiologic response (change in lesion size on DCE-MRI). Hypothesis 2: Decreases in \[tCho\] within the tumor precede decreases in tumor volume on DCE-MRI, thus enabling earlier discrimination between responders from non-responders. The primary objective of the study is to assess the correlation of serial high-speed magnetic resonance spectroscopic imaging (MRSI) of \[tCho\] with pCR following NAC for HNBC. The secondary objective is to compare the time course of \[tCho\] on serial high-speed MRSI and tumor volume on serial DCE-MRI for predicting early NAC treatment response in HNBC. Subjects' participation will start approximately 2 weeks before initiation of neoadjuvant therapy and end after surgery. Patients will undergo up to 5 MRI scans in total as 2 are clinical MRIs and 3 are research scans. The clinical pretreatment MRI scan and a post treatment MRI scan are standard and will be ordered at the discretion of the treating provider.The post treatment MRI is done after clinical response and before surgery. This helps guide the surgeon about what amount of tissue should be removed at surgery. The minimum time between clinical and research MRI scans is 24 hours. The 3 research MRIs will be performed on a 3T Siemens scanner equipped with 16 channel Hologic breast coil. Breast anatomy will be imaged using a bilateral localizer, an axial T 2-weighted turbo-spin-echo scan, and a fat-suppressed T1-weighted sagittal gradient echo scan. Dynamic non-fat-suppressed T1-weighted axial 3D GRE scans are collected before and with 20s delay at four time points after Gd-HP-DO3A administration (total scan time: 7.5 min). Subtraction images are created using the pre-contrast image as the mask. A diffusion weighted multi-slice EPI scan will be performed to compute apparent diffusion coefficient (ADC) maps online (total scan time: 3:14 min). An axial low-resolution multi-slice multi-echo gradient echo scan will be performed to compute field maps for slice and laterality specific auto-shimming. Spectroscopic imaging will be performed using 3D PEPSI. The MR measurement protocol will be performed at 3 time points: (1) prior to treatment typically several days before NAC (ideally 24h before NAC) (MRSI, DW-MRI, DCE-MRI), (2) 20-52 hours after the beginning of the first cycle of NAC (MRSI, DW-MRI), and (3) between the first and second cycle of NAC (MRSI, DW-MRI, DCE-MRI). Surgery will be performed within 3 to 12 weeks of last chemotherapy. RCB will be obtained from the final pathologic findings.