Objective:To verify the applicability of Dynamic Contrast Enhanced Magnetic Resonance Imaging（DCE-MRI）to evaluate the breast cancer therapy using the high intensity focused uhrasound（HIFU）.Methods:Both DCE-MRI and conventional T

1

W/T

2

W images were acquired for the total 8 subjects.Two consecutive scans were performed for every patient（before operation and 2 weeks after operation）while four were performed for only 2 patients（additional for 6 months and 12 months after operation）.The breast cancer therapy by HIFU was assessed hy comparing the changes of signal

the dynamic patterns of time-signal intensity curve

the early-phase contrast enhancement ratios and vessel anatomies around cancer focuses.Results: The shortened T

2

signals were observed in cancer focuses of 5 subjects while 3 still showed longer T

2

values which were differentiated by the high intensity in T

2

W images.The early-phase contrast enhancement ratios of those 5 subjects decreased from 60%～80% to

<

60% after the HIFU therapy

but this was less proved for the other 3.No clear signal peaks were observed in the dynamic enhancement time-signal intensity curve for all subjects

while before the surgery

5 curves are in Type A and others in Type B.After the therapy

no enhanced complex vasculatures were discernible around cancer focuses for all subjects

compared to the clear visibility of complicated high intensity vasculatures with main vessels enlarged and curved in the pre-surgery scans.Conclusion:As a novel noninvasive imaging technique

the DCE-MRI can be used to effectively evaluate the HIFU therapy for breast cancer.