Accuracy of Contrast-Enhanced Ultrasound Compared With Magnetic Resonance Imaging in Assessing the Tumor Response After Neoadjuvant Chemotherapy for Breast Cancer.
OBJECTIVE
This pilot study compared contrast enhanced ultrasound (US) with contrast-enhanced magnetic resonance imaging (MRI) in assessing the treatment response in patients with breast cancer receiving preoperative neoadjuvant chemotherapy (NAC).


METHODS
This prospective Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study included 30 patients, from January 2014 to October 2015, with invasive breast cancer detected by mammography, conventional US imaging, or both and scheduled for NAC. Informed consent was obtained. Contrast-enhanced US (perflutren lipid microspheres, 10 μL/kg) and MRI (gadopentetate dimeglumine, 0.1 mmol/kg) scans were performed at baseline before starting NAC and after completing NAC before surgery. Results of the imaging techniques were compared with each other and with histopathologic findings obtained at surgery using the Spearman correlation. Tumor size and enhancement parameters were compared for 15 patients with contrast-enhanced US, MRI, and surgical pathologic findings.


RESULTS
The median tumor size at baseline was 3.1 cm on both contrast-enhanced US and MRI scans. The Spearman correlation showed strong agreement in tumor size at baseline between contrast-enhanced US and MRI (r = 0.88; P < .001) but less agreement in tumor size after NAC (r = 0.66; P = .004). Trends suggested that contrast-enhanced US (r = 0.75; P < .001) had a better correlation than MRI (r = 0.42; P = .095) with tumor size at surgery. Contrast-enhanced US was as effective as MRI in predicting a complete pathologic response (4 patients; 75.0% accuracy for both) and a non-complete pathologic response (11 patients; 72.7% accuracy for both).


CONCLUSIONS
Contrast enhanced US is a valuable imaging modality for assessing the treatment response in patients receiving NAC and had a comparable correlation as MRI with breast cancer size at surgery.
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Sandy C
SC
Lee
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Edward
E
Grant
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Pulin
P
Sheth
Department of Internal Medicine, Section of Hematology/Oncology, Louisiana State University, New Orleans, Louisiana, USA.
Agustin A
AA
Garcia
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Bhushan
B
Desai
Department of Preventive Medicine , Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Lingyun
L
Ji
Department of Preventive Medicine , Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Susan
S
Groshen
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Darryl
D
Hwang
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Mary
M
Yamashita
Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Linda
L
Hovanessian-Larsen
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D010865:Pilot Projects; D011446:Prospective Studies; D016896:Treatment Outcome; D016217:Ultrasonography, Mammary / Q000379:methods*; D055815:Young Adult
D000970:Antineoplastic Agents; D003287:Contrast Media
breast cancer; breast ultrasound; contrast-enhanced ultrasound; magnetic resonance imaging; neoadjuvant chemotherapy; ultrasound