Abstract P2-03-02: A non-invasive modality the US virtual touch tissue quantification (VTTQ) for evaluation of breast cancer
Authors: Tamaki K , Tamaki N , Kamada Y , Uehara K , Sasano H , Miyashita M , Ishida T , Ohuchi N 
Published: August 2014

Abstract
Introduction
Acoustic radiation force impulse (ARFI) imaging is a newly developed ultrasound-based modality which could evaluate the wave propagation speed and tissue stiffness more precisely and objectively. ARFI does not require any external compression, and so even in deep tissues could, provide complementary information to conventional ultrasound (US), potentially improving the characterization of tissue and focal lesions. The generated waves can provide quantification of the shear wave velocity, termed Virtual Touch Tissue Quantification (VTTQ). VTTQ is an intrinsic and reproducible property of the tissue, and this tissue quantification could provide objective and reproducible data. This is the first study to evaluate the biological features of breast tissues using newly developed non-invasive diagnostic system VTTQ.
Methods
180 patients including 115 invasive ductal carcinoma (IDC), 30 ductal carcinoma in situ (DCIS), 4 mucinous carcinoma, 7 invasive lobular carcinoma (ILC), 8 fibroadenoma (FA), 12 fibrocystic change (FCC) and 4 intraductal papilloma were studied at Nahanishi Clinic Okinawa. We first compared results of VTTQ according to each histological subtype, and determined the optimal cutoff values for VTTQ to distinguish benign from malignant tissues using the receiver operating characteristic (ROC) method. In addition, we also examined the correlation between VTTQ velocities and Ki-67, estrogen receptor (ER), progesterone receptor (PgR) or human epidermal growth factor receptor 2 (HER2) in the cases of IDC using the linear regression analyses and Student's t test.
Results
There were statistically significant differences of VTTQ velocities between IDC and DCIS (P = 0.003), mucinous carcinoma (P = 0.009), FA (P&lt;0.001), papilloma (P&lt;0.001) or FCC (P&lt;0.001). There were significant differences between DCIS and FA (P = 0.016), papilloma (P&lt;0.001) or FCC (P&lt;0.001). Significant differences were also detected between mucinous carcinoma and papilloma (P&lt;0.001) or FCC (P = 0.003), between ILC and papilloma (P = 0.012) or FCC (P = 0.003) and between FA and papilloma (P = 0.030). VTTQ velocities were statistically higher in malignant cases than in benign cases (p&lt;0.05, respectively) and the best cutoff value for the VTTQ velocity which could differentiate benign from malignant cases was 2.89 m/second. There were statistically significant correlations between VTTQ velocity and Ki-67 labeling index (r = 0.338, r2 = 0.114 and P&lt;0.001), and significant inverse correlations between VTTQ and ER (r = -0.311, r2 = 0.097 and P&lt;0.001) or PgR (r = -0.361, r2 = 0.131 and P&lt;0.001) status of IDC. There was also a significant differences of the average velocities between HER2 positive (6.39±1.44 m/second) and negative (4.43±1.41 m/second) cases (P&lt;0.001).
Conclusion
VTTQ was valuable for examination of breast cancer pathology in a non-invasive fashion. The results still could suggest the value of VTTQ examination in the clinical management of breast cancer patients. VTTQ has huge potential for examining axillary lymph node status instead of sentinel lymph node biopsy, and examining the responsiveness of neoadjuvant chemotherapy in midcourse evaluation without invasive biopsy.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-02.