This study was carried out at a tertiary cancer care center in South India between July 2013 to June 2014 after approval by the Institutional Review Board and Ethics committee.
Consecutive patients with solid/solid-cystic breast masses
BIRADS 3 or 4 lesions,
which were biopsied after ARFI elastography
2 or 5 lesions
Calcified lesions with non-calcified area <1cm
Prior biopsy/FNAC/Surgery/radiation on the same breast
In eligible patients,
Virtual Touch Imaging (VTI) and ARFI Virtual Touch tissue Quantification (VTQ) imaging were performed on Siemens ACUSON S2000 ultrasound system,
equipped with 18L6 HD (5.5-18MHz) and 9L4 (4-9MHz) linear transducers,
by one of the two radiologists,
having more than 6 years of experience in breast sonography and were also trained in VTI and VTQ imaging.
Image acquisition technique:
On conventional US,
breast lesions were detected using 18 MHz linear probe and morphologically charcterized.
Following this 9MHz probe was kept gently on the skin surface without applying any external compression,
when scanning the maximal area plane of the lesion,
fixed the probe and shifted to VTI mode,
place the region of interest (ROI) to the lesion,
asked the patient to hold the breath for a while till the appropriate VTI image was obtained.
On VTI mode,
area ratio of the lesion was calculated based on size on elastography image and conventional US image which was displayed on the monitor on left side.
the sonographer shifted to VTQ ARFI mode,
placed the ROI (size 5 mm x 5 mm) within the lesion to detect shear wave velocity in meters per second (m/s),
repeated until covered the maximum region and recorded the maximal shear wave velocity (SWV).
ARFI Data collection:
Minimum of 3 measurements of SWV were made in both,
within the lesion and the surrounding normal breast tissue at the same depth,
following which mean values were calculated.
The SWV ranging between 0-9m/s were displayed on the monitor and rest were displayed as "x.xx m/s".
Lesions with SWV of X.XX m/s,
if they appeared white on VTI image,
we recorded as score of 0 and,
9.1 when the VTI image was dark or black because stiffer the tissue,
darker the image on VTI.
quantitative values were obtained for all lesions included in this study.
Diagnostic performance of ARFI/ Shear Wave Elastography was evaluated with Reciever Operating Characteristic (ROC) curve.