Llewellyn Sim MBBS, FRCR, Presenter: Nothing to Disclose

Lester Leong, Abstract Co-Author: Nothing to Disclose

To assess the performance and value of elastography in diagnosing breast cancer relative to conventional ultrasound.

From Sept 07 to March 08, 99 women with 110 sonographically visible breast lesions undergoing biopsy were evaluated independently with conventional ultrasound, elastography and combined ultrasound and elastography. The images were acquired with a Siemens Antares Ultrasound unit and BI-RADS scores were assigned to standardize ultrasound interpretation. The elastogram was classified as benign, malignant or equivocal; based on the strain pattern, the length and area ratios of the lesion seen on elastogram versus the ultrasound. Validation of radiological diagnosis was by histopathology. The sensitivity, specificity, PPV, NPV and accuracy of each test were compared individually and with the combination of ultrasound and elastography. To obtain a parameter for diagnostic performance, ROC curves were plotted using the BI-RADS scores and elastogram ratios and the area under the curve compared. The optimal length and area ratios to distinguish benign and malignant lesions on elastography were also obtained from the ROC curve.  

The mean age of the patients was 46.7 years. Of the 110 breast lesions, 26 were malignant and 84 were benign on histology. The sensitivity, specificity and accuracy of conventional ultrasound was 88.5%, 42.9% and 53.6% respectively. The sensitivity, specificity and accuracy of elastography was 96.2%, 75% and 80% respectively, and that of combined ultrasound and elastography was 84.6%, 79.8% and 80.9% respectively. The results obtained by the latter two were significantly better than conventional ultrasound (P<0.0005). The optimal length and area ratios to distinguish benign and malignant lesions on elastography were both 1.12, which gave the best overall sensitivity, specificity and accuracy.  

Breast elastography has a higher sensitivity, specificity and accuracy than conventional ultrasound. Combining both evaluations gives higher specificity, the same accuracy but reduces sensitivity, relative to elastography alone. The use of breast elastography alone or combined with ultrasound provides more accurate diagnosis of breast cancer.

The better performance of breast elastography improves sonographic diagnosis of breast cancer, re-inforces a benign ultrasound finding and potentially reduces unnecessary biopsies.

Sim, L, Leong, L, Clinical Use of Elastography in Diagnosing Breast Cancer.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009434.html