Can endoscopic ultrasound elastography help distinguish benign from malignant tissue?

A major limitation of endoscopic ultrasound (EUS) examination is its limited capacity to determine the exact nature of a lesion.

The differential diagnosis between benign and malignant lymph nodes and focal pancreatic masses based on the EUS appearance is difficult and frequently requires EUS-guided fine needle aspiration (EUS-FNA) for confirmation of malignancy. Elastography has recently been presented as a novel technique that can be applied during ultrasound (US) examination to assess and measure tissue elasticity. Knowing that malignant tissues are generally harder than normal surrounding tissue, elastography might provide interesting clinical information to help distinguish benign from malignant tissue based on their specific tissue consistency.

A research article to be published on April 7, 2009 in the World Journal of Gastroenterology addresses this question. A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass or lymph node. Knowing that malignant tissues are generally harder than normal surrounding tissue, elastography might provide interesting clinical information to help distinguish benign from malignant tissue based on their specific tissue consistency.

The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%, respectively, compared to 92.3% and 68.9%, respectively, for the conventional B-mode images. The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%, respectively, compared to 78.6% and 50.0%, respectively, for the B-mode images. The kappa coefficient is 0.785 for the pancreatic masses and 0.657 for the lymph nodes.

EUS elastography is superior compared to conventional B-mode imaging and appears able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivi-ty, specificity and accuracy. It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes.