Preliminary investigation into the use of ultrasound elastography during brain tumour resection

Abstract

Introduction Differentiation of brain tumours from normal brain, during surgical resection is, in part, based on their differing mechanical properties. Brain tumours have variable stiffness characteristics. Surgical evaluations on stiffness are, at best, subjective. Ultrasound elastography is a non-invasive method for imaging mechanical properties of tissues such as stiffness at depth. It is hypothesized that this technique may assist in differentiating tumour from the brain in an intraoperative setting. Methods This study evaluated the feasibility of the intraoperative use of ultrasound elastography during brain tumour resection. A total of 24 patients were recruited for the study. Surgical findings on tumour stiffness were compared with the elastogram findings. Furthermore, visibility of the brain-tumour interface on ultrasound echography compared with ultrasound elastography was analysed. Results Ultrasound elastography was found to have a sensitivity of 100% and specificity of 75% at detecting that tumour had a different stiffness to the brain when compared with surgical findings. The technique was also found to have a 100% sensitivity and specificity at the detection of intratumoral stiffness heterogeneity compared with surgical findings. The presence of fluid-filled cysts limited the quality of the elastograms. Ultrasound elastography did not detect the brain-tumour interface as accurately as conventional echography. Conclusion These findings suggest that ultrasound elastography in combination with conventional B-mode ultrasound may be a useful adjunct to differentiate tumour from the brain.