CT-enhanced ultrasound image of a totally deflated lung for image-guided minimally invasive tumor ablative procedures.

A technique is proposed to enhance the quality of intraoperative ultrasound (US) images of a deflated lung undergoing minimally invasive tumor ablative procedure. Since US images are very sensitive to residual air remaining in deflated lung, lung US images have very poor quality, and hence, are not appropriate for image-guided procedures. Therefore, a reliable and high-quality intraoperative image of the lung is a paramount necessity for tumor localization and fusion with real-time navigation data during such procedures. The proposed technique employs information of a deflated lung's computed tomography (CT) image constructed preoperatively in order to enhance those of the intraoperative US images. The enhancement is performed via two concurrent registration processes. The output is an enhanced US image of the deflated lung oriented and positioned accurately within its preoperative CT counterpart. Ex vivo experiments were conducted to evaluate the performance of the proposed technique. The obtained results indicate that very considerable improvement was achieved in the quality of the input intraoperative US images of the deflated lung.