3D ultrasound-histology registration for validation of prostate cancer imaging methods

S.G. Schalk, T.A. Saidov, H. Wijkstra, M. Mischi

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic

Abstract

Several ultrasound (US) methods for localization of PCa, like contrast-enhanced US imaging [1] and elastography [2], are emerging, but any of these methods need accurate validation prior to introduction into the clinic. The current gold standard for validation is histologic analysis of the prostate after excision, which requires accurate registration between histology slices and US images. This task is complicated by misalignment between histology and US data, as well as deformation of the prostate due to pressure from the transrectal US (TRUS) probe and to the fixation process after excision. Moreover, besides the prostate contours, no reliable landmarks are present in US. In this abstract, a solution to the validation issue is proposed by means of a dedicated 3D surface-based registration algorithm. To reconstruct the prostate shape, contours are manually drawn in a 2D TRUS transversal apex-to-base video. By correlating the mid area of the video with a sagittal image, the 3D location of the contours is estimated. In addition, a 3D reconstruction of the histology, including cancer location, is realized by aligning and interpolating 4-mm-thick prostate slices. From both prostate shapes, triangulated meshes are constructed. The two meshes are registered by a combination of an affine and an elastic transformation. Volumetric deformation is estimated by interpolation of the surface displacements without use of any internal landmark. Preliminary validation was performed by an in vitro experiment with four prostate-mimicking phantoms pierced by five elastic wires. The resulting average registration error was 1.6 mm, which is far below the histology slicing resolution of 4 mm. The method’s feasibility was tested in 12 human prostates for which we were able to overlay data from histopathologic analysis onto US imaging planes. In conclusion, the presented registration algorithm shows promising performance for accurate validation of US-based PCa imaging techniques. Future employment of the method for MRI validation or fusion can also be envisaged
Original languageEnglish
Title of host publicationProceedings of the 4th Dutch Bio-Medical Engineering Conference (BME2013), 24-25 January 2013, Egmond aan Zee, The Netherlands
Pages234-234
Publication statusPublished - 2013

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