title: Large-field-of-view optical elastography using digital image correlation for biological soft tissue investigation.
abstract: In minimally invasive surgery the haptic feedback, which represents an important tool for the localization of abnormalities, is no longer available. Elastography is an imaging technique that results in quantitative elastic parameters. It can hence be used to replace the lost sense of touch, as to enable tissue localization and discrimination. Digital image correlation is the chosen elastographic imaging technique. The implementation discussed here is clinically sound, based on a spectrally engineered illumination source that enables imaging of biological surface markers (blood vessels) with high contrast. Mechanical loading and deformation of the sample is performed using a rolling indenter, which enables the investigation of large organs (size of kidney) with reduced measurement time compared to a scanning approach. Furthermore, the rolling indentation results in strain contrast improvement and an increase in detection accuracy. The successful application of digital image correlation is first demonstrated on a silicone phantom and later on biological samples. Elasticity parameters and their corresponding four-dimensional distribution are generated via solving the inverse problem (only two-dimensional displacement field and strain map experimentally available) using a well-matched hyperelastic finite element model.
authors.affiliation: Universität Stuttgart , Institut für Technische Optik, Stuttgart, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Claus
authors.affiliation: Universität Stuttgart , Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre, Stuttgart, Germany.
authors.forename: Marijo
authors.initials: M
authors.lastname: Mlikota
authors.affiliation: Universität Stuttgart , Institut für Technische Optik, Stuttgart, Germany.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Geibel
authors.affiliation: Universität Stuttgart , Institut für Technische Optik, Stuttgart, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reichenbach
authors.affiliation: Universität Stuttgart , Institut für Technische Optik, Stuttgart, Germany.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Pedrini
authors.affiliation: Eberhard Karls Universität Tübingen , Klinik für Urologie, Universitätsklinikum Tübingen, Tübingen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Mischinger
authors.affiliation: Universität Stuttgart , Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre, Stuttgart, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Schmauder
authors.affiliation: Universität Stuttgart , Institut für Technische Optik, Stuttgart, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Osten
keywords: displacement measurement; elastography; image correlation; soft tissue FE modeling; strain measurement