title: Interventional Photoacoustic Imaging of the Human Placenta with Ultrasonic Tracking for Minimally Invasive Fetal Surgeries.
abstract: Image guidance plays a central role in minimally invasive fetal surgery such as photocoagulation of inter-twin placental anastomosing vessels to treat twin-to-twin transfusion syndrome (TTTS). Fetoscopic guidance provides insufficient sensitivity for imaging the vasculature that lies beneath the fetal placental surface due to strong light scattering in biological tissues. Incomplete photocoagulation of anastamoses is associated with postoperative complications and higher perinatal mortality. In this study, we investigated the use of multi-spectral photoacoustic (PA) imaging for better visualization of the placental vasculature. Excitation light was delivered with an optical fiber with dimensions that are compatible with the working channel of a fetoscope. Imaging was performed on anex vivonormal term human placenta collected at Caesarean section birth. The photoacoustically-generated ultrasound signals were received by an external clinical linear array ultrasound imaging probe. A vein under illumination on the fetal placenta surface was visualized with PA imaging, and good correspondence was obtained between the measured PA spectrum and the optical absorption spectrum of deoxygenated blood. The delivery fiber had an attached fiber optic ultrasound sensor positioned directly adjacent to it, so that its spatial position could be tracked by receiving transmissions from the ultrasound imaging probe. This study provides strong indications that PA imaging in combination with ultrasonic tracking could be useful for detecting the human placental vasculature during minimally invasive fetal surgery.
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Xia
authors.affiliation: Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, Wolfson House, London WC1E 6BT, United Kingdom.
authors.forename: Efthymios
authors.initials: E
authors.lastname: Maneas
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Daniil I
authors.initials: DI
authors.lastname: Nikitichev
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Mosse
authors.affiliation: Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, Wolfson House, London WC1E 6BT, United Kingdom.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Sato Dos Santos
authors.affiliation: Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, Wolfson House, London WC1E 6BT, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Vercauteren
authors.affiliation: Institute for Women's Health, University College London, 86-96 Chenies Mews, London WC1E 6HX, United Kingdom.
authors.forename: Anna L
authors.initials: AL
authors.lastname: David
authors.affiliation: Department of Obstetrics and Gynecology, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Deprest
authors.affiliation: Translational Imaging Group, Centre for Medical Image Computing, Department of Medical Physics and Biomedical Engineering, University College London, Wolfson House, London WC1E 6BT, United Kingdom.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Ourselin
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Beard
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Adrien E
authors.initials: AE
authors.lastname: Desjardins
mesh_terms: D000465:Algorithms; D005260:Female; D020669:Fetoscopes; D005332:Fetoscopy / Q000379:methods*; D006801:Humans; D061088:Photoacoustic Techniques / Q000379:methods*; D010920:Placenta / Q000098:blood supply / Q000000981:diagnostic imaging*; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*