Hinnerk Schulz-Hildebrandt

@article{10.1167/tvst.11.5.28,

title = {Dynamic Contrast Microscopic Optical Coherence Tomography As a Novel Method for Assessing Corneal Epithelium During Exposure to Benzalkonium Chloride},

author = {Gwen Musial and Tabea Kohlfaerber and Martin Ahrens and Hinnerk Schulz-Hildebrandt and Philipp Steven and Gereon H\"{u}ttmann},

url = {https://doi.org/10.1167/tvst.11.5.28},

doi = {10.1167/tvst.11.5.28},

issn = {2164-2591},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Translational Vision Science \& Technology},

volume = {11},

number = {5},

pages = {28-28},

abstract = { Microscopic optical coherence tomography (mOCT) has an imaging resolution of 1 µm in all voxel dimensions, but individual epithelial cells are difficult to resolve due to lack of scattering contrast. Adding dynamic contrast processing to mOCT (dmOCT) results in color images that enable visualization of individual cells and possibly give information on cellular function via the calculation of a motility coefficient. We propose this technique as a novel method of evaluating the ocular surface after exposure to a toxic chemical, benzalkonium chloride (BAK). Ex vivo cross-section images were acquired with a custom-built, frequency-domain mOCT system. Eyes were explanted from healthy adult C57BL/6 mice and imaged every 30 minutes with five sets of dmOCT scans at each imaging time. Total epithelium and stroma thicknesses were measured from a single mOCT B-scan, and measures of color changes (hue) and the motility coefficient were acquired from dmOCT scans. After 30-minute exposures to 0.005% BAK, local motility decreased and total epithelium thickness increased compared to controls. For basal epithelium cells, local motility decreased after 60-minute exposures, and the hue shifted red after 90-minute exposures. Stroma thickness did not significantly swell until 150-minute exposures to BAK. dmOCT allows us to view the behavior of the cornea epithelium under toxic stress due to BAK, revealing parallel swelling of the extracellular matrix and changes in local subcellular motion. The evaluation of the cornea epithelium using dmOCT is helpful to our understanding of the toxic effects of BAK. },

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tppubtype = {article}

}

@article{Munter:21,

title = {Microscopic optical coherence tomography (mOCT) at 600 kHz for 4D volumetric imaging and dynamic contrast},

author = {Michael M\"{u}nter and Mario Pieper and Tabea Kohlfaerber and Ernst Bodenstorfer and Martin Ahrens and Christian Winter and Robert Huber and Peter K\"{o}nig and Gereon H\"{u}ttmann and Hinnerk Schulz-Hildebrandt},

url = {http://www.osapublishing.org/boe/abstract.cfm?URI=boe-12-10-6024},

doi = {10.1364/BOE.425001},

year  = {2021},

date = {2021-10-01},

urldate = {2021-10-01},

journal = {Biomed. Opt. Express},

volume = {12},

number = {10},

pages = {6024--6039},

publisher = {OSA},

abstract = {Volumetric imaging of dynamic processes with microscopic resolution holds a huge potential in biomedical research and clinical diagnosis. Using supercontinuum light sources and high numerical aperture (NA) objectives, optical coherence tomography (OCT) achieves microscopic resolution and is well suited for imaging cellular and subcellular structures of biological tissues. Currently, the imaging speed of microscopic OCT (mOCT) is limited by the line-scan rate of the spectrometer camera and ranges from 30 to 250 kHz. This is not fast enough for volumetric imaging of dynamic processes in vivo and limits endoscopic application. Using a novel CMOS camera, we demonstrate fast 3-dimensional OCT imaging with 600,000 A-scans/s at 1.8\ textmum axial and 1.1 textmum lateral resolution. The improved speed is used for imaging of ciliary motion and particle transport in ex vivo mouse trachea. Furthermore, we demonstrate dynamic contrast OCT by evaluating the recorded volumes rather than en face planes or B-scans. High-speed volumetric mOCT will enable the correction of global tissue motion and is a prerequisite for applying dynamic contrast mOCT in vivo. With further increase in imaging speed and integration in flexible endoscopes, volumetric mOCT may be used to complement or partly replace biopsies.},

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pubstate = {published},

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}

@article{https://doi.org/10.1002/rcs.2327,

title = {Instrument Localization for Endovascular Aneurysm Repair \textendash Comparison of two methods based on Tracking Systems or using Imaging},

author = {Sonja J\"{a}ckle and Annkristin Lange and Ver\'{o}nica Garc\'{i}a-V\'{a}zquez and Tim Eixmann and Florian Matysiak and Malte Maria Sieren and Marco Horn and Hinnerk Schulz-Hildebrandt and Gereon H\"{u}ttmann and Floris Ernst and Stefan Heldmann and Torben P\"{a}tz and Tobias Preusser},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/rcs.2327},

doi = {https://doi.org/10.1002/rcs.2327},

year  = {2021},

date = {2021-09-04},

journal = {The International Journal of Medical Robotics and Computer Assisted Surgery},

volume = {n/a},

number = {n/a},

pages = {e2327},

abstract = {Abstract Background In endovascular aortic repair (EVAR) procedures, medical instruments are currently navigated with a two-dimensional imaging based guidance requiring X-rays and contrast agent. Methods Novel approaches for obtaining the three-dimensional instrument positions are introduced. First, a method based on fiber optical shape sensing, one electromagnetic sensor and a preoperative computed tomography (CT) scan is described. Second, an approach based on image processing using one 2D fluoroscopic image and a preoperative CT scan is introduced. Results For the tracking based method, average errors from 1.81 to 3.13 mm and maximum errors from 3.21 to 5.46 mm were measured. For the image-based approach, average errors from 3.07 to 6.02 mm and maximum errors from 8.05 to 15.75 mm were measured. Conclusion The tracking based method is promising for usage in EVAR procedures. For the image-based approach are applications in smaller vessels more suitable, since its errors increase with the vessel diameter. This article is protected by copyright. All rights reserved.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jaeckle2021c,

title = {3D Stent Graft Guidance based on Tracking Systems for Endovascular Aneurysm Repair:},

author = {Sonja J\"{a}ckle and Tim Eixmann and Florian Matysiak and Malte Maria Sieren and Marco Horn and Hinnerk Schulz-Hildebrandt and Gereon H\"{u}ttmann and Torben P\"{a}tz},

url = {https://doi.org/10.1515/cdbme-2021-1004},

doi = {doi:10.1515/cdbme-2021-1004},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Current Directions in Biomedical Engineering},

volume = {7},

number = {1},

pages = {17--20},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{CEREDA2021100085,

title = {Clinical Evaluation of an Instrument-Integrated OCT-Based Distance Sensor for Robotic Vitreoretinal Surgery},

author = {Matteo Giuseppe Cereda and Salvatore Parrulli and Y G M Douven and Koorosh Faridpooya and Saskia Romunde and Gereon H\"{u}ttmann and Tim Eixmann and Hinnerk Schulz-Hildebrandt and Gernot Kronreif and Maarten Beelen and Marc D Smet},

url = {https://www.sciencedirect.com/science/article/pii/S2666914521000750},

doi = {https://doi.org/10.1016/j.xops.2021.100085},

issn = {2666-9145},

year  = {2021},

date = {2021-01-01},

journal = {Ophthalmology Science},

volume = {1},

number = {4},

pages = {100085},

abstract = {Purpose 

To assess the efficacy of an instrument-integrated OCT (iiOCT)-based distance sensor during robotic vitreoretinal surgery using the Preceyes Surgical System (PSS; Preceyes B.V.). 

Design 

Single-center interventional study. 

Participants 

Patients requiring vitreoretinal surgery. 

Methods 

Five patients were enrolled. Standard preoperative OCT images were obtained. After vitrectomy, a predefined set of actions was performed using the iiOCT-based sensor. Images then were processed to assess the signal-to-noise ratio (SNR) at various angles to the retina and at different distances between the instrument tip and the retinal surface. Preoperative and intraoperative OCT images were compared qualitatively and quantitatively. 

Main Outcomes Measures 

The feasibility in performing surgical tasks using the iiOCT-based sensor during vitreoretinal surgery, the SNR when imaging the retina, differences among intraoperative and preoperative OCT images, and characteristics of intraoperative retinal movements detected with the iiOCT-based probe. 

Results 

Surgeons were able to perform all the tasks but one. The PSS was able to maintain a fixed distance. The SNR of the iiOCT-based sensor signal was adequate to determine the distance to the retina and to control the PSS. Analysis of iiOCT-based sensor A-scans identified 3 clearly distinguishable retinal layers, including the inner retinal boundary and the interface at the retinal pigment epithelium\textendashBruch's membrane. Thickness values differed by less than 5% from that measured by preoperative OCT, indicating its accuracy. The Fourier analysis of iiOCT-based sensor recordings identified anteroposterior retinal movements attributed to heartbeat and respiration. 

Conclusions 

This iiOCT-based sensor was tested successfully and promises reliable use during robot-assisted surgery. An iiOCT-based sensor is a promising step toward OCT-guided robotic retinal surgery.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{SIEREN2021,

title = {Radiation-free Thoracic Endovascular Aneurysm Repair with Fiberoptic and Electromagnetic Guidance:A Phantom Study},

author = {Malte Maria Sieren and Sonja J\"{a}ckle and Tim Eixmann and Hinnerk Schulz-Hildebrandt and Florian Matysiak and Mark Preuss and Ver\'{o}nica Garc\'{i}a-V\'{a}zquez and Erik Stahlberg and Markus Kleemann and J\"{o}rg Barkhausen and Jan Goltz and Marco Horn},

url = {https://www.sciencedirect.com/science/article/pii/S1051044321016079},

doi = {https://doi.org/10.1016/j.jvir.2021.12.025},

issn = {1051-0443},

year  = {2021},

date = {2021-01-01},

journal = {Journal of Vascular and Interventional Radiology},

abstract = {Purpose 

The purpose of this study was to evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent-graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom. 

Materials and Methods 

An anthropomorphic phantom was manufactured based on computed tomography angiography (CTA) data from a patient. An aortic stent-graft application system was equipped with a fiber Bragg gratings fiber and three electromagnetic sensors. The stent-graft was navigated in the phantom by three interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and pre- and post-interventional CTA. Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent-graft application system and the tip/end of the stent-graft. 

Results 

The procedure resulted in technical success with a mean error below 3 mm for the entire application system and \<2 mm for the position of the tip of the stent-graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on a par with comparable, routinely used stent-graft application systems. 

Conclusion 

Our study demonstrates successful stent-graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent-grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.},

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pubstate = {published},

tppubtype = {article}

}