1. Articles from Ralf Brinkmann

    1-7 of 7
    1. Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy

      Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy

      Purpose : Selective retina therapy (SRT) is a novel treatment for retinal pathologies, solely targeting the RPE. During SRT, the detection of an immediate tissue reaction is challenging, as tissue effects remain limited to intracellular RPE photodisruption. Time-resolved ultra-high axial resolution optical coherence tomography (OCT) is thus evaluated for the monitoring of dynamic optical changes at and around the RPE during SRT. Methods : An experimental OCT system with an ultra-high axial resolution of 1.78 μm was combined with an SRT system and time-resolved OCT M-scans of the target area were recorded from four patients undergoing SRT. Optical coherence tomography scans ...

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    2. Comprehensive Detection, Grading, and Growth Behavior Evaluation of Subthreshold and Low Intensity Photocoagulation Lesions by Optical Coherence Tomographic and Infrared Image Analysis

      Comprehensive Detection, Grading, and Growth Behavior Evaluation of Subthreshold and Low Intensity Photocoagulation Lesions by Optical Coherence Tomographic and Infrared Image Analysis

      To correlate the long-term clinical effect of photocoagulation lesions after 6 months, as measured by their retinal damage size, to exposure parameters. We used optical coherence tomographic (OCT)-based lesion classes in order to detect and assess clinically invisible and mild lesions. Methods . In this prospective study, 488 photocoagulation lesions were imaged in 20 patients. We varied irradiation diameters (100/300 µm), exposure-times (20–200 ms), and power. Intensities were classified in OCT images after one hour, and we evaluated OCT and infrared (IR) images over six months after exposure. Results . For six consecutive OCT-based lesion classes, the following parameters ...

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    3. Calibration of histological retina specimens after fixation in Margo’s solution and paraffin embedding to in-vivo dimensions, using photography and optical coherence tomography

      Calibration of histological retina specimens after fixation in Margo’s solution and paraffin embedding to in-vivo dimensions, using photography and optical coherence tomography

      Background The extent of retinal tissue deformation by histological processing needs to be separately measured for every workup protocol. This work presents a simple approach for its quantitative assessment, and shows lateral and axial scaling factors for a common protocol. We calibrated histological measurements by in-vivo photographic and optical coherence tomographic (OCT) measurements, using retinal photocoagulation lesions as calibration markers. Methods We evaluated four rabbit eyes that were examined histologically after fixation in Margo’s solution (1 % paraformaldehyde:1.25 % glutaraldehyde), isopropanol dehydration, paraffin embedding and hematoxylin and eosin staining. Distances between 51 pairs of laser lesions were compared in ...

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    4. Photocoagulation in rabbits: Optical coherence tomographic lesion classification, wound healing reaction, and retinal temperatures

      Photocoagulation in rabbits: Optical coherence tomographic lesion classification, wound healing reaction, and retinal temperatures

      Background and Objective The rabbit is the most common animal model to study retinal photocoagulation lesions. We present a classification of retinal lesions from rabbits, that is based on optical coherence tomographic (OCT) findings, temperature data, and OCT-follow-up data over 3 months. Materials and Methods Four hundred eighty-six photocoagulation lesions (modified Zeiss Visulas® 532 nm CW laser, lesion diameter 133 µm, exposure duration 200 milliseconds or variable, power variable) were analyzed from six eyes of three chinchilla gray rabbits. During the irradiation of each lesion, we used an optoacoustics-based method to measure the retinal temperature profile. Two hours, 1 week ...

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    5. Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation

      Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation

      We conducted a study to correlate the retinal temperature rise during photocoagulation to the afterward detected tissue effect in optical coherence tomography (OCT). 504 photocoagulation lesions were examined in 20 patients. The retinal temperature increase was determined in real-time during treatment based on thermoelastic tissue expansion which was probed by repetitively applied ns laser pulses. The tissue effect was examined on fundus images and OCT images of individualized lesions. We discerned seven characteristic morphological OCT lesion classes. Their validity was confirmed by increasing visibility and diameters. Mean peak temperatures at the end of irradiation ranged from approx. 60 °C to ...

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    6. Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT

      Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT

      Visualizing retinal photocoagulation by real-time OCT measurements may considerably improve the understanding of thermally induced tissue changes and might enable a better reproducibility of the ocular laser treatment. High speed Doppler OCT with 860 frames per second imaged tissue changes in the fundus of enucleated porcine eyes during laser irradiation. Tissue motion, measured by Doppler OCT with nanometer resolution, was correlated with the temperature increase, which was measured non-invasively by optoacoustics. In enucleated eyes, the increase of the OCT signal near the retinal pigment epithelium (RPE) corresponded well to the macroscopically visible whitening of the tissue. At low irradiance, Doppler ...

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    7. Structural changes of the retina after conventional laser photocoagulation and selective retina treatment (SRT) in spectral domain OCT.

      Background: Spectral domain optical coherence tomography (SD-OCT) in patients can deliver retinal cross-sectional images with high resolution. This may allow the evaluation of the extent of damage to the retinal pigment epithelium (RPE) and the neurosensory retina after laser treatment. This article aims to investigate the value of SD-OCT in comparing laser lesions produced by conventional laser photocoagulation and selective retina treatment (SRT). Material and Methods: In a retrospective study, conventional retinal laser (CRL) lesions and SRT laser lesions were evaluated with SD-OCT. One hundred seventy-five CRL lesions were investigated in 10 patients with diabetic maculopathy at timepoints between 1 ...

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    1-7 of 7
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    1. (4 articles) University of Lübeck
    2. (2 articles) Carsten Framme
    3. (2 articles) Reginald Birngruber
    4. (1 articles) Massachusetts General Hospital
    5. (1 articles) Harvard University
    6. (1 articles) University of Bern
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    Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation Photocoagulation in rabbits: Optical coherence tomographic lesion classification, wound healing reaction, and retinal temperatures Calibration of histological retina specimens after fixation in Margo’s solution and paraffin embedding to in-vivo dimensions, using photography and optical coherence tomography Comprehensive Detection, Grading, and Growth Behavior Evaluation of Subthreshold and Low Intensity Photocoagulation Lesions by Optical Coherence Tomographic and Infrared Image Analysis Time-Resolved Ultra–High Resolution Optical Coherence Tomography for Real-Time Monitoring of Selective Retina Therapy Retinal Vascular Features in Ocular Blunt Trauma by Optical Coherence Tomography Angiography Non-invasive imaging of a choroidal macrovessel Correlation between optical coherence tomography, multifocal electroretinogram findings and visual acuity in diabetic macular edema Digital Wavefront Sensing Ciliary body length revisited by anterior segment optical coherence tomography: implications for safe access to the pars plana for intravitreal injections Evaluation of retinal vascular structure after epiretinal membrane surgery by optical coherence tomography angiography