1
|
Aumiller M, Arazar A, Sroka R, Dietrich O, Rühm A. Investigations on correlations between changes of optical tissue properties and NMR relaxation times. Photodiagnosis Photodyn Ther 2024; 45:103968. [PMID: 38215958 DOI: 10.1016/j.pdpdt.2024.103968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 01/14/2024]
Abstract
BACKGROUND Accurate light dosimetry is a complex remaining challenge in interstitial photodynamic therapy (iPDT) for malignant gliomas. The light dosimetry should ideally be based on the tissue morphology and the individual optical tissue properties of each tissue type in the target region. First investigations are reported on using NMR information to estimate changes of individual optical tissue properties. METHODS Porcine brain tissue and optical tissue phantoms were investigated. To the porcine brain, supplements were added to simulate an edema or high blood content. The tissue phantoms were based on agar, Lipoveneous, ink, blood and gadobutrol (Gd-based MRI contrast agent). The concentrations of phantom ingredients and tissue additives are varied to compare concentration-dependent effects on optical and NMR properties. A 3-tesla whole-body MRI system was used to determine T1 and T2 relaxation times. Optical tissue properties, i.e., the spectrally resolved absorption and reduced scattering coefficient, were obtained using a single integrating sphere setup. The observed changes of NMR and optical properties were compared to each other. RESULTS By adjusting the NMR relaxation times and optical tissue properties of the tissue phantoms to literature values, recipes for human brain tumor, white matter and grey matter tissue phantoms were obtained that mimic these brain tissues simultaneously in both properties. For porcine brain tissue, it was observed that with increasing water concentration in the tissue, both NMR-relaxation times increased, while µa decreased and µs' increased at 635 nm. The addition of blood to porcine brain samples showed a constant T1, while T2 shortened and the absorption coefficient at 635 nm increased. CONCLUSIONS In this investigation, by changing sample contents, notable changes of both NMR relaxation times and optical tissue properties have been observed and their relations examined. The developed dual NMR/optical tissue phantoms can be used in iPDT research, clinical training and demonstrations.
Collapse
Affiliation(s)
- Maximilian Aumiller
- Laser-Forschungslabor, LIFE Center, LMU University Hospital, LMU Munich, Planegg 82152, Germany; Department of Urology, LMU University Hospital, LMU Munich, Munich 81377, Germany.
| | - Asmerom Arazar
- Laser-Forschungslabor, LIFE Center, LMU University Hospital, LMU Munich, Planegg 82152, Germany
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, LMU University Hospital, LMU Munich, Planegg 82152, Germany; Department of Urology, LMU University Hospital, LMU Munich, Munich 81377, Germany
| | - Olaf Dietrich
- Department of Radiology, LMU University Hospital, LMU Munich, Munich 81377, Germany
| | - Adrian Rühm
- Laser-Forschungslabor, LIFE Center, LMU University Hospital, LMU Munich, Planegg 82152, Germany; Department of Urology, LMU University Hospital, LMU Munich, Munich 81377, Germany
| |
Collapse
|
2
|
Nickel F, Studier-Fischer A, Özdemir B, Odenthal J, Müller LR, Knoedler S, Kowalewski KF, Camplisson I, Allers MM, Dietrich M, Schmidt K, Salg GA, Kenngott HG, Billeter AT, Gockel I, Sagiv C, Hadar OE, Gildenblat J, Ayala L, Seidlitz S, Maier-Hein L, Müller-Stich BP. Optimization of anastomotic technique and gastric conduit perfusion with hyperspectral imaging and machine learning in an experimental model for minimally invasive esophagectomy. EUROPEAN JOURNAL OF SURGICAL ONCOLOGY 2023:S0748-7983(23)00444-4. [PMID: 37105869 DOI: 10.1016/j.ejso.2023.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/26/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023]
Abstract
INTRODUCTION Esophagectomy is the mainstay of esophageal cancer treatment, but anastomotic insufficiency related morbidity and mortality remain challenging for patient outcome. Therefore, the objective of this work was to optimize anastomotic technique and gastric conduit perfusion with hyperspectral imaging (HSI) for total minimally invasive esophagectomy (MIE) with linear stapled anastomosis. MATERIAL AND METHODS A live porcine model (n = 58) for MIE was used with gastric conduit formation and simulation of linear stapled side-to-side esophagogastrostomy. Four main experimental groups differed in stapling length (3 vs. 6 cm) and simulation of anastomotic position on the conduit (cranial vs. caudal). Tissue oxygenation around the anastomotic simulation site was evaluated using HSI and was validated with histopathology. RESULTS The tissue oxygenation (ΔStO2) after the anastomotic simulation remained constant only for the short stapler in caudal position (-0.4 ± 4.4%, n.s.) while it was impaired markedly in the other groups (short-cranial: -15.6 ± 11.5%, p = 0.0002; long-cranial: -20.4 ± 7.6%, p = 0.0126; long-caudal: -16.1 ± 9.4%, p < 0.0001). Tissue samples from avascular stomach as measured by HSI showed correspondent eosinophilic pre-necrotic changes in 35.7 ± 9.7% of the surface area. CONCLUSION Tissue oxygenation at the site of anastomotic simulation of the gastric conduit during MIE is influenced by stapling technique. Optimal oxygenation was achieved with a short stapler (3 cm) and sufficient distance of the simulated anastomosis to the cranial end of the gastric conduit. HSI tissue deoxygenation corresponded to histopathologic necrotic tissue changes. The experimental model with HSI and ML allow for systematic optimization of gastric conduit perfusion and anastomotic technique while clinical translation will have to be proven.
Collapse
Affiliation(s)
- F Nickel
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany; HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany
| | - A Studier-Fischer
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany; School of Medicine, Heidelberg University, Heidelberg, Germany
| | - B Özdemir
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - J Odenthal
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - L R Müller
- HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany; Division of Computer Assisted Medical Interventions, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Mathematics and Computer Science, Heidelberg University, Heidelberg, Germany
| | - S Knoedler
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - K F Kowalewski
- Department of Urology, Medical Faculty of Mannheim at the University of Heidelberg, Mannheim, Germany
| | - I Camplisson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, USA
| | - M M Allers
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - M Dietrich
- Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany
| | - K Schmidt
- Department of Anaesthesiology and Intensive Care Medicine, Essen University Hospital, Essen, Germany
| | - G A Salg
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - H G Kenngott
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - A T Billeter
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - I Gockel
- Department of Visceral, Transplantation, Thoracic and Vascular Surgery, Leipzig University Hospital, Leipzig, Germany
| | - C Sagiv
- DeePathology Ltd., Ra'anana, Israel
| | | | | | - L Ayala
- HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany; Division of Computer Assisted Medical Interventions, German Cancer Research Center (DKFZ), Heidelberg, Germany; Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - S Seidlitz
- HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany; Division of Computer Assisted Medical Interventions, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - L Maier-Hein
- HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany; Division of Computer Assisted Medical Interventions, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Mathematics and Computer Science, Heidelberg University, Heidelberg, Germany; Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - B P Müller-Stich
- Department of General, Visceral, and Transplantation Surgery, Heidelberg University Hospital, Heidelberg, Germany; HIDSS4Health - Helmholtz Information and Data Science School for Health, Heidelberg and Karlsruhe, Germany.
| |
Collapse
|
3
|
Tomanic T, Rogelj L, Stergar J, Markelc B, Bozic T, Brezar SK, Sersa G, Milanic M. Estimating quantitative physiological and morphological tissue parameters of murine tumor models using hyperspectral imaging and optical profilometry. JOURNAL OF BIOPHOTONICS 2023; 16:e202200181. [PMID: 36054067 DOI: 10.1002/jbio.202200181] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/27/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Understanding tumors and their microenvironment are essential for successful and accurate disease diagnosis. Tissue physiology and morphology are altered in tumors compared to healthy tissues, and there is a need to monitor tumors and their surrounding tissues, including blood vessels, non-invasively. This preliminary study utilizes a multimodal optical imaging system combining hyperspectral imaging (HSI) and three-dimensional (3D) optical profilometry (OP) to capture hyperspectral images and surface shapes of subcutaneously grown murine tumor models. Hyperspectral images are corrected with 3D OP data and analyzed using the inverse-adding doubling (IAD) method to extract tissue properties such as melanin volume fraction and oxygenation. Blood vessels are segmented using the B-COSFIRE algorithm from oxygenation maps. From 3D OP data, tumor volumes are calculated and compared to manual measurements using a vernier caliper. Results show that tumors can be distinguished from healthy tissue based on most extracted tissue parameters ( p < 0.05 ). Furthermore, blood oxygenation is 50% higher within the blood vessels than in the surrounding tissue, and tumor volumes calculated using 3D OP agree within 26% with manual measurements using a vernier caliper. Results suggest that combining HSI and OP could provide relevant quantitative information about tumors and improve the disease diagnosis.
Collapse
Affiliation(s)
- Tadej Tomanic
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Luka Rogelj
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Jost Stergar
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
- Jozef Stefan Institute, Ljubljana, Slovenia
| | - Bostjan Markelc
- Department of Experimental Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia
- Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia
| | - Tim Bozic
- Department of Experimental Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Simona Kranjc Brezar
- Department of Experimental Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor Sersa
- Department of Experimental Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia
- Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia
| | - Matija Milanic
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
- Jozef Stefan Institute, Ljubljana, Slovenia
| |
Collapse
|
4
|
Optical Characterization of Biological Tissues Based on Fluorescence, Absorption, and Scattering Properties. Diagnostics (Basel) 2022; 12:diagnostics12112846. [PMID: 36428905 PMCID: PMC9689259 DOI: 10.3390/diagnostics12112846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/09/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
Optical diagnostics methods are significantly appealing in biological applications since they are non-destructive, safe, and minimally invasive. Laser-induced fluorescence is a promising optical spectrochemical analytical technique widely employed for tissue classification through molecular analysis of the studied samples after excitation with appropriate short-wavelength laser light. On the other hand, diffuse optics techniques are used for tissue monitoring and differentiation based on their absorption and scattering characteristics in the red to the near-infrared spectra. Therefore, it is strongly foreseen to obtain promising results by combining these techniques. In the present work, tissues under different conditions (hydrated/dry skin and native/boiled adipose fat) were distinguished according to their fluorescence emission, absorption, and scattering properties. The selected tissues' optical absorption and scattering parameters were determined via Kubelka-Munk mathematical model according to the experimental tissue reflectance and transmittance measurements. Such measurements were obtained using an optical configuration of integrating sphere and spectrometer at different laser wavelengths (808, 830, and 980 nm). Moreover, the diffusion equation was solved for the fluence rate at the sample surface using the finite element method. Furthermore, the accuracy of the obtained spectroscopic measurements was evaluated using partial least squares regression statistical analysis with 0.87 and 0.89 R-squared values for skin and adipose fat, respectively.
Collapse
|
5
|
Freymüller C, Ströbl S, Aumiller M, Eisel M, Sroka R, Rühm A. Development of a microstructured tissue phantom with adaptable optical properties for use with microscopes and fluorescence lifetime imaging systems. Lasers Surg Med 2022; 54:1010-1026. [PMID: 35753039 DOI: 10.1002/lsm.23556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 04/22/2022] [Accepted: 04/24/2022] [Indexed: 11/08/2022]
Abstract
OBJECTIVES For the development and validation of diagnostic procedures based on microscopic methods, knowledge about the imaging depth and achievable resolution in tissue is crucial. This poses the challenge to develop a microscopic artificial phantom focused on the microscopic instead of the macroscopic optical tissue characteristics. METHODS As existing artificial tissue phantoms designed for image forming systems are primarily targeted at wide field applications, they are unsuited for reaching the formulated objective. Therefore, a microscopy- and microendoscopy-suited artificial tissue phantom was developed and characterized. It is based on a microstructured glass surface coated with fluorescent beads at known depths covered by a scattering agent with modifiable optical properties. The phantom was examined with different kinds of microscopy systems in order to characterize its quality and stability and to demonstrate its usefulness for instrument comparison, for example, regarding structural as well as fluorescence lifetime analysis. RESULTS The analysis of the manufactured microstructured glass surfaces showed high regularity in their physical dimensions in accordance with the specifications. Measurements of the optical parameters of the scattering medium were consistent with simulations. The fluorescent beads coating proved to be stable for a respectable period of time (about a week). The developed artificial tissue phantom was successfully used to detect differences in image quality between a research microscope and an endoscopy based system. Plausible causes for the observed differences could be derived based on the well known microstructure of the phantom. CONCLUSIONS The artificial tissue phantom is well suited for the intended use with microscopic and microendoscopic systems. Due to its configurable design, it can be adapted to a wide range of applications. It is especially targeted at the characterization and calibration of clinical imaging systems that often lack extensive positioning capabilities such as an intrinsic z-stage.
Collapse
Affiliation(s)
- Christian Freymüller
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Stephan Ströbl
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Research Center for Microtechnology, FH Vorarlberg, Dornbirn, Vorarlberg, Austria
| | - Maximilian Aumiller
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Maximilian Eisel
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Adrian Rühm
- Laser-Forschungslabor, LIFE Center, Department of Urology, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| |
Collapse
|
6
|
Heckl C, Aumiller M, Rühm A, Sroka R, Stepp H. Fluorescence and Treatment Light Monitoring for Interstitial Photodynamic Therapy. Photochem Photobiol 2020; 96:388-396. [PMID: 31886892 DOI: 10.1111/php.13203] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/12/2019] [Accepted: 11/21/2019] [Indexed: 01/20/2023]
Abstract
In interstitial photodynamic therapy, light is distributed to the tumor via light diffusers. The light dose and the related phototoxic effect achieved throughout the target volume critically depend on absorption, scattering and diffuser positioning. Using liquid tissue phantoms, we investigated the dependencies of treatment light transmission and protoporphyrin IX (PpIX) fluorescence on these parameters. This enabled monitoring hemoglobin oxygenation and methemoglobin formation during irradiation (635 nm, 200 mW cm-1 diffuser length). Starting with two parallel cylindrical diffusers at 10 mm radial separation, the light transmitted between the fibers was largely determined by the minimal distance between the diffusers, but rather insensitive to an additional axial displacement or tilting of one fiber with respect to the other. For fixed distance between the diffusor centers, however, tilting up to direct contact resulted in a 10-fold signal increase. For hemoglobin within erythrocytes, irradiation leads to photobleaching of PpIX without marked change in hemoglobin oxygenation until hemolysis occurs. Afterward, hemoglobin is rapidly deoxygenized and methemoglobin is formed, leading to a dramatic increase in absorption. For lysed blood, these effects start immediately. A comparison of intraoperative monitoring of the signals with the experimental results might help prevent insufficient treatment by reconsidering treatment planning or prolonging irradiation.
Collapse
Affiliation(s)
- Christian Heckl
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Maximilian Aumiller
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Adrian Rühm
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Herbert Stepp
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Munich, Germany.,Department of Urology, University Hospital, LMU Munich, Munich, Germany
| |
Collapse
|
7
|
He Y, Laugesen K, Kamp D, Sultan SA, Oddershede LB, Jauffred L. Effects and side effects of plasmonic photothermal therapy in brain tissue. Cancer Nanotechnol 2019. [DOI: 10.1186/s12645-019-0053-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Heat generated from plasmonic nanoparticles can be utilized in plasmonic photothermal therapy. A combination of near-infrared laser and plasmonic nanoparticles is compelling for the treatment of brain cancer, due to the efficient light-to-heat conversion and bio-compatibility. However, one of the challenges of plasmonic photothermal therapy is to minimize the damage of the surrounding brain tissue. The adjacent tissue can be damaged as a result of either absorption of laser light, thermal conductivity, nanoparticles diffusing from the tumor, or a combination hereof. Hence, we still lack the full understanding of the light–tissue interaction and, in particular, the thermal response.
Results
We tested the temperature change in three different porcine cerebral tissues, i.e., the stem, the cerebrum, and the cerebellum, under laser treatment. We find that the different tissues have differential optical and thermal properties and confirm the enhancement of heating from adding plasmonic nanoparticles. Furthermore, we measure the loss of laser intensity through the different cerebral tissues and stress the importance of correct analysis of the local environment of a brain tumor.
Conclusions
Our results stress the conclusion that a personalized analysis of the local environment is needed to balance the effect and side effects prior to plasmonic photothermal therapy.
Collapse
|