scholarly journals Optical Signature Analysis of Liver Ablation Stages Exploiting Spatio-Spectral Imaging

2021 ◽  
Vol 7 (2) ◽  
pp. 020306
Author(s):  
Mohamed Aref ◽  
Ramy Abdlaty ◽  
Mohamed Abbass ◽  
Ibrahim Aboughaleb ◽  
Ayman Nassar ◽  
...  
Keyword(s):  
Spatial Data ◽  
Thermal Ablation ◽  
Ex Vivo ◽  
Spectral Band ◽  
Region Of Interest ◽  
Tissue Temperature ◽  
Optical Parameters ◽  
Liver Sample ◽  
Noninvasive Technique ◽  
The Impact

Background and Objective: Thermal ablation modalities such as Radiofrequency ablation (RFA) / Microwave ablation (MWA) are deliberately used for marginally invasive tumor removal by escalating tissue temperature. For precise tumor extinguish, thermal ablation outcomes need routine monitoring for tissue necrosis in a challenging research task. The study aims to exploit hyperspectral imaging (HSI) to evaluate the impact of the liver tissue ablation. Materials and Methods: RFA with temperature range (≥80 °C) was accomplished on the ex vivo animal liver and evaluated using a spectral camera (400~1000 nm). The spectral signatures were extracted from the HSI data after the following processing steps: capturing three spectral data cubes for each liver sample with total 7-samples (before ablation, after ablation, and after ablation with sample slicing) using an HSI optical configuration. The custom HSI processing comprises “Top-hat and Bottom-hat transform” combined with “watershed transform” image segmentation to increase the intensity for a region of interest (ROI) of the investigated tissue, linking spectral and spatial data. Additionally, statistical analysis for HSI data was performed to exclusively select the best spectral band that discriminates between the normal, thermally-damaged, and ablated liver regions. Results: The variation of the optical parameters for the investigated liver samples provides variable interaction with the light diffuse reflection (Ŗd) over the spectrum range (400~1000 nm). Where, the extracting spectral information of the various tissue zones from the induced RFA linked to the hemoglobin, methemoglobin, and water permits variations. The generated spectral image after image enhancement utilizing “Top-hat and Bottom-hat transform” followed by “watershed segmentation”, showed high contrast between normal and thermal regions at a wavelength (600 nm). However, the wavelength (900 nm) shows a high variance between the normal and ablated regions. Finally, delineation of the thermal and ablated regions on the complemented enhanced image. Conclusion: HSI is considered a promising optical noninvasive technique for monitoring the RFA toward enhancing the ablation-based treatment for liver tumor outcomes.

scholarly journals Prospective study for commercial and low-cost hyperspectral imaging systems to evaluate thermal tissue effect on bovine liver samples

2021 ◽  
Author(s):  
Mohamed Aref ◽  
Abdallah Hussein ◽  
Abou-Bakr Youssef ◽  
Ibrahim Aboughaleb ◽  
Amr Sharawi ◽  
...  
Keyword(s):  
Light Source ◽  
Spatial Information ◽  
Ex Vivo ◽  
Low Cost ◽  
Ccd Camera ◽  
Tissue Temperature ◽  
Halogen Lamp ◽  
Liver Sample ◽  
Cost System ◽  
Polychromatic Light

Thermal ablation modalities, for example radiofrequency ablation (RFA) and microwave ablation, are intended to prompt controlled tumour removal by raising tissue temperature. However, monitoring the size of the resulting tissue damage during the thermal removal procedures is a challenging task. The objective of this study was to evaluate the observation of RFA on an ex vivo liver sample with both a commercial and a low-cost system to distinguish between the normal and the ablated regions as well as the thermally affected regions. RFA trials were conducted on five different ex vivo normal bovine samples and monitored initially by a custom hyperspectral (HS) camera to measure the diffuse reflectance (Rd) utilising a polychromatic light source (tungsten halogen lamp) within the spectral range 348–950 nm. Next, the light source was replaced with monochromatic LEDs (415, 565 and 660 nm) and a commercial charge-coupled device (CCD) camera was used instead of the HS camera. The system algorithm comprises image enhancement (normalisation and moving average filter) and image segmentation with K-means clustering, combining spectral and spatial information to assess the variable responses to polychromatic light and monochromatic LEDs to highlight the differences in the Rd properties of thermally affected/normal tissue regions. The measured spectral signatures of the various regions, besides the calculation of the standard deviations (δ) between the generated six groups, guided us to select three optimal wavelengths (420, 540 and 660 nm) to discriminate between these various regions. Next, we selected six spectral images to apply the image processing to (at 450, 500, 550, 600, 650 and 700 nm). We noticed that the optimum image is the superimposed spectral images at 550, 600, 650 and 700 nm, which are capable of discriminating between the various regions. Later, we measured Rd with the CCD camera and commercially available monochromatic LED light sources at 415, 565 and 660 nm. Compared to the HS camera results, this system was more capable of identifying the ablated and the thermally affected regions of surface RFA than the side-penetration RFA of the investigated ex vivo liver samples. However, we succeeded in developing a low-cost system that provides satisfactory information to highlight the ablated and thermally affected region to improve the outcome of surgical tumour ablation with much shorter time for image capture and processing compared to the HS system.

scholarly journals Influencing Factors of 2D Shear Wave Elastography of the Muscle – An Ex Vivo Animal Study

2018 ◽  
Vol 04 (02) ◽  
pp. E54-E60 ◽  
Author(s):  
Marga Rominger ◽  
Pascal Kälin ◽  
Monika Mastalerz ◽  
Katharina Martini ◽  
Volker Klingmüller ◽  
...  
Keyword(s):  
Shear Wave ◽  
Ex Vivo ◽  
Operation Mode ◽  
Region Of Interest ◽  
Shear Wave Elastography ◽  
Longitudinal Direction ◽  
Test Configuration ◽  
Linear Probe ◽  
The Impact ◽  
Placement Depth

AbstractTo evaluate measurement confounders on 2D shear wave elastography (2D-SWE) elastography of muscle. Ex vivo, porcine muscle was examined with a GE LOGIQ E9 ultrasound machine with a 9 L linear (9 MHz) and C1-6 convex probe (operating at 2.5 or 6 MHz). The influence of different confounders on mean shear wave velocity (SWVmean) was analyzed: probes, pressure applied by probe, muscle orientation, together with the impact of different machine settings such as frequency, placement depth and size of region of interest (ROI). The mean of twelve repeated SWVmean measurements (m/s) and coefficient of variation (CV; standard deviation/mean in %) were assessed for each test configuration. Reproducibility (CV) and maximum possible tissue depth of the linear probe were inferior to the convex probe. With the linear probe, there was a linear decrease of SWVmean with placement depth from 4.56 m/s to 1.81 m/s. A significant increase of SWVmean (p<0.001) was observed for larger ROI widths (range 3.96 m/s to 6.8 m/s). A change in the machine operation mode ('penetration' instead of 'general') led to a significant increase of SWVmean (p=0.04). SWVmean in the longitudinal direction of muscle was significantly higher than in cross section (p<0.001) (e. g. 4.56 m/s versus 3.42 m/s). An increase of linear probe pressure significantly increased muscle SWVmean from 5.29 m/s to 7.21 m/s (p<0.001). 2D-SWE of muscle is influenced by a wealth of parameters. Therefore, standardization of measurement is advisable before application in clinical research studies and routine patient assessment.

scholarly journals Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Daniele Tosi ◽  
Edoardo Gino Macchi ◽  
Alfredo Cigada
Keyword(s):  
Thermal Ablation ◽  
Rayleigh Scattering ◽  
Fiber Optic ◽  
Optical Measurement ◽  
Ex Vivo ◽  
Pressure Sensors ◽  
Fiber Optic Sensor ◽  
Tissue Temperature ◽  
Biophysical Parameters ◽  
Radiofrequency Thermal Ablation

Radiofrequency thermal ablation (RFA) is a procedure aimed at interventional cancer care and is applied to the treatment of small- and midsize tumors in lung, kidney, liver, and other tissues. RFA generates a selective high-temperature field in the tissue; temperature values and their persistency are directly related to the mortality rate of tumor cells. Temperature measurement in up to 3–5 points, using electrical thermocouples, belongs to the present clinical practice of RFA and is the foundation of a physical model of the ablation process. Fiber-optic sensors allow extending the detection of biophysical parameters to a vast plurality of sensing points, using miniature and noninvasive technologies that do not alter the RFA pattern. This work addresses the methodology for optical measurement of temperature distribution and pressure using four different fiber-optic technologies: fiber Bragg gratings (FBGs), linearly chirped FBGs (LCFBGs), Rayleigh scattering-based distributed temperature system (DTS), and extrinsic Fabry-Perot interferometry (EFPI). For each instrument, methodology forex vivosensing, as well as experimental results, is reported, leading to the application of fiber-optic technologiesin vivo. The possibility of using a fiber-optic sensor network, in conjunction with a suitable ablation device, can enable smart ablation procedure whereas ablation parameters are dynamically changed.

Variational Method for Estimating the Dipole Moment in the Second Excited State of Fluorescein Molecule from its Electronic UV Absorption Spectra

2019 ◽  
Vol 70 (10) ◽  
pp. 3538-3544
Author(s):  
Alina Costina Luca ◽  
Ana Cezarina Morosanu ◽  
Irina Macovei ◽  
Dan Gheorghe Dimitriu ◽  
Dana Ortansa Dorohoi ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Variational Method ◽  
Electronic State ◽  
Excited Electronic State ◽  
Spectral Band ◽  
Uv Absorption ◽  
Optical Parameters ◽  
Electrical Permittivity ◽  
Fluorescein Molecule

Electro-optical parameters of fluorescein molecule in the second excited electronic state and information on the interactions with solvents were obtained from a solvatochromic study. Parameters of the solvents such as the refractive index, electrical permittivity and Kamlet-Taft parameters (hydrogen bond acidity and basicity) were related with the experimentally recorded shifts of UV absorption spectral band of fluorescein dissolved in several solvents. Through a variational method, the electric dipole moment and polarizability in excited state of fluorescein molecule were estimated. The calculus requires some parameters of the fluorescein molecule in the ground electronic state, which were determined through a quantum-mechanical study.

Evaluation of the expediency of using thermal i magery data for decryption exogenous processes and vegetation

2018 ◽  
Vol 933 (3) ◽  
pp. 52-62
Author(s):  
V.S. Tikunov ◽  
I.A. Rylskiy ◽  
S.B. Lukatzkiy
Keyword(s):  
Spatial Data ◽  
Laser Scanning ◽  
Data Extraction ◽  
Spectral Band ◽  
Information Provision ◽  
Lidar Data ◽  
Thermal Imagery ◽  
Scanning Lidar ◽  
Field Works ◽  
Object Features

Innovative methods of aerial surveys changed approaches to information provision of projecting dramatically in last years. Nowadays there are several methods pretending to be the most efficient for collecting geospatial data intended for projecting – airborne laser scanning (LIDAR) data, RGB aerial imagery (forming 3D pointclouds) and orthoimages. Thermal imagery is one of the additional methods that can be used for projecting. LIDAR data is precise, it allows us to measure relief even under the vegetation, or to collect laser re-flections from wires, metal constructions and poles. Precision and completeness of the DEM, produced from LIDAR data, allows to define relief microforms. Airborne imagery (visual spectrum) is very widespread and can be easily depicted. Thermal images are more strange and less widespread, they use different way of image forming, and spectral features of ob-jects can vary in specific ways. Either way, the additional spectral band can be useful for achieving additional spatial data and different object features, it can minimize field works. Here different aspects of thermal imagery are described in comparison with RGB (visual) images, LIDAR data and GIS layers. The attempt to estimate the feasibility of thermal imag-es for new data extraction is made.

scholarly journals Marker for the pre-clinical development of bone substitute materials

2017 ◽  
Vol 3 (2) ◽  
pp. 711-715
Author(s):  
Michael de Wild ◽  
Simon Zimmermann ◽  
Marcel Obrecht ◽  
Michel Dard
Keyword(s):  
Bone Graft ◽  
Mechanical Stability ◽  
Clinical Performance ◽  
Ex Vivo ◽  
Region Of Interest ◽  
Defect Site ◽  
Novel Approach ◽  
Bone Substitute Materials ◽  
Clinical Experiments

AbstractThin mechanically stable Ti-cages have been developed for the in-vivo application as X-ray and histology markers for the optimized evaluation of pre-clinical performance of bone graft materials. A metallic frame defines the region of interest during histological investigations and supports the identification of the defect site. This standardization of the procedure enhances the quality of pre-clinical experiments. Different models of thin metallic frameworks were designed and produced out of titanium by additive manufacturing (Selective Laser Melting). The productibility, the mechanical stability, the handling and suitability of several frame geometries were tested during surgery in artificial and in ex-vivo bone before a series of cages was preclinically investigated in the female Göttingen minipigs model. With our novel approach, a flexible process was established that can be adapted to the requirements of any specific animal model and bone graft testing.

scholarly journals Synthesis of PVA/CeO2 Based Nanocomposites with Tuned Refractive Index and Reduced Absorption Edge: Structural and Optical Studies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1570
Author(s):  
Shujahadeen B. Aziz ◽  
Elham M. A. Dannoun ◽  
Dana A. Tahir ◽  
Sarkawt A. Hussen ◽  
Rebar T. Abdulwahid ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Edge ◽  
Ceo2 Nanoparticles ◽  
Poly Vinyl Alcohol ◽  
Optical Parameters ◽  
Single Oscillator Model ◽  
Vis Spectroscopy ◽  
The Impact ◽  
Host Polymer

In the current study, polymer nanocomposites (NCPs) based on poly (vinyl alcohol) (PVA) with altered refractive index and absorption edge were synthesized by means of a solution cast technique. The characterization techniques of UV–Vis spectroscopy and XRD were used to inspect the structural and optical properties of the prepared films. The XRD patterns of the doped samples have shown clear amendments in the structural properties of the PVA host polymer. Various optical parameters were studied to get more insights about the influence of CeO2 on optical properties of PVA. On the insertion of CeO2 nanoparticles (NPs) into the PVA matrix, the absorption edge was found to move to reduced photon energy sides. It was concluded that the CeO2 nanoparticles can be used to tune the refractive index (n) of the host polymer, and it reached up to 1.93 for 7 wt.% of CeO2 content. A detailed study of the bandgap (BG) was conducted using two approaches. The outcomes have confirmed the impact of the nanofiller on the BG reduction of the host polymer. The results of the optical BG study highlighted that it is crucial to address the ɛ” parameter during the BG analysis, and it is considered as a useful tool to specify the type of electronic transitions. Finally, the dispersion region of n is conferred in terms of the Wemple–DiDomenico single oscillator model.

scholarly journals Frequency and average gray-level information for thermal ablation status in ultrasound B-Mode sequences

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jens Ziegle ◽  
Alfredo Illanes ◽  
Axel Boese ◽  
Michael Friebe
Keyword(s):  
Thermal Ablation ◽  
Ex Vivo ◽  
Cell Damage ◽  
Potential Temperature ◽  
Image Sequences ◽  
Target Tissue ◽  
Gray Level ◽  
Porcine Liver ◽  
Time Frequency ◽  
Average Gray Level

AbstractDuring thermal ablation in a target tissue the information about temperature is crucial for decision making of successful therapy. An observable temporal and spatial temperature propagation would give a visual feedback of irreversible cell damage of the target tissue. Potential temperature features in ultrasound (US) B-Mode image sequences during radiofrequency (RF) ablation in ex-vivo porcine liver were found and analysed. These features could help to detect the transition between reversible and irreversible damage of the ablated target tissue. Experimental RF ablations of ex-vivo porcine liver were imaged with US B-Mode imaging and image sequences were recorded. Temperature was simultaneously measured within the liver tissue around a bipolar RF needle electrode. In the B-Mode images, regions of interest (ROIs) around the centre of the measurement spots were analysed in post-processing using average gray-level (AVGL) compared against temperature. The pole of maximum energy level in the time-frequency domain of the AVGL changes was investigated in relation to the measured temperatures. Frequency shifts of the pole were observed which could be related to transitions between the states of tissue damage.

scholarly journals 231 Impact of Brachyspira hyodysentariae on intestinal function and integrity

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 116-116
Author(s):  
Emma T Helm ◽  
Susanne J Lin ◽  
Nicholas Gabler ◽  
Eric R Burrough
Keyword(s):  
Ex Vivo ◽  
Potato Starch ◽  
Nutrient Digestibility ◽  
High Morbidity ◽  
Post Inoculation ◽  
Intestinal Function ◽  
Treatment Groups ◽  
Intestinal Integrity ◽  
Beet Pulp ◽  
The Impact

Abstract Swine dysentery (SD) induced by Brachyspira hyodysentariae (Bhyo) causes colitis and mucohemorrhagic diarrhea in grow-finish pigs, however little is known about the physiological changes that occur to the gastrointestinal tract during Bhyo infection. Thus, the objective of this study was to evaluate the impact of a Bhyo challenge on intestinal function and integrity of pigs fed two divergent diets. A total of 36 Bhyo negative gilts (24.3 ± 3.6 kg BW) were selected and assigned to one of three treatment groups (n=12 pigs/trt): 1) Bhyo negative, 20% DDGS diet (CON), 2) Bhyo challenged, 20% DDGS diet (DDGS), and 3) Bhyo challenged, 10% DDGS, 5% beet pulp and 5% resistant potato starch diet (RS). Pigs were fed diets 21 days prior to challenge and on days post inoculation (dpi) 0 and 1, pigs were inoculated with Bhyo or sham. Fecal samples were collected for ATTD and pigs were euthanized for colon collection within 72 hours of initial observation of clinical SD, or at the end of the study (dpi 10-16). Tissues were assessed for ex vivo measures of intestinal integrity and mitochondrial function. The challenge resulted in high morbidity, with 88% of DDGS and RS pigs developing clinical SD. Colon transepithelial resistance was increased in DDGS pigs compared with CON and RS pigs (P=0.005), and colon macromolecule permeability was reduced in both DDGS and RS pigs compared with CON pigs (P=0.006), likely due to mucoid discharge. Colonic mitochondrial oxygen consumption was not impacted by treatment (P &gt;0.10). Further, ATTD of DM, OM, N, and GE were reduced in DDGS pigs compared with CON pigs (P&lt; 0.001), whilst nutrient digestibility was not reduced in RS pigs. Taken together, these data show Bhyo does not appear to reduce ex vivo colonic integrity. Further, the RS diet may reduce severity of a Bhyo challenge.

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