3D Image Analysis Research Articles

Ultrahigh-Resolution 3D Imaging for Quantifying the Pore Nanostructure of Shale and Predicting Gas Transport

The pore and fracture microstructures are key to understanding gas flow in shales. The experimental determination of these microstructures is dependent on the measurement technique employed and its resolution. High-resolution three-dimensional imaging techniques coupled with image analysis and numerical simulations have been employed to characterize the petrophysical properties of shale samples. In this work, our particular focus is on using the Nano-CT and focused ion beam scanning electron microscopy (FIB-SEM) techniques at the same location in a shale rock sample to investigate the effect of their different resolutions and fields of view on the resulting imaged nanopore structure, as well as to determine any differences in the consequent measurements of the shale petrophysical properties. These petrophysical properties include porosity, permeability, pore volume and size distribution, the pore aspect ratio, the surface area to volume, and pore connectivity. The reconstructed matrix, kerogen, and pore space volumes from each approach showed significant scale-dependent differences in the microstructure. The shale sample displayed a high kerogen content with high connectivity. Porosity from the reconstructed shale volumes was observed to be 0.43 and 0.7% for FIB-SEM and Nano-CT approaches, respectively. The pore volume, size, surface area to volume ratio, and two orthogonal pore aspect ratio distributions have also been determined from the reconstructed image data by three-dimensional (3D) image analysis. These data show that voids within the rock are oblate at all scales. Permeabilities have been calculated from both the FIB-SEM and Nano-CT images and fall in the range of 2.55–9.92 nD. A simulation has also been produced based on the permeability calculation and parameters from the image analysis. The results of the simulation show connectivity in the x-, y-, and z-directions for both the FIB-SEM and Nano-CT images, with very low connectivity in the x-direction but higher connectivity in the y- and z-directions.

Serum nickel is associated with craniosynostosis risk: Evidence from humans and mice

BackgroundTo date, few studies have explored the effects of exposure to metal mixtures on adverse developmental outcomes, and no reported studies have linked metal exposure to craniosynostosis (CS). The purpose of this study is to investigate the association between metal exposure and the risk of CS by conducting epidemiological and experimental studies. MethodsInductively coupled plasma mass spectrometry (ICP-MS) was used to measure the concentrations of 6 metals (chromium [Cr], nickel [Ni], tin [Sn], arsenic [As], thallium [Tl], and lead [Pb]) in serum samples from 174 CS patients and 85 control individuals. Non-syndromic patients with isolated sagittal suture closure were selected as the case group, and healthy children matched by sex and age were selected as controls. Bayesian kernel machine regression (BKMR) models were used to account for joint metal effects. Multiple logistic regression analysis was used to explore the association between metal concentration and CS occurrence, with adjustment for potential confounders. During pregnancy, mice were exposed to Ni (0, 0.05, or 0.1 g/kg/day) until weaning, and the widths of the sutures and shapes of the skull were analysed by micro-CT 3D imaging and histological analysis. MC3T3-E1 cells were treated with Ni (0, 0.005, or 0.05 μg/mL) for 72 h. Alkaline phosphate (ALP) staining and Alizarin red staining were performed to observe the development of osteoblasts. The expression levels of osteoblast-related genes were also detected. ResultsA positive association between the metal mixture and CS risk was observed based on population data; the Ni group had the highest conditional posterior inclusion probability (PIP), at 0.8416, and in the fully adjusted model, the highest Ni exposure level had a more significant association with CS (coefficient = 2.65, 95% CI: 0.29, 5.02) than the lowest Ni exposure level. The mean widths of the sagittal sutures in mice were 8.8 ± 0.6 mm in the control group, 8.0 ± 0.8 mm in the 0.05 g/kg/day group and 6.8 ± 0.4 mm in the 0.1 g/kg/day group. After Ni exposure, ALP gene expression in skull tissue was increased, and ALP activity was increased in MC3T3-E1 cells. Moreover, increased collagen content in mouse skull sections and elevated osteocalcin (OCN) expression in MC3T3-E1 cells were observed in the Ni-treated groups compared to the control group. ConclusionsThis study is the first to provide evidence that increased serum Ni was associated with an increased risk of CS. Early life exposure to Ni promoted osteogenesis during skull growth, which may contribute to the development of CS.

The Influence of 3D Printed Aortic Models on the Evolution of Physician Modified Stent Grafts for the Urgent Treatment of Thoraco-abdominal and Pararenal Aortic Pathologies

The aim was to describe the outcomes of high risk patients with symptomatic or contained rupture of pararenal (PRAs) and thoraco-abdominal aortic aneurysms (TAAAs) with anatomy unsuitable for commercially available stent grafts who underwent fenestrated endovascular aneurysm repair (FEVAR) using physician modified stent grafts (PMSGs) planned with 3D image analysis software (3DIMAS), and 3D printed aortic models (3DAMs). Nineteen consecutive patients (17 male; mean age, 70±9 years) underwent PMSG-FEVAR between 2015 and 2019. 3DAMs to plan the PMSGs were introduced in 2018. End points were all cause mortality, freedom from any endoleak, target vessel patency, and re-intervention. Seven patients (36.8%) were treated with PMSGs using 3DIMAS (three PRAs, three type IV, and one type III TAAAs), and 12 patients (63.2%) received PMSGs using 3DAMs (five PRAs, seven type IV TAAAs). Six patients presented with contained aortic rupture and 13 patients were treated for symptomatic aortic aneurysm. Mean aortic diameter was 72±10mm. The choice of stent graft for fenestration was the Valiant Captivia Closed Web (Medtronic), except for one patient. Sixteen (84.2%) stent grafts were manufactured with four fenestrations. Technical success was 100%. Seventy-one renovisceral branch vessels were targeted with fenestrations. Mean length of hospital stay was 17.3±10.4 days. Thirty day mortality was 0%. Two patients developed reversible spinal cord injury. Mean follow up was 14.4 months (range 1-52 months). During follow up one non-aneurysm related death occurred, and two successful re-interventions were performed: one to re-establish renal artery patency, and one to treat a type 1c endoleak. PMSGs for urgent treatment of pararenal and thoraco-abdominal aortic aneurysms in high risk patients unsuitable for commercially available stent grafts are feasible and safe. 3D printing technology may improve urgent construction of patient specific devices for treatment of complex aortic pathologies and improve outcomes.

Analysis of the Columellar-Labial Angle in Perioral Aging.

The young face presents a convex and rounded aspect; with aging, this changes to a more concave and flattened aspect, with the angles of the face undergoing changes through soft tissue repositioning and bone remodeling. The columellar-labial angle is one of the features that change. The objective of the present study was to analyze the columellar-labial angle at different stages of adult life and assess its contribution to facial changes during aging. We analyzed a database (December 2017-March 2018) of 722 female patients, aged 21 to 88 years, and obtained anthropometric measurements of the columellar-labial angle with a Canfield Vectra 3D image analysis system. Our database originates from a private clinic where all patients were registered and photographed. Our analysis showed a decrease in the columellar-labial angle, mainly observed from patients aged 60 years and older. This decrease can be explained by the absorption of body structures that occurs during aging. The columellar-labial angle decreases with age, and this finding may provide a better understanding of the transformation that occurs with aging. Obtaining a clearer view of the changes that occur in the face will improve treatments for facial rejuvenation, either conservative or surgical, and provide a basis for future studies and knowledge expansion.

Recognition of Wrong Sports Movements Based on Deep Neural Network

During physical education (PE), the teaching quality is severely affected by problems like nonstandard technical movements or wrong demonstrative movements. High-speed photography can capture instantaneous movements that cannot be recognized with naked eyes. Therefore, this technology has been widely used to judge the sprint movements in track and field competitions, and assess the quality of artistic gymnastics. Inspired by three-dimensional (3D) image analysis, this paper proposes a method to recognize the standard and wrong demonstrative sports movements, based on 3D convolutional neural network (CNN) and graph theory. Firstly, a 3D posture perception strategy for demonstrative sports movements was constructed based on video sequence. Next, the authors provided the framework of the recognition system for standard and wrong demonstrative sports movements. After that, a 3D CNN was stablished to distinguish between standard and wrong demonstrative sports movements. The proposed method was proved effective and superior through experiments. The research results provide a good reference for the application of 3D image analysis in the recognition of other body behaviors and movements.

Exosomes isolated from two different cell lines using three different isolation techniques show variation in physical and molecular characteristics

Exosomes are the nanoscopic lipid bi-layered extracellular vesicles with the potential to be utilized as targeted therapeutics. In our investigation, we compared three major exosome isolation techniques that were Total Exosome Isolation reagent (TEI), Protein organic solvent precipitation (PROSPR) and differential ultracentrifugation (UC) based on the biophysical and physicochemical characteristics of exosomes isolated from COLO 205 and MCF-7 cancer cell's conditioned media with an aim to select a suitable method for translational studies. 3D image analysis and particle size distribution of exosomes from their HRTEM images depicted the morphological differences. Molecular and analytical characterization of exosomes using western blotting, Raman and ATR-FTIR spectroscopy and the multivariate analysis on the spectral data obtained, assessed for better molecular specifications and purity of particle. TEI method isolated exosomes with higher exosomal yield, purity, and recovery directly translatable into drug delivery and targeted therapeutics whereas ultracentrifuge had good recovery of particle morphology but showed particle aggregation and yielded exosomes with smaller mean size. PROSPR technique isolated a mixture of EVs, showed lower protein recovery in PAGE and western blotting but higher spectroscopic protein to lipid ratio and distinguishable EV population in multivariate analysis compared to exosomes isolated by TEI and UC. This comparative study should help in choosing a specific exosome isolation technique required for the objective of downstream applications.

High-Throughput Phenotyping of Morphological Seed and Fruit Characteristics Using X-Ray Computed Tomography.

Traditional seed and fruit phenotyping are mainly accomplished by manual measurement or extraction of morphological properties from two-dimensional images. These methods are not only in low-throughput but also unable to collect their three-dimensional (3D) characteristics and internal morphology. X-ray computed tomography (CT) scanning, which provides a convenient means of non-destructively recording the external and internal 3D structures of seeds and fruits, offers a potential to overcome these limitations. However, the current CT equipment cannot be adopted to scan seeds and fruits with high throughput. And there is no specialized software for automatic extraction of phenotypes from CT images. Here, we introduced a high-throughput image acquisition approach by mounting a specially designed seed-fruit container onto the scanning bed. The corresponding 3D image analysis software, 3DPheno-Seed&Fruit, was created for automatic segmentation and rapid quantification of eight morphological phenotypes of internal and external compartments of seeds and fruits. 3DPheno-Seed&Fruit is a graphical user interface design and user-friendly software with an excellent phenotype result visualization function. We described the software in detail and benchmarked it based upon CT image analyses in seeds of soybean, wheat, peanut, pine nut, pistachio nut and dwarf Russian almond fruit. R2 values between the extracted and manual measurements of seed length, width, thickness, and radius ranged from 0.80 to 0.96 for soybean and wheat. High correlations were found between the 2D (length, width, thickness, and radius) and 3D (volume and surface area) phenotypes for soybean. Overall, our methods provide robust and novel tools for phenotyping the morphological seed and fruit traits of various plant species, which could benefit crop breeding and functional genomics.

3D size and shape characterization of natural sand particles using 2D image analysis

The geometrical size and shape of sand particles are critically important for evaluating the characteristics of granular materials. These characteristics are commonly quantified via the analysis of 2D and 3D images. In the traditional procedure, a 2D particle image is captured by a digital camera only once and only limited amount information about a particle is acquired. In the present study, a framework that integrates image analysis and 3D laser scanning was developed and applied to 20 natural sand particles to study multiple acquisitions and evaluate the size and shape. The potential of single, two, three and multiple projections of sand particles to characterize morphological properties were studied and the relationships between the 3D and 2D parameters were established. The results show that the 3D morphological properties including the size (length, width, thickness, volume, and surface area) and shape (elongation, flatness, and sphericity) can be estimated using 2D morphological properties. The parameters measured on the maximum and minimum projections (from 20 acquisitions) or three orthogonal projections were found to be useful for estimating the 3D geometrical properties. A practical approach to obtain representative sand particle information from 2D image analysis is provided. The newly developed equations were verified and compared with previously published equations.

Digital anthropometry for body circumference measurements: Toward the development of universal three-dimensional optical system analysis software.

Background/ObjectiveDigital anthropometric (DA) assessments are increasingly being administered with three‐dimensional (3D) optical devices in clinical settings that manage patients with obesity and related metabolic disorders. However, anatomic measurement sites are not standardized across manufacturers, precluding use of published reference values and pooling of data across research centers.Subjects/MethodsThis study aimed to develop universal 3D analysis software by applying novel programming strategies capable of producing device‐independent DA estimates that agree with conventional anthropometric (CA) measurements made at well‐defined anatomic sites. A series of technical issues related to proprietary methods of 3D geometrical reconstruction and image analysis were addressed in developing major software components. To evaluate software accuracy, comparisons were made to CA circumference measurements made with a flexible tape at eleven standard anatomic sites in up to 35 adults scanned with three different commercial 3D optical devices.ResultsOverall, group mean CA and DA values across the three systems were in good agreement, with ∼2 cm systematic differences; CA and DA estimates were highly correlated (all p‐values <0.01); root‐mean square errors were low (0.51–3.27 cm); and CA‐DA bias tended to be small, but significant depending on anatomic site and device.ConclusionsAvailability of this software, with future refinements, has the potential to facilitate clinical applications and creation of large pooled uniform anthropometric databases.

Use of X-ray computed tomography and 3D image analysis to characterize internal browning in ‘Fuji’ apples after exposure to CO2 stress

In this study X-ray computed tomography (X-ray CT) was used to determine microstructural properties of ‘Fuji’ apple (Malus domestica Borkh.) tissue affected by internal browning (IB) and unaffected tissue after short-term exposure (3 days) to a storage atmosphere with 0.1 % O2 and 50 % CO2. The incidence of IB disorders were concentrated in the core of the fruit. IB developed in 31 % of fruit at varying degrees of severity, due to differences in microstructural and morphological properties of individual fruit. X-ray CT scanning was able to give pore and cell microstructural information such as porosity, length, sphericity, connectivity, equivalent diameter, and anisotropy. High-resolution scans showed that fruit tissue with IB had a lower total porosity and pore connectivity compared to unaffected fruit tissue, possibly due to membrane damage and flooding of intercellular spaces with cellular fluids. The pores in affected brown tissue were significantly more spherical as compared to the other tissue types. Low-resolution (full fruit) scans showed that the density of fruit tissue affected by IB was not significantly different from that of unaffected fruit tissue. Low porosity in the fruit core region restricts gas transport and predisposes the core region to CO2 induced IB. This work provided a novel and in-depth insight into the effects of short-term high CO2/low O2 stress conditions on the microstructural properties of South African grown ‘Fuji’ apples. Furthermore, this study showed that tissue microstructure influences the susceptibility of different regions within the same fruit to stress-induced IB symptoms.

A fast and accurate computation of 2D and 3D generalized Laguerre moments for images analysis

In this paper, we will present a new set of 2D and 3D continuous orthogonal moments based on generalized Laguerre orthogonal polynomials (GLPs) for 2D and 3D image analysis. However, the computation of the generalized Laguerre orthogonal moments (GLMs) is limited by the problems of discretization of the continuous space of the polynomials, approximation of the integrals by finite sums and of too high computation time. To remedy these problems, we will propose a new method for the fast and the precise computation of 2D and 3D GLMs. This method is based on the development of an exact calculation of the double and triple integrals which define the 2D and 3D GLMs, and on the matrix calculation to accelerate the processing time of the images instead of the direct calculation. In addition to the theoretical results obtained, several experiments are carried out to validate the efficiency of the 2D and 3D GLMs descriptors in terms of computation precision and accuracy and in terms of acceleration of computation time and 2D/3D image reconstruction. The experimental results clearly show the advantages and the effectiveness of GLMs compared to the continuous orthogonal moments of Legendre, Chebyshev, Gegenbauer and Gaussian-Hermite.

Reliability of 3D image analysis and influence of contrast medium administration on measurement of Hounsfield unit values of the proximal femur.

PurposeTo evaluate the reliability of 3D image analysis and the effect of an iodine contrast agent on the computed tomography (CT) Hounsfield unit (HU) values of the proximal femur.Materials and methodsFifty female patients (mean age, 61.3 years; age range, 50–79 years) who underwent both pre- and post-enhancement abdominopelvic CT scans were included in this retrospective study. Whole 3D volumes of the left proximal femur from the head to the lesser trochanter were extracted using the regional growth technique with commercial 3D software. Total volume, mean HU, and HU histogram analysis (HUHA) values of the extracted femur were calculated. HUHA distribution was classified into HUHAfat for the assumed fatty marrow (percentage of negative HU values) and HUHAdense-bone (percentage of HU values ≥ 126 HU). Reliability was assessed by calculating intra- and interobserver correlation coefficients (ICCs) and by drawing Bland–Altman plots. The effect of contrast medium administration was evaluated by the paired t-test.ResultsAll intra- and interobserver ICCs of 3D volume measurements showed excellent reproducibility (all ICCs > 0.90). On Bland–Altman analysis of two observers’ 3D volume measurements, the differences in the mean total volume, HUHAfat, HUHAdense-bone, and mean HU were 2.4 cm3, 0.17%, 0.6%, and 1.9 HU, respectively. The mean difference in HU after contrast agent administration (-2.2 HU) was not significant (P = 0.27). The mean difference in HUHAfat and HUHAdense-bone after contrast agent administration were -1.1% and -2.2%, respectively, on the Bland–Altman plot. HUHAfat and HUHAdense-bone showed significant differences (P < 0.05). The 95% limits of agreement for HUHAfat, HUHAdense-bone, and mean HU were -3.6% to 1.3%, -6.5% to 2.1%, and -30.0 to 25.5 HU, respectively.ConclusionImage analysis based on 3D volume measurement of the proximal femur showed excellent reliability, with the contrast agent administration showing negligible influence on the mean HU.

Characterization of pore structure parameters of foam concrete by 3D reconstruction and image analysis

The pore structure of foam concrete plays a meaningful role for its properties. In this paper, 3D reconstruction technology is applied to the analysis of foam concrete pore structure parameters. Firstly, the 3D point cloud data on the surface of the foamed concrete is obtained by the 3D reconstruction with projecting grating, and the target point cloud is obtained by RANSAC algorithm. The 3D point cloud data is reduced by the orthographic projection to generate a 2D image. Then the pore structure parameters of the foamed concrete are obtained through morphological means such as the unevenness of the edge of the image. In addition, the experimental results are compared with those fruits testing by MIP and Image-J analysis software. The results show that the proposed method has higher accuracy than the Image-J analysis software method in hole recognition and separation. The method proposed in this paper combines 3D reconstruction and image processing, which can effectively avoid the influence of environmental light and other factors on the experimental results in the analysis of cellular concrete pore structure. The pore structure parameters such as porosity, pore size and distribution of foam concrete can be quantified more accurately. This method is expected to be a new means for the analysis of porous materials.

The new technology of precise anatomical sublobar resection by using 3D medical image analyzer and a fluorescence guided surgery with transbronchial injection of indocyanine green

Background: The confirmation of an appropriate resection margin from the tumor is crucial for reducing the risk of local recurrence after sublobar resection for pulmonary malignancies.

DIGITAL ROCK ANALYSIS: AN ALTERNATIVE METHOD TO PREDICT PETROPHYSICAL PROPERTIES, CASE STUDY FROM MISHRIF FORMATION

The digital core analysis of petrophysical properties replace the use of conventional core analysis by reducing the required time for investigation. Also, the ability to capture pore geometries and fluid behavior at the pore-scale improves the understanding of complex reservoir structures. In this work, 53 samples of 2D thin section petrographic images were used for analyses from the core plugs taken from the Buzurgan oil field. Each sample was impregnated with blue-dyed epoxy, thin sectioned and then was stained for discrimination of carbonate minerals. Each thin section has been described in detail and illustrated by photomicrographs. The studied samples include a variety of rock types. Packstone is the most common rock type observed followed by grainstone and packstone – wackestone. Floatstone and dolostone are noted rarely in the studied interval. However, the samples of thin section images are processed and digitized, utilizing MATLAB programming and image analysis software. The entire workflow of digital core analysis from image segmentation to petrophysical rock properties determination was performed. A focused has been made on determining effective and total porosity, absolute permeability, and irreducible water saturation. Absolute permeability is estimated with the Kozeny-Carman permeability correlation model and Timur-Coates permeability correlation model. Irreducible water saturation simply is derived from total and effective porosity. Also, some pore void characteristics, such as area and perimeter, were calculated. The results of Digital 2D image analysis have been compared to laboratory core measurements to investigate the reliability and restrictions of the digital image interpretation techniques.

Digital Rock Samples Porosity Analysis by OTSU Thresholding Technique Using MATLAB

Porosity plays an essential role in petroleum engineering. It controls fluid storage in aquifers, connectivity of the pore structure control fluid flow through reservoir formations. To quantify the relationships between porosity, storage, transport and rock properties, however, the pore structure must be measured and quantitatively described. Porosity estimation of digital image utilizing image processing essential for the reservoir rock analysis since the sample 2D porosity briefly described. The regular procedure utilizes the binarization process, which uses the pixel value threshold to convert the color and grayscale images to binary images. The idea is to accommodate the blue regions entirely with pores and transform it to white in resulting binary image. This paper presents the possibilities of using image processing for determining digital 2D rock samples porosity in carbonate reservoir rocks. MATLAB code created which automatically segment and determine the digital rock porosity, based on the OTSU's thresholding algorithm. In this work, twenty-two samples of 2D thin section petrographic image reservoir rocks of one Iraqi oil field are studied. The examples of thin section images are processed and digitized, utilizing MATLAB programming. In the present study, we have focused on determining of micro and macroporosity of the digital image. Also, some pore void characteristics, such as area and perimeter, were calculated. Digital 2D image analysis results are compared to laboratory core investigation results to determine the strength and restrictions of the digital image interpretation techniques. Thin microscopic image porosity determined using OTSU technique showed a moderate match with core porosity.

Micro-CT imaging of tomato seeds: Predictive potential of 3D morphometry on germination

The relationship between seed physical characteristics and seed quality is widely investigated by using X-ray based imaging techniques. Recently the use of X-ray micro-tomography (micro-CT) is increasingly used for more accurate characterisation of the internal seed morphology. In this work a germination test was carried out along with the morphometric characterisation of tomato seed internal structure by means of X-ray micro-CT and 3D image analysis. The aim was to accurately evaluate the predictive potential of internal seed 3D morphology for germination outcomes. The visual assessment allowed the relationship between specific internal seed abnormalities and the different germination outcomes to be demonstrated experimentally. Univariate analysis of morphometric seed traits allowed 3D free space % and Sauter diameter, among the most discriminant parameters, to be identified as the most effective for the prediction of germination outcomes. Discriminant Analysis (DA) of 3D morphometric dataset correctly classified 96.3% of normal seedlings, 83.3% of ungerminated seeds and 63.6% of abnormal seedlings, providing a high overall prediction potential of 91.9%. The above analyses have also been performed referring to the germination at 5 days after sowing. As a side effect of the applied technique, an increase of abnormal seedlings was observed at increasing X-ray exposure level.

3D Visualization and Volume-Based Quantification of Rice Chalkiness In Vivo by Using High Resolution Micro-CT

BackgroundRice quality research attracts attention worldwide. Rice chalkiness is one of the key indexes determining rice kernel quality. The traditional rice chalkiness measurement methods only use milled rice as materials and are mainly based on naked-eye observation or area-based two-dimensional (2D) image analysis and the results could not represent the three-dimensional (3D) characteristics of chalkiness in the rice kernel. These methods are neither in vivo thus are unable to analyze living rice seeds for high throughput screening of rice chalkiness phenotype.ResultsHere, we introduced a novel method for 3D visualization and accurate volume-based quantification of rice chalkiness in vivo by using X-ray microcomputed tomography (micro-CT). This approach not only develops a novel volume-based method to measure the 3D rice chalkiness index, but also provides a high throughput solution for rice chalkiness phenotype analysis by using living rice seeds.ConclusionsOur method could be a new powerful tool for rice chalkiness measurement, especially for high throughput chalkiness phenotype screening using living rice seeds. This method could be used in chalkiness phenotype identification and screening, and would greatly promote the basic research in rice chalkiness regulation as well as the quality evaluation in rice production practice.

Micro- and Nano-Scale Pore Structure in Gas Shale Using Xμ-CT and FIB-SEM Techniques

Shale is a complex rock composed of a complex mixture of matrix minerals and kerogen and having a complex pore microstructure. The pore microstructure is highly dependent upon the scale at which it is considered. Such a microstructure is important for the assessment of the potential of gas shales based on the connectivity and pores at each scale and the ability of the rock to be hydraulically fractured. In this work, the three-dimensional (3D) structure of Bowland shale has been investigated at both microscopic and nanoscopic scales on the same sample for the first time using (i) a combination of serial sectioning, using focused ion beam (FIB) milling and scanning electron microscopy (SEM), and (ii) X-ray micro-computed tomography (Xμ-CT). The reconstructed matrix, kerogen, and pore space volumes from each approach showed significant scale-dependent differences in the microstructure. The shale samples displayed a high kerogen content with high connectivity. Porosity in the shale rock sample was observed to be prevalent in either the inorganic matrix, the kerogen, or both. Furthermore, the porosity from the reconstructed shale volumes was found to vary with locations, as sampled by FIB-SEM, within the shale samples taken for Xμ-CT. Pore volume, scale invariant surface area to volume ratios, and two orthogonal pore aspect ratio distributions were extracted from the reconstructed image data by 3D image analysis. These data show that voids within the rock are oblate at all scales. However, the smaller pores visible by FIB-SEM present higher scale invariant surface area to volume ratios, indicating that they are more likely to interlink the larger pores visible by Xμ-CT and form a small scale but highly connected pore network for fluid flow. Permeabilities have been calculated from both the FIB-SEM and Xμ-CT images and fall in the range 2.98 to 150 nD, broadly agreeing with experimental determinations from another author.

What factors affect the operative time of robot-assisted laparoscopic radical prostatectomy?

Robot-assisted radical prostatectomy (RARP) has gained prominence since the da Vinci surgical system was introduced in 2000. RARP has now become a standard procedure for treating cases with localized prostate cancer. However, no study has examined its surgical time by accurately measuring the pelvic visceral fat (PVF) volume. This study aimed to investigate the factors associated with prolonged console time and surgical difficulty by RARP surgeons. This study included 405 patients who underwent RARP between 2014 and 2019 at our institution. Given that the anatomical characteristics were considered to affect RARP, PVF and working space (WS) were estimated preoperatively by computed tomography using a 3D image analysis system. Univariate and multivariate logistic regression analyses were performed to identify the factors prolonging console time, such as body mass index (BMI), prostate volume, previous abdominal surgery, nerve-sparing procedure, PVF, and WS. We also investigated whether post-operative complications were associated with any of these factors. Larger PVF (p = 0.028, odds ratio (OR) 1.43), smaller WS (p < 0.001, OR 2.48), and the nerve-sparing procedure (p = 0.037, OR 1.61) were statistically significant factors associated with prolonged console time. Furthermore, higher BMI (p = 0.013, OR 1.49) and smaller pelvic width (p < 0.001, OR 2.63) were the alternative and more practical factors associated with prolonged console time. The post-operative anastomotic leakage occurrence rate increased with the number of risk factors, while post-operative complications did not change even in high-risk cases. PVF and WS are significant factors associated with prolonged console time in RARP cases. However, BMI can be as useful as PVF, since BMI significantly correlated with PVF. Additionally, pelvic width (PW) can be an alternative to WS, since PW correlated with WS. This study demonstrated that preoperative BMI and PW might predict the surgical risk and identify suitable RARP cases for novice surgeons.