Two-dimensional Computed Tomography Images Research Articles

Automated Midline Shift Detection and Quantification in Traumatic Brain Injury: A Comprehensive Review

AbstractTraumatic brain injury (TBI) often results in midline shift (MLS) that is a critical indicator of the severity and prognosis of head injuries. Automated analysis of MLS from head computed tomography (CT) scans using artificial intelligence (AI) techniques has gained much attention in the past decade and has shown promise in improving diagnostic efficiency and accuracy. This review aims to summarize the current state of research on AI-based approaches for MLS analysis in TBI cases, identify the methodologies employed, evaluate the performance of the algorithms, and draw conclusions regarding their potential clinical applicability. A comprehensive literature search was conducted, identifying 15 distinctive publications. The identified articles were analyzed for their focus on MLS detection and quantification using AI techniques, including their choice of AI algorithms, dataset characteristics, and methodology. The reviewed articles covered various aspects related to MLS detection and quantification, employing deep neural networks trained on two-dimensional or three-dimensional CT imaging datasets. The dataset sizes ranged from 11 patients' CT scans to 25,000 CT images. The performance of the AI algorithms exhibited variations in accuracy, sensitivity, and specificity, with sensitivity ranging from 70 to 100%, and specificity ranging from 73 to 97.4%. AI-based approaches utilizing deep neural networks have demonstrated potential in the automated detection and quantification of MLS in TBI cases. However, different researchers have used different techniques; hence, critical comparison is difficult. Further research and standardization of evaluation protocols are needed to establish the reliability and generalizability of these AI algorithms for MLS detection and quantification in clinical practice. The findings highlight the importance of AI techniques in improving MLS diagnosis and guiding clinical decision-making in TBI management.

Cardiac computed tomography angiography for assessment of endothelial insufficiency of left atrial appendage disc-like occluder.

This study was performed to explore the diagnostic value of cardiac computed tomography angiography (CCTA) for endothelial insufficiency (EIS) of a left atrial appendage (LAA) disc-like occluder. Fifty-nine patients with nonvalvular atrial fibrillation who underwent placement of an LAA disc-like occluder (LAmbre; Lifetech Scientific) in our hospital were retrospectively analyzed. Patients who were found to have contrast agent entering the LAA at the 3-month postoperative CCTA examination underwent Hounsfield unit (HU) measurement of the LAA and construction of a three-dimensional(3D) model of the device for preliminary discernment between peri-device leakage (PDL) and EIS. These patients were then further examined by transesophageal echocardiography (TEE) to check for concordance with the computed tomography (CT) findings. According to the CT and TEE results, all patients were divided into the PDL group, total endothelialization group, and EIS group. The endothelial conditions and other implantation-related results were also tracked at the 6-month follow-up. All 59 patients underwent successful implantation of the LAmbre LAA closure device with no severe adverse events during the procedure. Thirty-five patients were found to have contrast agent entering the LAA at the 3-month postoperative CCTA follow-up. Based on the CT HU measurement and the 3D construction analysis results, these 35 patients were divided into the PDL group (19 patients) and the EIS group (16 patients). In the PDL group, the contrast agent infiltrated from the shoulder along the periphery of the occluder on two-dimensional (2D)CT images, and the 3D model showed a gap between the LAA and the device cover. However, the CCTA images of the other 16 patients in the EIS group showed that the contrast agent in the occluder on the 2D CTA images and 3D construction model confirmed the absence of a gap between the LAA and the device cover. TEE confirmed all of the CT results. The 6-month follow-up results showed that 14 of 19 patients in the EIS group achieved total endothelialization, whereas this number in the PDL group was only five of 19 patients. CCTA can replace TEE for examination of the endothelialization status, and patients with EIS have a higher chance of endothelialization than patients with PDL.

Shape phenotype of thigh fat and muscle and risk of major adverse cardiovascular events after fragility hip fracture.

Although sarcopenia has been recognized as a predictor of mortality in elderly patients with hip fracture, the association of thigh fat and muscle with cardiovascular (CV) outcome remains unclear. We examined the impact of computed tomography (CT)-derived shape features of thigh fat and muscle on major adverse CV events (MACE) in elderly patients with hip fracture. We conducted a retrospective analysis of consecutive patients aged ≥65years who presented with hip fracture confirmed on pelvic bone CT scan and underwent hip fracture surgery at our institution from April 2019 to December 2021. The cross-sectional area (CSA) and compactness (CM) of both the muscle and fat at the upper-thigh level were calculated from two-dimensional CT images using AVIEW Research (v1.1.38, Coreline Soft, Co. Ltd, Seoul, South Korea). The shape features of thigh fat and muscle were categorized into four groups based on the combination of CSA and CM: fat CSA (fat area [FA])/fat CM (FCM), muscle CSA (muscle area [MA])/muscle CM (MCM), FA/MCM and MA/FCM. In each of them, subjects were categorized into four subgroups: high CSA/high CM, high CSA/low CM, low CSA/high CM and low CSA/low CM. The primary outcome was MACE after 30days of surgery, defined as a composite of all-cause death, acute myocardial infarction, stroke or hospitalization for heart failure. Of 356 patients enrolled (median age, 82years; 76.7% females), 72 (20.2%) had MACE over a median follow-up of 13.1months (ranges 5.9-21.0months). Patients with MACE had a significantly lower median FA (193.7 vs. 226.2cm2 , P<0.0001) and FCM (0.443 vs. 0.513, P=0.001) compared with those without MACE, but no significant differences were found in MA, MCM and FA-MA ratio between the two groups. In a multivariate Cox regression analysis, low FA (<240.1cm2 ) (adjusted hazard ratio [HR] 2.99, 95% confidence interval [CI] 1.39-6.44, P=0.005) and low FCM (<0.477) (adjusted HR 2.00, 95% CI 1.10-3.63, P=0.023) were associated with an increased risk of MACE. Among the shape phenotypes of thigh fat and muscle, the thigh fat phenotype of low FA/low FCM (adjusted HR 3.13, 95% CI 1.81-5.42, P<0.0001 [reference, high FA/high FCM]) was found to be an independent predictor of MACE. In elderly patients with fragility hip fracture, thigh CT-derived measures of FA and FCM may provide useful prognostic information for predicting adverse CV outcomes.

Patient-specific virtual three-dimensional surgical navigation for gastric cancer surgery: A prospective study for preoperative planning and intraoperative guidance.

Abdominal computed tomography (CT) can accurately demonstrate organs and vascular structures around the stomach, and its potential role for image guidance is becoming increasingly established. However, solely using two-dimensional CT images to identify critical anatomical structures is undeniably challenging and not surgeon-friendly. To validate the feasibility of a patient-specific 3-D surgical navigation system for preoperative planning and intraoperative guidance during robotic gastric cancer surgery. A prospective single-arm open-label observational study was conducted. Thirty participants underwent robotic distal gastrectomy for gastric cancer using a virtual surgical navigation system that provides patient-specific 3-D anatomical information with a pneumoperitoneum model using preoperative CT-angiography. Turnaround time and the accuracy of detecting vascular anatomy with its variations were measured, and perioperative outcomes were compared with a control group after propensity-score matching during the same study period. Among 36 registered patients, 6 were excluded from the study. Patient-specific 3-D anatomy reconstruction was successfully implemented without any problems in all 30 patients using preoperative CT. All vessels encountered during gastric cancer surgery were successfully reconstructed, and all vascular origins and variations were identical to operative findings. The operative data and short-term outcomes between the experimental and control group were comparable. The experimental group showed shorter anesthesia time (218.6 min vs. 230.3 min; P=0.299), operative time (177.1 min vs. 193.9 min; P=0.137), and console time (129.3 min vs. 147.4 min; P=0.101) than the control group, although the differences were not statistically significant. Patient-specific 3-D surgical navigation system for robotic gastrectomy for gastric cancer is clinically feasible and applicable with an acceptable turnaround time. This system enables patient-specific preoperative planning and intraoperative navigation by visualizing all the anatomy required for gastrectomy in 3-D models without any error. Clinicaltrials.gov, identifier NCT05039333.

Dual imaging modality of fluorescence and transmission X-rays for gold nanoparticle-injected living mice.

X-ray fluorescence (XRF) imaging for metal nanoparticles (MNPs) is a promising molecular imaging modality that can determine dynamic biodistributions of MNPs. However, it has the limitation that it only provides functional information. In this study, we aim to show the feasibility of acquiring functional and anatomic information on the same platform by demonstrating a dual imaging modality of pinhole XRF and computed tomography (CT) for gold nanoparticle (GNP)-injected living mice. By installing a transmission CT detector in an existing pinhole XRF imaging system using a two-dimensional (2D) cadmium zinc telluride (CZT) gamma camera, XRF and CT images were acquired on the same platform. Due to the optimal X-ray spectra for XRF and CT image acquisition being different, XRF and CT imaging were performed by 140 and 50kV X-rays, respectively. An amount of 40mg GNPs (1.9nm in diameter) suspended in 0.20ml of phosphate-buffered saline were injected into the three BALB/c mice via a tail vein. Then, the kidney and tumor slices of mice were scanned at specific time points within 60min to acquire time-lapse in vivo biodistributions of GNPs. XRF images were directly acquired without image reconstruction using a pinhole collimator and a 2D CZT gamma camera. Subsequently, CT images were acquired by performing CT scans. In order to confirm the validity of the functional information provided by the XRF image, the CT image was fused with the XRF image. After the XRF and CT scan, the mice were euthanized, and major organs (kidneys, tumor, liver, and spleen) were extracted. The ex vivo GNP concentrations of the extracted organs were measured by inductively coupled plasma mass spectrometry (ICP-MS) and L-shell XRF detection system using a silicon drift detector, then compared with the in vivo GNP concentrations measured by the pinhole XRF imaging system. Time-lapse XRF images were directly acquired without rotation and translation of imaging objects within an acquisition time of 2min per slice. Due to the short image acquisition time, the time-lapse in vivo biodistribution of GNPs was acquired in the organs of the mice. CT images were fused with the XRF images and successfully confirmed the validity of the XRF images. The difference in ex vivo GNP concentrations measured by the L-shell XRF detection system and ICP-MS was 0.0005-0.02% by the weight of gold (wt%). Notably, the in vivo and ex vivo GNP concentrations in the kidneys of three mice were comparable with a difference of 0.01-0.08wt%. A dual imaging modality of pinhole XRF and CT imaging system and L-shell XRF detection system were successfully developed. The developed systems are a promising modality for in vivo imaging and ex vivo quantification for preclinical studies using MNPs. In addition, we discussed further improvements for the routine preclinical applications of the systems.

Virtual Reality in the Preoperative Planning of Adult Aortic Surgery: A Feasibility Study.

Background: Complex aortic anatomy needs careful preoperative planning in which a patient-tailored approach with novel immersive techniques could serve as a valuable addition to current preoperative imaging. This pilot study aimed to investigate the technical feasibility of virtual reality (VR) as an additional imaging tool for preoperative planning in ascending aortic surgery. Methods: Ten cardiothoracic surgeons were presented with six patients who had each undergone a recent repair of the ascending aorta. Two-dimensional computed tomography images of each patient were assessed prior to the VR session. After three-dimensional (3D) VR rendering and 3D segmentation of the ascending aorta and aortic arch, the reconstructions were analyzed by each surgeon in VR via a head-mounted display. Each cardiothoracic surgeon completed a questionnaire after each planning procedure. The results of their assessments were compared to the performed operations. The primary endpoint of the present study was a change of surgical approach from open to clamped distal anastomosis, and vice versa. Results: Compared with conventional imaging, 80% of surgeons found that VR prepared them better for surgery. In 33% of cases (two out of six), the preoperative decision was adjusted due to the 3D VR-based evaluation of the anatomy. Surgeons rated CardioVR usefulness, user-friendliness, and satisfaction with median scores of 3.8 (IQR: 3.5–4.1), 4.2 (IQR: 3.8–4.6,) and 4.1 (IQR: 3.8–4.7) on a five-point Likert scale, respectively. Conclusions: Three-dimensional VR imaging was associated with improved anatomical understanding among surgeons and could be helpful in the future preoperative planning of ascending aortic surgery.

Evaluation of Aortic Tortuosity as a Negative Predictor of Abdominal Aortic Aneurysm Rupture

Traditionally, the maximal aortic diameter has been used as the key indication for the decision to repair an abdominal aortic aneurysm (AAA). Aortic tortuosity has been proposed as another consideration, and the reported data have suggested that ruptured AAAs (rAAAs) tend to be less tortuous than non-rAAAs at the same diameter. Our objective was to compare the degree of aortic tortuosity in patients with rAAAs with those who had undergone elective repair using two-dimensional computed tomography imaging.

Clinical experience of using virtual 3D modelling for pre and intraoperative guidance during robotic-assisted partial nephrectomy

Objective: Surgical planning for robotic-assisted partial nephrectomy is widely performed using two-dimensional computed tomography images. It is unclear to what extent two-dimensional images fully simulate surgical anatomy and case complexity. To overcome these limitations, software has been developed to reconstruct three-dimensional models from computed tomography data. We present the results of a feasibility study, to explore the role and practicality of virtual three-dimensional modelling (by Innersight Labs) in the context of surgical utility for preoperative and intraoperative use, as well as improving patient involvement. Methods: A prospective study was conducted on patients undergoing robotic-assisted partial nephrectomy at our high volume kidney cancer centre. Approval from a research ethics committee was obtained. Patient demographics and tumour characteristics were collected. Surgical outcome measures were recorded. The value of the three-dimensional model to the surgeon and patient was assessed using a survey. The prospective cohort was compared against a retrospective cohort and cases were individually matched using RENAL (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, location relative to polar lines) scores. Results: This study included 22 patients. Three-dimensional modelling was found to be safe for this prospective cohort and resulted in good surgical outcome measures. The mean (standard deviation) console time was 158.6 (35) min and warm ischaemia time was 17.3 (6.3) min. The median (interquartile range) estimated blood loss was 125 (50–237.5) ml. Two procedures were converted to radical nephrectomy due to the risk of positive margins during resection. The median (interquartile range) length of stay was 2 (2–3) days. No postoperative complications were noted and all patients had negative surgical margins. Patients reported improved understanding of their procedure using the three-dimensional model. Conclusion: This study shows the potential benefit of three-dimensional modelling technology with positive uptake from surgeons and patients. Benefits are improved perception of vascular anatomy and resection approach, and procedure understanding by patients. A randomised controlled trial is needed to evaluate the technology further. Level of evidence: 2b

Computed tomography image representation using the Legendre polynomial and spherical harmonics functions.

The representation of computed tomography (CT) images using the Legendre polynomial (LPF) and spherical harmonics (SHF) functions was investigated. We selected 100 two-dimensional (2D) CT images of 10 lung cancer patients and 33 three-dimensional (3D) CT images of head and neck cancer patients. The reproducibility of these special functions was evaluated in terms of the normalized cross-correlation (NCC). For the 2D images, the NCC was 0.990 ± 0.002 (1sd) with an LPF of order 70, whereas for the 3D images, the NCC was 0.971 ± 0.004 (1sd) with an SHF of degree 70. The results showed that the LPF was more efficient than the Fourier series. As the thoracic and head areas are cylindrical and spherical, respectively, expansions with the LPF and SHF achieved an efficient representation of the human body. CT image representation with analytical functions can be potentially beneficial, such as in X-ray scattering estimation.

Refined Locally Linear Transform-Based Spectral-Domain Gradient Sparsity and Its Applications in Spectral CT Reconstruction.

Spectral computed tomography (CT) is extension of the conventional single spectral CT (SSCT) along the energy dimension, which achieves superior energy resolution and material distinguishability. However, for the state-of-the-art photon counting detector (PCD) based spectral CT, because the emitted photons with a fixed total number for each X-ray beam are divided into several energy bins, the noise level is increased in each reconstructed channel image, and it further leads to an inaccurate material decomposition. To improve the reconstructed image quality and decomposition accuracy, in this work, we first employ a refined locally linear transform to convert the structural similarity among two-dimensional (2D) spectral CT images to a spectral-dimension gradient sparsity. By combining the gradient sparsity in the spatial domain, a global three-dimensional (3D) gradient sparsity is constructed, then measured with L1-, L0- and trace-norm, respectively. For each sparsity measurement, we propose the corresponding optimization model, develop the iterative algorithm, and verify the effectiveness and superiority with real datasets.

Quantitative analysis of fracture dynamic evolution in coal subjected to uniaxial and triaxial compression loads based on industrial CT and fractal theory

The dynamic evolution characteristics of fractures in coal under different compressive loads are of great significance to the recovery of coalbed methane (CBM). In this paper, the X-ray computer tomography (CT) detections of coal samples under uniaxial and triaxial compressive loading conditions were performed by using a developed triaxial in situ rig and an industrial CT scanner. The image processing technique, three-dimensional reconstruction method and statistical principles were employed to describe two-dimensional and three-dimensional fracture evolution in coal under uniaxial and triaxial compressive loads. The results showed that the developed triaxial in situ rig has an enough scanning resolution and is suitable to carry out CT scanning inspections under uniaxial and triaxial compressive loads for porous materials of coal and rock. The two-dimensional cross-sectional CT images effectively reflect the dynamic evolution of two-dimensional fractures during the deformation of coal. Confining pressure and minerals have a significant effect on fracture propagation in coal. The evolution characteristics of three-dimensional fractures can be clearly revealed by the reconstructed three-dimensional digital fracture models of coal. Euler number effectively reflects the fracture connectivity in coal at different deformation stages. During the deformation of coal, the fracture volume, fracture rate, fracture density and fracture connectivity mainly undergo a slow decrease stage, a slow increase stage and a sharp increase stage, display a good linear correlation with fractal dimension, and quantitatively characterize the evolution process of the three-dimensional fractures in coal. The fractal dimension calculated by the box-counting method effectively mirrors fracture propagation and fracture geometric complexity and can be employed to uncover the fracture dynamic evolution in coal under different compressive loading conditions.

Sex estimation in a modern Turkish population using the clavicle: a computed tomography study

ABSTRACT Morphometric analysis of the clavicle is a potential source of useful data for the estimation of sex. Clavicle is often retrieved intact from decomposed and scavenged remains when pelvis and skull, essential sex indicators, are often found damaged or missing. The objective of this study is to analyse clavicle morphometric data for sex estimation in a Turkish population. Computed tomography (CT) scans of the thorax of two hundred Turkish adult patients (71 male and 81 female patients with an age range of 22–80 years) were included. Furthermore, morphometric data for the left clavicle using two-dimensional (2D) and three-dimensional (3D) clavicle CT images were obtained, and six variables were measured in the clavicle images. Univariate and multivariate discriminant function analysis (DFA) was used to create population-specific functions for sex estimation. The classification accuracy for the cross-validated data ranged from 75% to 89% in the uni- and multivariate DFA. Stepwise discrimination analysis yielded an 89% accuracy rate for the maximum length and midshaft circumference variables. The study showed that the clavicle can provide useful data for estimating sex in a modern Turkish population and that when there is difficulty accessing bone collections, CT scans can provide useful data for sex estimation.

Automated extraction of left atrial volumes from two-dimensional computer tomography images using a deep learning technique

BackgroundPrecise segmentation of the left atrium (LA) in computed tomography (CT) images constitutes a crucial preparatory step for catheter ablation in atrial fibrillation (AF). We aim to apply deep convolutional neural networks (DCNNs) to automate the LA detection/segmentation procedure and create three-dimensional (3D) geometries. MethodsFive hundred eighteen patients who underwent procedures for circumferential isolation of four pulmonary veins were enrolled. Cardiac CT images (from 97 patients) were used to construct the LA detection and segmentation models. These images were reviewed by the cardiologists such that images containing the LA were identified/segmented as the ground truth for model training. Two DCNNs which incorporated transfer learning with the architectures of ResNet50/U-Net were trained for image-based LA classification/segmentation. The LA geometry created by the deep learning model was correlated to the outcomes of AF ablation. ResultsThe LA detection model achieved an overall 99.0% prediction accuracy, as well as a sensitivity of 99.3% and a specificity of 98.7%. Moreover, the LA segmentation model achieved an intersection over union of 91.42%. The estimated mean LA volume of all the 518 patients studied herein with the deep learning model was 123.3 ± 40.4 ml. The greatest area under the curve with a LA volume of 139 ml yielded a positive predictive value of 85.5% without detectable AF episodes over a period of one year following ablation. ConclusionsThe deep learning provides an efficient and accurate way for automatic contouring and LA volume calculation based on the construction of the 3D LA geometry.

Comparison of stand-alone cage and cage-with-plate for monosegmental cervical fusion and impact of virtual reality in evaluating surgical results

ObjectivesAfter ventral decompression of monosegmental cervical spondylotic stenosis, a stand-alone cage (SC) or cage-with-plate (CP) can be inserted for fusion. Postoperative radiological evaluation can be achieved using different imaging modalities. We retrospectively compared complications, as well as clinical and radiological outcomes for both fusion techniques, and analyzed the possible role of virtual reality (VR) in evaluating the postoperative results. Patients and methodsOne hundred seventeen patients were included (SC/CP: 54/63). Complications, as well as clinical and radiological outcomes of both fusion techniques were compared. Computed tomography (CT) scans were visualized via VR to measure the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region, and to assess the degree of the intersegmental ossification. ResultsThere were no significant differences between the two fusion techniques regarding perioperative complication rates, fusion rates, or pain parameter (visual analogue scale (VAS) of arm pain, neck disability index). However, advantages regarding subsidence, kyphosis, and VAS of neck pain were found when using the CP versus SC. Using the VR technique, there was no significant difference between the two fusion techniques in the mean size of the cross-sectional area at the end of follow-up. ConclusionDue to the long-term advantages of CP fusion, we prefer a monosegmental cervical spinal fusion using CP. Reconstruction of postsurgical two-dimensional CT images into three-dimensional images, and the spatial and anatomical presentation in VR models, improved the evaluation of these postoperative results.

Evaluation of Meso-damage Processes in Concrete by X-Ray CT Scanning Techniques Under Real-Time Uniaxial Compression Testing

Concrete damage characteristics were investigated by X-ray computed tomography (CT) under uniaxial compression, with medical X-ray CT and a loading device used to carry out real-time uniaxial compression scanning tests, obtaining two-dimensional CT images of crack generation, propagation, coalescence, and failure. Damage deterioration of internal structures under different loading conditions was analyzed by means of a digital image-processing technique, which allowed the recognition and extraction of meso cracks. Furthermore, the crack lengths were extracted and measured from CT images. Methods of divisional regions were applied to carry out the quantitative analysis of CT numbers in specific representative regions. The fractal dimensions (FDs) of crack propagation in CT images were estimated using the box-counting dimension, and the relationship between the strain, crack propagation, and FD examined. Complicated and disordered internal cracks were clearly observed with increased load. The results indicated that such CT tests were a promising means for identifying the evolution and propagation of internal cracks and for studying the mesoscopic damage fracture mechanism under uniaxial compression.

Nonlinear Finite Element Analysis of Intervertebral Disc: A Comparative Study

The aims of the study were i) to develop a finite element model of a functional spinal unit (FSU) without ligaments at cervical region, ii) to simulate different material properties of intervertebral disc for analysing degeneration and iii) to investigate the influence of disc degeneration on the biomechanical behaviour of a motion. To do so, two-dimensional computed tomography images of spine recorded from volunteer was converted into three-dimensional vertebrae model with different material properties section by section. Material properties of intervertebral disc are described nonlinear in finite element analysis. Moment was applied on superior endplate of vertebrae as 7.5 Nm. The boundary condition was described on the endplate of adjacent inferior vertebrae as fixed in space. Stress distribution over the nucleus and motions of the functional spinal unit were calculated using finite element analysis. The results were compared with physiological motions of functional spinal unit from literature. At the result, more realistic result of disc model was obtained by fluid filled cavity model with regard to maximum stress value on disc and intradiscal pressure. The fluid in the shell simulate incompressible feature like reality.

The Association Between Rotator Cuff Muscle Fatty Infiltration and Glenoid Morphology in Glenohumeral Osteoarthritis

Glenoid morphology and rotator cuff muscle quality are important anatomic factors that can impact longevity of the glenoid component following total shoulder arthroplasty (TSA). We hypothesized that rotator cuff muscle fatty infiltration is associated with increased pathologic glenoid bone loss in glenohumeral osteoarthritis (OA). We retrospectively reviewed 190 preoperative computed tomography (CT) scans of 175 patients (mean age, 66 years; range, 44 to 90 years) who underwent TSA for the treatment of primary glenohumeral OA. Two-dimensional orthogonal CT images were reformatted in the plane of the scapula from 3-dimensional images. Pathologic joint-line medialization was defined with use of the glenoid vault model. Pathologic glenoid version was measured directly. Glenoid morphology was graded according to a modified Walch classification (subtypes A1, A2, B1, B2, B3, C1, and C2). Rotator cuff muscle fatty infiltration was assessed and assigned a Goutallier score on the sagittal CT slice just medial to the spinoglenoid notch for each muscle. There was a significant difference in the Goutallier score for the supraspinatus, infraspinatus, and teres minor muscles between Walch subtypes (p ≤ 0.05). High-grade posterior rotator cuff muscle fatty infiltration was present in 55% (21) of 38 B3 glenoids compared with 8% (3) of 39 A1 glenoids. Increasing joint-line medialization was associated with increasing fatty infiltration of all rotator cuff muscles (p ≤ 0.05). Higher fatty infiltration of the infraspinatus, teres minor, and combined posterior rotator cuff muscles was associated with increasing glenoid retroversion (p ≤ 0.05). After controlling for joint-line medialization and retroversion, B3 glenoids were more likely to have fatty infiltration of the supraspinatus and infraspinatus muscles than B2 glenoids were. High-grade rotator cuff muscle fatty infiltration is associated with B3 glenoids, increased pathologic glenoid retroversion, and increased joint-line medialization. Additional studies are needed to determine the causal relationship between these muscle changes and glenoid wear, whether these muscle changes independently affect clinical and radiographic outcomes in anatomic TSA, and whether fatty infiltration can improve postoperatively with correction of pathologic version and/or joint-line restoration. This study investigates the association between different patterns of glenoid bone loss and rotator cuff muscle fatty infiltration. Both factors have been shown to affect clinical outcome following TSA.

MULTIFRACTAL ANALYSIS OF SEISMICALLY INDUCED SOFT-SEDIMENT DEFORMATION STRUCTURES IMAGED BY X-RAY COMPUTED TOMOGRAPHY

Unconsolidated soft sediments deform and mix complexly by seismically induced fluidization. Such geological soft-sediment deformation structures (SSDSs) recorded in boring cores were imaged by X-ray computed tomography (CT), which enables visualization of the inhomogeneous spatial distribution of iron-bearing mineral grains as strong X-ray absorbers in the deformed strata. Multifractal analysis was applied to the two-dimensional (2D) CT images with various degrees of deformation and mixing. The results show that the distribution of the iron-bearing mineral grains is multifractal for less deformed/mixed strata and almost monofractal for fully mixed (i.e. almost homogenized) strata. Computer simulations of deformation of real and synthetic digital images were performed using the egg-beater flow model. The simulations successfully reproduced the transformation from the multifractal spectra into almost monofractal spectra (i.e. almost convergence on a single point) with an increase in deformation/mixing intensity. The present study demonstrates that multifractal analysis coupled with X-ray CT and the mixing flow model is useful to quantify the complexity of seismically induced SSDSs, standing as a novel method for the evaluation of cores for seismic risk assessment.

Cricoid and left bronchial diameter in the pediatric population.

Lung isolation in the pediatric population can be problematic. The diameter and length of the right and left mainstem bronchi are not well described in young children. Information regarding these measurements may help determine the appropriate size of endotracheal tubes for endobronchial intubation as well as the development of lung isolation devices for the pediatric population. The present study is based on computed tomography (CT) measurements to evaluate airway dimensions. The goal of this study was to define the relationship between the diameters of the left mainstem bronchus (LMSB) and the cricoid ring, and to study the effect of age, weight, and height on these dimensions. The two-dimensional CT images of 102 children, ranging in age from 1 month to 10 years, undergoing radiological evaluation unrelated to airway symptomatology were examined. The cricoid dimensions (anteroposterior and transverse diameters) were measured using transverse plane images. The LMSB diameter was measured below the carina along the long axis of left main bronchus. Univariate regression analysis was used to determine whether one or more of the variables (age, gender, height, weight) had a predictable relationship with the cricoid and the LMSB diameters. The cricoid as well as the LMSB diameters increase with age, height, and weight. The relationship between the cricoid diameter and the LMSB diameter remains constant across all ages with a ratio of 0.78 ± 0.14. This ratio was slightly larger for girls than boys (0.81 ± 0.16 vs 0.77 ± 0.13). The cricoid to LMSB ratio (relationship) remains constant with respect to age, height, and weight.

Three-dimensional printing models improve understanding of spinal fracture—A randomized controlled study in China

Three-dimensional printing (3Dp) is being increasingly used in medical education. Although the use of such lifelike models is beneficial, well-powered, randomized studies supporting this statement are scarce. Two spinal fracture simulation models were generated by 3Dp. Altogether, 120 medical students (54.2% females) were randomized into three teaching module groups [two-dimensional computed tomography images (CT), 3D, or 3Dp] and asked to answer 10 key anatomical and 4 evaluative questions. Students in the 3Dp or 3D group performed significantly better than those in the CT group, although males in the 3D group scored higher than females. Students in the 3Dp group were the first to answer all questions, and there were no sex-related differences. Pleasure, assistance, effect, and confidence were more predominant in students in the 3Dp group than in those in the 3D and CT groups. This randomized study revealed that the 3Dp model markedly improved the identification of complex spinal fracture anatomy by medical students and was equally appreciated and comprehended by both sexes. Therefore, the lifelike fracture model made by 3Dp technology should be used as a means of premedical education.