Prognostic factors in pulmonary metastases resection from colorectal cancer: impact of right-sided colon cancer and early recurrence.

OBJECTIVE: This retrospective cohort study aimed to explore the surgical outcomes and prognostic factors of resection of pulmonary metastases (PM) from colorectal cancer (CRC). METHODS: Overall, 60 patients who underwent resection of PM from CRC between 2015 and 2021 at two institutions were reviewed. The primary outcome were overall survival (OS) and early recurrence after PM resection. The association between OS and right-sided colon cancer (RCC) was investigated. Early recurrence after PM resection was defined as recurrence within one year. RESULTS: The 5-year OS after CRC resection was 83.8% (95% confidence interval [CI] 67.5-92.4) and after PM resection was 69.4% (95% CI 47.5-83.6). In total, 25 patients had recurrence after PM resection (16 within 1 year and 9 after 1 year). In multivariable analysis for OS, RCC (hazard ratio [HR] 4.370, 95% CI 1.020-18.73; p = 0.047) and early recurrence after resection of PM (HR 17.23, 95% CI 2.685-110.6; p = 0.003) were risk factors for poor OS. In multivariable analysis for early recurrence after PM resection, higher value of carcinoembryonic antigen (CEA) (> 5.0 mg/dL) before PM resection was a risk factor for early recurrence (HR 3.275, 95% CI 1.092-9.821; p = 0.034). CONCLUSION: The RCC and early recurrence after PM resection were poor prognosis factors of OS. Higher value of CEA before PM resection was an independent risk factor for early recurrence after resection of PM. Comparitive study between surgery and nonsurgery is necessary in patients with higher CEA values.

Compensatory expansion of the right middle lobe: volumetric and functional analysis of the changes after right upper or lower lobectomy.

The right middle lobe often poorly expands after right upper lobectomy. Postoperative pulmonary function may be inferior after right upper lobectomy than after right lower lobectomy due to poor expansion of the middle lobe. This study examined the difference in the postoperative right middle lobe expansion and pulmonary function between right upper and right lower lobectomy. Patients who underwent right upper or right lower lobectomy through video-assisted thoracic surgery (n = 82) were enrolled in this retrospective study. Pulmonary function tests and computed tomography were performed preoperatively and at 1 year postoperatively. Using three-dimensional computed tomography volumetry, the preoperative and postoperative lung volumes were measured, and the predicted postoperative forced expiratory volume in 1 s was calculated. Middle lobe volume ratio (i.e., ratio of the postoperative to the preoperative middle lobe volume) and the postoperative forced expiratory volume in 1 s ratio (i.e., ratio of the measured to the predicted postoperative forced expiratory volume in 1 s) were compared between right upper and right lower lobectomy. Compared with the patients who underwent right upper lobectomy (n = 50), those who underwent right lower lobectomy (n = 32) had significantly higher middle lobe volume ratio (1.15 ± 0.32 vs. 1.63 ± 0.52, p < 0.001) and postoperative forced expiratory volume in 1 s ratio (1.12 ± 0.12 vs. 1.19 ± 0.13, p = 0.010). The right middle lobe showed more expansion and better recovery of postoperative pulmonary function after right lower lobectomy than after right upper lobectomy.

Influence of Power-Weighted Center of Echo Signal Within Window Function on Local Strain Rate Distribution in Left Ventricular Wall.

OBJECTIVE: The deviation of the power-weighted center of the echo signal from the geometric center within the velocity estimation window for calculating strain rate (SR) causes an estimation error. This study aimed to confirm whether an erroneous multilayer pattern in the SR distribution of the left ventricular wall could be corrected by considering the power-weighted center of the echo signal. METHODS: The SR distributions were measured locally in the transmural direction around the pre-ejection and early diastolic phases in healthy volunteers. The estimation error related to the power-weighted center of the echo signal was corrected using a previously proposed method, and the effectiveness of the correction was confirmed based on the accuracy of the estimated myocardial displacement. RESULTS: The SR distribution in early diastole was observed as multilayers of low- and high-amplitude negative SRs. However, this multilayer pattern disappeared after correction. In the pre-ejection phase, multilayers of positive and negative SRs were observed in the SR distributions with and without correction. This correction was sufficiently effective in accurately tracking the local peak of the echo signal. CONCLUSION: The multilayer pattern of low- and high-amplitude positive or negative SRs is caused by estimation errors related to the power-weighted center of the echo signal. The multilayer pattern of positive and negative SRs might not be caused by these errors and might relate to the actual change in myocardial thickness because the estimation errors do not convert the negative (positive) SR to positive (negative) in a homogeneous negative (positive) SR distribution.

A novel ultrasonic method for measuring minute sinusoidal displacement by network analyzer.

We developed a method for generating continuous sinusoidal displacements of an object to estimate viscoelastic parameters. However, the amplitude of the displacement caused by the ultrasonic excitation force under safe guidelines was small (a few micrometers), and it was difficult to stably measure the displacement. Therefore, to stably measure the amplitude of sinusoidal displacement as small as the order of micrometers, we proposed a novel method using a network analyzer. Ultrasonic waves were irradiated using an ultrasonic transducer on an object vibrating sinusoidally. The S parameter of the first reflected wave received from the surface of the object was measured using a network analyzer. The S parameter and the inverse Fourier transform were formulated theoretically, and the amplitude of the sinusoidal displacement of the object was estimated from the amplitude characteristics of the inverse Fourier-transformed signal. The proposed method was applied to measure sinusoidal displacements on the order of micrometers from 10 to 300 Hz on an object using a water tank experiment. The obtained sinusoidal displacement agreed well with the reference values measured using a laser displacement meter. The proposed method can accurately measure minute sinusoidal displacements that occur on an object.

Reduction in drain-related adverse events using the barbed suture method for chest tube wound closure.

OBJECTIVE: A chest tube is usually placed in patients undergoing general thoracic surgery. Although the barbed suture method has been introduced for chest tube wound closure, its superiority to the conventional suture methods for drain management remains unclear. The study aimed to determine whether the barbed suture method could reduce drain-related adverse events compared to the conventional method. METHODS: We retrospectively reviewed the medical records of patients who underwent general thoracic surgery between January 2021 and December 2022, 1 year before and after the introduction of the barbed suture method at our institution. Patients who underwent the barbed suture or conventional method were included. Univariate and multivariate analyses of drain-related adverse events were performed. RESULTS: Of the 250 participants, 110 and 140 underwent the barbed suture method and conventional suture method, respectively. The univariate analysis showed that a higher body mass index, preoperative malignant diagnosis, lobectomy, longer operative time, larger tube size, longer chest drainage duration, surgical complications, and conventional method were risk factors for drain-related adverse events. The multivariate analysis showed that the barbed suture method was a protective factor against drain-related adverse events (odds ratio 0.267; 95% confidence interval 0.103-0.691; P = 0.007). CONCLUSIONS: The barbed suture method could reduce drain-related adverse events compared to the conventional method. Therefore, it might be a potential standard method for chest tube wound closure in patients undergoing general thoracic surgery.

Estimation error in speed of sound caused by rotation of measured cross-section from short-axis plane of blood vessels: a preliminary study.

PURPOSE: Estimating the speed of sound (SoS) in ultrasound propagation media is important for improving the quality of B-mode images and for quantitative tissue characterization. We have been studying a method for estimating the SoS by measuring the reception time distribution of waves scattered from a scatterer at the elements in a probe. Previously, the measurement cross section was assumed to be perpendicular to the long axis of the blood vessel. In this study, we experimentally investigated the relationship between rotation angle [Formula: see text] of the probe relative to the short-axis plane of the blood vessel and the estimated SoS, [Formula: see text]. METHODS: Water tank and phantom experiments were conducted to investigate the characteristics of [Formula: see text] and element signals when the probe was rotated. RESULTS: The received signal powers at the elements around both edges greatly decreased as [Formula: see text] increased. We introduced a parameter representing the decrease in power, [Formula: see text], in the received signal at the elements at both edges relative to the center element. [Formula: see text] was estimated to be larger as [Formula: see text] increased, especially for [Formula: see text]. [Formula: see text] also increased as [Formula: see text] increased. An approximately proportional relationship existed between the errors in [Formula: see text] and [Formula: see text]. CONCLUSION: Based on these results, we can distinguish between the presence and the absence of SoS misestimations using the difference in power among the elements in the received signal. In the absence of misestimation, we can obtain the true SoS, even if the target has a non-negligible size, by applying our previously proposed methods.

Optimizing irradiation conditions for low-intensity pulsed ultrasound to upregulate endothelial nitric oxide synthase.

PURPOSE: Here we aimed to develop a minimally invasive treatment for ischemic heart disease and demonstrate that low-intensity pulsed ultrasound (LIPUS) therapy improves myocardial ischemia by promoting myocardial angiogenesis in a porcine model of chronic myocardial ischemia. Studies to date determined the optimal treatment conditions within the range of settings available with existing ultrasound equipment and did not investigate a wider range of conditions. METHODS: We investigated a broad range of five parameters associated with ultrasound irradiation conditions that promote expression of endothelial nitric oxide synthase (eNOS), a key molecule that promotes angiogenesis in human coronary artery endothelial cells (HCAEC). RESULTS: Suboptimal irradiation conditions included 1-MHz ultrasound frequency, 500-kPa sound pressure, 20-min total irradiation time, 32-48-[Formula: see text] pulse duration, and 320-[Formula: see text] pulse repetition time. Furthermore, a proposed index, [Formula: see text], calculated as the product of power and the total number of irradiation cycles applied to cells using LIPUS, uniformly revealed the experimental eNOS expression associated with the various values of five parameters under different irradiation conditions. CONCLUSION: We determined the suboptimal ultrasound irradiation conditions for promoting eNOS expression in HCAEC.

Modified multi-Rayleigh model-based statistical analysis of ultrasound envelope for quantification of liver steatosis and fibrosis.

PURPOSE: Quantitative diagnosis of the degree of fibrosis progression is currently a focus of attention for fatty liver in nonalcoholic steatohepatitis (NASH). However, previous studies have focused on either lipid droplets or fibrotic tissue, and few have reported the evaluation of both in patients whose livers contain adipose and fibrous features. Our aim was to evaluate fibrosis tissue and lipid droplets in the liver. METHODS: We used an analytical method combining the multi-Rayleigh (MRA) model and a healthy liver structure filter (HLSF) as a technique for statistical analysis of the amplitude envelope to estimate fat and fibrotic volumes in clinical datasets with different degrees of fat and fibrosis progression. RESULTS: Fat mass was estimated based on the non-MRA fraction corresponding to the signal characteristics of aggregated lipid droplets. Non-MRA fraction has a positive correlation with fat mass and is effective for detecting moderate and severe fatty livers. Progression of fibrosis was estimated using MRA parameters in combination with the HLSF. The proposed method was used to extract non-healthy areas with characteristics of fibrotic tissue. Fibrosis in early fatty liver suggested the possibility of evaluation. On the other hand, fat was identified as a factor that reduced the accuracy of estimating fibrosis progression in moderate and severe fatty livers. CONCLUSION: The proposed method was used to simultaneously evaluate fat mass and fibrosis progression in early fatty liver, suggesting the possibility of quantitative evaluation for discriminating between lipid droplets and fibrous tissue in the early fatty liver.

Multi-Layer Scene Representation from Composed Focal Stacks.

Multi-layer images are a powerful scene representation for high-performance rendering in virtual/augmented reality (VR/AR). The major approach to generate such images is to use a deep neural network trained to encode colors and alpha values of depth certainty on each layer using registered multi-view images. A typical network is aimed at using a limited number of nearest views. Therefore, local noises in input images from a user-navigated camera deteriorate the final rendering quality and interfere with coherency over view transitions. We propose to use a focal stack composed of multi-view inputs to diminish such noises. We also provide theoretical analysis for ideal focal stacks to generate multi-layer images. Our results demonstrate the advantages of using focal stacks in coherent rendering, memory footprint, and AR-supported data capturing. We also show three applications of imaging for VR.

Exemplar-Based Inpainting for 6DOF Virtual Reality Photos.

Multi-layer images are currently the most prominent scene representation for viewing natural scenes under full-motion parallax in virtual reality. Layers ordered in diopter space contain color and transparency so that a complete image is formed when the layers are composited in a view-dependent manner. Once baked, the same limitations apply to multi-layer images as to conventional single-layer photography, making it challenging to remove obstructive objects or otherwise edit the content. Object removal before baking can benefit from filling disoccluded layers with pixels from background layers. However, if no such background pixels have been observed, an inpainting algorithm must fill the empty spots with fitting synthetic content. We present and study a multi-layer inpainting approach that addresses this problem in two stages: First, a volumetric area of interest specified by the user is classified with respect to whether the background pixels have been observed or not. Second, the unobserved pixels are filled with multi-layer inpainting. We report on experiments using multiple variants of multi-layer inpainting and compare our solution to conventional inpainting methods that consider each layer individually.

guitARhero: Interactive Augmented Reality Guitar Tutorials.

This paper presents guitARhero, an Augmented Reality application for interactively teaching guitar playing to beginners through responsive visualizations overlaid on the guitar neck. We support two types of visual guidance, a highlighting of the frets that need to be pressed and a 3D hand overlay, as well as two display scenarios, one using a desktop magic mirror and one using a video see-through head-mounted display. We conducted a user study with 20 participants to evaluate how well users could follow instructions presented with different guidance and display combinations and compare these to a baseline where users had to follow video instructions. Our study highlights the trade-off between the provided information and visual clarity affecting the user's ability to interpret and follow instructions for fine-grained tasks. We show that the perceived usefulness of instruction integration into an HMD view highly depends on the hardware capabilities and instruction details.

Post-Synthetic Nucleobase Modification of Oligodeoxynucleotides by Sonogashira Coupling and Influence of Alkynyl Modifications on the Duplex-Forming Ability.

Recently, it was reported that the alkynyl modification of nucleobases mitigates the toxicity of antisense oligonucleotides (ASO) while maintaining the efficacy. However, the general effect of alkynyl modifications on the duplex-forming ability of oligonucleotides (ONs) is unclear. In this study, post-synthetic nucleobase modification by Sonogashira coupling in aqueous medium was carried out to efficiently evaluate the physiological properties of various ONs with alkynyl-modified nucleobases. Although several undesired reactions, including nucleobase cyclization, were observed, various types of alkynyl-modified ONs were successfully obtained via Sonogashira coupling of ONs containing iodinated nucleobases. Evaluation of the stability of the duplex formed by the synthesized alkynyl-modified ONs showed that the alkynyl modification of pyrimidine was less tolerated than that of purine, although both the modifications occurred in the major groove of the duplex. These results can be attributed to the bond angle of the alkyne on the pyrimidine and the close proximity of the alkynyl substituents to the phosphodiester backbone. The synthetic method developed in this study may contribute to the screening of the optimal chemical modification of ASO because various alkynyl-modified ONs that are effective in reducing the toxicity of ASO can be easily synthesized by this method.

Modified Egocentric Viewpoint for Softer Seated Experience in Virtual Reality.

Users in a prolonged experience of virtual reality adopt a sitting position according to their task, as they do in the real world. However, inconsistencies in the haptic feedback from a chair they sit on in the real world and that which is expected in the virtual world decrease the feeling of presence. We aimed to change the perceived haptic features of a chair by shifting the position and angle of the users' viewpoints in the virtual reality environment. The targeted features in this study were seat softness and backrest flexibility. To enhance the seat softness, we shifted the virtual viewpoint using an exponential formula soon after a user's bottom contacted the seat surface. The flexibility of the backrest was manipulated by moving the viewpoint, which followed the tilt of the virtual backrest. These shifts make users feel as if their body moves along with the viewpoint; as a result, they would perceive pseudo-softness or flexibility consistently with the body movement. Based on subjective evaluations, we confirmed that the participants perceived the seat as being softer and the backrest as being more flexible than the actual ones. These results demonstrated that only shifting the viewpoint could change the participants' perceptions of the haptic features of their seats, although significant changes created strong discomfort.

Speed-of-sound estimation in ultrasound propagation medium by considering size of target scatterer.

PURPOSE: Accurate speed-of-sound (SoS) estimation in an ultrasound propagation medium improves imaging quality and contributes to better diagnosis of diseases. In conventional time-delay-based SoS estimation approaches studied by several groups, a received wave is assumed to be scattered from an ideal point scatterer. In these approaches, the SoS is overestimated when the target scatterer has a non-negligible size. In this paper, we propose the SoS estimation method that considers target size. METHODS: In the proposed method, the error ratio of the estimated SoS using the conventional time-delay-based approach is determined from measurable parameters using the geometric relationship between the received elements and target. Subsequently, the SoS erroneously estimated using conventional estimation, assuming the ideal point scatterer as a target, is corrected by the determined estimation error ratio. To validate the proposed method, the SoS in water was estimated for several wire sizes. RESULTS: The SoS in the water was overestimated using the conventional SoS estimation method, with a maximum positive error of 38 m/s. The proposed method corrected the SoS estimates, and the errors were suppressed to within 6 m/s, irrespective of the wire diameter. CONCLUSION: The present results demonstrate that the proposed method can estimate the SoS by considering the target size without using information on the true SoS, true target depth, and true target size, which is applicable to in vivo measurements.

Metabolically Stable Anomeric Linkages Containing GalNAc-siRNA Conjugates: An Interplay among ASGPR, Glycosidase, and RISC Pathways.

Conjugation of synthetic triantennary N-acetyl-d-galactosamine (GalNAc) to small interfering RNA (siRNA) mediates binding to the asialoglycoprotein receptor (ASGPR) on the surface of hepatocytes, facilitating liver-specific uptake and siRNA-mediated gene silencing. The natural ß-glycosidic bond of the GalNAc ligand is rapidly cleaved by glycosidases in vivo. Novel GalNAc ligands with S-, and C-glycosides with both α- and ß-anomeric linkages, N-glycosides with ß-anomeric linkage, and the O-glycoside with α-anomeric linkage were synthesized and conjugated to siRNA either on-column during siRNA synthesis or through a high-throughput, post-synthetic method. Unlike natural GalNAc, modified ligands were resistant to glycosidase activity. The siRNAs conjugated to newly designed ligands had similar affinities for ASGPR and similar silencing activity in mice as the parent GalNAc-siRNA conjugate. These data suggest that other factors, such as protein-nucleic acid interactions and loading of the antisense strand into the RNA-induced silencing complex (RISC), are more critical to the duration of action than the stereochemistry and stability of the anomeric linkage between the GalNAc moiety of the ligand conjugated to the sense strand of the siRNA.

Lateral M-Mode: Ultrasound Visualization of Displacement Along Longitudinal Direction at Intima-Media Complex.

Quantification of the dynamics of the carotid artery wall is useful in evaluating arteriosclerosis and atherosclerosis. As the carotid artery wall moves not only in the radial direction but also in the longitudinal direction, longitudinal movement should be considered in the analysis of the dynamic properties of the carotid artery wall. In this study, we propose a "lateral M-mode" method for visualizing the longitudinal movement of the intima-media complex (IMC). For the lateral M-mode, we set the target line in the longitudinal direction along the IMC and visualize the signals on the target line frame-by-frame by correcting the position of the target line along the radial displacement estimated by the phased tracking method. Differentiating the envelope signals between consecutive ultrasound beams was effective in visualizing the lateral movement of the IMC. The precision of the longitudinal displacement of the IMC estimated using the conventional block-matching method was validated by comparing it with the lateral M-mode. Because the conventional M-mode sequence plays an important role in evaluation of the dynamics of various tissues, the proposed "lateral M-mode" contributes to a detailed understanding of vascular dynamics and the development of diagnostic methods for vascular diseases.

Good Keyframes to Inpaint.

Diminished Reality (DR) propagates pixels from a keyframe to subsequent frames for real-time inpainting. Keyframe selection has a significant impact on the inpainting quality, but untrained users struggle to identify good keyframes. Automatic selection is not straightforward either, since no previous work has formalized or verified what determines a good keyframe. We propose a novel metric to select good keyframes to inpaint. We examine the heuristics adopted in existing DR inpainting approaches and derive multiple simple criteria measurable from SLAM. To combine these criteria, we empirically analyze their effect on the quality using a novel representative test dataset. Our results demonstrate that the combined metric selects RGBD keyframes leading to high-quality inpainting results more often than a baseline approach in both color and depth domains. Also, we confirmed that our approach has a better ranking ability of distinguishing good and bad keyframes. Compared to random selections, our metric selects keyframes that would lead to higher-quality and more stably converging inpainting results. We present three DR examples, automatic keyframe selection, user navigation, and marker hiding.