羽石 秀昭

Abstract Positron emission tomography (PET) is a valuable tool for diagnosing malignant tumors. Intraoperative PET imaging is expected to allow the more accurate localization of tumors that need resections. However, conventional devices feature a large detector ring that obstructs surgical procedures, preventing their intraoperative application. This paper proposes a new PET device, Scratch-PET, for image-guided tumor resection. The key feature of Scratch-PET is its use of a hand-held detector to scan the surgical field, ensuring open space for surgery while measuring annihilation radiation with a fixed detector array placed below the patient. We developed a prototype device using two detectors: the hand-held detector and a fixed detector, to demonstrate the feasibility of the proposed concept. Both detectors consisted of 16 × 16 arrays of lutetium yttrium orthosilicates (3 × 3 × 15 mm³) coupled one-to-one with 16 × 16 silicon photomultiplier arrays. The position and orientation of the hand-held detector are tracked using an optical tracking sensor that detects attached markers. We measured a ²²Na multi-rod phantom and two ²²Na point sources separately for 180 s while moving the hand-held detector. The rod diameters were 6.0, 5.0, 4.0, 3.0, 2.2, and 1.6 mm. Each point source was placed at the field-of-view center and 35 mm off-center which was outside the sensitive area when the hand-held detector was positioned facing the fixed detector. The 2.2 mm rods were partially resolved, and both point sources were successfully visualized. The potential of the proposed device to visualize small tumors was validated.

Abstract Purpose Despite a global decrease in the number of COVID-19 patients, early prediction of the clinical course for optimal patient care remains challenging. Recently, the usefulness of image generation for medical images has been investigated. This study aimed to generate short-term follow-up chest CT images using a latent diffusion model in patients with COVID-19. Materials and methods We retrospectively enrolled 505 patients with COVID-19 for whom the clinical parameters (patient background, clinical symptoms, and blood test results) upon admission were available and chest CT imaging was performed. Subject datasets (n = 505) were allocated for training (n = 403), and the remaining (n = 102) were reserved for evaluation. The image underwent variational autoencoder (VAE) encoding, resulting in latent vectors. The information consisting of initial clinical parameters and radiomic features were formatted as a table data encoder. Initial and follow-up latent vectors and the initial table data encoders were utilized for training the diffusion model. The evaluation data were used to generate prognostic images. Then, similarity of the prognostic images (generated images) and the follow-up images (real images) was evaluated by zero-mean normalized cross-correlation (ZNCC), peak signal-to-noise ratio (PSNR), and structural similarity (SSIM). Visual assessment was also performed using a numerical rating scale. Results Prognostic chest CT images were generated using the diffusion model. Image similarity showed reasonable values of 0.973 ± 0.028 for the ZNCC, 24.48 ± 3.46 for the PSNR, and 0.844 ± 0.075 for the SSIM. Visual evaluation of the images by two pulmonologists and one radiologist yielded a reasonable mean score. Conclusions The similarity and validity of generated predictive images for the course of COVID-19-associated pneumonia using a diffusion model were reasonable. The generation of prognostic images may suggest potential utility for early prediction of the clinical course in COVID-19-associated pneumonia and other respiratory diseases.

RATIONALE AND OBJECTIVES: To analyze morphological changes in patients with COVID-19-associated pneumonia over time, a nonrigid registration technique is required that reduces differences in respiratory phase and imaging position and does not excessively deform the lesion region. A nonrigid registration method using deep learning was applied for lung field alignment, and its practicality was verified through quantitative evaluation, such as image similarity of whole lung region and image similarity of lesion region, as well as visual evaluation by a physician. MATERIALS AND METHODS: First, the lung field positions and sizes of the first and second CT images were roughly matched using a classical registration method based on iterative calculations as a preprocessing step. Then, voxel-by-voxel transformation was performed using VoxelMorph, a nonrigid deep learning registration method. As an objective evaluation, the similarity of the images was calculated. To evaluate the invariance of image features in the lesion site, primary statistics and 3D shape features were calculated and statistically analyzed. Furthermore, as a subjective evaluation, the similarity of images and whether nonrigid transformation caused unnatural changes in the shape and size of the lesion region were visually evaluated by a pulmonologist. RESULTS: The proposed method was applied to 509 patient data points with high image similarity. The variances in histogram characteristics before and after image deformation were confirmed. Visual evaluation confirmed the agreement between the shape and internal structure of the lung field and the natural deformation of the lesion region. CONCLUSION: The developed nonrigid registration method was shown to be effective for quantitative time series analysis of the lungs.

皮弁移植手術とは,皮膚欠損を皮弁と呼ばれる健常領域の皮膚で補う手術である.皮弁移植手術では血管閉塞による術後の壊死が重大な合併症として挙げられる.本研究は,ラット腹部に作製した血行を温存した皮弁モデルへの栄養血管である動脈や静脈を結紮し,虚血または鬱血状態で皮弁表皮の分光反射率の変化を経時的に観察することで,壊死の機序の解明や,壊死初期段階での血流悪化の早期発見に向けた技術の開発を目的とする.動物実験により血管結紮前後の皮弁表皮の分光反射画像を撮影し,皮弁画像の各画素において分散を用いて撮影時刻間での分光反射率の変動を調査した結果,動脈結紮,静脈結紮両モデルともに,結紮側において分光反射率の変動が大きいことが確認された.結紮に伴う血流の変化が反映されていると考えられ,血流悪化の把握や,動脈閉塞,静脈閉塞の判別に有効である可能性が示唆された.(著者抄録)

Abstract A stroke is a medical emergency and thus requires immediate treatment. Paramedics should accurately assess suspected stroke patients and promptly transport them to a hospital with stroke care facilities; however, current assessment procedures rely on subjective visual assessment. We aim to develop an automatic evaluation system for central facial palsy (CFP) that uses RGB cameras installed in an ambulance. This paper presents two evaluation indices, namely the symmetry of mouth movement and the difference in mouth shape, respectively, extracted from video frames. These evaluation indices allow us to quantitatively evaluate the degree of facial palsy. A classification model based on these indices can discriminate patients with CFP. The results of experiments using our dataset show that the values of the two evaluation indices are significantly different between healthy subjects and CFP patients. Furthermore, our classification model achieved an area under the curve of 0.847. This study demonstrates that the proposed automatic evaluation system has great potential for quantitatively assessing CFP patients based on two evaluation indices.

SIGNIFICANCE: Evaluation of biological chromophore levels is useful for detection of various skin diseases, including cancer, monitoring of health status and tissue metabolism, and assessment of clinical and physiological vascular functions. Clinically, it is useful to assess multiple different chromophores in vivo with a single technique or instrument. AIM: To investigate the possibility of estimating the concentration of four chromophores, bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin from diffuse reflectance spectra in the visible region. APPROACH: A new diffuse reflectance spectroscopic method based on the multiple regression analysis aided by Monte Carlo simulations for light transport was developed to quantify bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin. Three different experimental animal models were used to induce hyperbilirubinemia, hypoxemia, and melanogenesis in rats. RESULTS: The estimated bilirubin concentration increased after ligation of the bile duct and reached around 18  mg/dl at 50 h after the onset of ligation, which corresponds to the reference value of bilirubin measured by a commercially available transcutaneous bilirubin meter. The concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin decreased and increased, respectively, as the fraction of inspired oxygen decreased. Consequently, the tissue oxygen saturation dramatically decreased. The time course of melanin concentration after depilation of skin on the back of rats was indicative of the supply of melanosomes produced by melanocytes of hair follicles to the growing hair shaft. CONCLUSIONS: The results of our study showed that the proposed method is capable of the in vivo evaluation of percutaneous bilirubin level, skin hemodynamics, and melanogenesis in rats, and that it has potential as a tool for the diagnosis and management of hyperbilirubinemia, hypoxemia, and pigmented skin lesions.

Lower extremity lymphedema (LEL) is a common complication after gynecological cancer treatment, which significantly reduces the quality of life. While early diagnosis and intervention can prevent severe complications, there is currently no consensus on the optimal screening strategy for postoperative LEL. In this study, we developed a computer-aided diagnosis (CAD) software for LEL screening in pelvic computed tomography (CT) images using deep learning. A total of 431 pelvic CT scans from 154 gynecological cancer patients were used for this study. We employed ResNet-18, ResNet-34, and ResNet-50 models as the convolutional neural network (CNN) architecture. The input image for the CNN model used a single CT image at the greater trochanter level. Fat-enhanced images were created and used as input to improve classification performance. Receiver operating characteristic analysis was used to evaluate our method. The ResNet-34 model with fat-enhanced images achieved the highest area under the curve of 0.967 and an accuracy of 92.9%. Our CAD software enables LEL diagnosis from a single CT image, demonstrating the feasibility of LEL screening only on CT images after gynecologic cancer treatment. To increase the usefulness of our CAD software, we plan to validate it using external datasets.

PURPOSE: As of March 2023, the number of patients with COVID-19 worldwide is declining, but the early diagnosis of patients requiring inpatient treatment and the appropriate allocation of limited healthcare resources remain unresolved issues. In this study we constructed a deep-learning (DL) model to predict the need for oxygen supplementation using clinical information and chest CT images of patients with COVID-19. MATERIALS AND METHODS: We retrospectively enrolled 738 patients with COVID-19 for whom clinical information (patient background, clinical symptoms, and blood test findings) was available and chest CT imaging was performed. The initial data set was divided into 591 training and 147 evaluation data. We developed a DL model that predicted oxygen supplementation by integrating clinical information and CT images. The model was validated at two other facilities (n = 191 and n = 230). In addition, the importance of clinical information for prediction was assessed. RESULTS: The proposed DL model showed an area under the curve (AUC) of 89.9% for predicting oxygen supplementation. Validation from the two other facilities showed an AUC > 80%. With respect to interpretation of the model, the contribution of dyspnea and the lactate dehydrogenase level was higher in the model. CONCLUSIONS: The DL model integrating clinical information and chest CT images had high predictive accuracy. DL-based prediction of disease severity might be helpful in the clinical management of patients with COVID-19.

Regarding vascularized lymph node transfer (VLNT) for lymphedema, partial blood flow impairment in transferred lymph node (LN) flaps may adversely affect the therapeutic results. We investigated the clinical and histological effects of partial blood flow impairment in LN flaps. In upper extremity lymphedema cases, based on ultrasonographic examination at 2 weeks after VLNT, we compared the treatment results depending on whether the postoperative blood flow in transferred LNs was good (Group G) or poor (Group P). Novel partial ischemia and congestion of LN flap mouse models were developed to determine their histological features. In 42 cases, significant differences were observed between Group G (n = 37) and Group P (n = 5) based on the amount of volume reduction (136.7 ± 91.7 mL and 55.4 ± 60.4 mL, respectively; p = 0.04) and lymph flow recanalization rate in indocyanine green fluorescent lymphography (67.6% and 0%, respectively; p = 0.0007). In mouse models, thrombi formation in the marginal sinus and numerous Myl9/12-positive immunocompetent cells in follicles were observed in congested LNs. Blood flow maintenance in the transferred LNs is an essential factor influencing the therapeutic effect of VLNT. Postoperatively, surgeons should closely monitor blood flow in the transferred LNs, particularly in cases of congestion.

Micro-computed tomography (micro-CT) enables the non-destructive acquisition of three-dimensional (3D) morphological structures at the micrometer scale. Although it is expected to be used in pathology and histology to analyze the 3D microstructure of tissues, micro-CT imaging of tissue specimens requires a long scan time. A high-speed imaging method, sparse-view CT, can reduce the total scan time and radiation dose; however, it causes severe streak artifacts on tomographic images reconstructed with analytical algorithms due to insufficient sampling. In this paper, we propose an artifact reduction method for 3D volume projection data from sparse-view micro-CT. Specifically, we developed a patch-based lightweight fully convolutional network to estimate full-view 3D volume projection data from sparse-view 3D volume projection data. We evaluated the effectiveness of the proposed method using physically acquired datasets. The qualitative and quantitative results showed that the proposed method achieved high estimation accuracy and suppressed streak artifacts in the reconstructed images. In addition, we confirmed that the proposed method requires both short training and prediction times. Our study demonstrates that the proposed method has great potential for artifact reduction for 3D volume projection data under sparse-view conditions.

Sparse-view computed tomography (CT), an imaging technique that reduces the number of projections, can reduce the total scan duration and radiation dose. However, sparse data sampling causes streak artifacts on images reconstructed with analytical algorithms. In this paper, we propose an artifact reduction method for sparse-view CT using deep learning. We developed a light-weight fully convolutional network to estimate a fully sampled sinogram from a sparse-view sinogram by enlargement in the vertical direction. Furthermore, we introduced the band patch, a rectangular region cropped in the vertical direction, as an input image for the network based on the sinogram’s characteristics. Comparison experiments using a swine rib dataset of micro-CT scans and a chest dataset of clinical CT scans were conducted to compare the proposed method, improved U-net from a previous study, and the U-net with band patches. The experimental results showed that the proposed method achieved the best performance and the U-net with band patches had the second-best result in terms of accuracy and prediction time. In addition, the reconstructed images of the proposed method suppressed streak artifacts while preserving the object’s structural information. We confirmed that the proposed method and band patch are useful for artifact reduction for sparse-view CT.

Retinitis pigmentosa (RP) is a group of genetic disorders, characterized by degeneration of photoreceptor cells which is the main cause of choroidal thinning. It is one of the leading causes of blindness worldwide. Thus, an investigation of choroidal changes is required for a better understanding of disease and diagnosis of RP. In this paper, we propose an automatic technique for measuring the choroidal parameters in optical coherence tomography (OCT) images of eyes with RP. The parameters include the total choroidal area (TCA), luminal area (LA), stromal area (SA), and choroidal thickness (CT). We applied our recently proposed, dense dilated U-Net segmentation model, called ChoroidNET, for segmenting the choroid layer and choroidal vessels for our RP dataset. Choroid segmentation is an important task since the measurement results depend on it. Comparison with other state-of-the-art models shows that ChoroidNET provides a better quantitative and qualitative segmentation of the choroid layer and choroidal vessels. Next, we measure the choroidal parameters based on the segmentation results of ChoroidNET. The proposed method achieves high reliability with an intraclass correlation coefficient (0.961, 0.940, 0.826, 0.916) for TCA, LA, SA, and CT, respectively.

PURPOSE: The quantitative assessment of impaired lung motions and their association with the clinical characteristics of COPD patients is challenging. The aim of this study was to measure respiratory kinetics, including asynchronous movements, and to analyze the relationship between lung area and other clinical parameters. MATERIALS AND METHODS: This study enrolled 10 normal control participants and 21 COPD patients who underwent dynamic MRI and pulmonary function testing (PFT). The imaging program was implemented using MATLAB®. Each lung area was detected semi-automatically on a coronal image (imaging level at the aortic valve) from the inspiratory phase to the expiratory phase. The Dice index of the manual measurements was calculated, with the relationship between lung area ratio and other clinical parameters, including PFTs then evaluated. The asynchronous movements of the diaphragm were also evaluated using a sagittal image. RESULTS: The Dice index for the lung region using the manual and semi-automatic extraction methods was high (Dice index = 0.97 ± 0.03). A significant correlation was observed between the time corrected lung area ratio and percentage of forced expiratory volume in 1 s (FEV1%pred) and residual volume percentage (RV%pred) (r = -0.54, p = 0.01, r = 0.50, p = 0.03, respectively). The correlation coefficient between each point of the diaphragm in the group with visible see-saw like movements was significantly lower than that in the group without see-saw like movements (value = -0.36 vs 0.95, p = 0.001). CONCLUSION: Semi-automated extraction of lung area from Cine MRI might be useful for detecting impaired respiratory kinetics in patients with COPD.

The ductus arteriosus (DA) constriction and restrictive foramen ovale (FO) are known as the leading cause of compromise and death of fetuses with dextro-transposition of the great arteries (d-TGA). Although the d-TGA fetal hemodynamics is of great importance in making diagnosis and management of the congenital heart defect, it remains poorly understood, particularly in terms of abnormal DA and FO. In this study, we developed a closed-loop 0-1D multiscale model of the fetal cardiovascular system (CVS) specified for the d-TGA circulation and conducted a systematic study of the impact of the DA constriction and restrictive FO on fetal hemodynamics. We found that the DA constriction led to a pronounced increase in the pulmonary artery pressure, pulmonary and mitral valve (PV and MV) regurgitation as well as left heart volume the restrictive FO was responsible for reducing MV E/A ratio, ie, the ratio of peak early filling and late diastolic filling velocities, and PV peak systolic flow (PSV) but could increase both aortic valve (AV) PSV and aortic isthmus systolic index (ISI). Moreover, the amount of blood flowing through the DA was observed equivalent to that through the FO the influence of DA constriction on the cerebral and placental perfusions are larger than that of the FO. Our results demonstrate that the proposed fetal cardiovascular model may be a useful tool for studying the underlying mechanisms associated with d-TGA fetal circulation and providing insights into its complex physiology and pathology.

In catheterization for hepatoma, contrast areas in X-ray angiograms are enhanced to visualize the blood vessel structures. However, it is difficult to observe the entire blood vessel in several cases due to an incomplete contrast filling during imaging. The present paper generates a vascular roadmap that enables visualization of an entire blood vessel by combining multiple enhanced images. Since images of different temporal phases are distorted by body motion, corrections by non-rigid registration are needed. We first estimated the feature-based deformations between temporally adjacent images. Then, we registered temporally distant images by accumulating the images. Finally, the vascular roadmap was generated by blending the motion-corrected images. The proposed method was applied to 13 angiograms and was compared with other registration methods. As a result, the proposed method achieved efficient deformation with a shorter processing time and generated a vascular roadmap with improved vascular structure visibility.

Microcirculation plays an important role by supplying oxygen and nutrients to maintain our lives. It is known that, as pathogenesis of sepsis, the microcirculation is impaired at the early stage of sepsis. In this case, it is expected that thrombomodulin alfa (TM alfa) works for the recovery of microcirculation. Direct observation of the impairment and recovery of microcirculation related to sepsis may give us clear understanding of those phenomena. In this study, we conducted experiments to observe microcirculation of septic model rats with an optical system. In these experiments, by attaching a chamber to the back of each rat, the same region of the microcirculation was consecutively monitored. Then, these rats were divided into three groups: control model rats (sham group), septic model rats (diseased group), and septic model rats to which TM alfa was administered (treated group). Each group includes five rats. In the diseased group smaller vessels disappeared and larger vessels became thinner. On the other hand, the treated group showed at first the degradation of microcirculation then the recovery. This may indicate effectiveness of TM alfa. We also estimated the blood velocity and blood vessel diameter from the acquired motion pictures to evaluate condition of the microcirculation. As a result, we quantitatively confirmed while blood velocity and blood vessel diameter of the diseased group decreased, that of the treated group decreased and then recovered. It should be noted that the set of motion pictures obtained in these experiments has potentially useful information for further analysis and is to be open to relevant researchers.

In plastic surgery, free tissue graft procedures are an essential part of fixing tissue-lack injuries or diseases. However, tissue necrosis caused by vascular occlusions or poor vascular anastomosis is a severe problem for prognosis. Follow-up surgery in the early-stage of necrosis caused by congestion or ischemia is essential to salvage the tissue, but making a diagnosis is difficult because of the slight features of these states. Therefore, a diagnosis support system that can capture the features of blood circulation of the skin flap is required to improve prognosis. We focused on system design and analysis by using spectral characteristics of blood circulation of a skin flap for this purpose. The system to be constructed is composed of a two-channel narrow-band illuminant and a color camera and can capture six-channel spectral signals. The narrow-band illuminant is designed by combining 13 kinds of light-emitting diode (LED) spectra. In this study, we first measured reflectance spectra of the early-stage skin flap necrosis of the rat model to design the narrow-band illuminant spectra. We blocked the flow of the target vessel and observed necrosis progression. A prototyped skin flap chamber was used for stable observation of spectral reflectance measurements. An evaluation experiment was conducted using a color camera and the spectrally tunable light source. Skin flap images were captured under the designed-illuminants and a conventional illuminant reproduced by the spectrally tunable light source. We confirmed the effectiveness of the designed system by improvements in necrosis region detection.

血流のある皮膚・皮下組織や深部組織により構成される皮弁を用いた遊離皮弁移植術は重要な手技であるが,術後の血管吻合不良や血管閉塞に伴う壊死が発生する可能性がある.壊死の回避には早期の血管再吻合が必要だが,目視での早期発見は困難である.そこでわれわれは,壊死領域を早期に診断するための簡便な撮影システム構築を目指している.具体的には,適当な波長帯と強度を選択したLED光源を2種類用意し,この光源の連続切替とRGBカメラ撮影により,6次元の信号を取得し診断に利用する.本研究では基礎実験として,ラットの皮弁壊死モデルを作製し,ラット皮弁の血管結紮後早期の分光反射率を取得することで光源設計を行った.得られた光源スペクトルを用いて,設計した光源下と従来光源下で得られるRGBカメラ画像をシミュレーションにより作成し,壊死領域の抽出を行った.従来の白色光下のRGB画像に比べて,提案システム光源のRGB画像では,より高い感度で壊死領域の抽出を実現した.(著者抄録)

血流のある皮膚・皮下組織や深部組織により構成される皮弁を用いた遊離皮弁移植術は重要な手技であるが,術後の血管吻合不良や血管閉塞に伴う壊死が発生する可能性がある.壊死の回避には早期の血管再吻合が必要だが,目視での早期発見は困難である.そこでわれわれは,壊死領域を早期に診断するための簡便な撮影システム構築を目指している.具体的には,適当な波長帯と強度を選択したLED光源を2種類用意し,この光源の連続切替とRGBカメラ撮影により,6次元の信号を取得し診断に利用する.本研究では基礎実験として,ラットの皮弁壊死モデルを作製し,ラット皮弁の血管結紮後早期の分光反射率を取得することで光源設計を行った.得られた光源スペクトルを用いて,設計した光源下と従来光源下で得られるRGBカメラ画像をシミュレーションにより作成し,壊死領域の抽出を行った.従来の白色光下のRGB画像に比べて,提案システム光源のRGB画像では,より高い感度で壊死領域の抽出を実現した.(著者抄録)

Peripheral hemodynamics, measured via the blood volume pulse and vasomotion, provide a valuable way of monitoring physiological state. Camera imaging-based systems can be used to measure these peripheral signals without contact with the body, at distances of multiple meters. While researchers have paid attention to non-contact imaging photoplethysmography, the study of peripheral hemodynamics and the effect of autonomic nervous system activity on these signals has received less attention. Using a method, based on a tissue-like model of the skin, we extract melanin [Formula: see text] and hemoglobin [Formula: see text] concentrations from videos of the hand and face and show that significant decreases in peripheral pulse signal power (by 36% ± 29%) and vasomotion signal power (by 50% ± 26%) occur during periods of cognitive and psychological stress. Via three experiments we show that similar results are achieved across different stimuli and regions of skin (face and hand). While changes in peripheral pulse and vasomotion power were significant the changes in pulse rate variability were less consistent across subjects and tasks.

We propose a simple and affordable imaging technique to evaluate transcutaneously multiple physiological parameters by using a digital red-green-blue camera. In this method, the RGB-values were converted into tristimulus values in the CIE (Commission Internationale de rEclairage) XYZ color space, which is compatible with the common color spaces. Monte Carlo simulation for light transport in biological tissue was then performed to specify the relationship among the XYZ-values and the concentrations of oxygenated hemoglobin, deoxygenated hemoglobin, bilirubin, and melanin. The concentration of total hemoglobin and tissue oxygen saturation were also calculated from the estimated concentrations of oxygenated and deoxygenated hemoglobin. In vivo experiments with bile duct ligation in rats demonstrated that the estimated bilirubin concentration increased after ligation of the bile duct and reached around 22 mg/dl at 116 h after the onset of ligation, which corresponds to the ground truth value of bilirubin measured by a commercially available transcutaneous bilirubinometer. Experiments with rats while varying the fraction of inspired oxygen demonstrated that oxygenated hemoglobin and deoxygenated hemoglobin decreased and increased, respectively, as the fraction of inspired oxygen decreased. Consequently, tissue oxygen saturation dramatically decreased. We further extended the method to a non-contact imaging photo-plethysmograph and estimation of the percutaneous oxygen saturation. An empirical formula to estimate percutaneous oxygen saturation was derived from the pulse wave amplitudes of oxygenated and deoxygenated hemoglobin. The estimated percutaneous oxygen saturation dropped remarkably when a faction of inspired oxygen was below 19%, indicating the onset of hypoxemia due to hypoxia, whereas the tissue oxygen saturation decreased gradually according to the reduction of the faction of inspired oxygen. The results in this study indicate the potential of this method for imaging of multiple physiological parameters in skin tissue and evaluating an optical biomedical imaging technique that enables cost-effective, easy-to-use, portable, remotely administered, and/or point-of-care solutions. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

To determine whether real-time intraoperative serial radiographic imaging of the marginal artery and vasa recta is feasible in patients undergoing low anterior resection, we attempted such imaging in a porcine model using a specialized fluoroscopic digital X-ray system and thin flat panel detector. Of the possible complications after low anterior resection, anastomotic dehiscence is one of the most serious, with poor blood supply in the anastomotic region being a chief contributor. General anesthesia was induced in a male domestic pig, and a midline incision was made from the xiphoid process to just above the bladder. The rectum was transected at the peritoneal reflection and then mobilized by dissection of the right leaf of the sigmoid mesocolon from the inferior mesenteric artery to the superior rectal artery. The rectal stump was pulled out and placed directly on the detector. Noniodine contrast agent was injected, and blood flow to and from the area surrounding the rectum was evaluated. Serial radiographs depicting the superior rectal artery, colonic, rectal, surrounding mesenteric tissue, and the vasa recta were obtained. The region where the marginal artery ran along the distal portion of the rectal stump was poorly poor imaged in all 3 imaging phases. Diameters of arteries were easily determined. The success we had in radiographically observing blood flow in tissues that would be involved in low anastomosis convinced us that such intraoperative evaluation is clinically feasible.

While zero- and one-dimensional multiscale modeling of the adult cardiovascular system (CVS) has been recognized as a useful tool in cardiovascular research and clinical applications, there are still not any generic cardiovascular models for a broad range of age groups. To study age-related alterations in cardiovascular parameters and hemodynamics, we here presented a versatile multiscale cardiovascular model considering the cardiovascular growth and development during aging. An adult cardiovascular model was first established by utilizing population-averaged physiological data. We then introduced an allometric scaling law-based approach to estimate age-related cardiovascular parameters for infants, children, and adolescents, by using the newly defined scaling exponents for different types of cardiovascular parameters. The model was validated to be capable of predicting the age-related alterations in hemodynamics through a comprehensive comparison with available in vivo measurements. Moreover, a variance-based global sensitivity analysis was performed for all cardiovascular parameters under normal and abnormal conditions to identify which are the most important model inputs in affecting model outputs. Our results indicate that the present generic cardiovascular model provides a robust and useful tool for evaluating normal cardiovascular functions over a broad age range for biomedical engineering applications.

© 2019 IEEE. In the medical field, visual diagnosis is one of the most important ways for evaluation. Observing tissue structure is effective for improving precision of surgery. We focused on an emphatic illuminant which brought a fine view of micro blood vessel structures. In this paper, we simulated the illuminant and evaluated it by subjective evaluation. In an evaluation experiment, to compare two illuminant conditions, a conventional and the emphatic illuminant, 14 LEDs fixed to the light unit were spectrally adjusted to demonstrate the two illuminants. We set a rat cecum as a target to observe the structure of micro blood vessels. The effectiveness of the emphatic illuminant was confirmed by ratio of detected blood vessel region to the ground truth.