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To overcome the increasing burden on pathologists in diagnosing gastric biopsies, we developed an artificial intelligence-based system for the pathological diagnosis of gastric biopsies (AI-G), which is expected to work well in daily clinical practice in multiple institutes. The multistage semantic segmentation for pathology (MSP) method utilizes the distribution of feature values extracted from patches of whole-slide images (WSI) like pathologists' "low-power view" information of microscopy. The training dataset included WSIs of 4511 gastric biopsy tissues from 984 patients. In tissue-level validation, MSP AI-G showed better accuracy (91.0%) than that of conventional patch-based AI-G (PB AI-G) (89.8%). Importantly, MSP AI-G unanimously achieved higher accuracy rates (0.946 ± 0.023) than PB AI-G (0.861 ± 0.078) in tissue-level analysis, when applied to the cohorts of 10 different institutes (3450 samples of 1772 patients in all institutes, 198-555 samples of 143-206 patients in each institute). MSP AI-G had high diagnostic accuracy and robustness in multi-institutions. When pathologists selectively review specimens in which pathologist's diagnosis and AI prediction are discordant, the requirement of a secondary review process is significantly less compared with reviewing all specimens by another pathologist.

The purpose of this study was to develop a deep learning-based computer-aided diagnosis system for skin disease classification using photographic images of patients. The targets are 59 skin diseases, including localized and diffuse diseases captured by photographic cameras, resulting in highly diverse images in terms of the appearance of the diseases or photographic conditions. ResNet-18 is used as a baseline model for classification and is reinforced by metric learning to boost generalization in classification by avoiding the overfitting of the training data and increasing the reliability of CADx for dermatologists. Patient-wise classification is performed by aggregating the inference vectors of all the input patient images. The experiment using 70,196 images of 13,038 patients demonstrated that classification accuracy was significantly improved by both metric learning and aggregation, resulting in patient accuracies of 0.579 for Top-1, 0.793 for Top-3, and 0.863 for Top-5. The McNemar test showed that the improvements achieved by the proposed method were statistically significant. This study presents a deep learning-based classification of 59 skin diseases using multiple photographic images of a patient. The experimental results demonstrated that the proposed classification reinforced by metric learning and aggregation of multiple input images was effective in the classification of patients with diverse skin diseases and imaging conditions.

BACKGROUND The Accreditation Council for Lung Cancer CT Screening of Japan established guidelines for the certification of Radiological Technologists in 2009. OBJECTIVE To analyze the trends in examination pass rates of the Radiological Technologists and discuss the reasons. METHODS The cohort comprised 1593 Radiological Technologists (as examinees) based on 10-year of data (with a total of 17 examination runs). First, the examinees' written test results were analyzed. Second, an abnormal finding detection test was conducted using >100 client PCs connected to a dedicated server containing low-dose lung cancer CT screening images of 60 cases. The passing scores were correct answer rate >60% and sensitivity (TP) of >90%, respectively. RESULTS Overall, 1243 examinees passed with an overall rate of 78%. The average pass rate for the written test was 91%, whereas that for the abnormal findings detection test was 85%. There was a moderate correlation between the test pass rate and average years of clinical experience of the examinees for the abnormal findings detection test (R = 0.558), whereas no such correlation existed for the written test (R = 0.105). CONCLUSIONS In order for accredited Radiological Technologists to serve as primary screeners of low-dose computed tomography, it is important to revise the educational system according to current standard practices.

Unsupervised learning can discover various unseen abnormalities, relying on large-scale unannotated medical images of healthy subjects. Towards this, unsupervised methods reconstruct a 2D/3D single medical image to detect outliers either in the learned feature space or from high reconstruction loss. However, without considering continuity between multiple adjacent slices, they cannot directly discriminate diseases composed of the accumulation of subtle anatomical anomalies, such as Alzheimer's Disease (AD). Moreover, no study has shown how unsupervised anomaly detection is associated with either disease stages, various (i.e., more than two types of) diseases, or multi-sequence Magnetic Resonance Imaging (MRI) scans. Therefore, we propose unsupervised Medical Anomaly Detection Generative Adversarial Network (MADGAN), a novel two-step method using GAN-based multiple adjacent brain MRI slice reconstruction to detect brain anomalies at different stages on multi-sequence structural MRI: (Reconstruction) Wasserstein loss with Gradient Penalty + 100 L1 loss-trained on 3 healthy brain axial MRI slices to reconstruct the next 3 ones-reconstructs unseen healthy/abnormal scans; (Diagnosis) Average L2 loss per scan discriminates them, comparing the ground truth/reconstructed slices. For training, we use two different datasets composed of 1,133 healthy T1-weighted (T1) and 135 healthy contrast-enhanced T1 (T1c) brain MRI scans for detecting AD and brain metastases/various diseases, respectively. Our Self-Attention MADGAN can detect AD on T1 scans at a very early stage, Mild Cognitive Impairment (MCI), with Area Under the Curve (AUC) 0.727, and AD at a late stage with AUC 0.894, while detecting brain metastases on T1c scans with AUC 0.921., 23 pages, 11 figures, submitted to BMC Bioinformatics. Extended version of arXiv:1906.06114

Deep Learning-based medical imaging research has been actively conducted thanks to its high diagnostic accuracy comparable to that of expert physicians. However, to apply developed Computer Aided Diagnosis (CAD) systems to various data collected from different hospitals, we should prepare sufficient training data in terms of quality/quantity; unfortunately, especially in Japan, we need to overcome each hospital’s different ethical codes to obtain such multi-institutional data. Therefore, we built a cloud platform for (i) collecting multi-modal large- scale medical images from hospitals through medical societies and (ii) conducting various Deep Learning-based CAD research via collaboration between Japanese medical societies and institutes of informatics. Each hospital first provides the data to the corresponding medical society among 6 societies (e.g., Japan Radiological Society and Japanese Society of Pathology) based on their modality among 8 modalities (e.g., Computed Tomography and Whole Slide Imaging (WSI)); then, each society uploads them, possibly with annotation, to our cloud plat- form established in November 2017. We have collected over 80 million medical images by December 2019, and over 60 registered researchers have conducted CAD research on the platform. We presented the achieved results at major international conferences/in medical journals; their ongoing clinical applications include remote WSI diagnosis. We plan to further increase the number of images/modalities and apply our research results to a clinical environment.

Unsupervised learning can discover various unseen diseases, relying on large-scale unannotated medical images of healthy subjects. Towards this, unsupervised methods reconstruct a single medical image to detect outliers either in the learned feature space or from high reconstruction loss. However, without considering continuity between multiple adjacent slices, they cannot directly discriminate diseases composed of the accumulation of subtle anatomical anomalies, such as Alzheimer's Disease (AD). Moreover, no study has shown how unsupervised anomaly detection is associated with disease stages. Therefore, we propose a two-step method using Generative Adversarial Network-based multiple adjacent brain MRI slice reconstruction to detect AD at various stages: (Reconstruction) Wasserstein loss with Gradient Penalty + L1 loss---trained on 3 healthy slices to reconstruct the next 3 ones---reconstructs unseen healthy/AD cases; (Diagnosis) Average/Maximum loss (e.g., L2 loss) per scan discriminates them, comparing the reconstructed/ground truth images. The results show that we can reliably detect AD at a very early stage with Area Under the Curve (AUC) 0.780 while also detecting AD at a late stage much more accurately with AUC 0.917; since our method is fully unsupervised, it should also discover and alert any anomalies including rare disease., Comment: 10 pages, 4 figures, Accepted to Lecture Notes in Bioinformatics (LNBI) as a volume in the Springer series

Despite the success of Convolutional Neural Network-based Computer-Aided Diagnosis research, its clinical applications remain challenging. Accordingly, developing medical Artificial Intelligence (AI) fitting into a clinical environment requires identifying/bridging the gap between AI and Healthcare sides. Since the biggest problem in Medical Imaging lies in data paucity, confirming the clinical relevance for diagnosis of research-proven image augmentation techniques is essential. Therefore, we hold a clinically valuable AI-envisioning workshop among Japanese Medical Imaging experts, physicians, and generalists in Healthcare/Informatics. Then, a questionnaire survey for physicians evaluates our pathology-aware Generative Adversarial Network (GAN)-based image augmentation projects in terms of Data Augmentation and physician training. The workshop reveals the intrinsic gap between AI/Healthcare sides and solutions on Why (i.e., clinical significance/interpretation) and How (i.e., data acquisition, commercial deployment, and safety/feeling safe). This analysis confirms our pathology-aware GANs' clinical relevance as a clinical decision support system and non-expert physician training tool. Our findings would play a key role in connecting inter-disciplinary research and clinical applications, not limited to the Japanese medical context and pathology-aware GANs., Comment: 13 pages, 2 figure, accepted to AIAI 2020

Purpose The aim of this feasibility study using phantoms was to propose a novel method for obtaining computer-generated realistic virtual nodules in lung computed tomography (CT). Methods In the proposed methodology, pulmonary nodule images obtained with a CT scanner are deconvolved with the point spread function (PSF) in the scan plane and slice sensitivity profile (SSP) measured for the scanner; the resultant images are referred to as nodule-like object functions. Next, by convolving the nodule-like object function with the PSF and SSP of another (target) scanner, the virtual nodule can be generated so that it has the characteristics of the spatial resolution of the target scanner. To validate the methodology, the authors applied physical nodules of 5-, 7- and 10-mm-diameter (uniform spheres) included in a commercial CT test phantom. The nodule-like object functions were calculated from the sphere images obtained with two scanners (Scanner A and Scanner B); these functions were referred to as nodule-like object functions A and B, respectively. From these, virtual nodules were generated based on the spatial resolution of another scanner (Scanner C). By investigating the agreement of the virtual nodules generated from the nodule-like object functions A and B, the equivalence of the nodule-like object functions obtained from different scanners could be assessed. In addition, these virtual nodules were compared with the real (true) sphere images obtained with Scanner C. As a practical validation, five types of laboratory-made physical nodules with various complicated shapes and heterogeneous densities, similar to real lesions, were used. The nodule-like object functions were calculated from the images of these laboratory-made nodules obtained with Scanner A. From them, virtual nodules were generated based on the spatial resolution of Scanner C and compared with the real images of laboratory-made nodules obtained with Scanner C. Results Good agreement of the virtual nodules generated from the nodule-like object functions A and B of the phantom spheres was found, suggesting the validity of the nodule-like object functions. The virtual nodules generated from the nodule-like object function A of the phantom spheres were similar to the real images obtained with Scanner C; the root mean square errors (RMSEs) between them were 10.8, 11.1, and 12.5 Hounsfield units (HU) for 5-, 7-, and 10-mm-diameter spheres, respectively. The equivalent results (RMSEs) using the nodule-like object function B were 15.9, 16.8, and 16.5 HU, respectively. These RMSEs were small considering the high contrast between the sphere density and background density (approximately 674 HU). The virtual nodules generated from the nodule-like object functions of the five laboratory-made nodules were similar to the real images obtained with Scanner C; the RMSEs between them ranged from 6.2 to 8.6 HU in five cases. Conclusions The nodule-like object functions calculated from real nodule images would be effective to generate realistic virtual nodules. The proposed method would be feasible for generating virtual nodules that have the characteristics of the spatial resolution of the CT system used in each institution, allowing for site-specific nodule generation.

Purpose: In lung cancer computed tomography (CT) screening, the performance of a computer-aided detection (CAD) system depends on the selection of the image reconstruction kernel. To reduce this dependence on reconstruction kernels, the authors propose a novel application of an image filtering method previously proposed by their group. Methods: The proposed filtering process uses the ratio of modulation transfer functions (MTFs) of two reconstruction kernels as a filtering function in the spatial-frequency domain. This method is referred to as MTF ratio filtering. Test image data were obtained from CT screening scans of 67 subjects who each had one nodule. Images were reconstructed using two kernels: f STD (for standard lung imaging) and f SHARP (for sharp edge-enhancement lung imaging). The MTF ratio filtering was implemented using the MTFs measured for those kernels and was applied to the reconstructed f SHARP images to obtain images that were similar to the f STD images. A mean filter and a median filter were applied (separately) for comparison. All reconstructed and filtered images were processed using their prototype CAD system. Results: The MTF ratio filtered images showed excellent agreement with the f STD images. The standard deviation for the difference between these images was very small, ∼6.0 Hounsfield units (HU). However, the mean and median filtered images showed larger differences of ∼48.1 and ∼57.9 HU from the f STD images, respectively. The free-response receiver operating characteristic (FROC) curve for the f SHARP images indicated poorer performance compared with the FROC curve for the f STD images. The FROC curve for the MTF ratio filtered images was equivalent to the curve for the f STD images. However, this similarity was not achieved by using the mean filter or median filter. Conclusions: The accuracy of MTF ratio image filtering was verified and the method was demonstrated to be effective for reducing the kernel dependence of CAD performance.

A 37-year-old female patient with myotonic dystrophy was scheduled for laparoscopic cholecystectomy for gall stone under general anesthesia with continuous propofol infusion. Rocuronium was administered with careful monitoring using TOF- Watch®, measuring train-of-four count (Tc), TOF ratio (Tr), and posttetanic count The total amount of rocuronium was 70 mg ; 0.6 mg .kg⁻1 for anesthetic induction and 0.3 mg .kg⁻1 when Tc exceeded 1. When the operation was completed, Tc was 4, Tr was uncountable and she showed reaction to calling her name. Then sugammadex 2 mg .kg⁻1, rapidly antagonized the neuromuscular block, such that the Tr recovered to 100% but tidal volume was 250 ml in 3 minutes. Additional dorsage of sugammadex, 2 mg .kg⁻1, was required for tidal volume to recover to 530 ml. After 20 minutes of first administration of sugammadex, we extubated the tracheal tube without respiratory depression. To avoid respiratory depression, we did not use postoperative opioids. Intraoperative transversus abdominis plane block and postoperative thoracic epidural block with ropivacaine were successful for postoperative pain relief.

Detection of small pulmonary nodules is the goal of lung cancer screening. Computer-aided detection (CAD) systems are recommended to use in lung cancer computed tomography (CT) screening to increase the accuracy of nodule detection. Size and density of lung nodules are primary factors in determining the risk of malignancy. Therefore, purpose of this study is to apply computer-simulated virtual nodules based on the point spread function (PSF) measured in same scanner (maintaining spatial resolution condition) to assess the CAD system performance dependence on nodule size and density. Virtual nodules with density differences between lung background and nodule density (ΔCT) values (200, 300 and 400 HU) and different sizes (4 to 8 mm) were generated and fused on clinical images. CAD detection was performed and free-response receiver operating characteristic (FROC) curves were obtained. Results show that both density and size of virtual nodules can affect detection efficiency. Detailed results are possible to use for quantitative analysis of a CAD system performance. This study suggests that PSF-based virtual nodules could be effectively used to assess the lung cancer CT screening CAD system performance dependence on nodule size and density.

A computed tomography (CT) image simulation technique based on the point spread function (PSF) was applied to analyze the accuracy of CT‐based clinical evaluations of lung nodule density. The PSF of the CT system was measured and used to perform the lung nodule image simulation. Then, the simulated image was resampled at intervals equal to the pixel size and the slice interval found in clinical high‐resolution CT (HRCT) images. On those images, the nodule density was measured by placing a region of interest (ROI) commonly used for routine clinical practice, and comparing the measured value with the true value (a known density of object function used in the image simulation). It was quantitatively determined that the measured nodule density depended on the nodule diameter and the image reconstruction parameters (kernel and slice thickness). In addition, the measured density fluctuated, depending on the offset between the nodule center and the image voxel center. This fluctuation was reduced by decreasing the slice interval (i.e., with the use of overlapping reconstruction), leading to a stable density evaluation. Our proposed method of PSF‐based image simulation accompanied with resampling enables a quantitative analysis of the accuracy of CT‐based evaluations of lung nodule density. These results could potentially reveal clinical misreadings in diagnosis, and lead to more accurate and precise density evaluations. They would also be of value for determining the optimum scan and reconstruction parameters, such as image reconstruction kernels and slice thicknesses/intervals. PACS numbers: 87.57.‐s, 87.57.cf, 87.57.Q‐

The stiff-person syndrome (SPS) is a rare autoimmune neurologic disorder that affects the gamma-aminobutyric acid (GABA) mediated inhibitory network in the central nervous system with anti-glutamic acid decarboxylase (GAD) antibodies. SPS is characterized by muscle rigidity and painful episodic spasms in axial and lower limb muscles. This case report describes successful peri-operative management of a 61-year-old female (height, 158 cm; weight, 60 kg, ASA-PS 2) with her right upper arm fracture who was scheduled for open reduction and internal fixation. This patient had bulbar paralysis, dysphagia and muscle rigidity associated with a high titer of anti-GAD auto antibodies (2,800 U x ml(-1)). She was diagnosed as SPS and has been treated with predonisolone (30 mg x day(-1)) and diazepam (20 mg x day(-1)) for 1 year. Predonisolone (15 mg) and diazepam (30 mg) was given orally before induction of general anesthesia with propofol, remifentanil and rocuronium bromide. Posture change from supine to beach-chair position led to sudden drop in blood pressure to 38/25 mmHg, which recovered promptly by injecting intravenous ephedrine hydrochloride (28 mg) and hydrocortisone (100 mg). Postanesthetic course was uneventful without postoperative neurologic abnormalities.

Purpose: While the acquisition of projection data in a computed tomography (CT) scanner is generally carried out once, the projection data is often removed from the system, making further reconstruction with a different reconstruction filter impossible. The reconstruction kernel is one of the most important parameters. To have access to all the reconstructions, either prior reconstructions with multiple kernels must be performed or the projection data must be stored. Each of these requirements would increase the burden on data archiving. This study aimed to design an effective method to achieve similar image quality using an image filtering technique in the image space, instead of a reconstruction filter in the projection space for CT imaging. The authors evaluated the clinical feasibility of the proposed method in lung cancer screening. Methods: The proposed technique is essentially the same as common image filtering, which performs processing in the spatial-frequency domain with a filter function. However, the filter function was determined based on the quantitative analysis of the point spread functions (PSFs) measured in the system. The modulation transfer functions (MTFs) were derived from the PSFs, and the ratio of the MTFs was used as the filter function. Therefore, using an image reconstructed withmore » a kernel, an image reconstructed with a different kernel was obtained by filtering, which used the ratio of the MTFs obtained for the two kernels. The performance of the method was evaluated by using routine clinical images obtained from CT screening for lung cancer in five subjects. Results: Filtered images for all combinations of three types of reconstruction kernels (''smooth,''''standard,'' and ''sharp'' kernels) showed good agreement with original reconstructed images regarded as the gold standard. On the filtered images, abnormal shadows suspected as being lung cancers were identical to those on the reconstructed images. The standard deviations (SDs) for the difference between filtered images and reconstructed images ranged from 1.9 to 23.5 Hounsfield units for all kernel combinations; these SDs were much smaller than the noise SDs in the reconstructed images. Conclusions: The proposed method has good performance and is clinically feasible in lung cancer screening. This method can be applied to images reconstructed on any scanner by measuring the PSFs in each system.« less

Rationale and Objectives To investigate the volume-doubling time (VDT) of histologically proved pulmonary nodules showing ground glass opacity (GGO) at multidetector CT (MDCT) using computer-aided three-dimensional volumetry. Materials and Methods We retrospectively evaluated 47 GGO nodules (mixed n = 28, pure n = 19) that had been examined by thin-section helical CT more than once. They were histologically confirmed as atypical adenomatous hyperplasia (AAH, n = 13), bronchioloalveolar carcinoma (BAC, n = 22), and adenocarcinoma (AC, n = 12). Using computer-aided three-dimensional volumetry software, two radiologists independently performed volumetry of GGO nodules and calculated the VDT using data acquired from the initial and final CT study. We compared VDT among the three pathologies and also compared the VDT of mixed and pure GGO nodules. Results The mean VDT of all GGO nodules was 486.4 ± 368.6 days (range 89.0–1583.0 days). The mean VDT for AAH, BAC, and AC was 859.2 ± 428.9, 421.2 ± 228.4, and 202.1 ± 84.3 days, respectively; there were statistically significant differences for all comparative combinations of AAH, BAC, and AC (Steel-Dwass test, P Conclusion The evaluation of VDT using computer-aided volumetry may be helpful in assessing the histological entities of GGO nodules.

To evaluate the effect of computer-aided diagnosis (CAD) on radiologists' detection of pulmonary nodules.Fifty chest computed tomographic (CT) examination cases were used. The mean nodule size was 0.81 cm +/- 0.60 (SD) (range, 0.3-2.9 cm). Alternative free-response receiver operating characteristic (ROC) analysis with a continuous rating scale was used to compare the observers' performance in detecting nodules with and without use of CAD. Five board-certified radiologists and five radiology residents participated in an observer performance study. First they were asked to rate the probability of nodule presence without using CAD; then they were asked to rate the probability of nodule presence by using CAD.For all radiologists, the mean areas under the best-fit alternative free-response ROC curves (Az) without and with CAD were 0.64 +/- 0.08 and 0.67 +/- 0.09, respectively, indicating a significant difference (P.01). For the five board-certified radiologists, the mean Az values without and with CAD were 0.63 +/- 0.08 and 0.66 +/- 0.09, respectively, indicating a significant difference (P.01). For the five resident radiologists, the mean Az values without and with CAD were 0.66 +/- 0.04 and 0.68 +/- 0.04, respectively, indicating a significant difference (P =.02). At observer performance analyses, there were no significant differences in Az values obtained either without (P =.61) or with (P =.88) CAD between the board-certified radiologists and the residents. For all radiologists, in the detection of pulmonary nodules 1.0 cm in diameter or smaller, the mean Az values without and with CAD were 0.60 +/- 0.11 and 0.64 +/- 0.11, respectively, indicating a significant difference (P.01).Use of the CAD system improved the board-certified radiologists' and residents' detection of pulmonary nodules at chest CT.

We studied the reasons for difficulty with tracheal intubation over a fibrescope, and whether cricoid pressure facilitated intubation, in 50 patients. After induction of anaesthesia and neuromuscular blockade in 10 patients (phase 1), we attempted to clarify the reasons for difficulty in advancing a tracheal tube over an orally-inserted fibrescope, by observing through another fibrescope that was inserted nasally into the pharynx. In the next 40 patients (phase 2), we studied the effect of cricoid pressure on the success rate of tracheal intubation over the fibrescope. After a fibrescope (with a tracheal tube over it) had been inserted orally into the trachea, patients were randomly allocated to receive either criocoid pressure or sham pressure, and the success rate of intubation within 60 s was assessed. In phase 1, the tube was advanced into the trachea without difficulty in three of 10 patients. In the remaining seven patients, the tube impacted on the epiglottis in one patient and on the arytenoid cartilage in another two patients, and the tube migrated into the hypopharynx in the remaining four patients. In phase 2, tracheal intubation was successful within 60 s in seven of 21 patients (33%) without cricoid pressure, compared with 12 of 19 patients (63%) when cricoid pressure was applied (95% CI for difference 2-59%; p = 0.04). We conclude that cricoid pressure facilitates fibrescope-aided tracheal intubation.

Purpose. We compared the anticonvulsant effects of sevoflurane with those of isoflurane and halothane in amygdaloid kindling and bicuculline-induced seizures in cats. Methods. In a crossover design, the effects of 70% nitrous oxide, and 0.3, 0.6, and 1.5 minimum alveolar concentration (MAC) of volatile anesthetics were studied in five cats in which the amygdala was electrically stimulated at the current used for establishing the kindled state. The effects of 0.6 and 1.5 MAC of volatile anesthetics were studied in another five cats, in which 0.2 mg·kg−1 of bicuculline was administered IV. Results. In the amygdaloid kindling model, all four anesthetics decreased the duration of after-discharge (AD), the rise of multiunit activity in midbrain reticular formation (R-MUA), and the behavior scores compared with findings without anesthetics. Halothane, at 1.5 MAC, significantly decreased the number of cats showing AD (P < 0.05). In the bicuculline-induced seizure model, all five cats showed repetitive spikes during 1.5 MAC of sevoflurane, whereas only two and three cats, respectively, showed the repetitive spikes during 1.5 MAC of isoflurane and halothane. All three volatile anesthetics decreased the rise of R-MUA, the duration of the repetitive spikes, and the behavior scores. The suppression of the rise in R-MUA and the behavior scores with 1.5 MAC of sevoflurane was significantly less than that with 1.5 MAC of isoflurane. Conclusion. The anticonvulsant effects of sevoflurane were less potent than those of halothane in the amygdaloid kindling model and less potent than those of isoflurane in the bicuculline-induced seizure model.

We propose the application of virtual nodules to evaluate the performance of computer-aided detection (CAD) of lung nodules in cancer screening using low-dose CT.The virtual nodules were generated based on the spatial resolution measured for a CT system used in an institution providing cancer screening and were fused into clinical lung images obtained at that institution, allowing site specificity. First, we validated virtual nodules as an alternative to artificial nodules inserted into a phantom. In addition, we compared the results of CAD analysis between the real nodules (n = 6) and the corresponding virtual nodules. Subsequently, virtual nodules of various sizes and contrasts between nodule density and background density (ΔCT) were inserted into clinical images (n = 10) and submitted for CAD analysis.In the validation study, 46 of 48 virtual nodules had the same CAD results as artificial nodules (kappa coefficient = 0.913). Real nodules and the corresponding virtual nodules showed the same CAD results. The detection limits of the tested CAD system were determined in terms of size and density of peripheral lung nodules; we demonstrated that a nodule with a 5-mm diameter was detected when the nodule had a ΔCT 220 HU.Virtual nodules are effective in evaluating CAD performance using site-specific scan/reconstruction conditions. Advances in knowledge: Virtual nodules can be an effective means of evaluating site-specific CAD performance. The methodology for guiding the detection limit for nodule size/density might be a useful evaluation strategy.

Both nitrous oxide (N(2)O) and xenon are N:-methyl-D-aspartate receptor antagonists that have psychotomimetic effects and cause neuronal injuries in the posterior cingulate and retrosplenial cortices. We investigated the effect of xenon, xenon with ketamine, N(2)O, and N(2)O with ketamine on c-Fos expression in the rat posterior cingulate and retrosplenial cortices, a marker of psychotomimetic effects. Brain sections were prepared, and c-Fos expression was detected with immunohistochemical methods. A loss of microtubule-associated protein 2, a marker of neuronal injury, was also investigated. The number of Fos-like immunoreactivity positive cells by ketamine IV at a dose of 5 mg/kg under 70% N(2)O (128 +/- 12 cells per 0.5 mm(2)) was significantly more than those under 30% (15 +/- 2 cells per 0.5 mm(2)) and 70% xenon (2 +/- 1 cells per 0.5 mm(2)). Despite differences in c-fos immunoreactivity, there was no loss of microtubule-associated protein 2 immunoreactivity in any group examined. Xenon may suppress the adverse neuronal effects of ketamine, and combined use of xenon and ketamine seems to be safe in respect to neuronal adverse effects.

We studied the efficacy of the laryngeal tube (VBM, Germany) during intermittent positive-pressure ventilation in 50 patients. After induction of anaesthesia and neuromuscular blockade, a size 4 laryngeal tube was inserted for patients of height 155 cm or greater. After insertion of the laryngeal tube, its pharyngeal and oesophageal balloons were inflated to an intracuff pressure of 60 cmH2O. An Ambu self-inflating bag was attached to the laryngeal tube and the lungs were ventilated manually at 15 breath.min−1. It was possible to ventilate the lungs at the first attempt in 47 patients (94%). The airway pressure at which air leaked around the laryngeal tube exceeded 18 cmH2O in 41 patients (82%), and was > 30 cmH2O in 25 (50%). Median [interquartile range (range)] leak pressure was 30 [20–30 (6 to > 30)] cmH2O. Median [interquartile range (range)] tidal volume was 587 [533–653 (133–800)] ml or 8.8 [8.2–10.6 (1.9–12.6)] ml.kg−1. We conclude that the laryngeal tube has a potential role in airway management during intermittent positive-pressure ventilation for anaesthesia or cardiopulmonary resuscitation.

Purpose: To assess the ease of fibrescope-assisted tracheal intubation while the patient’s head and neck were placed in the neutral or the manual in-line position, and to determine if the intubating laryngeal mask facilitated fibreoptic intubation in these positions. Methods: In 84 patients, the patient’s head and neck were placed in the neutral position (pillow placed under occiput), and in another 40 patients the head and neck were stabilized by the manual in-line method (no pillows under occiput). In both groups, after induction of anesthesia with 2.0 – 2.5 mg·kg−1 propofol, 50 – 100µg fentanyl and 1.0 mg·kg−1 vecuronium, patients were allocated randomly into two groups: in Group C tracheal intubation was attempted using only a fibrescope, whereas in Group L fibreoptic intubation through the intubating laryngeal mask was attempted. Results: In group C the success rate of fibreoptic tracheal intubation within two minutes was higher in the neutral position (31 of 42 patients (73%) than in the manual in-line position (8 of 20 patients (40%)). In contrast, in group L the success rate was similar between the two positions. Tracheal intubation was easier in group L than in group C (P

We studied 70 patients to see if cricoid pressure applied after insertion of the laryngeal mask altered the success rate of tracheal intubation through the mask. After induction of anaesthesia and neuromuscular blockade, patients were randomly allocated to have either cricoid pressure (Group C) or sham pressure (Group S). The view of the glottis through the laryngeal mask was assessed before and after the test pressure, and tracheal intubation through the mask was attempted using a fibreoptic bronchoscope. The test pressure did not alter the view of the glottis in any patient in group S, whereas it narrowed the glottic aperture in 16 out of 35 patients in group C. The fibrescope was inserted into the trachea in all patients in group S and in 25 patients in group C. The success rate of tracheal intubation in group S (31 patients) was significantly higher than in group C (21 patients, P

We studied 40 anaesthetised and paralysed patients, in a randomised manner, to compare the ease of tracheal intubation either using a Macintosh laryngoscope and gum elastic bougie (group C) with the ease of tracheal intubation through the intubating laryngeal mask using a fibreoptic bronchoscope (group L), during manual in-line stabilisation of the patient's head and neck. In both groups, a maximum of 120 s was allowed for attempts at tracheal intubation. The ease of placement of the intubating laryngeal mask or tracheal intubation was assessed using a 100-mm visual analogue scale (VAS). In patients in whom tracheal intubation succeeded, time for intubation was measured. The intubating laryngeal mask was placed successfully in 19 of 20 patients, with the median VAS of 18 mm (95% CI: 13–32 mm). The success rate of tracheal intubation in group L (17 patients) was significantly higher than in group C (nine patients) (p

Large concentrations of sevoflurane and isoflurane, but not halothane, induce spikes in the electroencephalogram. To elucidate whether these proconvulsant effects affect lidocaine-induced seizures, we compared the effects of sevoflurane, isoflurane, and halothane in cats. Fifty animals were allocated to 1 of 10 groups: 70% nitrous oxide (N2O), 0.6 minimum alveolar anesthetic concentration (MAC) + 70% N2O, 1.5 MAC + 70% N2O, and 1.5 MAC of each volatile agent in oxygen. Lidocaine 4 mg x kg(-1) x min(-1) was infused IV under mechanical ventilation with muscle relaxation. Electroencephalogram in the cortex, amygdala, and hippocampus and multiunit activities in the midbrain reticular formation (R-MUA) were recorded. Lidocaine induced spikes first from the amygdala or hippocampus in the 70% N2O and halothane groups and from the cortex in the sevoflurane and isoflurane groups. Lidocaine induced seizures in all cats in the 70% N2O and 0.6 MAC + N2O groups. Seizure occurrence was reduced in the 1.5 MAC + N2O group (P0.05 versus 70% N2O). The onset of seizure was delayed in the 0.6 MAC + N2O and 1.5 MAC groups for sevoflurane and isoflurane, but not for halothane, compared with the 70% N2O group (P0.05). Lidocaine increased R-MUA with seizure by 130%+/-56% in the 70% N2O group. The increase of R-MUA with seizure was more suppressed in the volatile anesthetic groups than in the 70% N2O group (P0.05). In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased.Increasingly, epidural blockade is combined with general anesthesia to achieve stress-free anesthesia and continuous pain relief in the postoperative period. In the present study, sevoflurane and isoflurane attenuated seizure when the blood lidocaine concentration was accidentally increased.

The effects of sevoflurane and propofol, in combination with continuous epidural blockade, on blood pressure control and time of recovery from anesthesia were compared.Adult patients were allocated to either a sevoflurane (n=54) or a propofol (n=64) group. Anesthesia was induced with either inhalation of 5% sevoflurane or intravenous administration of 2 mg·kgThe number of cases requiring a change in the dose of either anesthetics or vasoactive agents was not different between the groups. However, the arterial pressure and heart rate were more stable in the propofol group than in the sevoflurane group (P0.05). The length of time before tracheal extubation was shorter in the sevoflurane group (10.4±5.2 min, mean±SD) than the propofol group (15.0±11.2 min,P0.05).Propofol anesthesia, in combination with continuous epidural blockade, results in more stable intraoperative hemodynamics than sevoflurane anesthesia, but requries a longer recovery time and results in larger interindividual variability than sevoflurane anesthesia.

Suppression of response to a given stimulus by anaesthetics might be considered as a summation of the suppression of basal (pre-stimulus) activity and response capability (increased by stimulus). Anaesthetic suppression of each component in brain and cardiovascular variables by halothane, isoflurane or sevoflurane was compared in cats.Thirty cats were allocated to one of three groups (n = 10 in each) according to the anaesthetic given. The sciatic nerve was stimulated after maintaining the end-tidal concentration of the anaesthetic at 1.3 or 2.0 MAC for at least 30 min. Cortical electroencephalogram (EEG), multi-unit activity in the mid-brain reticular formation (R-MUA), mean arterial pressure (MAP) and heart rate (HR) were measured before and after electrical sciatic nerve stimulation.The EEG patterns and R-MUA indicated greater suppression of activity in the brain by isoflurane (31 +/- 4% of awake state at 1.3 MAC, mean +/- SEM) and sevoflurane (38 +/- 5%) than by halothane (61 +/- 5%, P0.05), before stimulation. The R-MUA following the stimulation was not different among agents. The MAP and HR were not different among groups before stimulation, but following stimulation were greater in the sevoflurane group (137 +/- 9 and 103 +/- 9 mmHg at 1.3 and 2.0 MAC) than in the halothane group (103 +/- 5 and 76 +/- 3 mmHg, P0.05).Isoflurane and sevoflurane have greater suppressive action on the basal CNS activity than halothane at the same MAC, and that these two anaesthetics have a weak suppressive action on the response capability to peripheral stimulation.

Romano-Ward (R-W) syndrome is an autosomal dominant hereditary disorder and is characterized by a prolonged QT interval on the electrocardiogram (ECG), syncope, and sudden death. We report here a case of cesarian section in a patient with R-W syndrome whose QT prolongation was successfully managed with landiolol, a selective beta1 receptor blocker. A 25-year-old woman with R-W syndrome was scheduled for cesarean section. In the operating room, the patient's ECG showed tachycardia (102 beats x min(-1)) and marked QT prolongation (QTc = 0.56 s). After spinal anesthesia, the patient's heart rate (HR) increased to 130 beats/min accompanied by a slight decrease in arterial blood pressure to 97/57 mmHg and the QTc was prolonged to 0.57 s. Landiolol was continuously infused at a rate of 0.04 mg.kg(-1) x min(-1) and the HR gradually decreased to 80-90 beats x min(-1) accompanied by the normalization of QTc to 0.48 s. We thought that the use of landiolol was more rational and was preferable to a nonselective beta receptor blocker for a term-pregnant woman because blockade of the beta2 receptor might cause uterine contraction. After the use of landiolol, intraoperative and postoperative courses in both the patient and the baby were uneventful.

We study the magnetic ordering of an anisotropic Heisenberg ferromagnet on a triangular lattice with antiferromagnetic next-nearest-neighbor interactions by means of the mean field theory and a computer simulation. We find that, as the temperature is decreased, an incommensurate short-range order state and a ferromagnetic long-range phase appear successively. The phase transition between them is of the first order and the relaxation time of the transition is very long. Hence, we suggest that the low temperature phase realized in nature is a domain state in which ferromagnetic domains with various sizes are tangled with each other. We also suggest that the model would be applicable to the compound LiNiO 2 .

The effect of the transverse magnetic field h x on the spin dynamics of a one dimensional Ising-like S =1/2 antiferromagnet is discussed. Based on a picture of the propagating domain walls, we obtain dynamical spin correlation functions along the magnetic field S x x ( k ,ω) and perpendicular to it S y y ( k ,ω). A remarkable effect is seen in S y y ( k ,ω) for π/2 ≤ k ≤π, where the spectral weight moves toward the low energy side with the increase of h x . The theory is applied to the analysis of the spin dynamics of CsCoCl 3 , taking into account weak interchain interactions. Zeeman ladders occur and S y y ( k , ω) for k ∼π exhibits a novel feature under the existence of h x .

Summary The laryngeal mask airway has a potential role during cardiopulmonary resuscitation, but its placement becomes more difficult during manual in-line stabilisation of the neck, and the device cannot reliably prevent pulmonary aspiration. The ProSeal® laryngeal mask airway has a theoretical advantage of reducing aspiration because of its drainage tube, but its ease of placement during stabilisation of the neck is unknown. We studied 20 patients to compare ease of placement and the sealing effect between the standard and ProSeal® laryngeal mask airways. In a randomised cross-over fashion, after induction of anaesthesia and neuromuscular blockade, the standard and ProSeal® laryngeal mask airways were placed in turn. Placement was significantly easier for the ProSeal® laryngeal mask airway (successful at the first attempt in 16 patients and at the second attempt in the remaining four patients) than for the laryngeal mask airway (successful at the first attempt in 12 of 20 patients and at the second attempt in three patients, and failed (> two attempts) in the remaining five patients; p = 0.04). The airway pressure at which gas leaked around the device was greater forthe ProSeal® than the laryngeal mask airway (mean difference 5.8 cmH2O; 95% CI 2.9–8.7 cmH2O; p = 0.0008).

Esmolol is used in clinical practice as a beta-1 adrenergic antagonist in Europe and North America, but it is still under investigation in Japan. It has a high specificity for beta-1 adrenoceptors relative to the beta-2 subtype. When the antagonizing effect to isoproterenol-induced increase in heart rate (beta-1) or bronchodilation (beta2) is calculated, the ratio of esmolol is reported to be 42.7, which is higher than that of propranolol (0.85) [1]. Based on its high specificity for beta-1 adrenoceptors, esmolol can be used for the treatment of tachycardia in patients with bronchial asthma. Another adrenoceptor subtype, the beta-3 receptor, was found, and its molecular structure was reported by Emorine et al. [2] in 1989. Beta-3 adrenoceptors play roles in thermogenesis, lipolysis, anti-obesity function, and anti-diabetic function, and their genetic variation has been correlated with hereditary obesity and diabetogenesis [3]. Furthermore, their functions in the cardiovascular system have recently been studied [4]. Although the affinities and effects of various drugs affecting beta-adrenoceptors on the beta-3 subtype have been investigated, the effect of esmolol has not been reported, to our knowledge. Beta3 adrenoceptors are distributed in adipose tissues with a high density, and beta-3 adrenergic agonists increase temperature to a greater extent in the interscapular brown adipose tissue than in the rectum in rats [5,6]. In the present study, we investigated the effect of esmolol on the beta-3 adrenoceptors by studying the temperature difference between the interscapular brown adipose tissue and the rectum in rats. The study was approved by our Institutional Animal Care Committee. Forty-five Wistar rats, weighing 200‐300 g, were used. The rats were anesthetized with pentobarbital, 50 mg·kg 1 i.p. A polyethylene catheter (0.9-mm-diameter) was placed in the femoral vein. Thermistor probes were inserted into the interscapular

An 86-year-old woman was scheduled to receive fourth reconstructive surgery for femoral bone fracture under general anesthesia. She had been suspected with narrow angle glaucoma due to headache and bloodshot eyes during gastroscopy. During transfer to our hospital, she fell down and suffered from the right femoral neck fracture. The patient underwent femoral head replacement under spinal anesthesia. Later, she received surgeries twice uneventfully under spinal anesthesia; removal and re-implantation of the femoral bone head due to infection of the implanted head. Six months later, she fell down again and femoral bone was fractured during rehabilitation. Anesthesia was induced with propofol followed by rocuronium 0.9 mg x kg(-1) i.v. Anesthesia was maintained with propofol and remifentanil, and rocuronium was administered to maintain PTC of 10 or less. The surgery was completed in 150 minutes. At the end of surgery, a laryngeal mask was inserted and the tracheal tube was removed. TOF ratio recovered to 80% 8 minutes after sugammadex 2 mg kg(-1) i.v., and increased to 100% 3 minutes after additional 1 mg x kg(-1). Intraocular pressure stayed below 20 mmHg during the intervention. We could achieve full reversal of neuromuscular blockade and suppress increase in intraocular pressure with use of sugammadex.

With the wide dissemination of computed tomography (CT) screening for lung cancer, measuring the nodule volume accurately with computer-aided volumetry software is increasingly important. Many studies for determining the accuracy of volumetry software have been performed using a phantom with artificial nodules. These phantom studies are limited, however, in their ability to reproduce the nodules both accurately and in the variety of sizes and densities required. Therefore, we propose a new approach of using computer-simulated nodules based on the point spread function measured in a CT system. The validity of the proposed method was confirmed by the excellent agreement obtained between computer-simulated nodules and phantom nodules regarding the volume measurements. A practical clinical evaluation of the accuracy of volumetry software was achieved by adding simulated nodules onto clinical lung images, including noise and artifacts. The tested volumetry software was revealed to be accurate within an error of 20 % for nodules >5 mm and with the difference between nodule density and background (lung) (CT value) being 400–600 HU. Such a detailed analysis can provide clinically useful information on the use of volumetry software in CT screening for lung cancer. We concluded that the proposed method is effective for evaluating the performance of computer-aided volumetry software.

We report a patient with subacute myelo-optico-neuropathy (SMON) in whom spinal anesthesia was employed to treat fracture of the femur neck. An 87-year-old woman was diagnosed as having SMON at the age of 45. The patient was admitted to our hospital with fracture of the femur neck. Aspiration pneumonia was also suspected with shadow in the right lung on the chest X-P The percutaneous oxygen saturation (Spo2) with room air was 77%. Spinal anesthesia with 5 mg of 0.5% hyperbaric bupivacaine and 20 mcg of fentanyl was performed at L3-4. The level of anesthesia was T4. During surgery, no severe pain in the lower limbs was observed. Three hours after the end of surgery, the level of anesthesia was T9. On the day after surgery, the extent of dysesthesia and reflex were similar to those before surgery. General anesthesia has been chosen in SMON patients, because there was a report of severe pain of the lower limbs after spinal anesthesia with dibucaine. In our patient, general anesthesia was considered inappropriate due to hypoxemia. We used a mixture of bupivacaine and fentanyl for spinal anesthesia, because the neurotoxicity of bupivacaine is weaker than that of dibucaine.

To investigate the volume-doubling time (VDT) of histologically proved pulmonary nodules showing ground glass opacity (GGO) at multidetector CT (MDCT) using computer-aided three-dimensional volumetry.We retrospectively evaluated 47 GGO nodules (mixed n = 28, pure n = 19) that had been examined by thin-section helical CT more than once. They were histologically confirmed as atypical adenomatous hyperplasia (AAH, n = 13), bronchioloalveolar carcinoma (BAC, n = 22), and adenocarcinoma (AC, n = 12). Using computer-aided three-dimensional volumetry software, two radiologists independently performed volumetry of GGO nodules and calculated the VDT using data acquired from the initial and final CT study. We compared VDT among the three pathologies and also compared the VDT of mixed and pure GGO nodules.The mean VDT of all GGO nodules was 486.4 ± 368.6 days (range 89.0-1583.0 days). The mean VDT for AAH, BAC, and AC was 859.2 ± 428.9, 421.2 ± 228.4, and 202.1 ± 84.3 days, respectively; there were statistically significant differences for all comparative combinations of AAH, BAC, and AC (Steel-Dwass test, P.01). The mean VDT for pure and mixed GGO nodules was 628.5 ± 404.2 and 276.9 ± 155.9 days, respectively; it was significantly shorter for mixed than pure GGO nodules (Mann-Whitney U-test, P.01).The evaluation of VDT using computer-aided volumetry may be helpful in assessing the histological entities of GGO nodules.