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Background: Whether or not antiganglioside antibodies are related to axonal or demyelinating Guillain-Barré syndrome (GBS) is still a matter of controversy, as detailed in previous studies conducted in Western and Asian countries.Objective: To clarify whether antiganglioside antibodies are associated with axonal dysfunction in Japanese and Italian GBS patient cohorts.Methods: Clinical and electrophysiological profiles were reviewed for 156 GBS patients collected from Japan (n=103) and Italy (n=53). Serum IgG antibodies against GM1, GM1b, GD1a and GalNAc-GD1a were measured by ELISA in the same laboratory. Electrodiagnostic criteria and results of serial electrophysiological studies were used for classification of GBS subtypes: acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN).Results: In both Japanese and Italian cohorts, any of the antibodies were positive in 36% of the patients, and antibody positivity had a significant association with the AMAN electrodiagnosis. Approximately 30% of Japanese and Italian antiganglioside positive patients showed the AIDP pattern at the first examination whereas sequential studies showed that most finally showed the AMAN pattern. Clinically, seropositive patients more frequently had preceding diarrhoea and pure motor neuropathy in both Japanese and Italian cohorts; vibratory sensation was normal in 97% of Japanese and in 94% of Italian seropositive patients.Conclusions: In GBS, clinical and electrophysiological features appear to be determined by antiganglioside antibodies, and the antibodies are associated with motor axonal GBS in both Japan and Italy. Classification of the GBS subtypes as a disease entity should be made, combining the results of antiganglioside assays and serial electrodiagnostic studies. [ABSTRACT FROM AUTHOR]

Background and Objectives: The visual analog scale (VAS) is commonly used to assess pain intensity. However, the VAS is of limited value if patients fail to reliably report. Objective assessments are therefore clearly preferable. Previous reports suggest that elevated salivary alpha-amylase may reflect increased physical stress. There is a close association between salivary alpha-amylase and plasma norepinephrine under stressful physical conditions. In this study, we have determined the usefulness of a portable salivary alpha-amylase analyzer as an objective biomarker of stress.Methods: Thirty patients (male/female = 15/15, age: 60.5 +/- 15.3 years) with chronic low back or leg pain (pain (+) group) and 20 pain-free control patients undergoing elective surgery under general anesthesia with epidural analgesia (pain (-) group) were recruited. Patients received epidural block with 5 to 10 mL 1% lidocaine. VAS, blood pressure, and heart rates were assessed before and 30 and 45 minutes after the epidural block. Salivary alpha-amylase was simultaneously measured using a portable analyzer. The relationship between the VAS and salivary alpha-amylase in chronic pain patients was assessed.Results: After the epidural block both heart rate and systolic blood pressure decreased by approximately 8%. In the pain (+) group, the epidural block markedly decreased the VAS pain scale and salivary alpha-amylase from 56 +/- 22 to 19 +/- 16 mm (P < .01) and from 82 +/- 48 to 45 +/- 28 U/mL (P < .01), respectively, with a significant correlation between the 2 measures (r = 0.561, P < .01). In contrast, salivary alpha-amylase did not change significantly in the pain (-) group.Conclusions: Because there was a significant correlation between VAS pain scale and salivary alpha-amylase, we suggest that this biomarker may be a good index for the objective assessment of pain intensity. In addition, a simple to use portable analyzer may be useful for such assessment. [ABSTRACT FROM AUTHOR]

Purpose: Recently, a new method has been devised to measure the anisotropic 2-dimensional noise power spectrum (2D-NPS) in computed tomography. The 2D-NPS varied with the X-ray tube angle θ in the helical scan; it was defined as 2D-NPS θ . However, the method requires many scans to obtain the 2D-NPS θ for each θ with less statistical variability and is laborious. In the present study, the 2D-NPS θ was assumed to be an identical anisotropic 2D-NPS that rotated around the origin of the spatial frequency domain in conjunction with the rotation of the X-ray tube. We defined the identical 2D-NPS as 2D-NPS rot and proposed its measurement method with fewer scans., Methods: The 2D-NPS θ (θ from 0° to 180° in an increment of 30°) were obtained from noise images acquired by a hundred scans of a water phantom. In the proposed method, the 2D-NPS θ were obtained from noise images by 2 scans, rotated backward around the origin by θ to generate the identical 2D-NPS, and averaged to generate the 2D-NPS rot ., Results: The 2D-NPS rot , when it was rotated by θ, agreed well with the corresponding 2D-NPS θ . Absolute values of the mean and standard deviation of percentage errors of the 2D-NPS rot with the corresponding 2D-NPS θ at each θ were less than 0.70% and 6.12%, respectively., Conclusion: The proposed method was suggested to be valid for simple measurement of anisotropic 2D-NPS.

Purpose: Since childhood exposure to radiation has been demonstrated to increase cancer risk with increase in radiation dose, reduced radiation exposure during computed tomography (CT) evaluation is desired for adolescent idiopathic scoliosis (AIS). Therefore, this retrospective study aimed to investigate the radiation dose of dual-source CT using a spectral shaping technique and the accuracy of the thoracic pedicle screw (TPS) placement for posterior spinal fusion (PSF) in patients with AIS., Methods: Fifty-nine female patients with thoracic AIS who underwent PSF using CT-guided TPSs were included and divided into two groups comprised of 23 patients who underwent dual-source CT (DSCT) with a tin filter (DSCT group) and 36 who underwent conventional multislice CT (MSCT group). We assessed the CT radiation dose using the CT dose index (CTDI vol ), effective dose (ED), and accuracy of TPS insertion according to the established Neo's classification., Results: The DSCT and MSCT groups differed significantly (p < 0.001) in the mean CTDI vol (0.76 vs. 3.31 mGy, respectively) and ED (0.77 vs. 3.47 mSv, respectively). Although the correction rate of the main thoracic curve in the DSCT group was lower (65.7% vs. 71.2%) (p = 0.0126), the TPS accuracy (Grades 0-1) was similar in both groups (381 screws [88.8%] vs. 600 screws [88.4%], respectively) (p = 0.8133). No patient required replacement of malpositioned screws., Conclusion: Spectral shaping DSCT with a tube-based tin filter allowed a 75% radiation dose reduction while achieving TPS insertion accuracy similar to procedures based on conventional CT without spectral shaping., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to evaluate the impact of region of interest (ROI) size on noise-power spectrum (NPS) measurement in computed tomography (CT) images and to propose a novel method for measuring NPS independent of ROI size. The NPS was measured using the conventional method with an ROI of size P × P pixels in a uniform region in the CT image; the NPS is referred to as NPS R=P . NPSs R=256, 128, 64, 32, 16, and 8 were obtained and compared to assess their dependency on ROI size. In the proposed method, the true NPS was numerically modeled as an NPS model , with adjustable parameters, and a noise image with the property of the NPS model was generated. From the generated noise image, the NPS was measured using the conventional method with a P × P pixel ROI size; the obtained NPS was referred to as NPS' R=P . The adjustable parameters of the NPS model were optimized such that NPS' R=P was most similar to NPS R=P . When NPS' R=P was almost equivalent to NPS R=P , the NPS model was considered the true NPS. NPSs R=256, 128, 64, 32, 16, and 8 obtained using the conventional method were dependent on the ROI size. Conversely, the NPSs (optimized NPSs model ) measured using the proposed method were not dependent on the ROI size, even when a much smaller ROI (P = 16 or 8) was used. The proposed method for NPS measurement was confirmed to be precise, independent of the ROI size, and useful for measuring local NPSs using a small ROI., (© 2023. The Author(s), under exclusive licence to Japanese Society of Radiological Technology and Japan Society of Medical Physics.)

Purpose: The noise power spectrum (NPS) in computed tomography (CT) images potentially varies with the X-ray tube angle in a spiral orbit of the helical scan. The purpose of this study was to propose a method for measuring the NPS for each angle of the X-ray tube., Methods: Images of the water phantom were acquired using a helical scan. As a conventional method, we measured the two-dimensional (2D) NPS from each image and averaged them; the obtained 2D-NPS was referred to as NPS conventional . In the proposed method, we made the X-ray tube angle θ (0°≤θ<360°) to correspond to the image according to each slice position of the images that located within the travel distance of the CT scan table per 360° rotation of the X-ray tube. We obtained the 2D-NPS from each image and assigned the θ (0°, 30°, 60°, 90°, 120°, 150°, 180°); the obtained 2D-NPS was referred to as NPSs θ . The NPSs θ was compared to the NPS conventional . Also, we investigated the dependency of the NPSs θ on the θ., Results: The NPS conventional was found to be isotropic, and in contrast, the NPSs θ was anisotropic. The NPSs θ showed a continuously rotational change while increasing the θ. There was an excellent correlation (R 2 >0.999) between the rotation angle of NPS θ and the θ., Conclusion: The proposed method was demonstrated to be effective for evaluating anisotropic noise characteristics depending on the X-ray tube angle.

Background: Imaging examinations are crucial for diagnosing acute ischemic stroke, and knowledge of a patient's body weight is necessary for safe examination. To perform examinations safely and rapidly, estimating body weight using head computed tomography (CT) scout images can be useful., Objective: This study aims to develop a new method for estimating body weight using head CT scout images for contrast-enhanced CT examinations in patients with acute ischemic stroke., Methods: This study investigates three weight estimation techniques. The first utilizes total pixel values from head CT scout images. The second one employs the Xception model, which was trained using 216 images with leave-one-out cross-validation. The third one is an average of the first two estimates. Our primary focus is the weight estimated from this third new method., Results: The third new method, an average of the first two weight estimation methods, demonstrates moderate accuracy with a 95% confidence interval of ±14.7 kg. The first method, using only total pixel values, has a wider interval of ±20.6 kg, while the second method, a deep learning approach, results in a 95% interval of ±16.3 kg., Conclusions: The presented new method is a potentially valuable support tool for medical staff, such as doctors and nurses, in estimating weight during emergency examinations for patients with acute conditions such as stroke when obtaining accurate weight measurements is not easily feasible.

Hirosaki University has regularly offered health support activities to residents of X town in Fukushima, and thus, some interactive benefits are expected as a service-learning experience for nursing students. This study aimed to clarify the experiences of students who participated in service-learning and consider which methods and content were effective. In total, 52 nursing students were recruited into the program, which was held from 2018 to 2021. The roles of students included assisting in health consultations related to a radiation disaster. Questionnaires designed by researchers with experience in risk communication programs were conducted on the students after the program, and included the reasons why they joined, their most memorable experiences, and their opinions regarding required support for residents. The data were analyzed by content analysis. The nursing students thought about the health of residents through health support activities in the affected areas. Furthermore, by communicating with residents via on-site service-learning, they could experience the humanity of the residents and the current status of the affected areas, learn the importance of person-to-person relationships, and think about reconstruction. Thus, service-learning was found to be effective and to offer substantial benefits for both residents and students in affected areas.

Purpose: Various approaches in noise power spectrum (NPS) analysis are currently used for measuring a patient's longitudinal (z-direction) NPS from three-dimensional (3D) CT volume data. The purpose of this study was to clarify the relationship between those NPSs and 3D-NPS based on the central slice theorem., Methods: We defined the 3D-NPS(f x , f y , f z ) that was calculated by 3D Fourier transform (FT) from 3D noise data (3D-Noise(x, y, z), x-y scan plane). Here, f x , f y and f z are spatial frequencies corresponding to the axes of x, y and z, respectively. Based on the central slice theorem, we described three relationships as follows. (1) The f z -directional NPS calculated from the 3D-Noise(x=0, y=0, z) is equal to the profile obtained by projecting 3D-NPS(f x , f y , f z ) in f x - and f y -directions. (2) The f z -directional NPS calculated from the profile obtained by projecting 3D-Noise(x=0, y, z) in the y-direction is equal to the profile at f y =0 in the data obtained by projecting 3D-NPS(f x , f y , f z ) in the f x -direction. (3) The f z -directional NPS calculated from the profile obtained by projecting 3D-Noise(x, y, z) in x and y-directions is equal to the profile of 3D-NPS(f x =0, f y =0, f z ). To verify them, we compared the NPSs measured from actual 3D noise data that were obtained using a cylindrical water phantom., Results: In each relationship (1)-(3), the f z -directional NPS matched the profile obtained from the 3D-NPS(f x , f y , f z )., Conclusion: Based on the central slice theorem, we clarified the relationships between f z -directional NPSs and 3D-NPS. We should understand them and then consider which method should be used for f z -directional NPS measurement.

Purpose: The noise power spectrum (NPS) of a CT scanner is commonly measured from a single noise image. However, since CT images are three-dimensional (3D) volume data, they have 3D noise characteristics (3D-NPS). In this study, we clarify the relationship among NPSs measured by various approaches in NPS analysis based on the central slice theorem. Its validity is verified by the NPS measurements using actual 3D noise data., Methods: We defined the NPS z-projection (f x , f y ) that was calculated by the 2D Fourier transform (FT) from the 2D projection of 3D noise data in the patient longitudinal direction, the 3D-NPS(f x , f y , f z ) that was calculated by the 3D-FT from the 3D noise data, and the 2D-NPS(f x , f y ) that was calculated by the 2D-FT from a single noise image; f x , f y , and f z are spatial frequencies corresponding to the axes of x, y, and z in the reconstructed CT volume, respectively. Based on the central slice theorem, we described that the NPS z-projection (f x , f y =0) was equal to the 3D-NPS(f x , f y =0, f z =0), and the NPS(2D-NPS(f x , f y =0)) was different from the 3D-NPS(f x , f y =0, f z =0). To verify them, we compared the NPSs calculated from actual 3D noise data that were obtained using a cylindrical water phantom., Results: The 3D-NPS(f x , f y =0, f z =0) matched the NPS z-projection (f x , f y =0) and was different from the 2D-NPS(f x , f y =0)., Conclusion: Based on the central slice theorem, we clarified the relationship among NPSs measured by various approaches in NPS analysis; it is important to understand this and then select an appropriate noise data handling and NPS measurement method.

A novel method for measuring the slice sensitivity profile (SSP) of computed tomography (CT) images reconstructed using an iterative reconstruction (IR) algorithm is proposed herein. A phantom that included a low-contrast spherical object was scanned and consecutive cross-sectional images were reconstructed. The mean CT values in a region including the sphere were measured for all images and plotted as a function of slice position along the longitudinal [Formula: see text] direction to yield a mean CT value profile [Formula: see text]. Next, we numerically generated an object function corresponding to the sphere and obtained the mean CT value profile [Formula: see text]. Subsequently, the SSP was modeled as a product of the Gaussian and cosine functions. We convolved [Formula: see text] with the modeled SSP to obtain [Formula: see text]. The difference between [Formula: see text] and [Formula: see text] was evaluated using the root mean square error (RMSE), which was minimized via optimization of the SSP model parameters. To validate the methodology, we first used filtered back projection (FBP) images to compare the SSPs determined using the proposed and standard coin methods. Subsequently, the proposed method was applied to measure the SSPs of four types of IR algorithms in two scanners. The SSPs of the FBP images determined using the proposed and coin methods showed good agreement. Additionally, in the SSP measurements using the proposed method, [Formula: see text] agreed well with [Formula: see text] for every IR algorithm. The RMSEs for all measurements were less than 0.7 HU, indicating the accuracy of the SSPs. Thus, the proposed method is effective for obtaining valid SSPs., (© 2021. Japanese Society of Radiological Technology and Japan Society of Medical Physics.)

Purpose: A method for measuring the slice sensitivity profile (SSP) of computed tomography (CT) images reconstructed with iterative reconstruction (IR) algorithms was reported by the AAPM Task Group 233 (TG233). In this method, the phantom plane edge is slightly slanted with respect to the scan plane to obtain a composite oversampled edge-spread function (ESF). However, it is expected that a fine-sampled ESF can be obtained directly from images reconstructed with a small slice increment without slanting the edge plane. This study aimed to investigate the validity of using a non-slanted edge plane., Methods: In the proposed non-slanted edge method, the phantom was positioned so that the plane edge was perpendicular to the longitudinal z-axis, and images were reconstructed with a 1-mm slice thickness and 0.1-mm increment. The mean CT value was obtained in each slice and plotted as a function of slice position along the z-axis, thereby generating the ESF. The SSP was calculated from the ESF by differentiation. In the TG 233-recommended slanted edge method, the SSP was obtained by following the procedure described in the TG233 report. To validate the methodology, we first used filtered back projection (FBP) images to compare SSPs obtained using the non-slanted edge method, slanted edge method, and a standard method using a high-contrast thin object (coin). Next, for two types of IR algorithms, we compared the SSPs obtained using the non-slanted and slanted edge methods., Results: For the FBP images, the SSP measured using the non-slanted edge method agreed well with SSPs measured using the coin and slanted edge methods. For the IR images, the SSPs measured using the non-slanted and slanted edge methods showed good agreement., Conclusions: The non-slanted edge method was demonstrated to be valid. The simplicity and practicality of the method allows routine and accurate determination of the SSP., (© 2020 American Association of Physicists in Medicine.)

Purpose: The method using a numerical slit (slit method) is used commonly to obtain the one-dimensional (1D) noise power spectrum (NPS) in computed tomography. However, the relationship between the 1D-NPS obtained by the slit method and the original two-dimensional (2D) NPS derived by the 2D Fourier transformation has not been elucidated clearly. The purpose of this study was to clarify their relationship based on the well-known central slice theorem (projection slice theorem) and validate it using computer simulation analysis., Methods: With the application of the central slice theorem, we described that the 1D-NPS obtained by the slit method was equal to the central slice (profile) in the 2D-NPS when we set the slit length to the maximum (i.e. the matrix size of the noise image). To verify this, we generated computer-simulated noise images with the known 2D-NPS (true 2D-NPS). From those images, we obtained the 1D-NPS that was obtained by the slit method and compared it with the central slice in the true 2D-NPS., Results: When we set the slit length to the maximum, the 1D-NPS obtained by the slit method showed good agreement with the central slice in the true 2D-NPS., Conclusion: We clarified the relationship between the 1D-NPS obtained by the slit method and the 2D-NPS using a theoretical approach and the computer simulation. We had to maximize the slit length to achieve the accurate measurement of the 1D-NPS using the slit method.

To achieve an accurate stopping power ratio (SPR) prediction in particle therapy treatment planning, we previously proposed a simple conversion to the SPR from dual-energy (DE) computed tomography (CT) data via electron density and effective atomic number (Z eff ) calibration (DEEDZ-SPR). This study was conducted to carry out an initial implementation of the DEEDZ-SPR conversion method with a clinical treatment planning system (TPS; VQA, Hitachi Ltd., Tokyo) for proton beam therapy. Consequently, this paper presents a proton therapy plan for an anthropomorphic phantom to evaluate the stability of the dose calculations obtained by the DEEDZ-SPR conversion against the variation of the calibration phantom size. Dual-energy x-ray CT images were acquired using a dual-source CT (DSCT) scanner. A single-energy CT (SECT) scan using the same DSCT scanner was also performed to compare the DEEDZ-SPR conversion with the SECT-based SPR (SECT-SPR) conversion. The scanner-specific parameters necessary for the SPR calibration were obtained from the CT images of tissue substitutes in a calibration phantom. Two calibration phantoms with different sizes (a 33 cm diameter phantom and an 18 cm diameter phantom) were used for the SPR calibrations to investigate the beam-hardening effect on dosimetric uncertainties. Each set of calibrated SPR data was applied to the proton therapy plan designed using the VQA TPS with a pencil beam algorithm for the anthropomorphic phantom. The treatment plans with the SECT-SPR conversion exhibited discrepancies between the dose distributions and the dose-volume histograms (DVHs) of the 33 cm and 18 cm phantom calibrations. In contrast, the corresponding dose distributions and the DVHs obtained using the DEEDZ-SPR conversion method coincided almost perfectly with each other. The DEEDZ-SPR conversion appears to be a promising method for providing proton dose plans that are stable against the size variations of the calibration phantom and the patient.

The patient was a 50-year-old woman. Pembrolizumab was started for bladder cancer recurrence. From the day after the second administration, ptosis, diplopia, restriction of eye movement, muscle weakness, fatigue resistance, increase in serum creatine kinase (CK) level, and muscle pain were observed. Tests for anti-acetylcholine receptor (AChR) antibody and anti-muscle specific kinase (MuSK) antibody were negative. Electrophysiological examination of the neuromuscular junction showed negative results, and electromyography revealed no myogenic changes. We considered that the immune checkpoint inhibitor caused neuromuscular damage. The patient's symptoms were gradually improved by immunotherapy, such as steroid and plasma exchange. In this case, tests for the anti-titin antibody, an anti-striational antibody, were positive. We considered that myasthenia gravis-like symptoms and serum CK level elevation might have been caused by impairment of excitation-contraction coupling, and not the neuromuscular junction.