論文

Treatment strategies for pediatric rheumatic diseases have changed substantially over the past two decades, driven by the development of biologics and cytokine-targeted molecular therapy. Therapeutic approaches that modulate both innate and adaptive immune responses have improved prognosis in these immune-mediated disorders, and early diagnosis with timely intervention is associated with better outcomes. However, affected children often present with non-specific symptoms, and reliable biomarkers remain limited in juvenile idiopathic arthritis (JIA); thus, the diagnostic delay remains common. Imaging is an important adjunct in pediatric rheumatology; in selected scenarios, it can be pivotal for establishing a definitive diagnosis and for assessing disease subtype, complications, and treatment response. This review presents an imaging-focused overview of pediatric rheumatic diseases. We begin with a brief review of current immunologic concepts, including the autoinflammatory–autoimmune continuum, then illustrate typical imaging findings, discuss key differential diagnoses, and summarize the diagnostic strengths and limitations of major imaging modalities. We discuss in detail the major JIA subtypes based on the PRINTO classification, which aims to improve clinical coherence, facilitate risk stratification, and clarify relationships between pediatric and adult rheumatic entities. We also highlight interferonopathies—disorders characterized by a type I interferon signature—which provide a useful framework for understanding the mechanistic links between autoinflammation and autoimmunity along the continuum and for contextualizing selected autoimmune diseases, including systemic lupus erythematosus, juvenile dermatomyositis, and Sjögren's syndrome.

Objective: Previous studies have shown that patient characteristics, such as fasting blood glucose, can modulate hepatic 18F-fluorodeoxyglucose (FDG) uptake; however, the drug-specific effects of different antidiabetic agents on hepatic and whole-body FDG distribution remain poorly understood. Therefore, in this study, we aimed to evaluate the impact of biguanide therapy, as well as insulin and other antidiabetic medications, on hepatic FDG uptake and dynamic positron emission tomography (PET) kinetic parameters [the static mean standardized uptake value normalized by lean body mass (SULmean), dynamic metabolic rate of glucose (Ki), and the FDG distribution volume (DV)] in patients with diabetes, using a multiparametric dynamic FDG-PET/computed tomography (CT) protocol. Methods: This retrospective study included 107 patients with diabetes who underwent dynamic whole-body FDG-PET/CT after a 4-h fast and drug withdrawal between January 2022 and May 2025. Patients with hepatic structural abnormalities or artifacts were excluded. PET kinetic parameters (SULmean, Ki, and DV) were measured in the liver and analyzed for associations with clinical variables, including biguanide and insulin therapy, via multivariate regression. Results: Among the 107 patients included, 44 and 9 received biguanide and insulin, respectively. Multivariate regression showed that biguanide therapy, but not insulin use or other clinical variables, was significantly associated with increased hepatic SULmean (p = 0.037). No clinical variables were significantly associated with Ki or DV in the corresponding models. These findings suggest that biguanide therapy elevates static hepatic FDG uptake, whereas hepatic glucose metabolic dynamics, as assessed by Ki and DV, did not show significant alterations associated with the antidiabetic medications evaluated in our cohort under standard pre-scan preparation. Conclusions: Our study demonstrates that biguanide therapy increases static hepatic FDG accumulation without interfering with the underlying glucose metabolic dynamics (Ki and DV). The observed increase in SULmean is numerically significant but visually minimal; thus, its impact on routine diagnostic interpretation is likely minimal.

Recent advances in immunologic and molecular research on rheumatic diseases have significantly improved understanding of the diverse group of immune-mediated disorders. Rheumatic diseases were traditionally considered autoimmune diseases, caused by impaired adaptive immunity and often associated with pathogenic autoantibodies. However, in the late 20th century, certain genetic rheumatic diseases-such as tumor necrosis factor receptor-associated periodic syndrome (TRAPS) and familial Mediterranean fever (FMF)-were found to result from antigen-independent activation of innate immune cells and the subsequent cytokine-mediated inflammation. This discovery introduced the new concept of autoinflammatory diseases, characterized by dysregulation of innate immunity. Although autoimmune and autoinflammatory diseases were initially regarded as distinct categories, substantial overlap has become evident. For instance, autoantibodies can be detected in disorders primarily affecting innate immunity, while recent cytokine-targeting therapies have proven effective for classic autoimmune diseases, such as systemic lupus erythematosus (SLE) and dermatomyositis. These insights led to the concept of an autoinflammatory-autoimmune continuum, highlighting that dysregulation of the interaction between innate and adaptive immune systems contributes to the clinical symptoms of rheumatic diseases. The authors explore clinical, imaging, pathophysiologic, and therapeutic aspects of pediatric rheumatic diseases through the lens of this continuum, providing a comprehensive overview of current diagnostic and treatment strategies. © RSNA, 2026 Supplemental material is available for this article.

Purpose: To quantify lung and lobar volumes superimposed on the mediastinum and diaphragm on upright chest radiographs using upright multidetector row CT and to compare them with supine measurements. Materials and Methods: In this prospective study, asymptomatic Asian participants underwent both upright and supine multidetector row CT within 2 hours. Lung and lobar volumes were measured in each position. Ray-sum images were reconstructed to delineate mediastinal and diaphragmatic boundaries, and superimposed volumes in the posteroanterior direction were calculated. These CT-derived volumes were considered to approximate lung fields projected over the mediastinum and diaphragm on radiographs. Percentages of superimposed volumes relative to total lung and lobar volumes were determined. Mixed-effects models and multiple linear regression analyses were used. Results: The study included 132 participants (mean age ± SD, 47.4 years ± 11.4; 85 female; mean body mass index ± SD, 22.2 ± 3.4 [calculated by dividing weight in kilograms by height in meters squared]). The proportion of lung volume superimposed on the mediastinum and diaphragm was 23.9% ± 3.1 in the upright position, significantly lower than 25.7% ± 3.3 in the supine position (P < .001), despite a 9.8% increase in total lung volume upright. Superimposed percentages of the right upper, middle, and lower lobes and the left upper and lower lobes in the upright position were 10.4% ± 2.5, 7.5% ± 3.2, 28.8% ± 7.9, 12.3% ± 1.9, and 46.0% ± 8.3, respectively. All lobes except the left lower lobe showed significantly lower superimposition upright than supine (all P < .03). Multiple linear regression identified older age, higher body mass index, and male sex as independent predictors of greater superimposition in the upright position (all P < .03). Conclusion: Lung volume superimposed on the mediastinum and diaphragm was lower on upright than supine chest radiographs despite greater lung volume in the upright position. University Hospital Medical Information Network Clinical Trials Registry: UMIN000026586.

Background: Treatment options for patients with chronic thromboembolic pulmonary hypertension ineligible for pulmonary endarterectomy (inoperable CTEPH) include balloon pulmonary angioplasty (BPA) and riociguat. However, these two treatment options have not been compared prospectively. We aimed to compare the safety and efficacy of BPA and riociguat in patients with inoperable CTEPH. Methods: This open-label, randomised controlled trial was conducted at four high-volume CTEPH centres in Japan. Patients aged 20–80 years with inoperable CTEPH (mean pulmonary arterial pressure ≥25 to <60 mm Hg and pulmonary artery wedge pressure ≤15 mm Hg) and WHO functional class II or III were randomly assigned (1:1) to BPA or riociguat via a computer program located at the registration centre using a minimisation method with biased-coin assignment. In the BPA group, the aim was for BPA to be completed within 4 months of the initial date of the first procedure. BPA was repeated until mean pulmonary arterial pressure decreased to less than 25 mm Hg. The frequency of BPA procedures depended on the difficulty and number of the lesions. In the riociguat group, 1·0 mg riociguat was administered orally thrice daily. When the systolic blood pressure was maintained at 95 mm Hg or higher, the dose was increased by 0·5 mg every 2 weeks up to a maximum of 2·5 mg thrice daily; dose adjustment was completed within 4 months of the date of the first dose. The primary endpoint was change in mean pulmonary arterial pressure from baseline to 12 months, measured in the full analysis set (patients who were enrolled and randomly assigned to one of the study treatments, and had at least one assessment after randomisation). BPA-related complications and indices related to clinical worsening were recorded throughout the study period. Adverse events were recorded throughout the study period and evaluated in the safety analysis set (patients who were enrolled and randomely assigned to one of the study treatments, and had received part of or all the study treatments). This trial is registered in the Japan Registry of Clinical Trials (jRCT; jRCTs031180239) and is completed. Findings: Between Jan 8, 2016, and Oct 31, 2019, 61 patients with inoperable CTEPH were enrolled and randomly assigned to BPA (n=32) or riociguat (n=29). Patients in the BPA group underwent an average of 4·7 (SD 1·6) BPA procedures. In the riociguat group, the mean maintenance dose was 7·0 (SD 1·0) mg/day at 12 months. At 12 months, mean pulmonary arterial pressure had improved by −16·3 (SE 1·6) mm Hg in the BPA group and −7·0 (1·5) mm Hg in the riociguat group (group difference −9·3 mm Hg [95% CI −12·7 to −5·9]; p<0·0001). A case of clinical worsening of pulmonary hypertension occurred in the riociguat group, whereas none occurred in the BPA group. The most common adverse event was haemosputum, haemoptysis, or pulmonary haemorrhage, affecting 14 patients (44%) in the BPA group and one (4%) in the riociguat group. In 147 BPA procedures done in 31 patients, BPA-related complications were observed in 17 procedures (12%) in eight patients (26%). Interpretation: Compared with riociguat, BPA was associated with a greater improvement in mean pulmonary arterial pressure in patients with inoperable CTEPH at 12 months, although procedure-related complications were reported. These findings support BPA as a reasonable option for inoperable CTEPH in centres with experienced BPA operators, with attention to procedure-related complications. Funding: Bayer Yakuhin. Translation: For the Japanese translation of the abstract see Supplementary Materials section.

Background: Computed tomography (CT) imaging is widely used for diagnosing and determining the severity of coronavirus disease 2019 (COVID-19). Chest CT imaging can be used to calculate the epicardial adipose tissue (EAT) and upper abdominal visceral adipose tissue (Abd-VAT) areas. The EAT is the main source of inflammatory cytokines involved in chest inflammatory diseases; thus, the EAT area might be a more useful severity predictor than the Abd-VAT area for COVID-19. However, to the best of our knowledge, there are no large-scale reports that sufficiently consider this issue. In addition, there are no reports on the characteristics of patients with normal body mass index (BMI) and high adipose tissue. Aim: The purpose of this study was to analyze whether the EAT area, among various adipose tissues, was the most associated factor with COVID-19 severity. Using a multicenter COVID-19 patient database, we analyzed the associations of chest subcutaneous, chest visceral, abdominal subcutaneous, and Abd-VAT areas with COVID-19 outcomes. In addition, the clinical significance of central obesity, commonly disregarded by BMI, was examined. Methods: This retrospective cohort study evaluated patients with COVID-19 aged ≥18 years In Japan. Data including from chest CT images collected between February 2020 and October 2022 in four hospitals of the Japan COVID-19 Task Force were analyzed. Patient characteristics and COVID-19 severity were compared according to the adipose tissue areas (chest and abdominal subcutaneous adipose tissue [Chest-SAT and Abd-SAT], EAT, and Abd-VAT) calculated from chest CT images. Results: We included 1077 patients in the analysis. Patients with risk factors of severe COVID-19 such as old age, male sex, and comorbidities had significantly higher areas of EAT and Abd-VAT. High EAT area but not high Abd-VAT area was significantly associated with COVID-19 severity (adjusted odds ratio (aOR): 2.66, 95 % confidence interval [CI]: 1.19–5.93). There was no strong correlation between BMI and VAT. Patients with high VAT area accounted for 40.7 % of the non-obesity population (BMI < 25 kg/m2). High EAT area was also significantly associated with COVID-19 severity in the non-obesity population (aOR: 2.50, 95 % CI: 1.17–5.34). Conclusions: Our study indicated that VAT is significantly associated with COVID-19 severity and that EAT is the best potential predictor for risk stratification in COVID-19 among adipose tissue areas. Body composition assessment using EAT is an appropriate marker for identifying obesity patients overlooked by BMI. Considering the next pandemic of the global health crisis, our findings open new avenues for implementing appropriate body composition assessments based on CT imaging.

Objectives: The clinical relevance of computed tomography (CT)-based airway tree structure is unclear. Herein, we used artificial intelligence to segment the airway tree and pneumonia regions, measuring total airway count (TAC) and pneumonia volume to examine whether their combination is more closely associated with clinical outcomes in patients with coronavirus disease (COVID-19) than pneumonia volume alone. Materials and methods: We examined clinical data and chest CT from 781 hospitalized COVID-19 patients in a multicenter retrospective cohort in Japan, focusing on the percentage of critical outcomes (high-flow oxygen, invasive mechanical ventilation, or death). Additionally, 197 patients were followed up for 3 months to monitor TAC and pneumonia volume. Results: Critical outcomes were observed in 63 (8.8%) patients, with higher TAC in those patients. Patients were divided into four groups based on cutoff values of 17.6% for pneumonia volume percent and 255 for TAC: Group A (low TAC, low pneumonia volume), Group B (high TAC, low pneumonia volume), Group C (low TAC, high pneumonia volume), and Group D (high TAC, high pneumonia volume). Group D had the worst outcomes, highest levels of inflammation, fibrosis markers, and complications, as well as a significantly higher risk of critical outcomes after adjusting for age, body mass index, sex, total lung volume and comorbidities. In the 3-month longitudinal analysis, pneumonia volume, but not TAC, improved in critical cases. Conclusions: The integrated assessment of TAC and pneumonia volume effectively predicted critical outcomes in COVID-19 patients and may be useful for various respiratory diseases, including infectious or interstitial pneumonia. Key Points: Question Total airway counts (TAC) on computed tomography (CT) scan is associated with respiratory disease progression, but clinical relevance of CT-based airway tree structure is unclear. Findings The integrated assessment of TAC and pneumonia volume effectively predicted critical outcomes in COVID-19 patients. Clinical relevance This metric can potentially be applied to various respiratory diseases, including infectious or interstitial pneumonia.

This review provides a comprehensive overview of recent transformative advancements in diagnostic imaging that position Japan at the forefront of radiological innovation. We highlight pivotal innovations that enhance diagnostic capabilities and redefine clinical workflows. The article begins with upright multidetector computed tomography (MDCT), a groundbreaking technology offering novel insights into posture-dependent anatomical and physiological changes. We then explore significant progress in breast and gynecologic imaging, including advancements in artificial intelligence computer-aided (AI-CAD) synthesized mammograms, automated breast ultrasound (ABUS), and abbreviated MRI protocols. These innovations address unique regional challenges in early cancer detection. Significant innovations in abdominal radiology, spanning advanced CT (including photon-counting detector CT), accelerated MRI, and AI applications, are also discussed. The review further delves into glymphatic system research, where advanced MRI techniques, particularly DTI-ALPS, are unraveling new insights into brain waste clearance and neurological disorders. Finally, we examine the future of Japanese radiology through the lens of AI, with a focus on Large Language Models (LLMs). We discuss their growing role in diagnostic support, report generation, and information extraction, as well as important societal and ethical considerations. These collective advancements underscore Japan’s dynamic contributions to radiological innovation, poised to significantly impact global healthcare practices by improving disease detection, optimizing workflows, and extending healthy life expectancy in an aging society.

Background: Conducting carbon ion radiotherapy (CIRT) in upright posture has several technical advantages over that in conventional supine posture for pancreatic cancer treatment. However, few studies have investigated effects of upright positioning on anatomy and CIRT dose distributions. Purpose: This study compared anatomy and dose distributions in CIRT for pancreatic cancer between supine and upright postures. Methods: Fourteen pairs of computed tomography (CT) images obtained from asymptomatic volunteers in these postures were analyzed. Clinical target volume (CTV), organs-at-risk (OARs), and gastrointestinal gas contours were delineated within a planning volume for each CT image, and a CIRT dose distribution was calculated. The anatomical differences between these postures were evaluated by comparing volumes and 3D rendered images of the contours, while the dosimetric differences were assessed with 12 dosimetric metrics. Moreover, a proximal overlap volume of the OARs and possible change in water-equivalent path length due to gastrointestinal gas were calculated for all coplanar beam angles to compare ranges of applicable beam angles and potential range uncertainty between these postures. Results: The bowel contour volumes in the upright posture were more than 46% smaller than those in the supine posture because the bowel was shifted. The upright posture provided a smaller dose to the bowel and higher dose coverage to the CTV than the supine posture. The possible water-equivalent path length changes due to the stomach and duodenum gas decreased at most beam angles in the upright posture. Conclusions: The upright CIRT had several anatomical and dosimetric advantages for pancreatic cancer treatment over conventional supine CIRT. This technique will be useful in applying the patient-specific beam angle arrangement and precise dose delivery with reduced range uncertainty.

Objective: Obesity is a risk factor of chronic kidney disease (CKD), contributing to the rising incidence of cardiometabolic diseases. Renal sinus fat (RSF) is an ectopic fat depot located at the renal cavity that could impair renal function and hemodynamic through compression of renal structures. The major purpose of this study was to explore the relationship between RSF accumulation and renal dysfunction in CKD patients. Methods: We evaluated the associations between computed tomography measured RSF volume and key clinical and histologic parameters involved in renal function and hemodynamics in 132 well-characterized CKD patients who underwent renal biopsy (median age: 62 years; 63.6% men). Results: RSF volume normalized by renal volume (RSF%) positively correlated with obesity-related traits such body mass index and visceral fat volume (VFV) (all P < 0.001) whereas it negatively correlated with estimated glomerular filtration rate (eGFR) (ρ = −0.42, P < 0.001) and 24-h urinary creatinine clearance (CCr) (ρ = −0.34, P < 0.001). Notably, we found robust positive correlations between RSF% and renal resistive index (RRI) measured by the Doppler ultrasound (ρ = 0.40, P < 0.001), and the histological severity of global glomerular sclerosis (ρ = 0.48, P < 0.001) and interstitial fibrosis and tubular atrophy (IFTA) (ρ = 0.35, P < 0.001). In the multivariate linear regression models, after accounting for potential confounders including VFV, RSF% remained significantly associated with CCr (β = −0.26, P < 0.001), RRI (β = 0.17, P = 0.022), global glomerular sclerosis (β = 0.21, P = 0.002), and IFTA (β = 0.17, P = 0.012). Conclusion: RSF accumulation is associated with renal dysfunction and hemodynamic abnormalities independent of visceral adiposity. Our results suggest that RSF may have a potential unique role in the pathogenesis of CKD.

Radiologists are witnessing astonishing innovation and advancement of CT technologies and their clinical applications. This review highlights how photon-counting CT (PCCT), upright CT, and artificial intelligence (AI) may impact cardiothoracic CT applications for imaging and diagnosis. PCCT relies on new detectors that can bin the separate photon energies and allow for lower radiation dose and better spatial resolution. The clinical applications of PCCT in the coronary arteries are becoming the new standard for cardiac CT imaging. New upright CT has shown the benefits of imaging in the upright position and offers new insight into how the upright position affects biomechanics and physiology. Four-dimensional CT, which can be used to directly image perfusion, is challenging MRI and MR angiography for primacy in this area. The burgeoning role of AI and informatics is changing the way radiologists interpret and report many imaging examinations. The future is bright and promises lower radiation and intravenous contrast agent doses and higher spatial resolution, and will further incorporate deep learning to improve the effectiveness of CT.

Objective This study aimed to investigate the utility of CT quantification of lung volume for predicting critical outcomes in COVID-19 patients. Methods This retrospective cohort study included 1200 hospitalised patients with COVID-19 from 4 hospitals. Lung fields were extracted using artificial intelligence-based segmentation, and the percentage of the predicted (%pred) total lung volume (TLC (%pred)) was calculated. The incidence of critical outcomes and posthospitalisation complications was compared between patients with low and high CT lung volumes classified based on the median percentage of predicted TLCct (n=600 for each). Prognostic factors for residual lung volume loss were investigated in 208 patients with COVID-19 via a follow-up CT after 3 months. Results The incidence of critical outcomes was higher in the low TLCct (%pred) group than in the high TLCct (%pred) group (14.2% vs 3.3%, p<0.0001). Multivariable analysis of previously reported factors (age, sex, body mass index and comorbidities) demonstrated that CT-derived lung volume was significantly associated with critical outcomes. The low TLCct (%pred) group exhibited a higher incidence of bacterial infection, heart failure, thromboembolism, liver dysfunction and renal dysfunction than the high TLCct (%pred) group. TLCct (%pred) at 3 months was similarly divided into two groups at the median (71.8%). Among patients with follow-up CT scans, lung volumes showed a recovery trend from the time of admission to 3 months but remained lower in critical cases at 3 months. Conclusion Lower CT lung volume was associated with critical outcomes, posthospitalisation complications and slower improvement of clinical conditions in COVID-19 patients.

Introduction: Increased intraabdominal fat volume (IAFV) is associated with systemic inflammation and various cardiometabolic diseases. However, the clinical implication of IAFV in patients on peritoneal dialysis (PD) is unclear. In addition, the association of intraabdominal fat-free volume (IAFFV), which could mainly reflect the volume of visceral organs that serve as a potential source of inflammatory uremic toxins, with PD-associated clinical outcomes remains unknown. Methods: We retrospectively measured IAFV and IAFFV in the 108 patients on PD using abdominal computed tomography at initiation of PD. The participants were followed up until PD cessation, death, or study completion. We investigated the relationships between IAFV and IAFFV and the risks of peritonitis and PD discontinuation (defined by a composite endpoint of death or transfer to hemodialysis). Results: The median follow-up period was 46 (interquartile range 24–82) months. The baseline obesity-related traits significantly (P < 0.05) differed between high-IAFV (≥ 2935 cm3) and low-IAFV (< 2935 cm3) groups. However, the log-rank tests found no differences in the incidence of peritonitis and PD discontinuation between groups. In contrast, both peritonitis-free survival and time on PD therapy were shorter in high-IAFFV (≥ 4796 cm3) group than in low-IAFFV (< 4796 cm3) group (all P < 0.05). In the Cox regression models, IAFFV remained a strong risk factor for peritonitis even after adjusting for confounders (hazard ratio: 2.16, 95% confidence interval: 1.07–4.38). Conclusions: We demonstrate that IAFFV is an independent risk factor of peritonitis in patients o nPD. Additional studies are needed to identify specific intraabdominal component(s) involved in the pathogenesis of PD-associated adverse events.

Purpose: Graft-notch impingement and large graft bending angle (GBA) in anterior cruciate ligament reconstruction (ACLR) carry a risk of graft failure and subsequent poor postoperative outcomes. Most studies have analyzed the impingement rate and GBA using computed tomography (CT) in the supine position, but not in the standing condition. This study aimed to assess the graft impingement and GBA using upright multi-detector CT (MDCT). Methods: We analyzed 43 knee joints of 23 healthy volunteers (women, n = 13; men, n = 10) in a single-leg standing position using an upright 320-detector-row CT. We defined the putative position of the graft tunnel in three-dimensional models and assessed the impingement rate and GBA of both the anteromedial (AMB) and posterolateral bundles (PLB). Result: The impingement rate for the AMB with a 6-mm graft diameter (81.4 %) was significantly higher than that for the PLB (0.7 %; P < 0.001). The modified AMB tunnel position, which connects the midpoint between the traditional AM and PL tunnel apertures of the femur to the most medial point within the tibial AM footprint, reduced the impingement rate by 14.0 % (P < 0.001). The impingement rate of the modified AMB with a 10-mm graft diameter (32.6 %) was significantly lower than that of the traditional AMB with a 6-mm graft diameter (81.4 %; P < 0.001). The GBA of the modified AMB was significantly smaller than that of the traditional AMB (P < 0.001). Conclusion: This study indicated high graft-notch impingement rates and large GBA for traditional AMB in the standing position, highlighting potential biomechanical challenges associated with traditional double-bundle ACLR configurations.

Objectives: To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. Methods: Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA-950) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. Results: ROC analysis revealed significantly better performance (P < 0.0001) of tomosynthesis than radiography for the detection of pulmonary emphysema. The average sensitivity, specificity, positive predictive value and negative predictive value of tomosynthesis were 0.875, 0.968, 0.955 and 0.910, respectively, whereas the values for radiography were 0.479, 0.913, 0.815 and 0.697, respectively. For both tomosynthesis and radiography, the sensitivity increased with increasing LAA-950. Conclusions: The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA-950. Key Points: • Tomosynthesis showed significantly better diagnostic performance for pulmonary emphysema than radiography. • Interobserver agreement for tomosynthesis was significantly higher than that for radiography. • Sensitivity increased with increasing LAA -950 in both tomosynthesis and radiography. • Tomosynthesis imparts a similar radiation dose to two projection chest radiography. • Radiation dose and cost of tomosynthesis are lower than those of MDCT. © 2013 European Society of Radiology.

Objectives: The purpose of this study was to select the optimal monochromatic level for virtual monochromatic spectral (VMS) imaging to minimize the image noise of the liver parenchyma and to acquire a high contrast-to-noise ratio (CNR) of hypovascular hepatic metastases in the portal-dominant phase. Materials and Methods: This study was conducted with the approval of our institutional review board, and written informed consent was obtained from all the participating patients. Ninety patients with hepatic metastases were scanned by fast kilovoltage switching dual-energy computed tomography in the portal-dominant phase. One hundred one sets of VMS images in the range of 40 to 140 keV at 1-keV intervals were reconstructed. The image noise of the liver parenchyma in each patient and the CNR of each metastasis (n = 303) were measured on all the 101 VMS image sets. Data were analyzed by the paired t test and mixed-effects model. Bonferroni's method was used for multiple comparisons. Results: The lowest noise of the liver parenchyma was obtained in 6, 15, 31, 29, 7, 1, and 1 patient at 67, 68, 69, 70, 71, 72, and 73 keV, respectively. The mean noise of the liver parenchyma on the 69-keV VMS images in all 90 patients was significantly lower than that on the 67-, 68-, 71-, 72-, and 73-keV VMS images (P < 0.001); however, there was no significant difference in the mean noise of the liver parenchyma between the 69-keV and 70-keV VMS images (P = 0.279). For 95% of the hepatic metastases (288/303 metastases), the highest metastasis-to-liver CNR was obtained in the 66-to 71-keV VMS images. The mean metastasis-to-liver CNR for the 303 metastases was numerically highest at 68 keV; however, there was no significant difference in the mean metastasis-to-liver CNR between the 68-keV and 69-keV images (P = 0.737) or between the 68-keV and 70-keV images (P = 0.103). Conclusions: VMS imaging at approximately 70 keV (69-70 keV) yielded the lowest image noise of the liver parenchyma and a high CNR for hypovascular hepatic metastases in the portal-dominant phase. © 2012 by Lippincott Williams & Wilkins.

© 2017 The Association of University Radiologists Rationale and Objectives Diaphragmatic motion in a standing position during tidal breathing remains unclear. The purpose of this observational study was to evaluate diaphragmatic motion during tidal breathing in a standing position in a health screening center cohort using dynamic chest radiography in association with participants’ demographic characteristics. Materials and Methods One hundred seventy-two subjects (103 men; aged 56.3 ± 9.8 years) underwent sequential chest radiographs during tidal breathing using dynamic chest radiography with a flat panel detector system. We evaluated the excursions of and peak motion speeds of the diaphragms. Associations between the excursions and participants’ demographics (gender, height, weight, body mass index [BMI], smoking history, tidal volume, vital capacity, and forced expiratory volume) were investigated. Results The average excursion of the left diaphragm (14.9 ± 4.6 mm, 95% CI 14.2–15.5 mm) was significantly larger than that of the right (11.0 ± 4.0 mm, 95% CI 10.4–11.6 mm) (P < 0.001). The peak motion speed of the left diaphragm (inspiratory, 16.6 ± 4.2 mm/s; expiratory, 13.7 ± 4.2 mm/s) was significantly faster than that of the right (inspiratory, 12.4 ± 4.4 mm/s; expiratory, 9.4 ± 3.8 mm/s) (both P < 0.001). Both simple and multiple regression models demonstrated that higher BMI and higher tidal volume were associated with increased excursions of the bilateral diaphragm (all P < 0.05). Conclusions The average excursions of the diaphragms are 11.0 mm (right) and 14.9 mm (left) during tidal breathing in a standing position. The diaphragmatic motion of the left is significantly larger and faster than that of the right. Higher BMI and tidal volume are associated with increased excursions of the bilateral diaphragm.