Published papers

PURPOSE: To evaluate the performance of a deep learning-based computer-aided detection (CAD) software for detecting pulmonary nodules, masses, and consolidation on chest radiographs (CRs) and to examine the effect of readers' experience and data characteristics on the sensitivity and final diagnosis. MATERIALS AND METHODS: The CRs of 453 patients were retrospectively selected from two institutions. Among these CRs, 60 images with abnormal findings (pulmonary nodules, masses, and consolidation) and 140 without abnormal findings were randomly selected for sequential observer-performance testing. In the test, 12 readers (three radiologists, three pulmonologists, three non-pulmonology physicians, and three junior residents) interpreted 200 images with and without CAD, and the findings were compared. Weighted alternative free-response receiver operating characteristic (wAFROC) figure of merit (FOM) was used to analyze observer performance. The lesions that readers initially missed but CAD detected were stratified by anatomic location and degree of subtlety, and the adoption rate was calculated. Fisher's exact test was used for comparison. RESULTS: The mean wAFROC FOM score of the 12 readers significantly improved from 0.746 to 0.810 with software assistance (P = 0.007). In the reader group with < 6 years of experience, the mean FOM score significantly improved from 0.680 to 0.779 (P = 0.011), while that in the reader group with ≥ 6 years of experience increased from 0.811 to 0.841 (P = 0.12). The sensitivity of the CAD software and the adoption rate for the lesions with subtlety level 2 or 3 (obscure) lesions were significantly lower than for level 4 or 5 (distinct) lesions (50% vs. 93%, P < 0.001; and 55% vs. 74%, P = 0.04, respectively). CONCLUSION: CAD software use improved doctors' performance in detecting nodules/masses and consolidation on CRs, particularly for non-expert doctors, by preventing doctors from missing distinct lesions rather than helping them to detect obscure lesions.

Cerebrospinal fluid (CSF) leakage is a common complication associated with endoscopic endonasal skull-base surgery (EESBS). Postoperative mobilization-associated postural changes are considered to cause CSF leakage. However, no study has demonstrated a robust relationship between postural changes and CSF leakage. We used upright computed tomography (CT) to clarify the effects of postural changes on the reconstructed skull base (RSB) after EESBS. Thirty patients who underwent EESBS at our institution were prospectively included, and their upright and supine CTs were compared to measure morphological changes in the RSB. Patient clinical data were also collected from medical charts and surgical videos, and their relationships with morphological changes were assessed. In upright CTs, the RSB shifted intracranially by 0.94 (0.0-2.9) mm on average. This shift was larger in cases with lesions extending to the sphenoid sinus, dural defects, intraoperative pulsation of the RSB, and large bone windows. The direction of the change was opposite to intuitive movement driven by gravity because of reduced intracranial pressure in the sitting position. Thus, these shifts can be directly associated with postoperative CSF leakage caused by reconstruction material displacement. Skull-base reconstruction and postoperative postural management accounting for these morphological changes may be necessary for preventing CSF leakage.

CT performed in the supine position has been highly effective in diagnosing organic diseases such as cancer, arteriosclerosis, and infections, significantly contributing to increased life expectancy. In an aging society, extending healthy life expectancy becomes more critical, requiring early diagnosis of functional disorders. We have led the industry-academia collaboration in developing an upright MDCT system. Although this system maintains the same physical specifications as conventional MDCT, it differs significantly in imaging configuration-allowing supine, upright, and sitting positions-and offers improved workflow while requiring only two-thirds of the installation space. Unlike conventional MDCT, it allows for the assessment of anatomical changes under gravity. It also enables the objective diagnosis and grading of functional diseases, in which findings were not apparent on conventional CT, and enable the study of the pathogenesis of functional diseases which worsen symptoms in the upright position. Furthermore, it allows for noninvasive evaluation of dynamic functions such as swallowing and voiding, which can only be assessed in standing or sitting positions.

© ERS 2017. The MUC5B promoter polymorphism (rs35705950) has been associated with interstitial lung abnormalities (ILA) in white participants from the general population; whether these findings are replicated and influenced by the ILA subtype is not known. We evaluated the associations between the MUC5B genotype and ILA in cohorts with extensive imaging characterisation. We performed ILA phenotyping and MUC5B promoter genotyping in 5308 and 9292 participants from the AGES-Reykjavik and COPDGene cohorts, respectively. We found that ILA was present in 7% of participants from the AGES-Reykjavik, 8% of non-Hispanic white participants from COPDGene and 7% of African-American participants from COPDGene. Although the MUC5B genotype was strongly associated (after correction for multiple testing) with ILA (OR 2.1, 95% CI 1.8-2.4, p=1×10-26), there was evidence of significant heterogeneity between cohorts (I2=81%). When narrowed to specific radiologic subtypes, (e.g. subpleural ILA), the MUC5B genotype remained strongly associated (OR 2.6, 95% CI 2.2-3.1, p=1×10-30) with minimal heterogeneity (I2=0%). Although there was no evidence that the MUC5B genotype influenced survival, there was evidence that MUC5B genotype improved risk prediction for possible usual interstitial pneumonia (UIP) or a UIP pattern in non-Hispanic white populations. The MUC5B promoter polymorphism is strongly associated with ILA and specific radiologic subtypes of ILA, with varying degrees of heterogeneity in the underlying populations.

To compare the timing of subperiosteal new bone formation (SPNBF) and callus formation in femoral shaft fractures that occurred at birth between neonates with and without an underlying disease, we retrospectively evaluated the radiographs of 12 neonates with femoral fractures on birth day. Seven had no underlying disease, 3 had osteogenesis imperfecta, 1 had myotonic dystrophy, and 1 had arthrogryposis. We evaluated the timing of initial SPNBF/soft callus/hard callus formation. In neonates without an underlying disease, SPNBF and callus formation were not detected by day 6 on radiographs; SPNBF/soft callus/hard callus formation was first observed at day 14.29 ± 5.35/15.85 ± 4.49/21.43 ± 5.41, respectively (range 9–23/10–23/16–32). The three neonates with osteogenesis imperfecta had SPNBF/soft callus/hard callus formation on day 0/0/0, which was significantly earlier than in neonates without an underlying disease (all P = 0.017). In the neonate with myotonic dystrophy, SPNBF/soft callus/hard callus formation was first seen by day 14/14/14 and was first seen by day 20/43/68 in the neonate with arthrogryposis. In our restricted cohort, all neonates with femoral shaft fractures from birth trauma without an underlying disease showed SPNBF and soft callus formation by day 23. If SPNBF or callus formation is detected within 6 days, an underlying disease (e.g., osteogenesis imperfecta) may be considered. If these are not detected by day 23, injury after birth or other underlying diseases may be considered.

PURPOSE: Hybrid iterative reconstruction (IR) is useful to reduce noise in computed tomography (CT) images. However, it often decreases the spatial resolution. The ability of high spatial resolution kernels (harder kernels) to compensate for the decrease in the spatial resolution of hybrid IRs was investigated. METHODS: An elliptic cylindrical phantom simulating an adult abdomen was used. Two types of rod-shaped objects with ~330 and ~130 HU were inserted to simulate contrasts of arteries in CT angiography. Two multi-slice CT systems were used to scan the phantoms with 120 kVp and scan doses of 20 and 10 mGy. The task transfer functions (TTFs) were measured from the circular edges of the rod images. The noise power spectrum (NPS) was measured from the images of the water-only section. The CT images were reconstructed using a filtered back projection (FBP) with baseline kernels and two levels of hybrid IRs with harder kernels. The profiles of the clinical images across the aortic dissection flaps were measured to evaluate actual spatial resolutions. RESULTS: The TTF degradation of each hybrid IR was recovered by the harder kernels, whereas the noise reduction effect was retained, for both the 20 and 10 mGy. The profiles of the dissection flaps for the FBP were maintained by using the harder kernels. Even with the best combination of hybrid IR and harder kernel, the noise level at 10 mGy was not reduced to the level of FBP at 20 mGy, suggesting no capability of a 50% dose reduction while maintaining noise.

BACKGROUND: Although humans spend most of their day in a standing or sitting position, it is difficult to accurately evaluate the alignment of the shoulder girdle during daily activity, and its alignment changes between positions. The purpose of this study was to evaluate the 3-dimensional alignment of the shoulder girdle in the supine and standing positions by computed tomography (CT) and to assess the alignment changes of the shoulder girdle between these two positions. METHODS: CT scans of both shoulders of 100 healthy volunteers were prospectively taken in both supine and standing positions on the same day. The local 3-dimensional coordinate systems of the thorax, clavicle, and scapula were defined from the specific bony landmarks, and 3-dimensional angular rotations and positions of the clavicle and scapula were calculated. Differences in rotations and positions of the clavicle and scapula were evaluated between the supine and standing positions. RESULTS: Compared with the supine position, the clavicle showed significantly less elevation and greater retraction, and the scapula showed significantly less upward rotation, anterior tilting, and internal rotation in the standing position. Compared with the supine position, the clavicle center was located more inferiorly, posteriorly, and laterally, and the scapula center was located more inferiorly, posteriorly, and medially in the standing position. CONCLUSIONS: The present study showed that angular rotations and positions of the clavicle and scapula change significantly with position due to the effect of gravity.

BACKGROUND: Though alignment of the spine and lower extremities in the standing neutral position has been evaluated, a few studies evaluating the alignment of the upper extremities have also been made. This study assessed the normal alignment of the upper extremities in the standing neutral position and clarified the three-dimensional angular rotations of the upper extremity joints. METHODS: Computed tomography (CT) images of 158 upper extremities from 79 healthy volunteers were prospectively acquired in the standing neutral position using an upright CT scanner. Three-dimensional coordinate systems of the thorax, scapula, humerus, and forearm were designated, and three-dimensional angular rotations of the scapulothoracic, glenohumeral, and elbow joints were calculated. RESULTS: The median angle of the scapulothoracic joint was 9.2° (interquartile range [IQR], 5.2°-12.5°) of upward rotation, 29.0° (IQR, 24.9°-33.3°) of internal rotation, and 7.9° (IQR, 4.3°-11.8°) of anterior tilt. The median angle of the glenohumeral joint was 4.5° (IQR, 0.9°-7.8°) of abduction, 9.0° (IQR, 2.2°-19.0°) of internal rotation, and 0.3° (IQR, - 2.6°-3.1°) of extension. The median angle of the elbow joint was 9.8° (IQR, 6.9°-12.4°) of valgus, 90.2° (IQR, 79.6°-99.4°) of pronation, and 15.5° (IQR, 13.2°-18.1°) of flexion. Correlations in angular rotation values were found between the right and left upper extremities and between joints. CONCLUSIONS: This study clarified the three-dimensional angular rotation of upper extremity joints in the standing neutral position using an upright CT scanner. Our results may provide important insights for the functional evaluation of upper extremity alignment.

BACKGROUND: Two-dimensional (2D) coronal joint line orientation on radiography under weight-bearing conditions has been widely used in evaluating knee osteoarthritis (OA). However, the effects of tibial rotation remain unknown. The present study aimed to newly define three-dimensional (3D) joint surface orientation relative to the floor as an unchangeable 3D angle unaffected by tibial rotation using upright computed tomography (CT), and to investigate correlations between 3D and 2D parameters in knee OA. METHODS: Sixty-six knees in 38 patients with varus knee OA underwent standing hip-to-ankle digital radiography and upright CT. The 2D parameters measured on radiographs included femorotibial angle (FTA), tibial joint line angle (TJLA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and joint line convergence angle (JLCA). The 3D inner product angle between vectors of the tibial joint surface and the floor from CT was defined as the 3D joint surface-floor angle. RESULTS: Mean 3D joint surface-floor angle was 6.0 ± 3.6°. No correlation was identified between 3D joint surface-floor angle and 2D joint line parameters, even though FTA correlated substantially with 2D joint line parameters. No significant differences in 3D joint surface-floor angle were identified among Coronal Plane Alignment of the Knee (CPAK) types. CONCLUSIONS: The 3D joint surface orientation did not correlate with 2D coronal joint line orientation and was unaffected by CPAK classification types. This finding suggests that current 2D evaluations should be reconsidered for a better understanding of true knee joint line orientation.

BACKGROUND: The tibial tubercle-to-trochlear groove (TT-TG) distance and Insall-Salvati (I/S) ratio are widely used to determine the need for distal realignment in conjunction with medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellar dislocation. A TT-TG distance >20 mm and an I/S ratio >1.3 are significant anatomical risk factors for patellar instability. However, these parameters have traditionally been measured using non-weight-bearing (NWB) imaging modalities. As patellar dislocation occurs during weight-bearing actions, these two parameters should be measured under weight-bearing conditions. Thus, this study aimed to measure the TT-TG distance and I/S ratio using upright full-weight-bearing (FWB) computed tomography (CT) scans and compare the data with NWB CT scans. METHODS: This study included 49 knee joints of 26 healthy volunteers. CT images were obtained under both FWB and NWB standing conditions using a 320-detector row upright CT scanner. TT-TGs in the axial plane and I/S ratios in the sagittal plane were measured and compared. RESULTS: The average FWB TT-TG distance was 20.3 ± 3.9 mm, whereas the average NWB TT-TG distance was 12.3 ± 4.7 mm. The TT-TG level was significantly higher in the FWB condition than that in the NWB condition (P < 0.001). The I/S ratios were comparable between the FWB and NWB conditions (P = 0.29). CONCLUSIONS: The TT-TG distance in the standing weight-bearing condition was larger than the conventional TT-TG distance and surpassed the historical cutoff value of TT-TG, which may affect the indication of additional distal realignment in MPFL reconstruction for patellar instability.

OBJECTIVES: Cases of severe pectus excavatum presenting with worsening cardiopulmonary symptoms in the upright position have been reported. However, the underlying mechanism remains unclear. We evaluated posture-related morphological changes of the thorax in patients with pectus excavatum. METHODS: Chest morphology was evaluated preoperatively using upright and supine computed tomography in 21 patients with pectus excavatum and 35 healthy volunteers. The minimum anterior-posterior thoracic diameter, depression depth, and Haller index on horizontal sections, as well as the T6-12 plumb line distance on sagittal sections, were compared between the two positions. RESULTS: In patients with pectus excavatum (median age, 22 years; 18 males and 3 females), the minimum anterior-posterior diameter was smaller (4.5 vs 5.1 cm, P < 0.001) and the Haller index was greater (10.1 vs 6.4, P < 0.001) in the upright position than in the supine position. The T6-T12 plumb line distance was longer in the upright position (2.4 vs 0.8 cm, P < 0.001), while the depression depth showed no significant difference. Healthy volunteers exhibited similar changes. The degree of spinal curvature increased in the upright position due to the anterior shift of the lower thoracic vertebrae, resulting in a shorter anterior-posterior diameter, irrespective of chest wall deformity. One patient with dyspnoea only in the upright position exhibited compression of the right inferior pulmonary vein only on upright computed tomography. CONCLUSIONS: The minimum anterior-posterior diameter is shorter in the upright position. This may explain the worsening of cardiopulmonary symptoms in patients with severe pectus excavatum when in an upright position. CLINICAL TRIAL NUMBER: UMIN000036438 https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000041519.

BACKGROUND: The human subtalar joint is crucial for bipedal posture and locomotion, providing stability, adaptability, and force dissipation. While its kinematics have been studied, most research has been under non-weight-bearing conditions, leaving its function under physiological loading unclear. RESEARCH QUESTION: What is the three-dimensional kinematics of the human subtalar joint during weight-bearing postures, as quantified by the helical axis? METHODS: This study analyzed three-dimensional in vivo subtalar joint kinematics during weight-bearing using upright CT. Fifteen healthy elderly adults (11 females, 4 males; mean age: 64.9 ± 5.0 years) underwent CT scans in neutral, inverted, and everted postures using 10° coronal wedges. Kinematics were quantified via helical axis representation relative to two talar coordinate systems: the foot longitudinal axis and the talus principal axis. RESULTS: The helical axis ran obliquely from anterior-medial-dorsal to posterior-lateral-plantar, with inclination and deviation angles of 22.4° ± 9.6° and 35.2° ± 5.6° in the former system, and 36.5° ± 10.7° and 12.0° ± 7.1° in the latter. Rotation along the axis was 9.9° ± 3.8°, with minimal translation (0.5 ± 0.5 mm). SIGNIFICANCE: These findings suggest subtalar joint movement is more constrained under weight-bearing conditions than in non-weight-bearing studies. This study underscores the importance of weight-bearing analyses for clinical applications and understanding human foot adaptations for bipedalism.

© 2014, Springer Science+Business Media New York. Purpose: To evaluate the MRI findings of retroperitoneal low-flow vascular malformations (RLVMs) correlated with histopathological findings. Methods: Two radiologists reviewed the MRI findings of 4 RLVMs (3 with capillary malformations and 1 with a venous malformation). First, they evaluated the visibility, signal intensities, and signal homogeneity of each lesion on non-fat-suppressed breath-hold T2-weighted single-shot fast spin-echo (non-FS SSFSE) images and fat-suppressed T2-weighted fast spin-echo (FS T2-weighted FSE) images. Second, the kinetic patterns and the internal enhancement patterns were analyzed for each lesion on multi-phasic contrast-enhanced (CE) images. After these image analyses, the MRI findings were correlated with the histopathological findings. Result: Histopathologically, the 4 RLVMs did not exhibit remarkable degeneration and were present in the retroperitoneal fat tissue without clear capsules. On the non-FS SSFSE images, 3 of the 4 RLVMs could not be discriminated from the surrounding retroperitoneal fat tissue (invisible), and the remaining lesion was barely visible with an indistinct margin. On the FS T2-weighted FSE images, however, all the RLVMs were clearly visualized as homogeneous high-signal intensities. On the multi-phasic CE images, all the capillary malformations exhibited fast enhancement, while a venous malformation showed slow enhancement. Furthermore, the RLVMs tended to exhibit a centripetal filling pattern. Conclusion: The RLVMs blended in with the surrounding retroperitoneal fat tissue on non-FS SSFSE images, like phantoms, whereas they were clearly visualized on FS T2-weighted FSE images. On multi-phasic CE images, the RLVMs tended to exhibit a centripetal filling pattern. These imaging features may be useful diagnostic clues for RLVMs.

OBJECTIVE: In patients with hypertrophic obstructive cardiomyopathy (HOCM), left atrial (LA) volume measurement is very important to provide prognostic information. Recent studies demonstrated that multidetector CT (MDCT) is useful to assess the changes in LA volume. Our aim was to examine the utility of a follow-up cardiac MDCT for long-term evaluation of the effect of percutaneous transluminal septal myocardial ablation (PTSMA) on LA volume. METHODS: We studied a consecutive cohort of 20 patients with drug-refractory symptomatic HOCM after PTSMA. We evaluated LA volume analyses with cardiac MDCT on patients who underwent PTSMA as compared to echocardiography. RESULTS: Before PTSMA, 75% of all patients had heart failure-associated symptoms in the New York Heart Association functional class III/IV. All patients experienced relief from heart failure-associated symptoms after PTSMA. Cardiac MDCT showed significant reduction in the index of maximum LA volume during follow-up compared to before PTSMA in the same way as in echocardiography (93.6±34.1 mL/m(2) vs 82.6±35.3 mL/m(2), p=0.035). A Bland-Altman plot showed small mean differences and limits of agreement in the measurements of the index of maximum LA volume before and after PTSMA between echocardiography and MDCT. CONCLUSIONS: The follow-up cardiac MDCT was a useful tool to evaluate the effectiveness of PTSMA on reduction of LA volume. Cardiac MDCT might provide comparable measurements of the LA volume in patients with drug-refractory symptomatic HOCM before and after PTSMA compared to echocardiography.

Background: Dynamic X-ray (DXR) provides images of multiple phases of breath with less radiation exposure than CT. The exact images at end-inspiratory or end-expiratory phases can be chosen accurately. Purpose: To investigate the correlation of the projected lung area (PLA) by dynamic chest X-ray with pulmonary functions. Material and Methods: One hundred sixty-two healthy volunteers who received medical check-ups for health screening were included in this study. All subjects underwent DXR in both posteroanterior (PA) and lateral views and pulmonary function tests on the same day. All the volunteers took several tidal breaths before one forced breath as instructed. The outlines of lungs were contoured manually on the workstation with reference to the motion of diaphragm and the graph of pixel values. The PLAs were calculated automatically, and correlations with pulmonary functions and demographic data were analyzed statistically. Results: The PLAs have correlation with physical characteristics, including height, weight and BMI, and pulmonary functions such as vital capacity (VC) and forced expiratory volume in one second (FEV1). VC and FEV1 revealed moderate correlation with the PLAs of PA view in forced inspiratory phase (VC: right, r = 0.65; left, r = 0.69. FEV1: right, r = 0.54; left, r = 0.59). Multivariate analysis showed that body mass index (BMI), sex and VC were considered independent correlation factors, respectively. Conclusion: PLA showed statistically significant correlation with pulmonary functions. Our results indicate DXR has a possibility to serve as an alternate method for pulmonary function tests in subjects requiring contact inhibition including patients with suspected or confirmed covid-19.

Purpose: The aim of this study is to assess the role of traction bronchiectasis/bronchiolectasis and its progression as a predictor for early fibrosis in interstitial lung abnormalities (ILA). Methods: Three hundred twenty-seven ILA participants out of 5764 in the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study who had undergone chest CT twice with an interval of approximately five-years were enrolled in this study. Traction bronchiectasis/bronchiolectasis index (TBI) was classified on a four-point scale: 0, ILA without traction bronchiectasis/bronchiolectasis; 1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion; 2, ILA with mild to moderate traction bronchiectasis; 3, ILA and severe traction bronchiectasis and/or honeycombing. Traction bronchiectasis (TB) progression was classified on a five-point scale: 1, Improved; 2, Probably improved; 3, No change; 4, Probably progressed; 5, Progressed. Overall survival (OS) among participants with different TB Progression Score and between the TB progression group and No TB progression group was also investigated. Hazard radio (HR) was estimated with Cox proportional hazards model. Results: The higher the TBI at baseline, the higher TB Progression Score (P < 0.001). All five participants with TBI = 3 at baseline progressed; 46 (90 %) of 51 participants with TBI = 2 progressed. TB progression was also associated with shorter OS with statistically significant difference (adjusted HR = 1.68, P < 0.001). Conclusion: TB progression was visualized on chest CT frequently and clearly. It has the potential to be the predictor for poorer prognosis of ILA.

OBJECTIVES: To assess the association of projected lung area (PLA) measured by DXR with demographic data, pulmonary function, and COPD severity, and to generate PLA over time curves using automated tracking. METHODS: This retrospective study recruited healthy volunteers and COPD patients. Participants were classified into three groups: normal, COPD mild and COPD severe. PLA was calculated from the manually traced bilateral lung contours. PLA over time curves were produced using automated tracking, which was used to calculate slope and intercept by approximate line during forced expiration. The correlation of PLA, difference of PLA between end-inspiration and end-expiration (ΔPLA), slope, and intercept with demographic data and pulmonary function tests were investigated. The difference of PLA, ΔPLA, intercept, and slope among three groups were also evaluated. RESULTS: This study enrolled 45 healthy volunteers and 32 COPD patients. COPD severe group had larger PLA in both lungs at tidal/forced end-inspiration/expiration, smaller slope, and larger intercept than normal group (p < 0.001). PLA was correlated with % forced expiratory volume in one second (%FEV1) (rs from -0.42 to -0.31, p ≤ 0.01). ΔPLA in forced breathing showed moderate correlation with vital capacity (VC) (rs = 0.58, p < 0.001), while ΔPLA in tidal breathing showed moderate correlation with %FEV1 (rs = -0.52, p < 0.001) as well as mild correlation with tidal volume (rs = 0.24, p = 0.032). Intercept was slightly underestimated compared with manually contoured PLA (p < 0.001). CONCLUSION: COPD patients had larger PLA than healthy volunteers. PLA and ΔPLA in tidal breathing showed mild to moderate correlation with %FEV1.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have demonstrated efficacy over previous cytotoxic chemotherapies in clinical trials among various tumors. Despite their favorable outcomes, they are associated with a unique set of toxicities termed as immune-related adverse events (irAEs). Among the toxicities, ICI-related pneumonitis has poor outcomes with little understanding of its risk factors. This retrospective study aimed to investigate whether pre-existing interstitial lung abnormality (ILA) is a potential risk factor for ICI-related pneumonitis. MATERIALS AND METHODS: Patients with non-small cell lung cancer, malignant melanoma, renal cell carcinoma, and gastric cancer, who was administered either nivolumab, pembrolizumab, or atezolizumab between September 2014 and January 2019 were retrospectively reviewed. Information on baseline characteristics, computed tomography findings before administration of ICIs, clinical outcomes, and irAEs were collected from their medical records. Pre-existing ILA was categorized based on previous studies. RESULTS: Two-hundred-nine patients with a median age of 68 years were included and 23 (11.0%) developed ICI-related pneumonitis. While smoking history and ICI agents were associated with ICI-related pneumonitis (P = .005 and .044, respectively), the categories of ILA were not associated with ICI-related pneumonitis (P = .428). None of the features of lung abnormalities were also associated with ICI-related pneumonitis. Multivariate logistic analysis indicated that smoking history was the only significant predictor of ICI-related pneumonitis (P = .028). CONCLUSION: This retrospective study did not demonstrate statistically significant association between pre-existing ILA and ICI-related pneumonitis, nor an association between radiologic features of ILA and ICI-related pneumonitis. Smoking history was independently associated with ICI-related pneumonitis. Further research is warranted for further understanding of the risk factors of ICI-related pneumonitis.

OBJECTIVE: The engagement of the lap belt with the pelvis is critical for occupant safety during vehicle frontal crashes to prevent occupant submarining. This study aims to develop a predictive model for submarining risk based on anthropometric parameters and lap belt positioning using finite element (FE) analyses. METHODS: FE analyses were conducted using human body models representing various body shapes (a 50th percentile male, low and high BMI males, and a 5th percentile female) in three seated postures (standard, reclined, and slouched). The lap belt-ASIS overlap and the belt-pelvis angle were used as key parameters for predicting submarining risk. A logistic regression analysis was utilized to correlate submarining occurrence with the initial values of these two parameters at the beginning of impact. Subsequently, this submarining prediction model was applied to computer tomography (CT) measurements of human subjects in different seated postures (upright, reclined, and slouched), and submarining risks were calculated based on the developed model. RESULTS: FE simulations indicated that submarining was more likely to occur as the initial belt-pelvis angle approached zero and there was a smaller initial belt-ASIS overlap. The logistic regression analysis demonstrated that the initial belt-pelvis angle and belt-ASIS overlap were statistically significant for predicting submarining risk. The derived model effectively distinguished submarining occurrence based on the initial values of these two parameters. The application of the submarining model to CT measurements of human subjects showed that submarining risk was lower in the order of upright, slouched, and reclined postures. In the reclined posture, the high submarining risk was attributed to a small belt-ASIS overlap and a rearward-tilted pelvis angle; whereas in the slouched posture, the risk was mostly associated with a rearward-tilted pelvis angle. CONCLUSIONS: The submarining prediction model was developed based on the belt-pelvis angle and the belt-ASIS overlap. This predictive model may help to design restraint systems for various body types and seated postures of occupants.