One-year lung function decline in sarcoidosis.

BACKGROUND: The definition of progressive pulmonary fibrosis is based on a 1-year lung function decline. OBJECTIVES: To evaluate the epidemiology and clinical relevance of 1-year lung function decline in sarcoidosis. METHODS: A retrospective observational study at a general sarcoidosis clinic. RESULTS: Of the 198 patients, 42 (18.4 %) had a 1-year lung function decline (absolute 12-month decline in percentage predicted forced vital capacity [%FVC] of ≥5 % or percentage predicted diffusion capacity for carbon monoxide [%DLCO] of ≥10 %). A 1-year lung function decline was associated with a 2-year lung function decline (a relative 24-month decline in %FVC of ≥10 % or %DLCO of ≥15 %), which occurred in 13 (7.4 %) of the 175 patients with 24-month follow-up results. A 1-year lung function decline was not associated with survival; a 2-year lung function decline predicted mortality. CONCLUSIONS: Compared with a 24-month decline, a 12-month decline in lung function did not predict worse survival in sarcoidosis.

Subtyping emphysematous COPD by respiratory volume change distributions on CT.

BACKGROUND: There is considerable heterogeneity among patients with emphysematous chronic obstructive pulmonary disease (COPD). We hypothesised that in addition to emphysema severity, ventilation distribution in emphysematous regions would be associated with clinical-physiological impairments in these patients. OBJECTIVE: To evaluate whether the discordance between respiratory volume change distributions (from expiration to inspiration) in emphysematous and non-emphysematous regions affects COPD outcomes using two cohorts. METHODS: Emphysema was quantified using a low attenuation volume percentage on inspiratory CT (iLAV%). Local respiratory volume changes were calculated using non-rigidly registered expiratory/inspiratory CT. The Ventilation Discordance Index (VDI) represented the log-transformed Wasserstein distance quantifying discordance between respiratory volume change distributions in emphysematous and non-emphysematous regions. RESULTS: Patients with COPD in the first cohort (n=221) were classified into minimal emphysema (iLAV% <10%; n=113) and established emphysema with high VDI and low VDI groups (n=46 and 62, respectively). Forced expiratory volume in 1 s (FEV1) was lower in the low VDI group than in the other groups, with no difference between the high VDI and minimal emphysema groups. Higher iLAV%, more severe airway disease and hyperventilated emphysematous regions in the upper-middle lobes were independently associated with lower VDI. The second cohort analyses (n=93) confirmed these findings and showed greater annual FEV1 decline and higher mortality in the low VDI group than in the high VDI group independent of iLAV% and airway disease on CT. CONCLUSION: Lower VDI is associated with severe airflow limitation and higher mortality independent of emphysema severity and airway morphological changes in patients with emphysematous COPD.

Spinal intraosseous arteriovenous fistulas with perimedullary drainage associated with vertebral compression fracture: illustrative case.

BACKGROUND: Although osseous involvement is occasionally observed in spinal epidural arteriovenous fistulas (AVFs) or seen as a part of diseases of spinal arteriovenous metameric syndrome, purely intraosseous spinal AVFs are extremely rare. Their clinical and imaging characteristic features are not well known. The authors present a case of purely intraosseous AVFs associated with compression fracture. OBSERVATIONS: A 76-year-old man presented with back pain and progressive myelopathy. Computed tomography showed compression fracture of the T12 vertebral body and dilatation of perimedullary veins. Spinal angiography revealed an intraosseous AVF at the T12 spine level, which was fed by multiple feeders of ventral somatic branches and drained into the paravertebral and perimedullary veins. The intraosseous AVF was completely occluded by the combined techniques of transarterial and transvenous embolization with glue and a coil. The symptoms disappeared within 1 month after embolization. LESSONS: Although extremely rare, spinal intraosseous AVFs can develop after compression fracture and cause congestive myelopathy. Combined transarterial and transvenous embolization is useful for the specific case of spinal intraosseous AVFs with both paravertebral and perimedullary drainage.

Mycotic pseudoaneurysm in the internal carotid artery secondary to cranial base abscess diagnosed with optic neuritis: a case report.

Aspergillus-induced mycotic aneurysm is difficult to treat and often has poor outcomes with severe symptom progression. Early diagnosis is also difficult, and blood and cerebrospinal fluid tests often fail to reveal any findings. A 74-year-old man presented with recurrent nosebleeds in addition to symptoms of left optic neuritis. Contrast-enhanced computed tomography scan revealed a left internal carotid artery pseudoaneurysm protruding into the left Onodi cells, which was identified as the origin of bleeding. Endovascular left internal carotid artery occlusion was performed. One month postoperatively, external ophthalmoplegia and disorientation occurred. Although antibiotic treatment was continued for 1 month, consciousness loss and haematemesis occurred, and a new contralateral right internal carotid artery pseudoaneurysm ruptured, which resulted in death. At autopsy, Aspergillus infection centred on the skull base was pathologically found, although the sinus mucosal surface was normal. This case suggested a mycotic infection secondary to optic neuritis resulted in a left infectious pseudoaneurysm that spreads to the skull base and formed an aneurysm on the contralateral side 4 months thereafter. Therefore, the possibility that features of the Onodi cells contributed to the spread of inflammation inside and outside the skull and were involved in the formation of aneurysms inside and outside the dura mater was considered for the first time.

Associations of pulmonary and extrapulmonary computed tomographic manifestations with impaired physical activity in symptomatic patients with chronic obstructive pulmonary disease.

In patients with chronic obstructive pulmonary disease (COPD), emphysema, airway disease, and extrapulmonary comorbidities may cause various symptoms and impair physical activity. To investigate the relative associations of pulmonary and extrapulmonary manifestations with physical activity in symptomatic patients, this study enrolled 193 patients with COPD who underwent chest inspiratory/expiratory CT and completed COPD assessment test (CAT) and the Life-Space Assessment (LSA) questionnaires to evaluate symptom and physical activity. In symptomatic patients (CAT ≥ 10, n = 100), emphysema on inspiratory CT and air-trapping on expiratory CT were more severe and height-adjusted cross-sectional areas of pectoralis muscles (PM index) and adjacent subcutaneous adipose tissue (SAT index) on inspiratory CT were smaller in those with impaired physical activity (LSA < 60) than those without. In contrast, these findings were not observed in less symptomatic patients (CAT < 10). In multivariable analyses of the symptomatic patients, severe air-trapping and lower PM index and SAT index, but not CT-measured thoracic vertebrae bone density and coronary artery calcification, were associated with impaired physical activity. These suggest that increased air-trapping and decreased skeletal muscle and subcutaneous adipose tissue quantity are independently associated with impaired physical activity in symptomatic patients with COPD.

Deep learning-based algorithm improved radiologists' performance in bone metastases detection on CT.

OBJECTIVES: To develop and evaluate a deep learning-based algorithm (DLA) for automatic detection of bone metastases on CT. METHODS: This retrospective study included CT scans acquired at a single institution between 2009 and 2019. Positive scans with bone metastases and negative scans without bone metastasis were collected to train the DLA. Another 50 positive and 50 negative scans were collected separately from the training dataset and were divided into validation and test datasets at a 2:3 ratio. The clinical efficacy of the DLA was evaluated in an observer study with board-certified radiologists. Jackknife alternative free-response receiver operating characteristic analysis was used to evaluate observer performance. RESULTS: A total of 269 positive scans including 1375 bone metastases and 463 negative scans were collected for the training dataset. The number of lesions identified in the validation and test datasets was 49 and 75, respectively. The DLA achieved a sensitivity of 89.8% (44 of 49) with 0.775 false positives per case for the validation dataset and 82.7% (62 of 75) with 0.617 false positives per case for the test dataset. With the DLA, the overall performance of nine radiologists with reference to the weighted alternative free-response receiver operating characteristic figure of merit improved from 0.746 to 0.899 (p < .001). Furthermore, the mean interpretation time per case decreased from 168 to 85 s (p = .004). CONCLUSION: With the aid of the algorithm, the overall performance of radiologists in bone metastases detection improved, and the interpretation time decreased at the same time. KEY POINTS: • A deep learning-based algorithm for automatic detection of bone metastases on CT was developed. • In the observer study, overall performance of radiologists in bone metastases detection improved significantly with the aid of the algorithm. • Radiologists' interpretation time decreased at the same time.

Lung function decline in sarcoidosis.

BACKGROUND: A decline in lung function is the basis of the definition of progressive fibrosing interstitial lung disease. This study aimed to evaluate the epidemiology and clinical relevance of lung function decline in sarcoidosis. METHODS: This retrospective observational study was conducted at a general sarcoidosis clinic. Lung function decline was defined as a relative 24-month decline in the percentage of predicted forced vital capacity (%FVC) of ≥10% or the percentage of predicted diffusion capacity for carbon monoxide (%DLco) of ≥15%. The frequency of lung function decline and its associations with the subsequent 24-month change in lung function and survival time were analyzed. RESULTS: Of the 201 patients, 14 (7.0%) exhibited a 24-month decline in %FVC of ≥10% and 28 (16.6%) exhibited a 24-month decline in %DLco of ≥15%. A 24-month decline in lung function was not associated with a subsequent 24-month lung function decline. Eleven patients died during the median observational time of 148.3 months; 4 of the 11 deaths were associated with sarcoidosis. A 24-month decline in lung function was associated with worse survival even after the adjustment for composite physiological index (CPI) and pulmonary hypertension (PH): 24-month decline in %FVC ≥10%, hazard ratio (HR) adjusted for CPI = 21.8, HR adjusted for PH = 19.3 and 24-month decline in %DLco ≥15%, HR adjusted for PH = 6.74. CONCLUSIONS: A 24-month decline in lung function can be a risk factor for mortality in sarcoidosis irrespective of CPI and PH.

Radiologic evaluation of compensatory lung growth using computed tomography by comparison with histological data from a large animal model.

Non-invasive analysis using computed tomography (CT) data may be a promising candidate to evaluate neo-alveolarization in adult lungs following lung resection. This study evaluates and compares the validity of CT analysis with histologic morphometry for compensatory lung growth in a large animal model. We calculated the radiologic tissue volume and the radiologic lung weight from CT data taken at 1, 3, and 6 months post-surgery on 15 male beagle dogs that had a right thoractotomy, bilobectomy, or pneumonectomy (n = 5 in each group). Results were analyzed using one-way ANOVA and were subsequently compared to histologic findings of tissue samples at 6 months post-surgery using Pearson's correlation. An increase in radiologic tissue volume and radiologic lung weight was identified, which was positively correlated with histologic lung parenchymal amounts (correlation coefficient = 0.955 and 0.934, respectively, p < 0.001). Histology of lung specimens at 6 months post-surgery revealed an increase in the tissue amount in both Bilobectomy and Peumonectomy groups, which was consistent with compensatory lung growth. Radiologic tissue volume and radiologic lung weight reflected compensatory lung growth following lung resection. Radiologic assessment using CT data can be a promising clinical modality to evaluate postoperative lung growth.

High D-Dimer Concentration Is a Significant Independent Prognostic Factor in Patients with Acute Large Vessel Occlusion Undergoing Endovascular Thrombectomy.

OBJECTIVE: To investigate prognostic factors that affect the modified Rankin Scale score at 3 months after onset of acute stroke in patients with large vessel occlusion who underwent endovascular thrombectomy. METHODS: We retrospectively examined 87 consecutive patients who underwent endovascular cerebral thrombectomy for acute anterior circulation large vessel occlusion at Oita University Hospital and Nagatomi Neurosurgery Hospital from January 2014 to December 2020. RESULTS: Age, National Institutes of Health Stroke Scale score, and D-dimer concentration on admission were significant univariate prognostic factors related to modified Rankin Scale score at 3 months after stroke onset. Multivariate logistic regression analysis showed that D-dimer concentration was the only significant independent prognostic factor. The area under the receiver operating characteristic curve for D-dimer concentration and modified Rankin Scale score at 3 months was 0.715 (95% confidence interval 0.599-0.831); sensitivity and specificity were 60.6% and 80.0%, respectively, using a 1.9 µg/mL cutoff value. CONCLUSIONS: Prognosis may be worse in patients undergoing acute endovascular cerebral thrombectomy with high D-dimer concentration on admission. Other treatment options should be considered for these patients.

Ultrasound-guided lung biopsy with coaxial technique: pleural contact length affects the occurrence of pneumothorax after first puncture.

PURPOSE: To assess prebiopsy characteristics influencing the occurrence of pneumothorax after first puncture of ultrasound (US)-guided lung biopsy with coaxial technique. MATERIALS AND METHODS: From January 2007 to September 2018, 180 peripheral lung lesions in 174 patients who underwent B-mode US-guided lung biopsy with coaxial technique at single institution were included in this study. Technical success was defined as the ability to make a diagnosis using the acquired sample with/without an adverse event of pneumothorax. Statistical analyses of prebiopsy characteristics were performed to identify the most important cutpoint and to evaluate the effect on diagnostic accuracy. RESULTS: Of the 180 lesions (mean size, 37 mm ± 26.2; mean pleural contact length, 38.2 mm ± 34.4), technical success rate was 97.2% (175/180 lesions) and diagnostic accuracy rate was 91.6% (165/180 lesions). Pneumothorax occurred immediately after first puncture for seven of 180 lesions. Classification and regression tree analysis and Fisher's exact test showed the proportion of the pneumothorax immediately after first puncture was higher in lesions with pleural contact length less than 9.78 mm (p = 0.002). No significant difference was shown between the pneumothorax and non-pneumothorax after first puncture in technical success and final diagnosis success rate. CONCLUSION: Pleural contact length affects the occurrence of pneumothorax after first puncture of US-guided lung biopsy with coaxial technique.

Novel Artificial Intelligence-based Technology for Chest Computed Tomography Analysis of Idiopathic Pulmonary Fibrosis.

Rationale: There is a growing need to accurately estimate the prognosis of idiopathic pulmonary fibrosis (IPF) in clinical practice, given the development of effective drugs for treating IPF. Objectives: To develop artificial intelligence-based image analysis software to detect parenchymal and airway abnormalities on computed tomographic (CT) imaging of the chest and to explore their prognostic importance in patients with IPF. Methods: A novel artificial intelligence-based quantitative CT image analysis software (AIQCT) was developed by applying 304 high-resolution CT (HRCT) scans from patients with diffuse lung diseases as the training set. AIQCT automatically categorized and quantified 10 types of parenchymal patterns as well as airways, expressing the volumes as percentages of the total lung volume. To validate the software, the area percentages of each lesion quantified by AIQCT were compared with those of the visual scores using 30 plain high-resolution CT images with lung diseases. In addition, three-dimensional analysis for similarity with ground truth was performed using HRCT images from 10 patients with IPF. AIQCT was then applied to 120 patients with IPF who underwent HRCT scanning of the chest at our institute. Associations between the measured volumes and survival were analyzed. Results: The correlations between AIQCT and the visual scores were moderate to strong (correlation coefficient 0.44-0.95) depending on the parenchymal pattern. The Dice indices for similarity between AIQCT data and ground truth were 0.67, 0.76, and 0.64 for reticulation, honeycombing, and bronchi, respectively. During a median follow-up period of 2,184 days, 66 patients died, and 1 underwent lung transplantation. In multivariable Cox regression analysis, bronchial volumes (adjusted hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.16-1.53) and normal lung volumes (adjusted HR, 0.97; 95% CI, 0.94-0.99) were independently associated with survival after adjusting for the gender-age-lung physiology stage of IPF. Conclusions: Our newly developed artificial intelligence-based image analysis software successfully quantified parenchymal lesions and airway volumes. Bronchial and normal lung volumes on HRCT imaging of the chest may provide additional prognostic information on the gender-age-lung physiology stage of IPF.

Selective transvenous embolization combined with balloon angioplasty of the occluded inferior petrosal sinus for the treatment of cavernous sinus dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Angioplasty of the dural sinus has rarely been performed for the treatment of cavernous sinus dural arteriovenous fistulas. We evaluated the efficacy of selective transvenous embolization (TVE) combined with balloon angioplasty of the occluded inferior petrosal sinus (IPS) for the treatment of cavernous sinus dural arteriovenous fistulas (CSDAVFs). MATERIALS AND METHODS: A total of 8 consecutive patients with CSDAVFs with occlusion of the IPS treated by selective TVE with balloon angioplasty of the IPS from July 2018 to January 2019 were retrospectively reviewed. There were 6 females and 2 males with an average age of 77.6 years. All patients showed ocular symptoms. Angiography showed cortical venous reflux in 7 cases and localized shunted pouches at the medial portion of the cavernous sinus, intercavernous sinus, or laterocavernous sinus. Selective TVE was performed via the occluded IPS with bilateral femoral venous approaches, and the occluded IPS was reconstructed by angioplasty with a 2- to 3-mm diameter balloon during or after selective TVE. RESULTS: CSDAVFs disappeared immediately after treatment, and the occluded IPSs were successfully reconstructed with re-establishment of normal antegrade venous flow in all cases. No complications were observed, and symptoms resolved within 2 weeks after treatment. During the 7-month mean follow-up period (range 1-12 months), no cases showed recurrence of CSDAVFs. CONCLUSION: Selective TVE combined with balloon angioplasty of the occluded IPS is safe and effective for the treatment of CSDAVFs and re-establishes normal venous circulation in selected cases with localized shunted pouches.

Clinical, radiological and pathological features of idiopathic and secondary interstitial pneumonia with pleuroparenchymal fibroelastosis in patients undergoing lung transplantation.

AIMS: Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare type of idiopathic interstitial pneumonia, and pathological PPFE is also observed in patients with secondary interstitial pneumonia. This study aimed to evaluate the pathological findings associated with radiological PPFE-like lesions and the clinical and morphological features of patients with pathological PPFE. METHODS AND RESULTS: We retrospectively reviewed the pathology of the explanted lungs from 59 lung transplant recipients with radiological PPFE-like lesions. Pathological PPFE lesions were identified in 14 patients with idiopathic disease and in 12 patients with secondary disease. Pathological PPFE was associated with previous pneumothorax, volume loss in the upper lobes, and a flattened chest. Patients with idiopathic disease and those with secondary disease with pathological PPFE had similar clinical, radiological and pathological findings, whereas fibroblastic foci were more common in patients with idiopathic disease, and patients with secondary disease more frequently showed alveolar septal thickening with elastosis or fibrosis. Post-transplantation survival did not differ between patients with idiopathic and secondary disease with pathological PPFE (log-rank; P = 0.57) and was similar between patients with idiopathic disease with pathological PPFE and those with idiopathic pulmonary fibrosis (IPF) (log-rank; P = 0.62). CONCLUSIONS: Not all patients with interstitial pneumonia with radiological PPFE-like lesions have pathological PPFE. Characteristic clinical features can suggest the presence of pathological PPFE, and idiopathic and secondary cases with pathological PPFE are similar except for fibroblastic foci in idiopathic cases and alveolar septal thickening with elastosis or fibrosis in secondary cases. Patients with pathological PPFE have a similar prognosis to those with IPF after transplantation.

Antitussive Effect of a Chest Band in Patients with Interstitial Lung Disease: The Preliminary Results from a Pre-post Intervention Study.

Objective Evidence supporting the efficiency of clinically administered therapies against interstitial lung disease (ILD)-related cough is limited. Thus, we conducted a study to evaluate the efficacy of short-term use of chest bands on cough in patients with ILD. Methods This pre-post intervention study was performed at two university hospitals between April 2017 and August 2020. Scores of the visual analog scale (VAS) for cough severity (in terms of frequency and intensity), Leicester Cough Questionnaire (LCQ)-acute, and frequency scale for symptoms of gastroesophageal reflux disease (FSSG) were assessed before and after the use of the chest band (24/48 hours). Patients The study included patients with idiopathic interstitial pneumonias (IIPs) or connective tissue disease-associated interstitial lung disease (CTD-ILD). Results Four patients with IIPs and seven with CTD-ILD were included in the analysis. The cough intensity and LCQ-acute total score improved significantly after the use of the chest band (p=0.007 and p=0.005, respectively), although the cough frequency showed no significant reduction (p=0.074). Furthermore, the FSSG total and acid-reflux symptom scores improved (p=0.018 and p=0.027, respectively), and a negative correlation between the change in LCQ-acute total score and that in FSSG score for acid-reflux symptoms was observed (Spearman rho =-0.841, p=0.001). Conclusion The results of the current study suggest that chest bands might be useful for treating chronic refractory cough in patients with ILD and gastroesophageal reflux disease. However, these results should be interpreted with caution due to methodological limitations associated with this study.

Temporal subtraction CT with nonrigid image registration improves detection of bone metastases by radiologists: results of a large-scale observer study.

To determine whether temporal subtraction (TS) CT obtained with non-rigid image registration improves detection of various bone metastases during serial clinical follow-up examinations by numerous radiologists. Six board-certified radiologists retrospectively scrutinized CT images for patients with history of malignancy sequentially. These radiologists selected 50 positive and 50 negative subjects with and without bone metastases, respectively. Furthermore, for each subject, they selected a pair of previous and current CT images satisfying predefined criteria by consensus. Previous images were non-rigidly transformed to match current images and subtracted from current images to automatically generate TS images. Subsequently, 18 radiologists independently interpreted the 100 CT image pairs to identify bone metastases, both without and with TS images, with each interpretation separated from the other by an interval of at least 30 days. Jackknife free-response receiver operating characteristics (JAFROC) analysis was conducted to assess observer performance. Compared with interpretation without TS images, interpretation with TS images was associated with a significantly higher mean figure of merit (0.710 vs. 0.658; JAFROC analysis, P = 0.0027). Mean sensitivity at lesion-based was significantly higher for interpretation with TS compared with that without TS (46.1% vs. 33.9%; P = 0.003). Mean false positive count per subject was also significantly higher for interpretation with TS than for that without TS (0.28 vs. 0.15; P < 0.001). At the subject-based, mean sensitivity was significantly higher for interpretation with TS images than that without TS images (73.2% vs. 65.4%; P = 0.003). There was no significant difference in mean specificity (0.93 vs. 0.95; P = 0.083). TS significantly improved overall performance in the detection of various bone metastases.

Influence of Asthma Onset on Airway Dimensions on Ultra-high-resolution Computed Tomography in Chronic Obstructive Pulmonary Disease.

PURPOSE: Asthma onset before the age of 40 years is associated with distinct clinical manifestations in chronic obstructive pulmonary disease (COPD) patients, but its morphologic features remain unestablished. This study aimed to explore airway morphology in COPD patients with asthma onset before 40 years of age using ultra-high-resolution computed tomography (U-HRCT), which allows a more accurate quantitation of the lumen and the wall in smaller airways than using conventional CT. MATERIALS AND METHODS: Clinical data of 500 consecutive patients undergoing full inspiratory U-HRCT (1024×1024 matrix and 0.25 mm slice thickness) were retrospectively analyzed. COPD patients without asthma, COPD patients with asthma onset at age below or 40 years and above, and non-COPD smoker controls (N=137, 29, 34, and 22, respectively) were enrolled. The length, lumen area (LA), wall thickness and area (WA), and wall area percent (WA%) of the segmental (third-generation) to sub-subsegmental (fifth-generation) bronchus and the low attenuation volume percent (LAV%) were measured. RESULTS: LA and WA were smaller in the fourth and fifth generation in COPD patients than in non-COPD controls, regardless of the age of asthma onset. LA was smaller and WA% was larger in the fourth-generation and fifth-generation airways in COPD with asthma onset before 40 years than COPD without asthma, whereas WA did not differ between them. In multivariate analyses, asthma onset before 40 years was associated with smaller LA in COPD patients independent of demographics, use of inhaled corticosteroids and long-acting bronchodilators, airflow limitation, and LAV%. CONCLUSIONS: Asthma onset before 40 years of age could be associated with greater lumen narrowing of the airways in COPD.

Adaptive Voxel Matching for Temporal CT Subtraction.

Temporal subtraction (TS) technique calculates a subtraction image between a pair of registered images acquired from the same patient at different times. Previous studies have shown that TS is effective for visualizing pathological changes over time; therefore, TS should be a useful tool for radiologists. However, artifacts caused by partial volume effects degrade the quality of thick-slice subtraction images, even with accurate image registration. Here, we propose a subtraction method for reducing artifacts in thick-slice images and discuss its implementation in high-speed processing. The proposed method is based on voxel matching, which reduces artifacts by considering gaps in discretized positions of two images in subtraction calculations. There are two different features between the proposed method and conventional voxel matching: (1) the size of a searching region to reduce artifacts is determined based on discretized position gaps between images and (2) the searching region is set on both images for symmetrical subtraction. The proposed method is implemented by adopting an accelerated subtraction calculation method that exploit the nature of liner interpolation for calculating the signal value at a point among discretized positions. We quantitatively evaluated the proposed method using synthetic data and qualitatively using clinical data interpreted by radiologists. The evaluation showed that the proposed method was superior to conventional methods. Moreover, the processing speed using the proposed method was almost unchanged from that of the conventional methods. The results indicate that the proposed method can improve the quality of subtraction images acquired from thick-slice images.

Complete occlusion of right pulmonary artery in Behçet disease.

When a patient with Behçet disease presents with haemoptysis, pulmonary vascular involvement should be considered.

Improving breast mass classification by shared data with domain transformation using a generative adversarial network.

Training of a convolutional neural network (CNN) generally requires a large dataset. However, it is not easy to collect a large medical image dataset. The purpose of this study is to investigate the utility of synthetic images in training CNNs and to demonstrate the applicability of unrelated images by domain transformation. Mammograms showing 202 benign and 212 malignant masses were used for evaluation. To create synthetic data, a cycle generative adversarial network was trained with 599 lung nodules in computed tomography (CT) and 1430 breast masses on digitized mammograms (DDSM). A CNN was trained for classification between benign and malignant masses. The classification performance was compared between the networks trained with the original data, augmented data, synthetic data, DDSM images, and natural images (ImageNet dataset). The results were evaluated in terms of the classification accuracy and the area under the receiver operating characteristic curves (AUC). The classification accuracy improved from 65.7% to 67.1% with data augmentation. The use of an ImageNet pretrained model was useful (79.2%). Performance was slightly improved when synthetic images or the DDSM images only were used for pretraining (67.6 and 72.5%, respectively). When the ImageNet pretrained model was trained with the synthetic images, the classification performance slightly improved (81.4%), although the difference in AUCs was not statistically significant. The use of the synthetic images had an effect similar to the DDSM images. The results of the proposed study indicated that the synthetic data generated from unrelated lesions by domain transformation could be used to increase the training samples.

Lobar distribution of non-emphysematous gas trapping and lung hyperinflation in chronic obstructive pulmonary disease.

BACKGROUND: Lung hyperinflation in chronic obstructive pulmonary disease (COPD) is closely associated with emphysema and non-emphysematous gas trapping, termed functional small airway disease (fSAD), on inspiratory and expiratory computed tomography (CT). Because the cranial-caudal emphysema distribution affects pulmonary function and fSAD may precede emphysema on CT, we tested the hypothesis that lobar fSAD distribution would affect lung hyperinflation differently in COPD with minimal and established emphysema. METHODS: The volume percentages of fSAD and emphysema (fSAD% and Emph%) over the upper and lower lobes were measured using inspiratory and expiratory CT in 70 subjects with COPD. Subjects were divided into those with minimal and established emphysema (n = 36 and 34) using a threshold of 10% Emph% in the whole lung. RESULTS: In the minimal emphysema group, fSAD% in the upper and lower lobes was positively correlated with functional residual capacity (FRC) and residual volume to total lung capacity ratio (RV/TLC), and the correlation of fSAD% with RV/TLC was greater in the lower lobes. Conversely, in the established emphysema group, fSAD% in the upper and lower lobes was correlated with RV/TLC, but not with FRC. In multivariate analysis, fSAD% in the lower lobes, but not in the upper lobes, was associated with RV/TLC in subjects with minimal emphysema after adjusting for age, smoking status, and bronchodilator use. CONCLUSION: Non-emphysematous gas trapping in the upper and lower lobes has a distinct physiological effect, especially in COPD with minimal emphysema. This local evaluation might allow sensitive detection of changes in lung hyperinflation in COPD.