Advancing accuracy in breath testing for lung cancer: strategies for improving diagnostic precision in imbalanced data.

BACKGROUND: Breath testing using an electronic nose has been recognized as a promising new technique for the early detection of lung cancer. Imbalanced data are commonly observed in electronic nose studies, but methods to address them are rarely reported. OBJECTIVE: The objectives of this study were to assess the accuracy of electronic nose screening for lung cancer with imbalanced learning and to select the best mechanical learning algorithm. METHODS: We conducted a case‒control study that included patients with lung cancer and healthy controls and analyzed metabolites in exhaled breath using a carbon nanotube sensor array. The study used five machine learning algorithms to build predictive models and a synthetic minority oversampling technique to address imbalanced data. The diagnostic accuracy of lung cancer was assessed using pathology reports as the gold standard. RESULTS: We enrolled 190 subjects between 2020 and 2023. A total of 155 subjects were used in the final analysis, which included 111 lung cancer patients and 44 healthy controls. We randomly divided samples into one training set, one internal validation set, and one external validation set. In the external validation set, the summary sensitivity was 0.88 (95% CI 0.84-0.91), the summary specificity was 1.00 (95% CI 0.85-1.00), the AUC was 0.96 (95% CI 0.94-0.98), the pAUC was 0.92 (95% CI 0.89-0.96), and the DOR was 207.62 (95% CI 24.62-924.64). CONCLUSION: Electronic nose screening for lung cancer is highly accurate. The support vector machine algorithm is more suitable for analyzing chemical sensor data from electronic noses.

Ginseng-DF ameliorates intestinal mucosal barrier injury and enhances immunity in immunosuppressed mice by regulating MAPK/NF-κB signaling pathways.

PURPOSE: Dietary fiber (DF) has a good application prospect in effectively restoring the integrity of the intestinal mucosal barrier. Ginseng-DF has good physicochemical properties and physiological activity and shows positive effects in enhancing immunity. The aim of this study was to investigate the protective effect of Ginseng-DF on intestinal mucosal barrier injury induced by cyclophosphamide (CTX) in immunosuppressed mice and its possible mechanism. METHODS: The effects of Gginseng-DF on immune function in mice were studied by delayed-type hypersensitivy, lymphocyte proliferation assay and NK cytotoxicity assay, the T lymphocyte differentiation and intestinal barrier integrity were analyzed by flow cytometry and western blot. RESULTS: Ginseng-DF (2.5% and 5%) could attenuate the inhibition of DTH response by CTX, promote the transformation and proliferation of lymphocytes, and stimulate NK effector cell activity. At the same time, Ginseng-DF could restore the proportion of CD4+/CD8+ T lymphocytes induced by CTX to different extents, improved spleen tissue damage, promoted the secretion of immunoglobulin IgG, and enhanced body immunity. More importantly, Ginseng-DF could up-regulate the contents of TNF-α, IFN-γ, IL-6 and IL-1ß in serum and intestine of immunosuppressed mice to maintain the balance between Th1/Th2 cytokines, and improve the permeability of intestinal mucosal barrier. Meanwhile, Ginseng-DF could reduce intestinal epithelial cell apoptosis and improve intestinal adaptive immunity in CTX-induced immunosuppressed mice by regulating MAPK/NF-κB signaling pathway. CONCLUSION: Ginseng-DF can be used as a safe dietary supplement to enhance body immunity and reduce intestinal mucosal injury caused by CTX.

Mechanical and biological properties of poly-ε-caprolactone membrane for pleurodesis: A preclinical study in pigs.

BACKGROUND/PURPOSE: Biomaterial implants are emerging as a treatment choice for pleurodesis; however, the optimal biomaterial and form for managing spontaneous pneumothorax, particularly post-video-assisted thoracic surgery, remain under investigation. This study evaluated the mechanical and biological properties of the poly-ε-caprolactone (PCL) membrane as a sclerosing agent for pleurodesis in Landrace pigs. METHODS: Twenty-four Landrace pigs were split into two groups for mechanical abrasion and PCL membrane pleurodesis, with the latter group's PCL meshes inserted using video-assisted thoracic surgery. The mechanical and biological properties of the PCL membrane were assessed in pigs at three, six, and 12 months after the procedure. This assessment involved a range of techniques, such as the T-Peel test, macroscopic evaluation with a scoring scale, microscopic examination, and biomechanical and molecular weight analysis. RESULTS: The PCL membrane group outperformed the traditional abrasion group, with stronger adhesions seen over longer implantation durations. This group also showed superior and more consistent results in both macroscopic and microscopic evaluations compared to the control group. The membrane-based method was easier and faster to perform than the control group's method, and importantly, no mortality occurred following membrane implantation. CONCLUSION: This study is the pioneering effort to present long-term findings regarding the mechanical and biological properties of the PCL membrane in an in vivo animal model. The membrane demonstrated better adhesion ability than that of traditional abrasion and showed reassuring biocompatibility in both the pig model, suggesting its potential as treatment for patients with primary spontaneous pneumothorax. Further clinical studies are needed to support these observations.

20(S)-protopanaxatriol inhibited D-galactose-induced brain aging in mice via promoting mitochondrial autophagy flow.

Previous reports have confirmed that saponins (ginsenosides) derived from Panax ginseng. C. A. Meyer exerted obvious memory-enhancing and antiaging effects, and the simpler the structure of ginsenosides, the better the biological activity. In this work, we aimed to explore the therapeutic effect and underlying molecular mechanism of 20(S)-protopanaxatriol (PPT), the aglycone of panaxatriol-type ginsenosides, by establishing D-galactose (D-gal)-induced subacute brain aging model in mice. The results showed that PPT treatment (10 and 20 mg/kg) for 4 weeks could significantly restore the D-gal (800 mg/kg for 8 weeks)-induced impaired memory function, choline dysfunction, and redox system imbalance in mice. Meanwhile, PPT also significantly reduced the histopathological changes caused by D-gal exposure. Moreover, PPT could increase TFEB/LAMP2 protein expression to promote mitochondrial autophagic flow. Importantly, the results from molecular docking showed that PPT had good binding ability with LAMP2 and TFEB, suggesting that TFEB/LAMP2 might play an important role in PPT to alleviate D-gal-caused brain aging.

Uniportal versus multiportal nonintubated thoracoscopic anatomical resection for lung cancer: A propensity-matched analysis.

BACKGROUND/PURPOSE: No studies have compared between uniportal and multiportal nonintubated thoracoscopic anatomical resection for non-small cell lung cancer (NSCLC). We aimed to compare short- and long-term postoperative outcomes concerning these two methods. METHODS: Our retrospective dataset comprised patients with NSCLC who underwent uniportal or multiportal nonintubated thoracoscopic anatomical resection between January 2011 and December 2019. The primary outcome was recurrence-free survival. Propensity scores were matched according to age, sex, body mass index, pulmonary function, tumor size, cancer stage, and surgical method. RESULTS: In total, 1130 such patients underwent nonintubated video-assisted thoracoscopic surgery (VATS), and 490 consecutive patients with stage I-III NSCLC underwent nonintubated anatomical resection, including lobectomy and segmentectomy (uniportal, n = 158 [32.3%]; multiportal, n = 331 [67.7%]). The uniportal group had fewer dissected lymph nodes and lymph node stations. In paired group analysis, the uniportal group had shorter operation durations (99.8 vs. 138.2 min; P < 0.001), lower intensive care unit (ICU) admission rates and ICU admission intervals (7.0% vs. 27.8%; P < 0.001), and shorter postoperative hospital stays (4.1 days vs. 5.2 days; P < 0.001). The most common postoperative complication was prolonged air leaks. No surgical mortality was observed. The multiportal group had higher complication rates for grades ≥ II NSCLC; however, this difference was not significant (4.4% vs. 1.3%, respectively; P = 0.09). CONCLUSION: Nonintubated uniportal VATS for anatomical resection had better results for some perioperative outcomes than multiportal VATS. Oncological outcomes such as recurrence-free and overall survival remained uncompromised, despite fewer dissected lymph nodes.

Primary Tumor Resection for Stage IV Non-small-cell Lung Cancer Without Progression After First-Line Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Treatment: A Retrospective Case-Control Study.

BACKGROUND: In studies of stage IV epidermal growth factor receptor (EGFR)-mutant nonsmall-cell lung cancer (NSCLC), <10% of patients underwent surgery; thus, the effect of surgery in these patients remains unclear. We investigated whether primary lung tumor resection could improve the survival of patients with stage IV EGFR-mutant NSCLC without progression after first-line EGFR-tyrosine kinase inhibitor (EGFR-TKI) treatment. METHODS: This retrospective case-control study included patients treated with first-line EGFR-TKIs without progression on follow-up imaging. Patients in the surgery group (n = 56) underwent primary tumor resection, followed by TKI maintenance therapy. Patients in the control group (n = 224; matched for age, metastatic status, and Eastern Cooperative Oncology Group performance status) received only TKI maintenance therapy. Local ablative therapy for distant metastasis was allowed in both groups. The primary endpoint was progression-free survival. The secondary endpoints were overall survival, failure patterns, and complications/adverse events. RESULTS: The median time from TKI treatment to surgery was 5.1 months. For the surgery and control groups, the median follow-up periods were 34.0 and 38.5 months, respectively, with a median (95% confidence interval) progression-free survival of 29.6 (18.9-40.3) and 13.0 (11.8-14.2) months, respectively (P < 0.001). Progression occurred in 29/56 (51.8%) and 207/224 (92.4%) patients, respectively. The median overall survival in the surgery group was not reached. The rate of surgical complications of grade ≥2 was 12.5%; complications were treated conservatively. CONCLUSIONS: Primary tumor resection is feasible for patients with EGFR-mutant nonprogressed NSCLC during first-line EGFR-TKI treatment and may improve survival better than maintenance EGFR-TKI therapy alone.

The Long-Term Clinical Impact of Thoracic Endovascular Aortic Repair (TEVAR) for Advanced Esophageal Cancer Invading Aorta.

BACKGROUND: Advanced esophageal cancer invading the aorta is considered unsuitable for surgery with definitive chemotherapy or chemoradiation as the treatments of choice. In the current study, we evaluated the long-term clinical impact of combining thoracic endovascular aortic repair (TEVAR) with multimodality treatment in caring for such patients. METHODS: We evaluated 48 patients who had advanced esophageal cancer with aortic invasion. The oncological outcome, including overall survival (OS) and progression-free survival (PFS), after multimodality treatment with or without TEVAR is evaluated for these patients. RESULTS: Overall, 25/48 patients (52.1%) received a TEVAR procedure. There was no significant difference in OS (p = 0.223) between patients who did or did not receive TEVAR; however, patients who received TEVAR had significantly less local tumor recurrence (p = 0.020) and longer PFS (p = 0.019). This impact was most evident in patients who received both TEVAR and esophagectomy, with an incremental increase in hazard ratio (HR) for disease progression of 2.89 (95% confidence interval [CI] 0.86-9.96) and 4.37 (95% CI 1.33-14.33) observed under multivariable analysis, respectively, in comparison with patients who underwent only one or neither of these procedures (p = 0.005 for trend test). CONCLUSION: TEVAR is a feasible procedure for esophageal cancers invading the aorta and can be used for curative-intent resection to improve local tumor control and PFS.

Video-assisted thoracoscopic surgery for thoracic empyema in patients on maintenance hemodialysis.

OBJECTIVE: Thoracic empyema in uremic patients on maintenance hemodialysis is a challenging situation. The clinical characteristics are rarely reported, and the surgical outcomes remain unclear. We report our experience with video-assisted thoracoscopic surgery in these patients during 10-year period of time. METHODS: Between 2005 and 2015, we retrospectively reviewed the clinical characteristics, bacteriological studies, and thoracoscopic surgical results of 23 empyema patients undergoing maintenance hemodialysis. RESULTS: The mean patient age was 67.1 ± 12.9 years. All patients had additional preexisting systemic diseases. The mean duration of hemodialysis was 34.7 ± 25.8 months. The infections causing empyema were pneumonia in 11 (47.8%), blood stream infection in 8 (34.8%), and uremic pleuritis in 4 (17.4%). Among the 22 identified microorganisms, the most common pathogen was methicillin-resistant Staphylococcus aureus (31.8%). After thoracoscopic surgery, 8 patients (34.8%) required additional procedures for complications, including 2 patients who required repeated thoracoscopy for hemothorax and 6 (26.1%) patients who required open drainage for residual empyema. The mean hospital stay was 62.4 days, and 6 patients (26.1%) died in the hospital. Univariate and multivariate analyses revealed that maintenance hemodialysis longer than 5 years was a significant factor associated with in-hospital mortality (odds ratio: 14.8, 95% confidence interval 1.5-151.6; p < 0.0001). CONCLUSION: While surgical management of thoracic empyema in uremic patients undergoing maintenance hemodialysis is associated with high rates of complication and mortality, thoracoscopic surgery is feasible, especially for patients undergoing hemodialysis for less than 5 years.

Clinical outcome of subcentimeter non-small cell lung cancer after VATS resection: Single institute experience with 424 patients.

BACKGROUND/PURPOSE: Non-small cell lung cancer (NSCLC) presenting as subcentimeter lung tumor was increasing due to the popularity of low dose CT in recent years. However, the ideal surgical management is still controversial. We utilized our lung cancer surgery database to study the important issue, aiming to find the optimal treatment with VATS. METHODS: From January 2010 to December 2015, we retrospectively reviewed the clinical characteristics, staging, operation methods, and outcomes of 424 patients with subcentimeter lung cancer. Three groups distinguished by surgical methods were compared. RESULTS: There are 273, 57, and 94 undergoing VATS wedge resection, segmentectomy, and lobectomy, respectively. Of the nine recurrence or metastasis events, seven and two occurred within the wedge resection and lobectomy groups, respectively. The average follow-up time is 779 days (2.16 years). Furthermore, 97.4%, 100%, and 97.9% of patients in the wedge resection, segmentectomy, and lobectomy groups, respectively remained tumor-free during follow-up. The complication rate of approximately 1.5% did not differ significantly between the three groups. An obvious difference in disease-free survival between the three groups (p-value = 0.027; -2 log likelihood score and chi-square test). No cases of recurrence or metastasis were observed in the segmentectomy group. CONCLUSION: Lung cancer with subcentimeter size will be more and more encountered. VATS plays an important role in the management with good post-operative outcome, whether with wedge resection, segmentectomy and lobectomy. However, VATS segmentectomy can deliver 100% overall survival and progression-free survival in our series. Further randomized controlled trial should be conducted to prove the concept.

[Machine learning-based method for interpreting the guidelines of the diagnosis and treatment of COVID-19].

The outbreak of pneumonia caused by novel coronavirus (COVID-19) at the end of 2019 was a major public health emergency in human history. In a short period of time, Chinese medical workers have experienced the gradual understanding, evidence accumulation and clinical practice of the unknown virus. So far, National Health Commission of the People's Republic of China has issued seven trial versions of the "Guidelines for the Diagnosis and Treatment of COVID-19". However, it is difficult for clinicians and laymen to quickly and accurately distinguish the similarities and differences among the different versions and locate the key points of the new version. This paper reports a computer-aided intelligent analysis method based on machine learning, which can automatically analyze the similarities and differences of different treatment plans, present the focus of the new version to doctors, reduce the difficulty in interpreting the "diagnosis and treatment plan" for the professional, and help the general public better understand the professional knowledge of medicine. Experimental results show that this method can achieve the topic prediction and matching of the new version of the program text through unsupervised learning of the previous versions of the program topic with an accuracy of 100%. It enables the computer interpretation of "diagnosis and treatment plan" automatically and intelligently.

Mixed squamous cell and glandular papilloma of the lung: A case report of a novel mutation in the BRAF gene and coexistent HPV infection, possible relationship to ciliated muconodular papillary tumor.

Mixed squamous cell and glandular papilloma (mixed papilloma) is a very rare tumor, with fewer than 25 cases having been reported in the literature. Although a scattering of cases of p16Ink4a overexpression have been described to date, no human papillomavirus (HPV) DNA has been detected in these tumors, either by in situ hybridization (ISH) or polymerase chain reaction (PCR). This is the first case of mixed papilloma with PCR-confirmed HPV genotype 16, 35, 51 infections in an 18-year-old non-smoking male, coexisting with multiple atypical adenomatous hyperplasias (AAHs). Histologically, this tumor shows a predominant papillary architecture, covered by a mixture of stratified squamous cells, ciliated or non-ciliated cuboidal to columnar cells, mucous cells, and scattered goblet cells. Immunohistochemically, the squamous component was positive for p40, and the glandular cells were focally positive for TTF-1. Both components were diffusely immunoreactive to CK7. In addition, BRAF V600E mutation was also first demonstrated in mixed papilloma, but not in the AAHs. These findings suggest that HPV infection and the BRAF mutation may be important in the pathogenetic role in young non-smoking patients.

Modified single-port non-intubated video-assisted thoracoscopic decortication in high-risk parapneumonic empyema patients.

BACKGROUND: Parapneumonic empyema patients with coronary artery disease and reduced left ventricular ejection fraction are risky to receive surgical decortication under general anesthesia. Non-intubated video-assisted thoracoscopy surgery is successfully performed to avoid complications of general anesthesia. We performed single-port non-intubated video-assisted flexible thoracoscopy surgery in an endoscopic center. In this study, the possible role of our modified surgery to treat fibrinopurulent stage of parapneumonic empyema with high operative risks is investigated. METHODS: We retrospectively reviewed fibrinopurulent stage of parapneumonic empyema patients between July 2011 and June 2014. Thirty-three patients with coronary artery disease and reduced left ventricular ejection fraction were included in this study. One group received tube thoracostomy, and the other group received single-port non-intubated video-assisted flexible thoracoscopy surgery decortication. Patient demographics, characteristics, laboratory findings, etiology, and treatment outcomes were compared. RESULTS: Mean age of 33 patients (24 males, 9 females) was 76.2 ± 9.7 years. Twelve patients received single-port non-intubated video-assisted flexible thoracoscopy surgery decortication, and 21 patients received tube thoracostomy. Visual analog scale scores on postoperative first hour and first day were not significantly different in two groups (p value = 0.5505 and 0.2750, respectively). Chest tube drainage days, postoperative fever subsided days, postoperative hospital days, and total length of stay were significantly short in single-port non-intubated video-assisted flexible thoracoscopy surgery decortication (p value = 0.0027, 0.0001, 0.0009, and 0.0065, respectively). Morbidities were low, and mortality was significantly low (p value = 0.0319) in single-port non-intubated video-assisted flexible thoracoscopy surgery decortication. CONCLUSIONS: Single-port non-intubated video-assisted flexible thoracoscopy surgery decortication may be suggested to be a method other than tube thoracostomy to deal with fibrinopurulent stage of parapneumonic empyema patients with coronary artery disease and reduced left ventricular ejection fraction.

Study of poly-ɛ-caprolactone membranes for pleurodesis.

BACKGROUND/PURPOSE: Pleurodesis with biomaterial membrane is an emerging treatment method for pneumothorax. However, the ideal one for the common disease is still under debate. METHODS: We investigate the Poly-ε-caprolactone (PCL) membrane pleurodesis by using New Zealand White rabbits, which was sacrificed for examination one month later. Moreover, inflammation and fibrosis scoring were done under microscopic evaluation, as well as Western blot analysis in vitro and in vivo. RESULTS: Gross evaluation of pleurodesis score revealed that dense PCL membrane produced moderate pleural adhesion, while porous PCL membrane exhibited significantly higher pleurodesis scores. CONCLUSION: PCL membrane induced significant degree of adhesion, both within the abdomen and chest of the rabbits. The porous PCL membrane produces more intensive adhesion than dense one. Fibronectin plays an important role in the process of pleurodesis. Further study is required for the clinical application of the promising material.

Twenty-years of lung transplantation in Taiwan: Effects of cumulative institutional experience on early outcomes.

BACKGROUND/PURPOSE: Lung transplantation in Taiwan began in 1991, but the experience was limited and diverse in the early years. We examined the cumulative institutional experience of the largest lung transplant cohort in Taiwan. METHODS: A retrospective review of lung transplantations performed at a single institution from December 1995 through August 2016 was conducted. For comparative purposes, the cohort was divided into halves, with an early group (undergoing lung transplantation in the first decade) vs a late group (undergoing lung transplantation in the second decade). Standardized donor selection, organ procurement, and preservation protocols for brain-dead donors were applied. The outcomes measured were 30-day mortality and actuarial survival using the Kaplan-Meier method. RESULTS: The cohort included 50 recipients in the early group and 42 recipients in the late group. Compared with the early group, recipients in the late group were significantly older (38.8 ± 11.6 vs 44.8 ± 13.4 years, p = 0.024) and more of them required mechanical ventilation before transplant (26.0% vs 66.7%, p < 0.001). There were more female donors (12.0% vs 33.3%, p = 0.021) and gender-matched donors (34.0% vs 61.9%, p = 0.012) in the late group. A total of 87 recipients (94.6%) had cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) support during transplant, and CPB was used significantly less in the late group. Graft procedures (14.0% vs 47.6%, p < 0.001), delayed chest closure (0% vs 21.4%, p < 0.001), and early tracheostomy (24.0% vs 52.4%, p = 0.005) were performed more in the late group. The durations of hospital and ICU stays were comparable in both groups, but the 30-day mortality was significantly lower in the late group (30.0% vs 2.4%, p = 0.001). CONCLUSION: Although the results were undesirable in the first decade of the transplant program, the cumulative institutional experience led to significantly improved outcomes in the second decade of the transplant program.

Video-assisted thoracoscopic surgical thymectomy to treat early thymoma: a comparison with the conventional transsternal approach.

BACKGROUND: For thymoma, the feasibility of resection via video-assisted thoracoscopic surgery (VATS) remains controversial. The objective of our study was to compare the outcomes of VATS and transsternal thymectomy in order to evaluate the efficacy of the VATS method for treatment of early stage thymoma. METHODS: This study is a retrospective study of 120 patients who underwent thymectomy of early stage thymoma (Masaoka stage I and II) in a single medical center from 1991 to 2010. Of these patients, 76 patients underwent VATS thymectomy (VATS group) and 44 patients underwent the conventional transsternal approach (sternotomy group). We applied the Kaplan-Meier method to estimate overall survival (OS), recurrence-free survival (RFS), and time to tumor recurrence (TTR) of these two groups. RESULTS: The mean follow-up time was 61.9 months in the VATS group and 69.7 months in the sternotomy group. There was no surgery-related mortality or major complication. The VATS group had smaller specimen size (p < 0.05) and tumor size (p < 0.01), shorter length of stay (LOS) in the hospital (p < 0.01), and shorter duration of chest tube drainage (p < 0.05) than the sternotomy group. There were no significant differences between the two groups for OS, RFS, and TTR. CONCLUSIONS: In early stage thymoma, VATS thymectomy associated with shorter hospital LOS and shorter duration of pleural drainage compared with the conventional transsternal approach. Otherwise, the two approaches had similar oncologic outcomes during the mean 60-month follow-up period.

Acute thoracic empyema: clinical characteristics and outcome analysis of video-assisted thoracoscopic surgery.

BACKGROUND/PURPOSE: Acute thoracic empyema is a common clinical problem worldwide, resulting in substantial morbidity and mortality. The objective of this study was to report its clinical characteristics and to evaluate whether thoracoscopic surgery is associated with a lower rate of in-hospital mortality compared with nonoperative drainage. METHODS: Between 2001 and 2010, we retrospectively reviewed the clinical characteristics, bacteriological studies, and treatment outcomes of 602 patients with acute thoracic empyema. Thoracoscopic surgery was performed in 417 (69.2%) patients, while the remaining patients underwent nonoperative drainage. After treatment, 77 patients (12.8%) died in the hospital. A propensity score-based process, matched on potential risk factors for in-hospital mortality, was performed to select patients with equalized potential prognostic factors in the thoracoscopy and nonoperative groups. The log-rank test was used to compare the survival time with discharge between the two matched groups. RESULTS: Multivariate analysis showed that age, malignancy, chronic lung disease, chronic renal insufficiency, liver cirrhosis, polymicrobial infection, and positive bacterial culture were risk factors for in-hospital mortality. The propensity score-matched analysis showed that the in-hospital mortality difference was significant (p = 0.014) and the Kaplan-Meier survival analysis revealed a higher survival rate to discharge (p < 0.001 by log-rank test), both favoring thoracoscopy over nonoperative drainage. CONCLUSION: Acute thoracic empyema carries a high mortality rate, especially in elderly patients with coexisting medical conditions and polymicrobial and positive bacterial cultures. Our study results also showed that thoracoscopy is feasible and might provide better chances for survival in borderline operable patients than nonoperative drainage.

Role of computed tomographic scanning prior to thoracoscopic surgery for primary spontaneous pneumothorax.

BACKGROUND/PURPOSE: The role computed tomography (CT) performed prior to thoracoscopic surgery for primary spontaneous pneumothorax (PSP) remains unclear. METHODS: We retrospectively reviewed medical records of all patients who underwent thoracoscopic surgery for PSP during 2008-2012. Patients were stratified into two groups: CT group (patients who received preoperative CT scanning) and control group (patients who did not receive preoperative scanning). Short-term postoperative results and long-term pneumothorax recurrence rates were compared. RESULTS: A total of 298 patients were studied. Preoperative CT scanning was performed in 140 of them. The duration of operation, incidence of bullae formation, number of excised specimens, rate of complications, and postoperative hospital stay were similar between the two groups. After a mean follow-up of 20 months, the recurrence rates were 8.6% (12/140) in the CT group and 5.7% (9/158) in the control group (p = 0.371). In the CT group, five patients had unexpected pulmonary findings and three of them (60%) developed pneumothorax recurrence, the rate of which was significantly higher than that in patients without unexpected pulmonary findings (9/135, 6.7%, p = 0.004). Unexpected pulmonary lesions were more commonly noted in females (4/19, 21.1%) than in males (1/121, 0.8%; p < 0.001). CONCLUSION: Preoperative CT scanning was not associated with better results after thoracoscopic surgery for PSP and is, therefore, not justified as a routine examination prior to the operation. In female patients, however, preoperative CT scanning might be needed because these patients tended to have a higher incidence of unexpected pulmonary lesions, which were associated with a higher rate of recurrence.

Learning Robust Shape Regularization for Generalizable Medical Image Segmentation.

Generalizable medical image segmentation enables models to generalize to unseen target domains under domain shift issues. Recent progress demonstrates that the shape of the segmentation objective, with its high consistency and robustness across domains, can serve as a reliable regularization to aid the model for better cross-domain performance, where existing methods typically seek a shared framework to render segmentation maps and shape prior concurrently. However, due to the inherent texture and style preference of modern deep neural networks, the edge or silhouette of the extracted shape will inevitably be undermined by those domain-specific texture and style interferences of medical images under domain shifts. To address this limitation, we devise a novel framework with a separation between the shape regularization and the segmentation map. Specifically, we first customize a novel whitening transform-based probabilistic shape regularization extractor namely WT-PSE to suppress undesirable domain-specific texture and style interferences, leading to more robust and high-quality shape representations. Second, we deliver a Wasserstein distance-guided knowledge distillation scheme to help the WT-PSE to achieve more flexible shape extraction during the inference phase. Finally, by incorporating domain knowledge of medical images, we propose a novel instance-domain whitening transform method to facilitate a more stable training process with improved performance. Experiments demonstrate the performance of our proposed method on both multi-domain and single-domain generalization.