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We investigated the association between the results of a simplified cough test and pneumonia onset in 226 patients with acute stroke admitted to Suiseikai Kajikawa Hospital from April to December, 2018. For the simplified cough test, performed on admission, patients orally inhaled a mist of 1% citric acid-physiological saline using a portable mesh nebulizer. When the first cough was evoked or if it remained absent for 30 seconds (indicating an abnormal result), the test was ended. Patients also completed the repetitive saliva swallowing test (RSST) and modified water swallowing test. We monitored patients for pneumonia signs for 30 days post-admission. Eighteen patients exhibited an abnormal simplified cough test result. On multivariate analysis, an abnormal RSST result was independently associated with an abnormal simplified cough test result. Seventeen patients developed pneumonia. The adjusted Cox proportional hazard model for pneumonia onset revealed that the simplified cough test had predictive power for pneumonia onset (hazard ratio, 10.52; 95% confidence interval, 3.72-29.72). The simplified cough test is a strong indicator for predicting the pneumonia development in patients with acute stroke; it should be added to existing bedside screening tests for predicting pneumonia risk, allowing appropriate and timely intervention.

Background Surface-guided radiation therapy (SGRT) employs a non-invasive real-time optical surface imaging (OSI) technique for patient surface motion monitoring during radiotherapy. The main purpose of this study is to verify the real-time tracking accuracy of SGRT for respiratory motion and provide a fitting method to detect the time delay of gating. Methods A respiratory motion phantom was utilized to simulate respiratory motion using 17 cosine breathing pattern curves with various periods and amplitudes. The motion tracking of the phantom was performed by the Catalyst™ system. The tracking accuracy of the system (with period and amplitude variations) was evaluated by analyzing the adjusted coefficient of determination (A_R 2 ) and root mean square error (RMSE). Furthermore, 13 actual respiratory curves, which were categorized into regular and irregular patterns, were selected and then simulated by the phantom. The Fourier transform was applied to the respiratory curves, and tracking accuracy was compared through the quantitative analyses of curve similarity using the Pearson correlation coefficient (PCC). In addition, the time delay of amplitude-based respiratory-gating radiotherapy based on the OSI system with various beam hold times was tested using film dosimetry for the Elekta Versa-HD and Varian Edge linacs. A dose convolution-fitting method was provided to accurately measure the beam-on and beam-off time delays. Results A_R 2 and RMSE for the cosine curves were 0.9990–0.9996 and 0.110–0.241 mm for periods ranging from 1 s to 10 s and 0.9990–0.9994 and 0.059–0.175 mm for amplitudes ranging from 3 mm to 15 mm. The PCC for the actual respiratory curves ranged from 0.9955 to 0.9994, which was not significantly affected by breathing patterns. For gating radiotherapy, the average beam-on and beam-off time delays were 1664 ± 72 and 25 ± 30 ms for Versa-HD and 303 ± 45 and 34 ± 25 ms for Edge, respectively. The time delay was relatively stable as the beam hold time increased. Conclusions The OSI technique provides high accuracy for respiratory motion tracking. The proposed dose convolution-fitting method can accurately measure the time delay of respiratory-gating radiotherapy. When the OSI technique is used for respiratory-gating radiotherapy, the time delay for the beam-on is considerably longer than the beam-off.

We have developed a computational model of gas mixing and ventilation in the human lung represented as a bifurcating network. We have simulated multiple-breath washout (MBW), a clinical test for measuring ventilation heterogeneity (VH) in patients with obstructive lung conditions. By applying airway constrictions inter-regionally, we have predicted the response of MBW indices to obstructions and found that they detect a narrow range of severe constrictions that reduce airway radius to 10%-30% of healthy values. These results help to explain the success of the MBW test to distinguish obstructive lung conditions from healthy controls. Further, we have used a perturbative approach to account for intra-regional airway heterogeneity that avoids modelling each airway individually. We have found, for random airway heterogeneity, that the variance in MBW indices is greater when indices are already elevated due to constrictions. By quantifying this effect, we have shown that variability in lung structure and mechanical properties alone can lead to clinically significant variability in MBW indices (specifically the Lung Clearance Index-LCI, and the gradient of phase-III slopes-Scond), but only in cases simulating obstructive lung conditions. This method is a computationally efficient way to probe the lung's sensitivity to structural changes, and to quantify uncertainty in predictions due to random variations in lung mechanical and structural properties.

To evaluate the diagnostic performance of the initial chest CT to diagnose COVID-19 related pneumonia in a French population of patients with respiratory symptoms according to the time from the onset of country-wide confinement to better understand what could be the role of the chest CT in the different phases of the epidemic. Initial chest CT of 1064 patients with respiratory symptoms suspect of COVID-19 referred between March 18th, and May 12th 2020, were read according to a standardized procedure. The results of chest CTs were compared to the results of the RT-PCR. 546 (51%) patients were found to be positive for SARS-CoV2 at RT-PCR. The highest rate of positive RT-PCR was during the second week of confinement reaching 71.9%. After six weeks of confinement, the positive RT-PCR rate dropped significantly to 10.5% (p<0.001) and even 2.2% during the two last weeks. Overall, CT revealed patterns suggestive of COVID-19 in 603 patients (57%), whereas an alternative diagnosis was found in 246 patients (23%). CT was considered normal in 215 patients (20%) and inconclusive in 1 patient. The overall sensitivity of CT was 88%, specificity 76%, PPV 79%, and NPV 85%. At week-2, the same figures were 89%, 69%, 88% and 71% respectively and 60%, 84%, 30% and 95% respectively at week-6. At the end of confinement when the rate of positive PCR became extremely low the sensitivity, specificity, PPV and NPV of CT were 50%, 82%, 6% and 99% respectively. At the peak of the epidemic, chest CT had sufficiently high sensitivity and PPV to serve as a first-line positive diagnostic tool but at the end of the epidemic wave CT is more useful to exclude COVID-19 pneumonia.

Accurate segmentation of lung nodules is crucial in the development of imaging biomarkers for predicting malignancy of the nodules. Manual segmentation is time consuming and affected by inter-observer variability. We evaluated the robustness and accuracy of a publically available semiautomatic segmentation algorithm that is implemented in the 3D Slicer Chest Imaging Platform (CIP) and compared it with the performance of manual segmentation. CT images of 354 manually segmented nodules were downloaded from the LIDC database. Four radiologists performed the manual segmentation and assessed various nodule characteristics. The semiautomatic CIP segmentation was initialized using the centroid of the manual segmentations, thereby generating four contours for each nodule. The robustness of both segmentation methods was assessed using the region of uncertainty (δ) and Dice similarity index (DSI). The robustness of the segmentation methods was compared using the Wilcoxon-signed rank test (pWilcoxon<0.05). The Dice similarity index (DSIAgree) between the manual and CIP segmentations was computed to estimate the accuracy of the semiautomatic contours. The median computational time of the CIP segmentation was 10 s. The median CIP and manually segmented volumes were 477 ml and 309 ml, respectively. CIP segmentations were significantly more robust than manual segmentations (median δCIP = 14ml, median dsiCIP = 99% vs. median δmanual = 222ml, median dsimanual = 82%) with pWilcoxon~10-16. The agreement between CIP and manual segmentations had a median DSIAgree of 60%. While 13% (47/354) of the nodules did not require any manual adjustment, minor to substantial manual adjustments were needed for 87% (305/354) of the nodules. CIP segmentations were observed to perform poorly (median DSIAgree≈50%) for non-/sub-solid nodules with subtle appearances and poorly defined boundaries. Semi-automatic CIP segmentation can potentially reduce the physician workload for 13% of nodules owing to its computational efficiency and superior stability compared to manual segmentation. Although manual adjustment is needed for many cases, CIP segmentation provides a preliminary contour for physicians as a starting point.

There is a need for efficient techniques to assess abnormalities in the peripheral regions of the lungs, for example, for diagnosis of pulmonary emphysema. Considerable scientific efforts have been directed toward measuring lung morphology by studying recovery of inhaled micron-sized aerosol particles (0.4-1.5 µm). In contrast, it is suggested that the recovery of inhaled airborne nanoparticles may be more useful for diagnosis. The objective of this work is to provide a theoretical background for the use of nanoparticles in measuring lung morphology and to assess their applicability based on a review of the literature. Using nanoparticles for studying distal airspace dimensions is shown to have several advantages over other aerosol-based methods. 1) Nanoparticles deposit almost exclusively by diffusion, which allows a simpler breathing maneuver with minor artifacts from particle losses in the oropharyngeal and upper airways. 2) A higher breathing flow rate can be utilized, making it possible to rapidly inhale from residual volume to total lung capacity (TLC), thereby eliminating the need to determine the TLC before measurement. 3) Recent studies indicate better penetration of nanoparticles than micron-sized particles into poorly ventilated and diseased regions of the lungs; thus, a stronger signal from the abnormal parts is expected. 4) Changes in airspace dimensions have a larger impact on the recovery of nanoparticles. Compared to current diagnostic techniques with high specificity for morphometric changes of the lungs, computed tomography and magnetic resonance imaging with hyperpolarized gases, an aerosol-based method is likely to be less time consuming, considerably cheaper, simpler to use, and easier to interpret (providing a single value rather than an image that has to be analyzed). Compared to diagnosis by carbon monoxide ( ), the uptake of nanoparticles in the lung is not affected by blood flow, hemoglobin concentration or alterations of the alveolar membranes, but relies only on lung morphology.

Purpose Guillain–Barré Syndrome (GBS) is a life-threatening disease due to respiratory muscle involvement. This study aimed at objectively assessing the course of respiratory muscle function in GBS subjects within the first week of admission to an intensive care unit. Methods Medical Research Council Sum Score (MRC-SS), vigorimetry, spirometry, and respiratory muscle function tests (inspiratory/expiratory muscle strength: PI max /PE max , sniff nasal pressure: SnPna) were assessed twice daily. GBS Disability Score (GBS-DS) was assessed once daily. On days one (d1) and seven (d7), blood gases and twitch mouth pressure during magnetic phrenic nerve stimulation (Pmo,tw) were additionally evaluated. Results Nine subjects were included. MRC-SS, vigorimetry, PI max , and SnPna increased between d1 and d7. GBS-DS, spirometry and Pmo,tw remained unaltered. Only SnPna correlated closely with the MRC-SS on both d1 ( r  = 0.77, p  = 0.02) and d7 ( r  = 0.74, p  = 0.02). Conclusion SnPna was the only parameter that correlated with MRC-SS, while the current gold standard of spirometry measurement did not.

Linear endobronchial ultrasound (EBUS) is a safe and accurate diagnostic test for mediastinal adenopathy. Its feasibility through the nasal route has not been reported. The objective of this study was to document the feasibility of linear EBUS using the nasal route and compare its accuracy and safety with the oral route. A retrospective analysis of consecutive subjects who underwent an EBUS procedure under conscious sedation at our center was conducted. Nasal insertion of the bronchoscope was attempted in all subjects; the oral route was used in case of failed nasal insertion. Characteristics of the procedure and the diagnostic accuracy of EBUS were compared between the two insertion routes. From May to October 2012, 209 subjects underwent an EBUS. Complete data were available for 196 subjects. Nasal insertion of the EBUS bronchoscope was possible in 73.5 %. There was no difference between the two insertion routes in the location and number of stations sampled per subject. Procedure duration and complications (epistaxis, bronchial bleeding, desaturation, and pneumothorax) were similar between the two groups (2.1 % for nasal group vs 1.9 % for oral group). Minor epistaxis occurred in one subject in the nasal group. Comparing the nasal and oral groups, rates of adequate specimens were similar (90.5 vs 88.9 %, respectively; p = 0.68), and proportions of diagnostic specimens were not statistically different (51.4 vs 42.3 %, respectively; p = 0.26). Linear EBUS can be performed safely and with high accuracy via the nasal route. Controlled studies are required to determine which insertion route provides best patient comfort.

Disparity in the testing rate of SARS-CoV-2 amongst different countries and regions is a very big challenge in understanding the COVID-19 pandemic. Although some developed countries have a very high testing rate and subsequently a high number of confirmed cases, less developed countries have a low testing rate and an illusive positivity rate. Collection of the upper respiratory specimen is not often comfortable. The discomfort could be accompanied with epistaxis and headache in some patients. The trained personnel taking the swab is forced to protect self with personal protective equipment (PPE) to avoid infections that may result from the patient due to provoked cough, sneezing and spitting. This study looks into an efficient means of increasing the testing rate for COVID 19 without compromising the quality. A literature review was conducted on the different modalities of collecting upper respiratory specimens and assessing the efficacy of samples collected using different methods in terms of the laboratory yield of different pathogens. Self collection of upper respiratory tract specimen for diagnostic purposes is not new. Studies have demonstrated that trained staff-collected nasal swabs are not in any way superior to self-collected or parent-assisted swabs. The laboratory yield of different specimens is not determined by who took the sample but by the anatomical site from where the specimen was collected. Self collection of the upper respiratory swabs will not only increase the testing rate but also preserve the scarce PPE and reduces health care worker’s COVID 19 infection rate in South Africa.