Differences In Lung Volume Research Articles

High oxygen exposure’s impact on newborn mice: Temporal changes observed via micro-computed tomography

Introduction Bronchopulmonary dysplasia (BPD) impacts life expectancy and long-term quality of life. Currently, BPD mouse models exposed to high oxygen are frequently used, but to reevaluate their relevance to human BPD, we attempted an assessment using micro-computed tomography (µCT). Methods Newborn wildtype male mice underwent either 21% or 95% oxygen exposure for 4 days, followed until 8 wk. Weekly µCT scans and lung histological evaluations were performed independently. Results Neonatal hyperoxia for 4 days hindered lung development, causing alveolar expansion and simplification. Histologically, during the first postnatal week, the exposed group showed a longer mean linear intercept, enlarged alveolar area, and a decrease in alveolar number, diminishing by week 4. Weekly µCT scans supported these findings, revealing initially lower lung density in newborn mice, increasing with age. However, the high-oxygen group displayed higher lung density initially. This difference diminished over time, with no significant contrast to controls at 3 wk. Although no significant difference in total lung volume was observed at week 1, the high-oxygen group exhibited a decrease by week 2, persisting until 8 wk. Conclusion This study highlights µCT-detected changes in mice exposed to high oxygen. BPD mouse models might follow a different recovery trajectory than humans, suggesting the need for further optimization.

Covid 19 Pozitif Hastaların Akciğer ve Göğüs Hacminin Incelenmesi

Background: We aimed to reveal lung volume, lesion volume and thorax diameters in patients with Covid-19 positive in CT images according to gender and presence of ground glass opacity. Materials and Methods: We included CT images of 113 people (male;58, female;55) diagnosed with Covid-19 positive in our study. CT images of each patient were imported the DICOM datasets and thorax diameter measurements were performed by using MicroDicom. Moreover, lung volume and lesion volume parameters were calculated from the CT images using the three-dimensional imaging method (Vitrea). All measurement parameters were compared according to gender and ground glass opacity appearance. Results: The 113 patients (male;58, female;55) with a mean age of 44.57±14.59 diagnosed with Covid-19 were included in our study. There was a significant difference between the gender in the mean values of lung volume (males; 3530.90±1454.99 ml and females; 3149.92±1335.16 ml) and lesion volume (males; 434.59±664.19 ml and females; 557.10±671.99 ml) parameters. In addition, a significant difference in lung volume (p<0.001) and lesion volume (p<0.001) was obtained between the groups with ground glass opacity and without ground glass opacity. Moreover, A significant difference (p=0.001) in thorax anteroposterior diameter length was obtained between the groups the with/without ground glass opacity. However, there was no significant difference (p=0.542) between genders in thorax diameters. Conclussion: In our study, we found that in the females may have more lung damage from Covid-19. We believe that our work in the light of the available data, we believe that the findings of our study will contribute to early stages of the pandemic, in which vaccination has not yet , and the long-term effects of post-covid.

MRI prediction of fetal lung volumes and the impact on counselling

To assess whether lung volume percentages in congenital diaphragmatic hernia (CDH) differ depending on which formula is used to calculate the expected volume for gestation and any potential impact this may have on perinatal counselling. Forty-seven patients with left-sided CDH who had undergone fetal magnetic resonance imaging (MRI) at Sheffield Teaching Hospitals were reviewed. The lung volumes were measured on MRI and compared with the volumes that would be expected at the given gestation for each patient. Expected values were calculated using four formulae from the literature and the authors' in-house method. These measurements were used to calculate the percentage total lung volume observed compared with the expected lung volume in a healthy fetus of the same gestation. The differences in percentage lung volumes using these five methods were then compared with how they relate to predicted rates of survival. How predicted survival would change depending on which formula was used to calculate the percentage lung volume was investigated with a view to how this may change the counselling given to a family. In 10/47 (21%) patients, there was no change in the predicted percentage chance of survival depending on which formula was used to calculate the predicted lung volume. In 37/47 (79%), the predicted chance of survival changed depending on which formula was used to calculate the expected lung volume at the given gestation. In 20 (47%) of these cases, the change in predicted survival depending on which formula used was 45% (i.e., from 25% to 70% survival in four and from 50% to 95% survival in 16) and in two cases (4%) this difference was 70% (i.e., from 25% predicted survival to 95% predicted survival). There are several different methods for calculating expected lung volumes for any given gestation. When used to estimate the percentage lung volume in patients with CDH, there is a large difference in values depending on which method is used. This in turn leads to a large variation in predicted survival with some patients in this study having either a 25% or 95% chance of survival depending on which method is used. This has a huge impact on perinatal counselling and the difficult decisions made by families.

Dosimetric Comparison of Different Fractionated 3D Radiotherapy Regimens for Breast Conservation

Background and Objectives This study compared conventional dose fractionation and hypofractionation in breast cancer radiotherapy to optimize treatment planning using different physical indices Subjects and Methods In this retrospective study, the treatment plans of 30 patients eligible for radiotherapy for left-sided breast cancer were investigated. Patients were treated with a conventional dose- interval regimen and three hypofractionated regimens. Dosimetry indexes such as the homogeneity index, conformity index, and mean dose to the left breast, lung, and heart were extracted from the dose-volume histogram and compared with each other to study the four different treatment regimens. Results According to the data obtained, the mean dose to the left breast (PTV), heart and ipsilateral lung was significantly reduced in hypofractionation methods compared to conventional regimen. The homogeneity and the conformity index values showed no significant difference in any of the treatment regimens. The dose received showed no difference in lung volume. For heart, the volume of 38 and 43% of the prescribed dose were significantly higher in the conventional method than in the three hypofractionation regimens. Conclusion Hypofraction treatment regimens with fewer treatment fraction and a dose per fraction greater than 2Gy compared to conventional dose fractionation led to a dose reduction for the heart and the same side of the lung.

Comparison of different methods of initiating lung inflammation and the sex-specific effects on inflammatory parameters.

Sex as a biological variable is an essential element of preclinical research. Sex-specific differences in lung volume, alveolar number, body weight, and the relationship between lung and body weight result in important questions about generating equivalent injuries in males and females so that comparisons in their responses can be assessed. Few studies compare stimulus dosing methods for murine lung models investigating immune responses. To examine sex-specific effects, we explored several dosing techniques for three stimuli, LPS, Streptococcus pneumoniae, and influenza A, on survival, injury parameters in bronchoalveolar lavage (BAL), and immune cell numbers in single-cell lung suspensions after injury. These data demonstrate that body weight-based dosing produced fewer differences between sexes when compared with injury initiated with inocula containing the same number of organisms. Comparison of the lung and body weights showed that females had a greater lung-to-body weight ratio than males. However, in LPS-induced injury, adjusting the dose for sex differences in this ratio in addition to body weight provided no new information about sex differences compared with dosing by body weight alone, most likely due to the variability in measures of the immune response. Studies evaluating BAL volumes revealed that smaller but more lavages resulted in greater returns and lower protein concentrations, particularly in the smaller female lungs. Thus, designing dosing and measurement methods that generate equivalent injuries facilitates comparison of immune responses between sexes. Continued development of methods for both induction and evaluation of injury will likely facilitate identification of sex differences in immune responses.

Regular lung recruitment maneuvers during high-frequency oscillatory ventilation in extremely preterm infants: a randomized controlled trial

BackgroundLung recruitment maneuvers (LRMs) improve lung volume at initiation of high-frequency oscillatory ventilation (HFOV), but it is unclear when to repeat LRMs. We evaluated the efficiency of scheduled LRMs.MethodsIn a randomized controlled trial, extremely preterm infants on HFOV received either LRMs at 12-hour intervals and when clinically indicated (intervention) or only when clinically indicated (control). The primary outcome was the cumulative oxygen saturation index (OSI) over HFOV time, limited to 7 days. Additionally, LRMs were analyzed with respect to OSI improvement.ResultsFifteen infants were included in each group. The mean (SD) postmenstrual age and weight at HFOV start were 23 + 6 (0 + 5) weeks and 650 (115) g in the intervention group and 24 + 4 (0 + 6) weeks (p = 0.03) and 615 (95) g (p = 0.38) in the control group. The mean (SD) cumulative OSI amounted to 4.95 (1.72) in the intervention versus 5.30 (2.08) in the control group (p = 0.61). The mean (SD) number of LRMs in 12 h was 1.3 (0.2) in the intervention versus 1.1 (0.5) in the control group (p = 0.13). Performing LRM when FiO2 > 0.6 resulted in a mean OSI reduction of 3.6.ConclusionRegular versus clinically indicated LRMs were performed with equal frequency in preterm infants during HFOV, and consequently, no difference in lung volume was observed. LRMs seem to be most efficient at high FiO2.Trial registrationClinicalTrials.gov ID: NCT04289324 (28/02/2020).

Differences in lung and lobe volumes between supine and upright computed tomography in patients with idiopathic lung fibrosis

No clinical study has compared lung or lobe volumes on computed tomography (CT) between the supine and standing positions in patients with idiopathic lung fibrosis (IPF). This study aimed to compare lung and lobe volumes between the supine and standing positions and evaluate the correlations between the supine/standing lung volumes on CT and pulmonary function in patients with IPF. Twenty-three patients with IPF underwent a pulmonary function test and both low-dose conventional (supine position) and upright CT (standing position) during inspiration breath-holds. The volumes of the total lungs and lobes were larger in the standing than in the supine position in patients with IPF (all p < 0.05). Spearman's correlation coefficients between total lung volumes on chest CT in supine/standing positions and vital capacity (VC) or forced VC (FVC) were 0.61/0.79 or 0.64/0.80, respectively. CT-based volumes on upright CT were better correlated with VC and FVC than those on supine CT. Lung and lobe volumes in the standing position may be useful biomarkers to assess disease severity or therapeutic effect in patients with IPF.

Flow-controlled ventilation maintains gas exchange and lung aeration in a pediatric model of healthy and injured lungs: A randomized cross-over experimental study.

Flow-controlled ventilation (FCV) is characterized by a constant flow to generate active inspiration and expiration. While the benefit of FCV on gas exchange has been demonstrated in preclinical and clinical studies with adults, the value of this modality for a pediatric population remains unknown. Thus, we aimed at observing the effects of FCV as compared to pressure-regulated volume control (PRVC) ventilation on lung mechanics, gas exchange and lung aeration before and after surfactant depletion in a pediatric model. Ten anesthetized piglets (10.4 ± 0.2 kg) were randomly assigned to start 1-h ventilation with FCV or PRVC before switching the ventilation modes for another hour. This sequence was repeated after inducing lung injury by bronchoalveolar lavage and injurious ventilation. The primary outcome was respiratory tissue elastance. Secondary outcomes included oxygenation index (PaO2/FiO2), PaCO2, intrapulmonary shunt (Qs/Qt), airway resistance, respiratory tissue damping, end-expiratory lung volume, lung clearance index and lung aeration by chest electrical impedance tomography. Measurements were performed at the end of each protocol stage. Ventilation modality had no effect on any respiratory mechanical parameter. Adequate gas exchange was provided by FCV, similar to PRVC, with sufficient CO2 elimination both in healthy and surfactant-depleted lungs (39.46 ± 7.2 mmHg and 46.2 ± 11.4 mmHg for FCV; 36.0 ± 4.1 and 39.5 ± 4.9 mmHg, for PRVC, respectively). Somewhat lower PaO2/FiO2 and higher Qs/Qt were observed in healthy and surfactant depleted lungs during FCV compared to PRVC (p < 0.05, for all). Compared to PRVC, lung aeration was significantly elevated, particularly in the ventral dependent zones during FCV (p < 0.05), but this difference was not evidenced in injured lungs. Somewhat lower oxygenation and higher shunt ratio was observed during FCV, nevertheless lung aeration improved and adequate gas exchange was ensured. Therefore, in the absence of major differences in respiratory mechanics and lung volumes, FCV may be considered as an alternative in ventilation therapy of pediatric patients with healthy and injured lungs.

Neuroendocrine cell hyperplasia of infancy: Feasibility of objective evaluation with quantitative CT

ObjectiveTo describe quantitative CT parameters of children with a typical pattern for NEHI and compare them to controls. Materials and methodsEleven patients (7 boys) with NEHI and an available chest CT concordant NEHI were identified. Eleven age-, sex-, height-matched, with CT technique-matching were identified for comparison. An open-source software was used to segment the lung parenchyma into lobes using the fissures. Quantitative parameters such as low attenuation areas, mean lung density, kurtosis, skewness, ventilation heterogeneity, lung mass, and volume were calculated for both controls and cases. ResultsAnalysis of the lung parenchyma showed that patients with NEHI had a lower mean lung density (−615 HU vs −556 HU, p = 0.03) with higher ventilation heterogeneity (0.23 vs 0.19, p = 0.04), lung mass (232 g vs 146 g, p = 0.01) and volume (595 mL vs 339 mL, p = 0.008) compared to controls. Most lobes followed this trend, except the middle lobe that showed only a higher lung mass (32.9 g vs 19.6 g, p = 0.02) and volume (77.4 vs 46.9, p = 0.005) in patients with NEHI compared to controls. ConclusionQuantitative CT is a feasible technique in children with a typical pattern for NEHI and is associated with differences in attenuation, ventilation heterogeneity, and lung volume.

Exposure of inspiratory negative pressure breathing on cosmonauts during spaceflight

The aim of our study was to investigate the effects of inspiratory negative pressure breathing (NPBin) via impedance threshold device on breathing pattern and body fluid distribution in cosmonauts during spaceflight. The lung function (volumes and flows, breath-hold time) was estimated in details before NPBin exposure as well. The 16 cosmonauts participated in study on ISS board: they were examined before, during spaceflight and after landing. All cosmonauts included in the study were well trained for providing the experimental procedure by themselves. The mask with impedance threshold (−20 cm H2O on inhale) was used. Breathing rate, intramask pressure and electrical impedance of head, body and limbs have been monitoring before (5 min) and during NPBin (20 min). The obtained data has shown no significant differences in lung volumes and flows in comparison of preflight and spaceflight values. Generally, NPBin led to significant decrease of breathing rate. No statistically significant changes in electrical impedance of body and head at NPBin compared with tidal breathing were found. The effectiveness of NPBin as a preventing means for fluid shifts in cosmonauts (astronauts) during spaceflight is discussed and needs the further studies.

Donor Age and Recipient-Donor Sex and Height Mismatch Are Associated with Abnormal Pulmonary Reactance (X5) in Stable Recipients After Bilateral Lung Transplantation

<h3>Purpose</h3> Respiratory system reactance at 5Hz (X₅) reflects tissue elastance and inertance and is measured using oscillometry, a novel measurement of respiratory mechanics. Abnormal reactance (stiffness) has been observed in baseline and chronic lung allograft dysfunction. This study aims to assess predictors of pulmonary reactance in stable lung transplant (LTx) recipients. <h3>Methods</h3> A cross-sectional study was performed on bilateral lung transplant (LTx) recipients at 2 Australian centres between Jan-20 and Jun-21. Spirometry and oscillometry (TremoFlo C-100) were performed to obtain FEV₁ and FVC and X₅, respectively. Patients with acute and chronic lung allograft dysfunction (LAD) were excluded. Baseline lung allograft dysfunction (BLAD) was defined as failure to achieve FEV₁ or FVC >80%-predicted. Oostveen equations were used to generate predicted X₅ values. Abnormal X₅ was defined as Z-score ≤ -1.64. Logistic regression measured associations between baseline transplant predictors and risk of abnormal X_5. <h3>Results</h3> A total of 326 bilateral lung transplant recipients underwent oscillometry. 173 patients with LAD were excluded and 153 included for final analysis. Patients were at median (IQR) 1.9 (2.7) years after transplant. The median (IQR) concurrent FEV₁ as %-baseline FEV₁ was 96% (7). Abnormal X₅ was detected in 21 (13.7%) and normal X₅ in 132 (86.3%). Increasing donor age (OR 1.03, 95%CI 1.00-1.06, p=0.047), recipient-donor sex mismatch (Male:Female OR 5.15, 95%CI 1.70-15.59, p=0.004), donor-recipient height difference (OR 0.95, 95% CI 0.90-0.99, p=0.027) and spirometric BLAD (OR 7.21, 95%CI 2.59-20.06, p<0.001) were associated with an increased risk of abnormal X_5. <h3>Conclusion</h3> Undersizing of lungs, recipient-donor sex mismatch and increasing donor age are significantly associated with abnormal X₅. Differences in lung volume due to sex and size matching may partly explain this association. Increasing age is associated with decreased lung elastic recoil. Preliminary analysis is limited by the use of recipient anthropometrics to generate predicted values. Longitudinal studies are required to determine if the reactance trajectory may help predict patients at risk of poor outcomes.

Effect of 12 Weeks Modified “Dantien-Salee” Yoga Training on Pulmonary Function, Functional Fitness, and Quality of Life in Elderly Thai

Objective: To investigate the effect of 12 weeks Modified “Dantien-Salee” Yoga training (MDS) on pulmonary function, functional fitness, and quality of life (QoL) in elderly Thai. Material and Methods: The quasi-experimental study was conducted using a sample of twenty-four elderly subjects with no previous experience of yoga training. They were equally divided into a MDS group and control group. The MDS group were asked to attend a 70-minite session of MDS training three times a week over 12 weeks. The control group was asked to continue their normal daily routine over the same period. Pulmonary function tests, functional fitness assessments, and QoL by SF-36 assessments, were all measured at baseline and after the 12 weeks study period. A two-way repeated measures ANOVA was used to evaluate differences between groups. Results: There were no differences in spirometry and lung volumes over the intervention period. Both maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) showed tendency to improve in the MDS group but did not reach statistically significant level. Functional fitness and QoL improved significantly (p&lt;0.05) over the 12 weeks period in MDS group. Conclusion: MDS program led to improvement of functional fitness and enhance the QoL in the study group of elderly participants without significant change in pulmonary function parameters. The MDS program is safe and easy to practice. It should be considered as a mode for exercise prescription in the elderly. Keywords: Yoga; Elderly; Functional fitness; QoL

Application of Continuous Positive Airway Pressure for Thoracic Respiratory Motion Management: An Assessment in a Magnetic Resonance Imaging–Guided Radiation Therapy Environment

PurposePatient tolerability of magnetic resonance (MR)–guided radiation treatment delivery is limited by the need for repeated deep inspiratory breath holds (DIBHs). This volunteer study assessed the feasibility of continuous positive airway pressure (CPAP) with and without DIBH for respiratory motion management during radiation treatment with an MR-linear accelerator (MR-linac). Methods and MaterialsMR imaging safety was first addressed by placing the CPAP device in an MR-safe closet and configuring a tube circuit via waveguide to the magnet bore. Reproducibility and linearity of the final configuration were assessed. Six healthy volunteers underwent thoracic imaging in a 0.35T MR-linac, with one free breathing (FB) and 2 DIBH acquisitions being obtained at 5 pressures from 0 to 15 cm-H2O. Lung and heart volumes and positions were recorded; repeatability was assessed by comparing 2 consecutive DIBH scans. Blinded reviewers graded images for motion artifact using a 3-point grading scale. Participants completed comfort and perception surveys before and after imaging sessions. ResultsCompared with FB alone, FB-10, FB-12, and FB-15 cm H2O significantly increased lung volumes (+23%, +34%, +44%; all P <.05) and inferiorly displaced the heart (0.86 cm, 0.96 cm, 1.18 cm; all P < . 05). Lung volumes were significantly greater with DIBH-0 cm H2O compared with FB-15 cm H2O (+105% vs +44%, P = .01), and DIBH-15 cm H2O yielded additional volume increase (+131% vs +105%, P = .01). Adding CPAP to DIBH decreased lung volume differences between consecutive breath holds (correlation coefficient 0.97 at 15 cm H2O vs 0.00 at 0 cm H2O). The addition of 15 cm H2O CPAP reduced artifact scores (P = .03) compared with FB; all DIBH images (0-15 cm H2O) had less artifact (P < .01). ConclusionsThis work demonstrates the feasibility of integrating CPAP in an MR-linac environment in healthy volunteers. Extending this work to a larger patient cohort is warranted to further establish the role of CPAP as an alternative and concurrent approach to DIBH in MR-guided radiation therapy.

Abstract 10064: Pulmonary Hypertension in Patients with Connective Tissue Disease-associated Interstitial Lung Disease and Vascular Changes on Computed Tomography

Introduction: Pulmonary hypertension (PH) is a complication in patients with connective-tissue disease-associated interstitial lung disease (CTD-ILD) associated with mortality. In Idiopathic Pulmonary Fibrosis, increased vascular volume has been reported to be associated with poor outcomes. We sought to elicit whether similar changes could be observed in patients with CTD-ILD and pulmonary hypertension. Methods: We identified patients with a known diagnosis of CTD-ILD who had undergone chest CT, transthoracic echocardiography (TTE), and right heart catherization (RHC) using the Mass General Brigham Research Patient Data Repository (IRB #2018P000419). The electronic health records (EHR) were reviewed to confirm the diagnosis of CTD-ILD. A 3D reconstruction of the pulmonary vasculature using the Chest Imaging Platform ( www.chestimagingplatform.com ) to compute the total vascular volume was performed on thin sliced CT scans closest to the RHC. Vessels were separated into arterial and venous components using a deep learning approach. Statistical analysis was performed with R 4.01. Values are shown as medians and interquartile ranges and were compared using Wilcoxon Rank-Sum tests. Results: A total of 104 patients with CTD-ILD were identified: Pre-capillary PH (n=43), Isolated Post-capillary PH (n=9), Combined Pre- and Post-capillary PH (n=8), and PH Absent (n=44). There was no difference in patient age or lung volume by CT scan. On TTE, RVSP was elevated in PH (52 mmHg, IQR 41-64 mmHg vs 34 mm Hg, IQR 27-49 mmHg, p &lt; 0.0001), as was the arterial total vascular volume (118 mL, IQR 85-152 ml vs 100 mL, IQR 77-126 ml, p = 0.009) with no trend for significance for venous total vascular volume. Addition of total arterial volume remained a statistically significant predictor of presence of PH (p = 0.01) when added to logistic regression models predicting PH by TTE RVSP, with improvement in model AIC (106.1 to 97.9) and AUC (0.75 to 0.80) of the model. Conclusions: In this retrospective study of patients with CTD-ILD and available imaging and hemodynamics, patients with PH have increased arterial vascular volume compared to those without PH. Information derived from CT images routinely acquired in this population could be used to improve screening and phenotyping.

An Exploration of Lung Volume Effects on Swallowing in Chronic Obstructive Pulmonary Disease.

Purpose Chronic obstructive pulmonary disease (COPD) limits respiration, which may negatively impact airway safety during swallowing. It is unknown how differences in lung volume in COPD may alter swallowing physiology. This exploratory study aimed to determine how changes in lung volume impact swallow duration and coordination in persons with stable state COPD compared with older healthy volunteers (OHVs). Method Volunteers ≥ 45 years with COPD (VwCOPDs; n = 9) and OHVs (n = 10) were prospectively recruited. Group and within-participant differences were examined when swallowing at different respiratory volumes: resting expiratory level (REL), tidal volume (TV), and total lung capacity (TLC). Participants swallowed self-administered 20-ml water boluses by medicine cup. Noncued (NC) water swallows were followed by randomly ordered block swallowing trials at three lung volumes. Estimated lung volume (ELV) and respiratory-swallow patterning were quantified using spirometry and respiratory inductive plethysmography. Manometry measured pharyngeal swallow duration from onset of base of tongue pressure increase to offset of negative pressure in the pharyngoesophageal segment. Results During NC swallows, the VwCOPDs swallowed at lower lung volumes than OHVs (p = .011) and VwCOPDs tended to inspire after swallows more often than OHVs. Pharyngeal swallow duration did not differ between groups; however, swallow duration significantly decreased as the ELV increased in VwCOPDs (p = .003). During ELV manipulation, the COPD group inspired after swallowing more frequently at REL than at TLC (p = .001) and at TV (p = .002). In conclusion, increasing respiratory lung volume in COPD should improve safety by reducing the frequency of inspiration after a swallow.

Measurement of the Total Lung Volume Using an Adjusted Single-Breath Helium Dilution Method in Patients With Obstructive Lung Disease.

Background: Whole-body plethysmography (WBP) is the gold standard for measuring lung volume, but its clinical application is limited as it requires expensive equipment and is not simple to use. Studies have shown that the single-breath helium dilution (SBHD) method, which is commonly used in clinical practice, significantly underestimates lung volume in patients with obstructive lung disease (OLD). By comparing the differences in lung volume measured using SBHD and WBP, we aimed to establish a correction equation for the SBHD method to determine the total lung volume in patients with OLD of different severities.Methods: From 628 patients with OLD simultaneously subjected to SBHD and WBP, 407 patients enrolled between January 2018 and November 2019 were in the training group and 221 enrolled between December 2019 and December 2020 were in the prospective verification cohort. The multiple linear regression equation was used for data in the training group to establish a correction equation for SBHD to determine the total lung volume, and this was validated in the prospective validation cohort.Results: There was a moderate positive correlation between total lung capacity (TLC) determined using the SBHD [TLC (SBHD)] and WBP methods [TLC (WBP)] (r = 0.701; P < 0.05), and the differences between TLC (SBHD) and TLC (WBP) (ΔTLC) were related to the severity of obstruction. As the severity of obstruction increased, the TLC was underestimated by the SBHD method. We established the following correction equation: TLC (adjusted SBHD) (L) = −0.669 + 0.756*TLC(SBHD)(L) – 0.047*+0.039*height (cm)–0.009*weight(kg)(r2 = 0.753 and adjusted r2 = 0.751). Next, we validated this equation in the validation cohort. With the correction equation, no statistical difference was observed between TLC (adjusted SBHD) and TLC (WBP) among the obstruction degree groups (P > 0.05).Conclusions: The SBHD method is correlated with WBP to measure the total lung volume, but the SBHD method presents limitations in determining the total lung volume in patients with obstructive lung disease. Here, we established an effective and reliable correction equation in order to accurately assess the total lung volume of patients with OLD using the SBHD method.

Precise Segmentation of COVID-19 Infected Lung from CT Images Based on Adaptive First-Order Appearance Model with Morphological/Anatomical Constraints.

A new segmentation technique is introduced for delineating the lung region in 3D computed tomography (CT) images. To accurately model the distribution of Hounsfield scale values within both chest and lung regions, a new probabilistic model is developed that depends on a linear combination of Gaussian (LCG). Moreover, we modified the conventional expectation-maximization (EM) algorithm to be run in a sequential way to estimate both the dominant Gaussian components (one for the lung region and one for the chest region) and the subdominant Gaussian components, which are used to refine the final estimated joint density. To estimate the marginal density from the mixed density, a modified k-means clustering approach is employed to classify the Gaussian subdominant components to determine which components belong properly to a lung and which components belong to a chest. The initial segmentation, based on the LCG-model, is then refined by the imposition of 3D morphological constraints based on a 3D Markov–Gibbs random field (MGRF) with analytically estimated potentials. The proposed approach was tested on CT data from 32 coronavirus disease 2019 (COVID-19) patients. Segmentation quality was quantitatively evaluated using four metrics: Dice similarity coefficient (DSC), overlap coefficient, 95th-percentile bidirectional Hausdorff distance (BHD), and absolute lung volume difference (ALVD), and it achieved , , , and , respectively. The reported results showed the capability of the proposed approach to accurately segment healthy lung tissues in addition to pathological lung tissues caused by COVID-19, outperforming four current, state-of-the-art deep learning-based lung segmentation approaches.

Deep learning-based segmentation of the lung in MR-images acquired by a stack-of-spirals trajectory at ultra-short echo-times

BackgroundFunctional lung MRI techniques are usually associated with time-consuming post-processing, where manual lung segmentation represents the most cumbersome part. The aim of this study was to investigate whether deep learning-based segmentation of lung images which were scanned by a fast UTE sequence exploiting the stack-of-spirals trajectory can provide sufficiently good accuracy for the calculation of functional parameters.MethodsIn this study, lung images were acquired in 20 patients suffering from cystic fibrosis (CF) and 33 healthy volunteers, by a fast UTE sequence with a stack-of-spirals trajectory and a minimum echo-time of 0.05 ms. A convolutional neural network was then trained for semantic lung segmentation using 17,713 2D coronal slices, each paired with a label obtained from manual segmentation. Subsequently, the network was applied to 4920 independent 2D test images and results were compared to a manual segmentation using the Sørensen–Dice similarity coefficient (DSC) and the Hausdorff distance (HD). Obtained lung volumes and fractional ventilation values calculated from both segmentations were compared using Pearson’s correlation coefficient and Bland Altman analysis.To investigate generalizability to patients outside the CF collective, in particular to those exhibiting larger consolidations inside the lung, the network was additionally applied to UTE images from four patients with pneumonia and one with lung cancer.ResultsThe overall DSC for lung tissue was 0.967 ± 0.076 (mean ± standard deviation) and HD was 4.1 ± 4.4 mm. Lung volumes derived from manual and deep learning based segmentations as well as values for fractional ventilation exhibited a high overall correlation (Pearson’s correlation coefficent = 0.99 and 1.00). For the additional cohort with unseen pathologies / consolidations, mean DSC was 0.930 ± 0.083, HD = 12.9 ± 16.2 mm and the mean difference in lung volume was 0.032 ± 0.048 L.ConclusionsDeep learning-based image segmentation in stack-of-spirals based lung MRI allows for accurate estimation of lung volumes and fractional ventilation values and promises to replace the time-consuming step of manual image segmentation in the future.

Traditional Dual Growing Rod Technique in the Management of Early Onset Scoliosis and Its Effects on Spinal Growth and Lung Development: The Mid-Term Prospective Results.

Objective: The purpose of this study was to investigate the safety and effectiveness of the traditional dual growing rod (TDGR) technique, using only pedicle screws for fixation with more frequent lengthening while evaluating scoliosis correction in the growing spine, spinal growth rates, and the differences in lung volumes.Patients and methods: In this single-centre prospective study, 27 patients with a follow-up of over three years were included in the study. Only pedicle screws were used as foundations for fixation. Routine lengthening procedures were performed every six months. Data were recorded including the age of initial surgery, gender, number of lengthenings, follow-up, and complications. The Cobb angle of the major curve, kyphosis angle, T1- S1 length, space available for lung (SAL) ratio, coronal and sagittal balance, and the height of all patients were measured and recorded preoperatively, immediately postoperatively, and finally before and after every lengthening.Results: The average follow-up time was 46.3 months (36-64 months). The correction rate was 69.5% for Cobb angle and 43.2% for kyphosis between preoperative and final follow-up period. The time between two lengthenings was 6.9 months, and the mean T1-S1 length increase was 1.78 cm per year. The SAL ratio increased from 0.885 preinitially to 0.985 at the last follow-up. The complication rate was determined as 9.6% in 187 procedures. Acceptable improvements were determined in the specified parameters with low complication rates with the use of this technique.Conclusion: The TDGR technique with proximal and distal pedicle screws as anchors is a safe and effective treatment for deformity control in selected patients with early onset scoliosis (EOS). Repetitive surgical interventions are the negative side of this technique.

Coupling Continuous Positive Airway Pressure (CPAP) and MR-guided Radiation Therapy

Continuous positive airway pressure (CPAP) is a cost effective and readily available device that increases lung volumes and has shown promise in conventional x-ray-based radiation therapy (RT). However, limited data are available to quantify the impact of CPAP on lung reproducibility due to the use of ionizing radiation during imaging. We propose a novel pilot study combining CPAP with the powerful soft tissue capabilities of MR-guided RT to reduce the amount of radiation exposure to organs at risk, with the overarching goals of quantifying the impact of CPAP on lung stability under free-breathing (FB) and deep inspiration breath-hold (DIBH) conditions and assessing feasibility. An MR-safe configuration was devised by affixing several CPAP breathing circuits and verifying pressure maintenance using a manometer. Six healthy volunteers (median age 38, range: 28-54) underwent MRIs of the thorax (25 second TrueFISP, 1.5×1.5×3 mm3 resolution) using a 0.35T MR-Linac. FB and 2 verbally coached DIBH acquisitions were performed at CPAP of 0, 6, 10, 12, and 15 cm H20. To define a mutual coordinate system between successive datasets, automated rigid registration was performed (translations only) based on bony anatomy to the reference condition (FB, CPAP 0 cm H20). To quantify the linear relationship between lung volume and pressure under FB conditions, R2 was estimated for each subject. To study positioning reproducibility that may depend on increased pressures in the setting of DIBH, a Spearman correlation coefficient was calculated based on the centroid differences in lung volume. A paired t-test was used to compare the difference between pressures of 0, 6, 10, 12, and 15 cm H20. Image quality with and without CPAP under FB conditions were assessed. Surveys about volunteer perceptions of CPAP were administered after initial CPAP tolerability screening and following the imaging session based on a ten-point scale (10 = least tolerable). FB lung volumes increased as CPAP increased (R2 = 0.85 ± 0.13, range: 0.57 to 0.99) with visible reductions in motion artifacts. A significant negative correlation was observed between CPAP and the lung anterior/posterior centroid differences under DIBH, indicating a reduced difference on repeated measures (i.e., increased lung stability) as pressure increased. Paired t-tests showed significantly better reproducibility in lung volumes at pressures of 6, 10, 12, and 15 cm H20, as compared to 0 cm H20. Patient-reported difficulty tolerating CPAP was perceived to be lower after the study session (mean 2.0, range 1-4) than before (mean 2.83, range 1-5). This study confirms that integrating CPAP into MR-guided RT is feasible and well-tolerated. CPAP not only increases lung volumes under FB conditions, but also improves reproducibility of DIBH, offering potential for reducing treatment-related side effects regardless of treatment delivery platform.