Risk factors for radiation pneumonitis after rotating gantry intensity-modulated radiation therapy for lung cancer

The risk factors for severe radiation pneumonitis (RP) in patients with lung cancer who undergo rotating gantry intensity-modulated radiation therapy (IMRT) using volumetric modulated arc therapy (VMAT) or helical tomotherapy (HT) are poorly understood. Fifty-two patients who received rotating gantry IMRT for locally advanced lung cancer were included in this retrospective study. In total, 31 and 21 patients received VMAT and HT, respectively. The median follow-up duration was 14 months (range, 5.2–33.6). Twenty (38%) and eight (15%) patients developed grade ≥ 2 and ≥ 3 RP, respectively. In multivariate analysis, lung V5 ≥ 40% was associated with grade ≥ 2 RP (P = 0.02), and past medical history of pneumonectomy and total lung volume ≤ 3260 cc were independently associated with grade ≥ 3 RP (P = 0.02 and P = 0.03, respectively). Rotating gantry IMRT was feasible and safe in patients with lung cancer undergoing definitive radiotherapy. Reducing lung V5 may decrease the risk of symptomatic RP, and care should be taken to avoid severe RP after radiotherapy in patients with a past medical history of pneumonectomy and small total lung volume.

Relationship between Pneumonia and the Thymus Gland in Children with COVID-19: A Volumetric Computed Tomography Study

Objective Many studies showed that less-severe disease symptoms and fewer mortality rates have been reported in pediatric novel coronavirus disease 2019 (COVID-19) patients. In this study, we aimed to reveal the relationship between the volume of thymus gland, which provides T lymphocyte maturation in children, with the severity of lung involvement and blood laboratory values in pediatric patients with COVID-19 infection. Methods Thymus density and thymus and cardiac volumes were measured in pediatric COVID-19 patients and a control group that underwent thoracic tomography for reasons other than infection. Thymus/heart ratios were calculated to index the thymus volumes of the patients to their body dimensions. The severity of pneumonia was demonstrated by proportioning the involved lung parenchymal volume to the total lung volume in patients with typical involvement in thoracic tomography. The relationship between volumetric and blood laboratory values was statistically evaluated. Results Thymus density (p = 0.015) and thymus/heart ratio (p = 0.04) significantly differed between patients with COVID-19 infection and the control group. A correlation was observed between the pneumonia involvement rate and C-reactive protein (CRP) (k: 0.451, p = 0.08) and white blood cell (WBC; k: 0.419, p = 0.015) values in the thoracic tomography of the COVID-19 group. Conclusion The thymus gland is enlarged as an indicator of activation in COVID-19 infection. We hope that our study will guide new studies on the prognostic value of thymus size in lymphopenic patients with severe disease.

Evaluation of Nano-Particulate-Matter-Induced Lung Injury in Mice Using Quantitative Micro-Computed Tomography

Nano-particulate matters (NPM) induced the lung injury in mice were evaluated using quantitative micro-computed tomography in the present article. It is an important negative effect of health problems that NPM exposure provokes changes in the lung injury. The micro-computed tomography (CT) to assess lung injury in mouse models has been investigated. The dynamic structural changes in a NPM-induced lung injury mouse mode were monitored. Adults female BALB/C mice were repeatedly exposed to NPM, and micro-CT scans were performed at day 0, 3, 5 and 9. Lung samples were also collected for histological analysis at each time point. The total lung volume, the injured lung volume, and the normal lung volume were defined and calculated volume during the phase of NPM-exposure on the mice. The total and injured lung volumes of NPM-exposed mice were significantly larger than those of the mice at day 5 and 9. The data from micro-CT was consistent with alveolar enlargement and destruction by histological quantification from pathological section. The study for NPM-induced lung injury model by micro-CT may extend our understanding of the distinct pathophysiology of NPM induced lung injury in mice.

Automated Quantitative Lung CT Improves Prognostication in Non-ICU COVID-19 Patients beyond Conventional Biomarkers of Disease

(1) Background: COVID-19 continues to represent a worrying pandemic. Despite the high percentage of non-severe illness, a wide clinical variability is often reported in real-world practice. Accurate predictors of disease aggressiveness, however, are still lacking. The purpose of our study was to evaluate the impact of quantitative analysis of lung computed tomography (CT) on non-intensive care unit (ICU) COVID-19 patients’ prognostication; (2) Methods: Our historical prospective study included fifty-five COVID-19 patients consecutively submitted to unenhanced lung CT. Primary outcomes were recorded during hospitalization, including composite ICU admission for the need of mechanical ventilation and/or death occurrence. CT examinations were retrospectively evaluated to automatically calculate differently aerated lung tissues (i.e., overinflated, well-aerated, poorly aerated, and non-aerated tissue). Scores based on the percentage of lung weight and volume were also calculated; (3) Results: Patients who reported disease progression showed lower total lung volume. Inflammatory indices correlated with indices of respiratory failure and high-density areas. Moreover, non-aerated and poorly aerated lung tissue resulted significantly higher in patients with disease progression. Notably, non-aerated lung tissue was independently associated with disease progression (HR: 1.02; p-value: 0.046). When different predictive models including clinical, laboratoristic, and CT findings were analyzed, the best predictive validity was reached by the model that included non-aerated tissue (C-index: 0.97; p-value: 0.0001); (4) Conclusions: Quantitative lung CT offers wide advantages in COVID-19 disease stratification. Non-aerated lung tissue is more likely to occur with severe inflammation status, turning out to be a strong predictor for disease aggressiveness; therefore, it should be included in the predictive model of COVID-19 patients.

Motion corrected fetal body MRI provides reliable 3D lung volumes in normal and abnormal fetuses

Objective:Evaluate deformable slice-to-volume registration (DSVR) to calculate 3D-segmented total lung volume (TLV) in fetuses with congenital diaphragmatic hernia, congenital lung lesions and healthy controls, with comparison to 2D-manual segmentation. Design:Pilot study Setting:Regional fetal medicine referral centre Sample:Fetal MRIs performed for clinical indications (abnormal cases) or as research participants (healthy controls) Methods:Sixteen MRI datasets of fetuses (22-32 weeks GA). Diagnosis: CDH(n=5), CPAM(n=2), CDH with BPS(n=1) and healthy control(n=8). DSVR was used for reconstruction of 3D isotropic (0.85 mm) volumes of fetal body followed by semi-automated lung segmentation. The resulting 3D TLV were compared to the traditional 2D-based volumetry, and a normogram of DSVR-derived fetal lung volumes from 100 cases was produced. Main Outcome Measures:Concordance with 2D-volumetry assessed with Bland-Altman analysis, results of segmentations presented visually. Observed/Expected values were calculated for abnormal cases based upon the normogram. Results:DSVR-derived TLV values have high correlation with the 2D-based measurements but with a consistently lower volume; bias -1.44cm3 [95% limits: -2.6 to -0.3] with improved resolution able to exclude hilar structures even in severe motion corruption or in cases of lung hypoplasia. Conclusions:Application of DSVR for fetal MRI provides a solution for analysis of motion corrupted scans and does not suffer from the interpolation error inherent in 2D-segmentation as per current clinical practice. It increases information content of acquired data in terms of visualising organs in 3D space and quantification of volumes, which we believe will have important value for counselling and surgical planning. Keywords:Fetal MRI; congenital diaphragmatic hernia; CPAM; lung volume

Pulmonary Emphysema Regional Distribution and Extent Assessed by Chest Computed Tomography Is Associated With Pulmonary Function Impairment in Patients With COPD

Objective: This study aimed to evaluate how emphysema extent and its regional distribution quantified by chest CT are associated with clinical and functional severity in patients with chronic obstructive pulmonary disease (COPD).Methods/Design: Patients with a post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) < 0.70, without any other obstructive airway disease, who presented radiological evidence of emphysema on visual CT inspection were retrospectively enrolled. A Quantitative Lung Imaging (QUALI) system automatically quantified the volume of pulmonary emphysema and adjusted this volume to the measured (EmphCTLV) or predicted total lung volume (TLV) (EmphPLV) and assessed its regional distribution based on an artificial neural network (ANN) trained for this purpose. Additionally, the percentage of lung volume occupied by low-attenuation areas (LAA) was computed by dividing the total volume of regions with attenuation lower or equal to −950 Hounsfield units (HU) by the predicted [LAA (%PLV)] or measured CT lung volume [LAA (%CTLV)]. The LAA was then compared with the QUALI emphysema estimations. The association between emphysema extension and its regional distribution with pulmonary function impairment was then assessed.Results: In this study, 86 patients fulfilled the inclusion criteria. Both EmphCTLV and EmphPLV were significantly lower than the LAA indices independently of emphysema severity. CT-derived TLV significantly increased with emphysema severity (from 6,143 ± 1,295 up to 7,659 ± 1,264 ml from mild to very severe emphysema, p < 0.005) and thus, both EmphCTLV and LAA significantly underestimated emphysema extent when compared with those values adjusted to the predicted lung volume. All CT-derived emphysema indices presented moderate to strong correlations with residual volume (RV) (with correlations ranging from 0.61 to 0.66), total lung capacity (TLC) (from 0.51 to 0.59), and FEV1 (~0.6) and diffusing capacity for carbon monoxide DLCO (~0.6). The values of FEV1 and DLCO were significantly lower, and RV (p < 0.001) and TLC (p < 0.001) were significantly higher with the increasing emphysema extent and when emphysematous areas homogeneously affected the lungs.Conclusions: Emphysema volume must be referred to the predicted and not to the measured lung volume when assessing the CT-derived emphysema extension. Pulmonary function impairment was greater in patients with higher emphysema volumes and with a more homogeneous emphysema distribution. Further studies are still necessary to assess the significance of CTpLV in the clinical and research fields.

Lung volume head ratio: A potential parameter for prediction of respiratory distress in newborn

Objective: To evaluate the role of fetal lung biometry profile including fetal lung volume head ratio (LVHR) in predicting the occurrence of respiratory distress (RD) in early preterm newborn. Material and Method: Prospective analytical cohort study was done to evaluate the clinical value of fetal sonographic measures such as the total lung area (TLA), total lung volume (TLV), total lung area head ratio (TLHR), lung volume head ratio (LVHR) was measured in pregnant women between 30 to 34 week gestation , expected to deliver within the next 72 hours. The cases with RD were compared with controls who had normal outcome. Result: Total 30(27.4%) out of 110 subjects undergoing early preterm delivery had RD rest 80(72.6%) were controls. The total lung area was 694.1±373.1 mm2 in cases whereas 1149.0 ± 506 .7 mm2 in controls, with significant difference between the two groups(p<0.001). Similarly the lung volume (p<0.001) and the lung volume head ratio was significantly less (P<0.001) in cases compared to controls. The total lung volume was a better parameter (sensitivity-73.7%; specificity-86.4%) compared to total lung area (Sensitivity - 68.4%, Specificity - 81.5%). Among the lung head ratios, LVHR had best sensitivity - 95.5%, Specificity - 80.3%, PPV-58.3%, NPV - 97.0% at the cut off of 46.5. Conclusion: Respiratory distress was observed in nearly one-third of the preterm infants born between 30 and 34 weeks and could be predicted accurately in over nine out of ten cases using the novel parameter TLVR.

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 &lt; 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*FEV1FVC+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 &gt; 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.

Coronavirus Disease 2019: Hysteresis Effect of Chest CT and the Correlation with its Severity

Purpose: The purpose of this study was to investigate the influencing factors for chest CT hysteresis and severity of coronavirus disease 2019 (COVID-19). Methods: The chest CT data of patients with confirmed COVID-19 in 4 hospitals were retrospectively analyzed. An independent assessment was performed by one clinician using the DEXIN FACT Workstation Analysis System, and the assessment results were reviewed by another clinician. Furthermore, the mean hysteresis time was calculated according to the median time from progression to the most serious situation to improve chest CT in patients after fever relief. The optimal scaling regression analysis was performed by including variables with statistical significance in univariate analysis. In addition, a multivariate regression model was established to investigate the relationship of the percentage of lesion/total lung volume with lymphocyte and other variables. Results: In the included 166 patients with COVID-19, the average value of the most serious percentage of lesion/total lung volume was 6.62, of which 90 patients with fever had an average hysteresis time of 4.5 days after symptom relief, with a similar trend observed in those without fever. Multivariate analysis revealed that lymphocyte count in peripheral blood and transcutaneous oxygen saturation decreased with the increase of the percentage of lesion/total lung volume. Conclusion: There is a hysteresis effect in the improvement of chest CT image relative to fever relief in patients with COVID-19. The pulmonary lesions may be related to the severity as well as decreased lymphocyte count or percutaneous oxygen saturation.