First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography.

BACKGROUND: Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV. METHODS: Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces. RESULTS: Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2. CONCLUSIONS: EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place. TRIAL REGISTRATION: Not applicable.

Correlation of fetal lung area with MRI derived pulmonary volume.

BACKGROUND: Neonatal chest-Xray (CXR)s are commonly performed as a first line investigation for the evaluation of respiratory complications. Although lung area derived from CXRs correlates well with functional assessments of the neonatal lung, it is not currently utilised in clinical practice, partly due to the lack of reference ranges for CXR-derived lung area in healthy neonates. Advanced MR techniques now enable direct evaluation of both fetal pulmonary volume and area. This study therefore aims to generate reference ranges for pulmonary volume and area in uncomplicated pregnancies, evaluate the correlation between prenatal pulmonary volume and area, as well as to assess the agreement between antenatal MRI-derived and neonatal CXR-derived pulmonary area in a cohort of fetuses that delivered shortly after the antenatal MRI investigation. METHODS: Fetal MRI datasets were retrospectively analysed from uncomplicated term pregnancies and a preterm cohort that delivered within 72 h of the fetal MRI. All examinations included T2 weighted single-shot turbo spin echo images in multiple planes. In-house pipelines were applied to correct for fetal motion using deformable slice-to-volume reconstruction. An MRI-derived lung area was manually segmented from the average intensity projection (AIP) images generated. Postnatal lung area in the preterm cohort was measured from neonatal CXRs within 24 h of delivery. Pearson correlation coefficient was used to correlate MRI-derived lung volume and area. A two-way absolute agreement was performed between the MRI-derived AIP lung area and CXR-derived lung area. RESULTS: Datasets from 180 controls and 10 preterm fetuses were suitable for analysis. Mean gestational age at MRI was 28.6 ± 4.2 weeks for controls and 28.7 ± 2.7 weeks for preterm neonates. MRI-derived lung area correlated strongly with lung volumes (p < 0.001). MRI-derived lung area had good agreement with the neonatal CXR-derived lung area in the preterm cohort [both lungs = 0.982]. CONCLUSION: MRI-derived pulmonary area correlates well with absolute pulmonary volume and there is good correlation between MRI-derived pulmonary area and postnatal CXR-derived lung area when delivery occurs within a few days of the MRI examination. This may indicate that fetal MRI derived lung area may prove to be useful reference ranges for pulmonary areas derived from CXRs obtained in the perinatal period.

End-expiratory lung volumes as a potential indicator for COVID-19 associated acute respiratory distress syndrome: a retrospective study.

BACKGROUND: End-expiratory lung volume (EELV) has been observed to decrease in acute respiratory distress syndrome (ARDS). Yet, research investigating EELV in patients with COVID-19 associated ARDS (CARDS) remains limited. It is unclear whether EELV could serve as a potential metric for monitoring disease progression and identifying patients with ARDS at increased risk of adverse outcomes. STUDY DESIGN AND METHODS: This retrospective study included mechanically ventilated patients diagnosed with CARDS during the initial phase of epidemic control in Shanghai. EELV was measured using the nitrogen washout-washin technique within 48 h post-intubation, followed by regular assessments every 3-4 days. Chest CT scans, performed within a 24-hour window around each EELV measurement, were analyzed using AI software. Differences in patient demographics, clinical data, respiratory mechanics, EELV, and chest CT findings were assessed using linear mixed models (LMM). RESULTS: Out of the 38 patients enrolled, 26.3% survived until discharge from the ICU. In the survivor group, EELV, EELV/predicted body weight (EELV/PBW) and EELV/predicted functional residual capacity (EELV/preFRC) were significantly higher than those in the non-survivor group (survivor group vs. non-survivor group: EELV: 1455 vs. 1162 ml, P = 0.049; EELV/PBW: 24.1 vs. 18.5 ml/kg, P = 0.011; EELV/preFRC: 0.45 vs. 0.34, P = 0.005). Follow-up assessments showed a sustained elevation of EELV/PBW and EELV/preFRC among the survivors. Additionally, EELV exhibited a positive correlation with total lung volume and residual lung volume, while demonstrating a negative correlation with lesion volume determined through chest CT scans analyzed using AI software. CONCLUSION: EELV is a useful indicator for assessing disease severity and monitoring the prognosis of patients with CARDS.

Comparison of Forced Oscillation Technique, Lung Volumes by Body Plethysmography, and Spirometry in Moderate Persistent Adult Asthma.

BACKGROUND: Spirometry is used extensively, but airway oscillometry is gaining acceptance for evaluating obstructive airway disorders. Moderate persistent asthma requires daily treatment with inhaled corticosteroids (ICS). MATERIALS AND METHODS: We aimed to examine the relationship between airway oscillometry and lung volumes, which are the markers of lung physiology in obstructive airway disease and spirometry in the real-world clinical setting. A total of 72 adults with moderate persistent asthma followed up in our outpatient department from November 2021 to August 2022, and their clinical details and tests of spirometry, forced oscillation technique (FOT), and lung volumes by body plethysmography (BP) performed before and after bronchodilator administration were analyzed. RESULTS: The mean age of the study population was 40 years, and the majority (57%) were females. FOT detected airflow limitation in 12 of the 31 patients with normal spirometry. BP detected abnormalities in more patients than both spirometry and FOT (91.6 vs 73.6%, p < 0.001). Respiratory resistance 5 (R5) had a negative correlation with functional residual capacity (FRC) and total lung capacity (TLC). Reactance 5 (X5) correlated positively with inspiratory capacity (IC) and TLC and negatively with reserve volume (RV)/TLC ratio. A positive correlation was found between IC/TLC% and postbronchodilator X5 and between R5 and 19 and RV/TLC. R5 had a negative and X5 had a positive correlation with forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, and maximal mid expiratory flow rates (MMEF). ∇X5 had a negative correlation with FEV1, MMEF, and FEV1/FVC. Spirometry detected postbronchodilator responsiveness in more patients than FOT when only the R5 criterion was used and in a comparable number when the X5 criterion was added. ∇X5 and R5-R19/R5 declined significantly after bronchodilators. CONCLUSION: We concluded that there is a moderate correlation between FOT and spirometry and lung volumes by BP. FOT and spirometry should be used together to identify airflow obstruction and postbronchodilator responsiveness in asthma. Lung volumes by BP identify more abnormalities in adults with asthma than both spirometry and FOT. Thresholds to define postbronchodilator responsiveness (PBDR) for ∇X5 and R5-R19 need to be defined.

Pulmonary volumes and signs of chronic airflow limitation in quantitative computed tomography.

BACKGROUND: Computed tomography (CT) offers pulmonary volumetric quantification but is not commonly used in healthy individuals due to radiation concerns. Chronic airflow limitation (CAL) is one of the diagnostic criteria for chronic obstructive pulmonary disease (COPD), where early diagnosis is important. Our aim was to present reference values for chest CT volumetric and radiodensity measurements and explore their potential in detecting early signs of CAL. METHODS: From the population-based Swedish CArdioPulmonarybioImage Study (SCAPIS), 294 participants aged 50-64, were categorized into non-CAL (n = 258) and CAL (n = 36) groups based on spirometry. From inspiratory and expiratory CT images we compared lung volumes, mean lung density (MLD), percentage of low attenuation volume (LAV%) and LAV cluster volume between groups, and against reference values from static pulmonary function test (PFT). RESULTS: The CAL group exhibited larger lung volumes, higher LAV%, increased LAV cluster volume and lower MLD compared to the non-CAL group. Lung volumes significantly deviated from PFT values. Expiratory measurements yielded more reliable results for identifying CAL compared to inspiratory. Using a cut-off value of 0.6 for expiratory LAV%, we achieved sensitivity, specificity and positive/negative predictive values of 72%, 85% and 40%/96%, respectively. CONCLUSION: We present volumetric reference values from inspiratory and expiratory chest CT images for a middle-aged healthy cohort. These results are not directly comparable to those from PFTs. Measures of MLD and LAV can be valuable in the evaluation of suspected CAL. Further validation and refinement are necessary to demonstrate its potential as a decision support tool for early detection of COPD.

Novel Surface Topographic Assessment of Lung Volume and Pulmonary Function Tests in Idiopathic Scoliosis: A Preliminary Study.

OBJECTIVE: Severe spinal deformity results in restrictive pulmonary disease from thoracic distortions and lung-volume limitations. Though spirometry and body plethysmography are widely accepted tests for pulmonary function tests (PFTs), they are time-consuming and require patient compliance. This study investigates whether surface topographic [surface topography (ST)] measurements of body volume difference (BVD) and torso volume difference between maximum inhale and exhale correlate to values determined on PFTs. METHODS: This study included patients with idiopathic scoliosis and thoracic/thoracolumbar curves ≥40 degrees. Patients received ST scans, clinical examinations, and EOS biplanar radiographs on the same day. PFTs were performed within 3 months of ST/radiographic analysis. Univariate linear regression analysis was used to examine relationships between BVD, PFT values, and mean curves. RESULTS: Sixteen patients (14.6 ± 2.2 y, 69% females) with idiopathic scoliosis and mean thoracic/thoracolumbar curves of 62 degrees ± 15˚ degrees (45 degrees to 93 degrees) were assessed. BVD displayed statistically high-positive positive correlations with forced vital capacity ( R = 0.863, P < 0.0001), forced expiratory volume in 1 second ( R = 0.870, P < 0.001), vital capacity ( R = 0.802, P < 0.0001), and TLC ( R = 0.831, P < 0.0001. Torso volume difference showed similarly high positive correlations to forced vital capacity, forced expiratory volume in 1 second, vital capacity, and TLC, but not residual volume. No correlations emerged between the mean thoracic/thoracolumbar curve and BVD or PFT values. CONCLUSION: This study strongly endorses further investigation into ST scanning as an alternative to traditional PFTs for assessing pulmonary volumes. The noncontact and noninvasive nature of ST scanning presents a valuable alternative method for analyzing thoracic volume, particularly beneficial for patients unable to cooperate with standard PFTs. LEVEL OF EVIDENCE: Level II-prognostic.

Clinical validation of a capnodynamic method for measuring end-expiratory lung volume in critically ill patients.

RATIONALE: End-expiratory lung volume (EELV) is reduced in mechanically ventilated patients, especially in pathologic conditions. The resulting heterogeneous distribution of ventilation increases the risk for ventilation induced lung injury. Clinical measurement of EELV however, remains difficult. OBJECTIVE: Validation of a novel continuous capnodynamic method based on expired carbon dioxide (CO2) kinetics for measuring EELV in mechanically ventilated critically-ill patients. METHODS: Prospective study of mechanically ventilated patients scheduled for a diagnostic computed tomography exploration. Comparisons were made between absolute and corrected EELVCO2 values, the latter accounting for the amount of CO2 dissolved in lung tissue, with the reference EELV measured by computed tomography (EELVCT). Uncorrected and corrected EELVCO2 was compared with total CT volume (density compartments between - 1000 and 0 Hounsfield units (HU) and functional CT volume, including density compartments of - 1000 to - 200HU eliminating regions of increased shunt. We used comparative statistics including correlations and measurement of accuracy and precision by the Bland Altman method. MEASUREMENTS AND MAIN RESULTS: Of the 46 patients included in the final analysis, 25 had a diagnosis of ARDS (24 of which COVID-19). Both EELVCT and EELVCO2 were significantly reduced (39 and 40% respectively) when compared with theoretical values of functional residual capacity (p < 0.0001). Uncorrected EELVCO2 tended to overestimate EELVCT with a correlation r2 0.58; Bias - 285 and limits of agreement (LoA) (+ 513 to - 1083; 95% CI) ml. Agreement improved for the corrected EELVCO2 to a Bias of - 23 and LoA of (+ 763 to - 716; 95% CI) ml. The best agreement of the method was obtained by comparison of corrected EELVCO2 with functional EELVCT with a r2 of 0.59; Bias - 2.75 (+ 755 to - 761; 95% CI) ml. We did not observe major differences in the performance of the method between ARDS (most of them COVID related) and non-ARDS patients. CONCLUSION: In this first validation in critically ill patients, the capnodynamic method provided good estimates of both total and functional EELV. Bias improved after correcting EELVCO2 for extra-alveolar CO2 content when compared with CT estimated volume. If confirmed in further validations EELVCO2 may become an attractive monitoring option for continuously monitor EELV in critically ill mechanically ventilated patients. TRIAL REGISTRATION: clinicaltrials.gov (NCT04045262).

Pulmonary strain and end-expiratory lung volume during apnea test: a comparative analysis using electrical impedance tomography.

The apnea test, employed for brain death assessment, aims to demonstrate the absence of respiratory drive due to hypercapnia. The tracheal oxygen insufflation apnea test mode (I-AT) involves disconnecting the patient from invasive mechanical ventilation (iMV) for approximately 8 minutes while maintaining oxygenation. This test supports the diagnosis of brain death based on a specified increase in PaCO2. Common complications include hypoxemia and hemodynamic instability, and lung collapse-induced reduction in end-expiratory lung volume (EELV). In our case series utilizing electrical impedance tomography (EIT), we observed that continuous positive airway pressure during the apnea test (CPAP-AT) effectively mitigated lung collapse. This resulted in improved pulmonary strain compared to the disconnection of iMV. These findings suggest the potential benefits of routine CPAP-AT, particularly for potential lung donors, emphasizing the relevance of our study in providing quantitative insights into EELV loss and its association with pulmonary strain and potential lung injury.

La prueba de apnea es una técnica diagnóstica ampliamente utilizada para la evaluación de la muerte cerebral, con el objetivo de demostrar la ausencia de impulso respiratorio debido a la hipercapnia. La variante de la prueba de apnea con insuflación de oxígeno traqueal (I-AT) implica desconectar al paciente de la ventilación mecánica invasiva (iVM) durante aproximadamente 8 minutos, manteniendo la oxigenación mediante un catéter de insuflación. Esta prueba respalda el diagnóstico de muerte cerebral cuando se determina un aumento de la PaCO 2 superior a 20 mmHg en comparación con el valor inicial o un nivel de PaCO 2 superior a 60 mmHg al final de la prueba. En nuestra serie de casos, la implementación de la tomografía de impedancia eléctrica (EIT) reveló que la prueba de apnea con presión positiva continua (CPAPAT) mitiga eficazmente el colapso pulmonar. Este enfoque resulta en una mejora en la tensión pulmonar en comparación con la desconexión de iMV, demostrando su relevancia en el contexto de potenciales donantes de pulmones.

Lung volume measurement using chest CT in COVID-19 patients: a cohort study in Japan.

OBJECTIVE: This study aimed to investigate the utility of CT quantification of lung volume for predicting critical outcomes in COVID-19 patients. METHODS: This retrospective cohort study included 1200 hospitalised patients with COVID-19 from 4 hospitals. Lung fields were extracted using artificial intelligence-based segmentation, and the percentage of the predicted (%pred) total lung volume (TLC (%pred)) was calculated. The incidence of critical outcomes and posthospitalisation complications was compared between patients with low and high CT lung volumes classified based on the median percentage of predicted TLCct (n=600 for each). Prognostic factors for residual lung volume loss were investigated in 208 patients with COVID-19 via a follow-up CT after 3 months. RESULTS: The incidence of critical outcomes was higher in the low TLCct (%pred) group than in the high TLCct (%pred) group (14.2% vs 3.3%, p<0.0001). Multivariable analysis of previously reported factors (age, sex, body mass index and comorbidities) demonstrated that CT-derived lung volume was significantly associated with critical outcomes. The low TLCct (%pred) group exhibited a higher incidence of bacterial infection, heart failure, thromboembolism, liver dysfunction and renal dysfunction than the high TLCct (%pred) group. TLCct (%pred) at 3 months was similarly divided into two groups at the median (71.8%). Among patients with follow-up CT scans, lung volumes showed a recovery trend from the time of admission to 3 months but remained lower in critical cases at 3 months. CONCLUSION: Lower CT lung volume was associated with critical outcomes, posthospitalisation complications and slower improvement of clinical conditions in COVID-19 patients.

Updated reference values for static lung volumes from a healthy population in Austria.

BACKGROUND: Reference values for lung volumes are necessary to identify and diagnose restrictive lung diseases and hyperinflation, but the values have to be validated in the relevant population. Our aim was to investigate the Global Lung Function Initiative (GLI) reference equations in a representative healthy Austrian population and create population-derived reference equations if poor fit was observed. METHODS: We analysed spirometry and body plethysmography data from 5371 respiratory healthy subjects (6-80 years) from the Austrian LEAD Study. Fit with the GLI equations was examined using z-scores and distributions within the limits of normality. LEAD reference equations were then created using the LMS method and the generalized additive model of location shape and scale package according to GLI models. RESULTS: Good fit, defined as mean z-scores between + 0.5 and -0.5,was not observed for the GLI static lung volume equations, with mean z-scores > 0.5 for residual volume (RV), RV/TLC (total lung capacity) and TLC in both sexes, and for expiratory reserve volume (ERV) and inspiratory capacity in females. Distribution within the limits of normality were shifted to the upper limit except for ERV. Population-derived reference equations from the LEAD cohort showed superior fit for lung volumes and provided reproducible results. CONCLUSION: GLI lung volume reference equations demonstrated a poor fit for our cohort, especially in females. Therefore a new set of Austrian reference equations for static lung volumes was developed, that can be applied to both children and adults (6-80 years of age).

A non-invasive continuous and real-time volumetric monitoring in spontaneous breathing subjects based on bioimpedance-ExSpiron®Xi: a validation study in healthy volunteers.

Tidal volume (TV) monitoring breath-by-breath is not available at bedside in non-intubated patients. However, TV monitoring may be useful to evaluate the work of breathing. A non-invasive device based on bioimpedance provides continuous and real-time volumetric tidal estimation during spontaneous breathing. We performed a prospective study in healthy volunteers aimed at evaluating the accuracy, the precision and the trending ability of measurements of ExSpiron®Xi as compared with the gold standard (i.e. spirometry). Further, we explored whether the differences between the 2 devices would be improved by the calibration of ExSpiron®Xi with a pre-determined tidal volume. Analysis accounted for the repeated nature of measurements within each subject. We enrolled 13 healthy volunteers, including 5 men and 8 women. Tidal volume, TV/ideal body weight (IBW) and respiratory rate (RR) measured with spirometer (TVSpirometer) and with ExSpiron®Xi (TVExSpiron) showed a robust correlation, while minute ventilation (MV) showed a weak correlation, in both non/calibrated and calibrated steps. The analysis of the agreement showed that non-calibrated TVExSpiron underestimated TVspirometer, while in the calibrated steps, TVExSpiron overestimated TVspirometer. The calibration procedure did not reduce the average absolute difference (error) between TVSpirometer and TVExSpiron. This happened similarly for TV/IBW and MV, while RR showed high accuracy and precision. The trending ability was excellent for TV, TV/IBW and RR. The concordance rate (CR) was >95% in both calibrated and non-calibrated measurements. The trending ability of minute ventilation was limited. Absolute error for both calibrated and not calibrated values of TV, TV/IBW and MV accounting for repeated measurements was variably associated with BMI, height and smoking status. Conclusions: Non-invasive TV, TV/IBW and RR estimation by ExSpiron®Xi was strongly correlated with tidal ventilation according to the gold standard spirometer technique. This data was not confirmed for MV. The calibration of the device did not improve its performance. Although the accuracy of ExSpiron®Xi was mild and the precision was limited for TV, TV/IBW and MV, the trending ability of the device was strong specifically for TV, TV/IBW and RR. This makes ExSpiron®Xi a non-invasive monitoring system that may detect real-time tidal volume ventilation changes and then suggest the need to better optimize the patient ventilatory support.

Oscillometry for personalizing continuous distending pressure maneuvers: an observational study in extremely preterm infants.

RATIONALE: Lung recruitment and continuous distending pressure (CDP) titration are critical for assuring the efficacy of high-frequency ventilation (HFOV) in preterm infants. The limitation of oxygenation (peripheral oxygen saturation, SpO2) in optimizing CDP calls for evaluating other non-invasive bedside measurements. Respiratory reactance (Xrs) at 10 Hz measured by oscillometry reflects lung volume recruitment and tissue strain. In particular, lung volume recruitment and decreased tissue strain result in increased Xrs values. OBJECTIVES: In extremely preterm infants treated with HFOV as first intention, we aimed to measure the relationship between CDP and Xrs during SpO2-driven CDP optimization. METHODS: In this prospective observational study, extremely preterm infants born before 28 weeks of gestation undergoing SpO2-guided lung recruitment maneuvers were included in the study. SpO2 and Xrs were recorded at each CDP step. The optimal CDP identified by oxygenation (CDPOpt_SpO2) was compared to the CDP providing maximal Xrs on the deflation limb of the recruitment maneuver (CDPXrs). RESULTS: We studied 40 infants (gestational age at birth = 22+ 6-27+ 5 wk; postnatal age = 1-23 days). Measurements were well tolerated and provided reliable results in 96% of cases. On average, Xrs decreased during the inflation limb and increased during the deflation limb. Xrs changes were heterogeneous among the infants for the amount of decrease with increasing CDP, the decrease at the lowest CDP of the deflation limb, and the hysteresis of the Xrs vs. CDP curve. In all but five infants, the hysteresis of the Xrs vs. CDP curve suggested effective lung recruitment. CDPOpt_SpO2 and CDPXrs were highly correlated (ρ = 0.71, p < 0.001) and not statistically different (median difference [range] = -1 [-3; 9] cmH2O). However, CDPXrs were equal to CDPOpt_SpO2 in only 6 infants, greater than CDPOpt_SpO2 in 10, and lower in 24 infants. CONCLUSIONS: The Xrs changes described provide complementary information to oxygenation. Further investigation is warranted to refine recruitment maneuvers and CPD settings in preterm infants.

Prenatal MRI assessment of mediastinal shift angle as a feasible and effective risk stratification tool in isolated right-sided congenital diaphragmatic hernia.

OBJECTIVES: To develop a mediastinal shift angle (MSA) measurement method applicable to right-sided congenital diaphragmatic hernia (RCDH) in fetal MRI and to validate the predictive value of MSA in RCDH. METHODS: Twenty-seven fetuses with isolated RCDH and 53 controls were included in our study. MSA was measured on MRI axial image at the level of four-chamber view of the fetal heart. The angle between the sagittal midline landmark line and the left boundary landmark line touching tangentially the lateral wall of the left ventricle was used to quantify MSA for RCDH. Appropriate statistical analyses were performed to determine whether MSA can be regarded as a valid predictive tool for postnatal outcomes. Furthermore, predictive performance of MSA was compared with that of lung area to head circumference ratio (LHR), observed/expected LHR (O/E LHR), total fetal lung volume (TFLV), and observed/expected TFLV (O/E TFLV). RESULTS: MSA was significantly higher in the RCDH group than in the control group. MSA, LHR, O/E LHR, TFLV, and O/E TFLV were all correlated with postnatal survival, pulmonary hypertension (PH), and extracorporeal membrane oxygenation (ECMO) therapy (p < 0.05). Value of the AUC demonstrated good predictive performance of MSA for postnatal survival (0.901, 95%CI: (0.781-1.000)), PH (0.828, 95%CI: (0.661-0.994)), and ECMO therapy (0.813, 95%CI: (0.645-0.980)), which was similar to O/E TFLV but slightly better than TFLV, O/E LHR, and LHR. CONCLUSIONS: We developed a measurement method of MSA for RCDH for the first time and demonstrated that MSA could be used to predict postnatal survival, PH, and ECMO therapy in RCDH. CLINICAL RELEVANCE STATEMENT: Newly developed MRI assessment method of fetal MSA in RCDH offers a simple and effective risk stratification tool for patients with RCDH. KEY POINTS: • We developed a measurement method of mediastinal shift angle for right-sided congenital diaphragmatic hernia for the first time and demonstrated its feasibility and reproducibility. • Mediastinal shift angle can predict more prognostic information other than survival in right-sided congenital diaphragmatic hernia with good performance. • Mediastinal shift angle can be used as a simple and effective risk stratification tool in right-sided congenital diaphragmatic hernia to improve planning of postnatal management.

MRI prediction of fetal lung volumes and the impact on counselling.

AIM: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Improved donor lung size matching by estimation of lung volumes based on chest X-ray measurements.

RATIONALE: Organ size matching is an important determinant of successful allocation and outcomes in lung transplantation. While computed tomography (CT) is the gold standard, it is rarely used in an organ-donor context, and chest X-ray (CXR) may offer a practical and accurate solution in estimating lung volumes for donor and recipient size matching. We compared CXR lung measurements to CT-measured lung volumes and traditional estimates of lung volume in the same subjects. METHODS: Our retrospective study analyzed clinically obtained CXR and CT lung images of 250 subjects without evidence of lung disease (mean age 9.9 ± 7.8 years; 129 M/121F). From CT, each lung was semi-automatically segmented and total lung volumes were quantified. From anterior-posterior CXR view, each lung was manually segmented and areas were measured. Lung lengths from the apices to the mid-basal regions of each lung were measured from CXR. Quantified CT lung volumes were compared to the corresponding CXR lung lengths, CXR lung areas, height, weight, and predicted total lung capacity (pTLC). RESULTS: There are strong and significant correlations between CT volumes and CXR lung areas in the right lung (R2 = .89, p < .0001), left lung (R2 = .87, p < .0001), and combined lungs (R2 = .89, p < .0001). Similar correlations were seen between CT volumes and CXR measured lung lengths in the right lung (R2 = .79, p < .0001) and left lung (R2 = .81, p < .0001). This correlation between anatomical lung volume (CT) and CXR was stronger than lung-volume correlation to height (R2 = .66, p < .0001), weight (R2 = .43, p < .0001), or pTLC (R2 = .66, p < .0001). CONCLUSION: CXR measures correlate much more strongly with true lung volumes than height, weight, or pTLC. The ability to obtain efficient and more accurate lung volume via CXR has the potential to change our current listing practices of using height as a surrogate for lung size, with a case example provided.

Fetal lung MRI and features predicting post-natal outcome: a scoping review of the current literature.

The outcome for infants with fetal lung pathologies not only depends on the nature of the pathology, but the impact it has on the developing lungs. The main prognostic factor is the degree of pulmonary hypoplasia, but this is not detectable pre-natally. Imaging techniques aim to simulate these features with a variety of surrogate measurements, including lung volume and MRI signal intensity. Despite the complexity of the various research studies and lack of consistent methodology, this scoping review aims to summarise current applications, and promising techniques requiring further investigation.

Feasibility of dynamic chest radiography to calculate lung volumes in adult people with cystic fibrosis: a pilot study.

INTRODUCTION: Dynamic chest radiography (DCR) is a novel, low-dose, real-time digital imaging system where software identifies moving thoracic structures and can automatically calculate lung areas. In an observational, prospective, non-controlled, single-centre pilot study, we compared it with whole-body plethysmography (WBP) in the measurement of lung volume subdivisions in people with cystic fibrosis (pwCF). METHODS: Lung volume subdivisions were estimated by DCR using projected lung area (PLA) during deep inspiration, tidal breathing and full expiration, and compared with same-day WBP in 20 adult pwCF attending routine review. Linear regression models to predict lung volumes from PLA were developed. RESULTS: Total lung area (PLA at maximum inspiration) correlated with total lung capacity (TLC) (r=0.78, p<0.001), functional residual lung area with functional residual capacity (FRC) (r=0.91, p<0.001), residual lung area with residual volume (RV) (r=0.82, p=0.001) and inspiratory lung area with inspiratory capacity (r=0.72, p=0.001). Despite the small sample size, accurate models were developed for predicting TLC, RV and FRC. CONCLUSION: DCR is a promising new technology that can be used to estimate lung volume subdivisions. Plausible correlations between plethysmographic lung volumes and DCR lung areas were identified. Further studies are needed to build on this exploratory work in both pwCF and individuals without CF. TRIAL REGISTRATION NUMBER: ISRCTN64994816.