Ventilation-perfusion scintigraphy to predict postoperative pulmonary function in lung cancer patients undergoing pneumonectomy

Characterizing spatial differences between SPECT-ventilation and SPECT-perfusion in patients with lung cancer undergoing radiotherapy

This study investigates agreement between ventilation and perfusion for lung cancer patients undergoing radiotherapy. Ventilation-perfusion scans of nineteen patients with stage III lung cancer from a prospective protocol were compared using voxel-wise Spearman correlation-coefficients. The presented results show in about 25% of patients, ventilation and perfusion exhibit lower agreement.

Multireader Determination of Clinically Significant Obstruction Using Hyperpolarized 129Xe-Ventilation MRI

OBJECTIVE

The objective of our study was to identify the magnitude and distribution of ventilation defect scores (VDSs) derived from hyperpolarized (HP) 129Xe-MRI associated with clinically relevant airway obstruction.

MATERIALS AND METHODS

From 2012 to 2015, 76 subjects underwent HP 129Xe-MRI (48 healthy volunteers [mean age ± SD, 54 ± 17 years]; 20 patients with asthma [mean age, 44 ± 20 years]; eight patients with chronic obstructive pulmonary disease [mean age, 67 ± 5 years]). All subjects underwent spirometry 1 day before MRI to establish the presence of airway obstruction (forced expiratory volume in 1 second-to-forced vital capacity ratio [FEV1/FVC] < 70%). Five blinded readers assessed the degree of ventilation impairment and assigned a VDS (range, 0-100%). Interreader agreement was assessed using the Fleiss kappa statistic. Using FEV1/FVC as the reference standard, the optimum VDS threshold for the detection of airway obstruction was estimated using ROC curve analysis with 10-fold cross-validation.

RESULTS

Compared with the VDSs in healthy subjects, VDSs in patients with airway obstruction were significantly higher (p < 0.0001) and significantly correlated with disease severity (r = 0.66, p < 0.0001). Ventilation defects in subjects with airway obstruction did not show a location-specific pattern (p = 0.158); however, defects in healthy control subjects were more prevalent in the upper lungs (p = 0.014). ROC curve analysis yielded an optimal threshold of 12.4% ± 6.1% (mean ± SD) for clinically significant VDS. Interreader agreement for 129Xe-MRI was substantial (κ = 0.71).

CONCLUSION

This multireader study of a diverse cohort of patients and control subjects suggests a 129Xe-ventilation MRI VDS of 12.4% or greater represents clinically significant obstruction.

Prediction of postoperative lung function in lung cancer patients using perfusion scintigraphy

BACKGROUND

Predicting postoperative lung function is critical in lung cancer patients. Perfusion scintigraphy has been used to estimate postoperative function after lung resection.

PURPOSE

To evaluate the usefulness of the posterior oblique method in relation to other conventional processing methods for predicting postoperative lung function using lung perfusion scintigraphy.

MATERIAL AND METHODS

Fifty-five patients with non-small-cell lung cancer who underwent lobectomy were enrolled. Forced expiratory volume in 1 s (FEV1) values were obtained from preoperative and postoperative pulmonary function tests. After performing lung perfusion scintigraphy, predicted FEV1 values were calculated using the segment, conventional, posterior, and posterior oblique methods. Postoperative FEV1 values were compared with predicted FEV1 values.

RESULTS

The mean value of the preoperative FEV1 was 2.29 L and that of the postoperative FEV1 was 1.89 L. The mean values of the predicted postoperative FEV1 values for the segment, conventional, posterior, and posterior oblique were 1.83 L, 1.94 L, 1.88 L, and 1.89 L, respectively. Between the observed and predicted FEV1 values, there was a strong correlation without significant difference except for conventional method. Bland-Altman analysis showed that segment and posterior methods underestimated the FEV1, whereas conventional and posterior oblique methods overestimated the FEV1.

CONCLUSION

Predictions with each processing method of lung perfusion scintigraphy showed nearly similar results to the actual postoperative lung function. The posterior oblique method of lung perfusion scintigraphy showed a very small difference to such an extent as to be equal to the observed FEV1, implying that this method may be applied for predicting postoperative lung function in lung cancer patients.

Predicting Lung Function Following Lobectomy: A New Method to Adjust for Inherent Selection Bias

BACKGROUND

Predictions that overestimate post-lobectomy lung function are more likely than underestimates to lead to lobectomy. Studies of post-lobectomy lung function have included only surgical patients, so overestimates are overrepresented. This selection bias has led to incorrect estimates of prediction bias, which has led to inaccurate threshold values for determining lobectomy eligibility.

OBJECTIVE

The objective of this study was to demonstrate and adjust for this selection bias in order to arrive at correct estimates of prediction bias, the 95% limits of agreement, and adjusted threshold values for determining when exercise testing is warranted.

METHODS

We conducted a retrospective study of patients evaluated for lobectomy. We used multiple imputations to determine postoperative results for patients who did not have surgery because their predicted postoperative values were low. We combined these results with surgical patients to adjust for selection bias. We used the Bland-Altman method and the bivariate normal distribution to determine threshold values for surgical eligibility.

RESULTS

Lobectomy evaluation was performed in 114 patients; 79 had lobectomy while 35 were ineligible based on predicted values. Prediction bias using the Bland-Altman method changed significantly after controlling for selection bias. To achieve a postoperative FEV1 > 30% and DLCO ≥30%, a predicted FEV1 > 46% and DLCO ≥53% were required. Compared to current guidelines, using these thresholds would change management in 17% of cases.

CONCLUSION

The impact of selection bias on estimates of prediction accuracy was significant but can be corrected. Threshold values for determining surgical eligibility should be reassessed.

Prediction of postoperative lung function after major lung resection for lung cancer using volumetric computed tomography

OBJECTIVES

The study objectives were to assess the accuracy of volumetric computed tomography to predict postoperative lung function in patients with lung cancer in relation to anatomic segments counting and perfusion scintigraphy, to generate specific predictive equations for each functional parameter, and to evaluate accuracy and precision of these in a validation cohort.

METHODS

We assessed pulmonary functions preoperatively and 3 to 4 months postoperatively after lung resection for lung cancer (n = 114). Absolute and relative lung volumes (total and upper/middle/lower) were determined using volumetric software analysis for staging thoracic computed tomography scans. Predicted postoperative function was calculated by segments counting, scintigraphy, and volumetric computed tomography.

RESULTS

Volumetric computed tomography achieves a higher correlation and precision with measured postoperative lung function than segments counting or scintigraphy (correlation and intraclass correlation coefficients, 0.779-0.969 and 0.776-0.969; 0.573-0.887 and 0.552-0.882; and 0.578-0.834 and 0.532-0.815, respectively), as well as greater accuracy, determined by narrower agreement coefficients for forced vital capacity, forced expiratory volume in 1 second, lung diffusing capacity, and peak oxygen uptake. After validation in an independent cohort (n = 43), adjusted linear regression including volumetric estimation of decreased postoperative ventilation for postoperative lung function parameters explains 98% to 99% of variance.

CONCLUSIONS

Volumetric computed tomography is a reliable and accurate method to predict postoperative lung function in patients undergoing lung resection that provides better accuracy than conventional procedures. Because lung computed tomography is systematically performed in the staging of patients with suspected lung cancer, this volumetric analysis might simultaneously provide the information necessary to evaluate operability.

Pneumonectomy for Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer deaths and its incidence continues to increase. Emerging therapies as part of a multimodal approach are making more patients eligible for surgical resection. As more surgeons are treating locally advanced non-small cell lung cancer they find themselves recommending pneumonectomy as the surgical component of the multidisciplinary plan. Performing a pneumonectomy is technically demanding and is associated with many potential perioperative comorbidities. With the proper preparation, experience, and attention to perioperative care, pneumonectomy can be carried out safely with excellent outcomes and a good quality of life.

Which is Better - A Standalone Ventilation or Perfusion Scan or Combined Imaging to Predict Postoperative FEV1 in One Seconds in Patients Posted for Lung Surgeries with Borderline Pulmonary Reserve

Introduction

Forced expiratory volume in one second (FEV₁) is an independent predictor for respiratory morbidity. Reports are varied and controversial substantiating the use of either lung perfusion (Q) or ventilation (V) scintigraphy as a single stage investigation to predict postoperative (ppo) FEV₁ in patients scheduled for lung resection surgeries. It is said that there is no additional benefit by performing both V/Q scan. As per one of the recommendations, no further respiratory function tests are required for a lobectomy if the postbronchodilator FEV₁ is >1.5 l. We wanted to study the ppo FEV₁ in patients with FEV₁ of <1.5 L scheduled for lung surgeries. Being a high-risk population, we wanted to assess (a) whether the ppo changes by this combined V/Q imaging and (b) whether the incidence of respiratory complication in the postoperative setting of this subgroup is different, (c) and study the short- and long-term clinical outcome.

Materials and Methods

Fifty-two high-risk patients (with comorbidities) and borderline preoperative FEV₁ of 1.5 L or less planned for lung resection were enroled in this prospective study. V and Q scans were performed, and tracer uptake percentage was tabulated.

Results

Tracer uptake in each lung was quantitated. Manual method of ROI drawing is preferred in high risk patients with reduced pulmonary reserve over the automatic method. Based on uptake patterns by V/Q scans, 4 different types of patterns were tabulated. Eighty-eight percentage of centrally placed tumors showed the difference in uptake patterns. Chronic obstructive pulmonary disease patients usually showed more modest ventilatory defects (categorised as type 2 or 3). Lung tumours produce erratic uptake patterns (Type 4) which depend heavily on their location and extent. The range of FEV₁ predicted was 0.6-1.38 L/min.

Conclusion

We recommend that combined imaging should be performed in patients with borderline pulmonary reserve to derive the benefit of surgery as it provides a realistic ppo FEV₁ in patients with moderate to severely damaged lung. Centrally placed hilar or bronchial tumors (even those <2 cm in size), produce discrepancies in V/Q distribution pattern. Patient who was thought ineligible for surgery due to low baseline FEV₁ may be actually be operable by this combined imaging if uptake pattern is better in V or Q scan with a good outcome. Accurate estimation of postop FEV₁ in fact helps the surgical team to implement measures to prepare high risk patients to reduce postoperative complications, enable faster weaning from ventilatory support and ensure favourable prognosis.

Assessment and Optimisation of Lung Cancer Patients for Treatment with Curative Intent

Over the past decade the field of lung cancer management has seen many developments. Coupled with an ageing population and increasing rates of comorbid illness, the work-up for treatments with curative intent has become more complex and detailed. As well as improvements in imaging and staging techniques, developments in both surgery and radiotherapy may now allow patients who would previously have been considered unfit or not appropriate for treatment with curative intent to undergo radical therapies. This overview will highlight published studies relating to investigation and staging techniques, together with assessments of fitness, with the aim of helping clinicians to determine the most appropriate treatments for each patient. We also highlight areas where further research may be required.

Measurement of preoperative lobar lung function with computed tomography ventilation imaging: progress towards rapid stratification of lung cancer lobectomy patients with abnormal lung function

OBJECTIVES

In lung cancer preoperative evaluation, functional lung imaging is commonly used to assess lobar function. Computed tomography ventilation (CT-V) imaging is an emerging lung function imaging modality. We compared CT-V imaging assessment of lobar function and its prediction of postoperative lung function to that achieved by (i) positron emission tomography ventilation (PET-V) imaging and (ii) the standard anatomical segment counting (ASC) method. We hypothesized (i) that CT-V and PET-V have similar relative lobar function and (ii) that functional imaging and anatomic assessment (ASC) yield different predicted postoperative (ppo) lung function and therefore could change clinical management.

METHODS

In this proof-of-concept study, 11 patients were subjected to pulmonary function tests, CT-V and PET-V imaging. The Bland-Altman plot, Pearson's correlation and linear regression analysis were used to assess the agreement between the CT-V-, PET-V- and ASC-based quantification of lobar function and in the ppo lung function.

RESULTS

CT-V and PET-V imaging demonstrated strong correlations in quantifying relative lobar function (r = 0.96; P < 0.001). A Wilcoxon-signed rank test showed no significant difference in the lobar function estimates between the two imaging modalities (P = 0.83). The Bland-Altman plot also showed no significant differences. The correlation between ASC-based lobar function estimates with ventilation imaging was low, r < 0.45; however, the predictions of postoperative lung function correlated strongly between all three methods.

CONCLUSIONS

The assessment of lobar function from CT-V imaging correlated strongly with PET-V imaging, but had low correlations with ASC. CT-V imaging may be a useful alternative method in preoperative evaluation for lung cancer patients.

An Official American Thoracic Society/European Respiratory Society Statement: Research questions in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this Official American Thoracic Society (ATS)/European Respiratory Society (ERS) Research Statement is to describe evidence related to diagnosis, assessment, and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

METHODS

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarized, and then salient knowledge gaps were identified.

RESULTS

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulated via discussion and consensus.

CONCLUSIONS

Great strides have been made in the diagnosis, assessment, and management of COPD as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS Research Statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centered outcomes.

An official American Thoracic Society/European Respiratory Society statement: research questions in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this official American Thoracic Society (ATS)/European Respiratory Society (ERS) research statement is to describe evidence related to diagnosis, assessment and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarised, and then salient knowledge gaps were identified.

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulatedviadiscussion and consensus.

Great strides have been made in the diagnosis, assessment and management of COPD, as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS research statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centred outcomes.

Vibration response imaging versus perfusion scan in lung cancer surgery evaluation

OBJECTIVE

Ventilation/perfusion scan is a standard procedure in high-risk surgical patients to predict pulmonary function after surgery. Vibration response imaging is a technique that could be used in these patients. The objective of our study was to compare this imaging technique with the usual scanning technique for predicting postoperative forced expiratory volume.

METHODS

We assessed 48 patients with lung cancer who were candidates for lung resection. Forced spirometry, vibration response imaging, and ventilation/perfusion scan were performed in patients before surgery, and spirometry was performed after intervention.

RESULTS

We included 48 patients (43 men; mean age, 64 years) undergoing lung cancer surgery (32 lobectomies/16 pneumonectomies). On comparison of both techniques, for pneumonectomy, we found a concordance of 0.84 (95% confidence interval, 0.76-0.92) and Bland-Altman limits of agreement of -0.33 to +0.45, with an average difference of 0.064. By comparing postoperative spirometry with vibration response imaging, we found a concordance of 0.66 (95% confidence interval, 0.38-0.93) and Bland-Altman limits of agreement of -0.60 to +0.33, with an average difference of -0.13.

CONCLUSIONS

The 2 techniques presented good concordance values. Vibration response imaging shows non-negligible confidence intervals. Vibration response imaging may be useful in preoperative algorithms in patients before lung cancer surgery.

Tumor heterogeneity and permeability as measured on the CT component of PET/CT predict survival in patients with non-small cell lung cancer

PURPOSE

We prospectively examined the role of tumor textural heterogeneity on positron emission tomography/computed tomography (PET/CT) in predicting survival compared with other clinical and imaging parameters in patients with non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

The feasibility study consisted of 56 assessed consecutive patients with NSCLC (32 males, 24 females; mean age 67 ± 9.7 years) who underwent combined fluorodeoxyglucose (FDG) PET/CT. The validation study population consisted of 66 prospectively recruited consecutive consenting patients with NSCLC (37 males, 29 females; mean age, 67.5 ± 7.8 years) who successfully underwent combined FDG PET/CT-dynamic contrast-enhanced (DCE) CT. Images were used to derive tumoral PET/CT textural heterogeneity, DCE CT permeability, and FDG uptake (SUVmax). The mean follow-up periods were 22.6 ± 13.3 months and 28.5± 13.2 months for the feasibility and validation studies, respectively. Optimum threshold was determined for clinical stage and each of the above biomarkers (where available) from the feasibility study population. Kaplan-Meier analysis was used to assess the ability of the biomarkers to predict survival in the validation study. Cox regression determined survival factor independence.

RESULTS

Univariate analysis revealed that tumor CT-derived heterogeneity (P < 0.001), PET-derived heterogeneity (P = 0.003), CT-derived permeability (P = 0.002), and stage (P < 0.001) were all significant survival predictors. The thresholds used in this study were derived from a previously conducted feasibility study. Tumor SUVmax did not predict survival. Using multivariable analysis, tumor CT textural heterogeneity (P = 0.021), stage (P = 0.001), and permeability (P < 0.001) were independent survival predictors. These predictors were independent of patient treatment.

CONCLUSIONS

Tumor stage and CT-derived textural heterogeneity were the best predictors of survival in NSCLC. The use of CT-derived textural heterogeneity should assist the management of many patients with NSCLC.

Vibration response imaging in prediction of pulmonary function after pulmonary resection

BACKGROUND

Vibration response imaging (VRI) is a new technique that captures lung sounds generated by the flow of air through the lungs. It predicts postoperative values for an intended lung resection. In this study, we measured the predicted postoperative pulmonary function as determined by a perfusion lung scan and the VRI, and compared with results from the postoperative pulmonary function.

METHODS

This study was performed prospectively in patients who were candidates for major pulmonary resection. Each patient underwent a pulmonary function test, perfusion scintigraphy, and VRI within 1 week before operation. Postoperative lung function was measured at 4 to 6 weeks.

RESULTS

The study enrolled 44 patients. There were no significant differences for predicted postoperative forced expiratory volume in 1 second (ppoFEV(1)) and predicted postoperative diffusion capacity of the lung for carbon monoxide (ppoDlco) between scan and VRI. Both ppoFEV(1) and ppoDlco using a scan and VRI predicted the postoperative results well, respectively. The postoperative FEV(1) was correlated with ppoFEV(1) using a scan (r = 0.83, p < 0.001), and the ppoFEV(1) using a VRI (r = 0.83, p < 0.001). The postoperative Dlco was correlated with the ppoDlco using a scan (r = 0.85, p < 0.001), and the ppoDlco using a VRI (r = 0.80, p < 0.001).

CONCLUSIONS

The VRI was highly predictive of postoperative FEV(1) and Dlco for lung resection.

Predicting survival in potentially curable lung cancer patients

Lung cancer is the most common cause of cancer death with unchanged mortality for 50 years. Only localized nonsmall-cell lung cancer (NSCLC) is curable. In these patients it is essential to accurately predict survival to help identify those that will benefit from treatment and those at risk of relapse. Despite needing this clinical information, prospective data are lacking. We therefore prospectively identified prognostic factors in patients with potentially curable lung cancer. Over 2 years, 110 consecutive patients with confirmed localized NSCLC (stages 1-3A) were recruited from a single tertiary center. Prognostic factors investigated included age, gender, body mass index (BMI), performance status, comorbidity, disease stage, quality of life, and respiratory physiology. Patients were followed up for 3-5 years and mortality recorded. The data were analyzed using survival analysis methods. Twenty-eight patients died within 1 year, 15 patients died within 2 years, and 11 patients died within 3 years postsurgery. Kaplan-Meier survival estimates show a survival rate of 51% at 3 years. Factors significantly (p < 0.05) associated with poor overall survival were age at assessment, diabetes, serum albumin, peak VO(2) max, shuttle walk distance, and predicted postoperative transfer factor. In multiple-variable survival models, the strongest predictors of survival overall were diabetes and shuttle walk distance. The results show that potentially curable lung cancer patients should not be discriminated against with respect to weight and smoking history. Careful attention is required when managing patients with diabetes. Respiratory physiologic measurements were of limited value in predicting long-term survival after lung cancer surgery.