Coregistered ventilation and perfusion SPECT using krypton-81m and Tc-99m-labeled macroaggregated albumin with multislice CT utility for prediction of postoperative lung function in non-small cell lung cancer patients

SPECT/CT versus planar imaging to determine treatment strategy for non-small-cell lung cancer: a cost-effectiveness analysis

Aim: SPECT/CT has been found to improve predicted postoperative forced expiratory volume in one second (ppoFEV₁) assessments in patients with non-small-cell lung cancer (NSCLC). Methods: An economic simulation was developed comparing the cost-effectiveness of SPECT/CT versus planar scintigraphy for a US payer. Clinical outcomes and cost data were obtained through review of the published literature. Results: SPECT/CT increased the accuracy ppoFEV₁ assessment, changing the therapeutic decision for 1.3% of nonsurgical patients to a surgical option, while 3.3% of surgical patients shifted to more aggressive procedures. SPECT/CT led to an expected cost of $4694 per life year gained, well below typical thresholds. Conclusion: SPECT/CT resulted in substantially improved health outcomes and was found to be highly cost-effective.

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.

Pulmonary Functional Imaging: Part 1-State-of-the-Art Technical and Physiologic Underpinnings

Over the past few decades, pulmonary imaging technologies have advanced from chest radiography and nuclear medicine methods to high-spatial-resolution or low-dose chest CT and MRI. It is currently possible to identify and measure pulmonary pathologic changes before these are obvious even to patients or depicted on conventional morphologic images. Here, key technological advances are described, including multiparametric CT image processing methods, inhaled hyperpolarized and fluorinated gas MRI, and four-dimensional free-breathing CT and MRI methods to measure regional ventilation, perfusion, gas exchange, and biomechanics. The basic anatomic and physiologic underpinnings of these pulmonary functional imaging techniques are explained. In addition, advances in image analysis and computational and artificial intelligence (machine learning) methods pertinent to functional lung imaging are discussed. The clinical applications of pulmonary functional imaging, including both the opportunities and challenges for clinical translation and deployment, will be discussed in part 2 of this review. Given the technical advances in these sophisticated imaging methods and the wealth of information they can provide, it is anticipated that pulmonary functional imaging will be increasingly used in the care of patients with lung disease. © RSNA, 2021 Online supplemental material is available for this article.

Inspiratory/expiratory xenon-enhanced area-detector CT: Capability for quantitative assessment of lung ventilation changes in surgically treated non-small cell lung cancer patients

PURPOSE

To evaluate the capability of inspiratory/expiratory Xe-enhanced ADCT for assessment of changes in pulmonary function and regional ventilation of surgically treated NSCLC patients.

METHOD AND MATERIALS

Forty consecutive surgically treated NSCLC patients underwent pre- and postoperative inspiratory/expiratory Xe-enhanced ADCT and pulmonary function tests. For each patient, pre- and post-operative data were analyzed and pre- and post-operative wash-in (WI) and wash-out (WO) indexes and ventilation ratio (VR=[WI-WO]/WI) maps generated by means of pixel-by-pixel analyses. Differences between pre- and postoperative WI (ΔWI), WO (ΔWO) and VR (ΔVR) were also determined. To determine the relationship between all ventilation index changes and pulmonary functional loss, Pearson's correlation was used to correlate each ventilation index change with the corresponding pulmonary functional parameter change. In addition, stepwise regression analysis was performed for all ventilation index changes and each corresponding pulmonary functional parameter change.

RESULTS

FEV₁/FVC% change showed fair or good and significant correlations with ΔWI (r = 0.39, p = 0.01) and ΔVR (r = 0.68, p = 0.001), %FEV₁ change good or moderate and significant correlations with ΔWI (r = 0.56, p = 0.0001) and ΔVR (r = 0.76, p < 0.0001), and %VC change moderate yet significant correlation with ΔWI (r = 0.65, p < 0.0001) and ΔVR (r = 0.67, p < 0.0001). Stepwise regression analysis demonstrated that FEV₁/FVC% change (r² = 0.56, p < 0.0001) significantly affected two factors, ΔVR (p < 0.0001) and ΔWI (p = 0.006), as did %FEV₁ change (r² = 0.68, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)], and %VC change (r² = 0.63, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)].

CONCLUSION

Inspiratory/expiratory Xe-enhanced ADCT has the potential to demonstrate that pre- and postoperative ventilation status of surgically treated NSCLC patients correlates with pulmonary function.

Comparison of predicted postoperative forced expiratory volume in the first second (FEV1) using lung perfusion scintigraphy with observed forced expiratory volume in the first second (FEV1) post lung resection

Lung perfusion scintigraphy is done as a part of preoperative evaluation in lung cancer patients for the prediction of postoperative forced expiratory volume in the first second (FEV1). This study was performed to see the accuracy of prediction of postoperative FEV1 by perfusion scintigraphy for patients undergoing lobectomy/pneumonectomy by comparing it with actual postoperative FEV1 obtained by spirometry 4-6 months after surgery. We retrospectively reviewed 50 surgically resected lung cancer patients who underwent preoperative spirometry, lung perfusion study, and postoperative spirometry. Pearson's correlation coefficient was used to evaluate the relationship between predicted postoperative FEV1 (PPO FEV1) by lung perfusion scintigraphy and postoperative actual FEV1 measured by spirometry. Agreement between the two methods was analyzed with Bland-Altman method. The correlation between the PPO FEV1 and actual postoperative FEV1 was statistically significant (r = 0.847, P = 0.000). The correlation was better for pneumonectomy compared to lobectomy (r = 0.930 [P = 0.000] vs. 0.792 [P = 0.000]). The agreement analysis showed a mean difference of -0.0558 with a standard deviation (SD) of 0.284. The limits of agreement vary over a wide range from --0.625 to 0.513 L (mean ± 2 SD) for the entire group. For pneumonectomy, the mean difference was -0.0121 and SD 0.169 with limits of agreement varying between -0.30 L and 0.30 L. For lobectomy, the mean difference was -0.0826 and SD 0.336 with limits of agreement varying between -0.755 L and 0.590 L. Postoperative FEV1 predicted using lung perfusion scintigraphy shows good correlation with actual postoperative FEV1 and shows reasonably good agreement in patients undergoing pneumonectomy. The limits of agreement appear to be clinically unacceptable in patients undergoing lobectomy, where single-photon emission computed tomography (SPECT) or SPECT/CT techniques may improve prediction.

Predicting Postoperative Lung Function Following Lung Cancer Resection: A Systematic Review and Meta-analysis

BACKGROUND

Lung resection remains the gold standard treatment for early stage lung cancer; prediction of postoperative lung function is a key selection criterion for surgery with the aim of determining risk of postoperative dyspnoea. We aimed to identify the different prediction techniques used, and compare their accuracy.

METHODS

A systematic review and meta-analysis sought to synthesise studies conducted that assess prediction of postoperative lung function up to 18/02/2018 (n = 135). PROBAST was used to assess risk of bias in studies, 17 studies were judged to be at low risk of bias.

FINDINGS

Meta-analysis revealed CT volume and density measurement to be the most accurate (mean difference 71 ml) and precise (standard deviation 207 ml) of the reported techniques used for predicting FEV1; evidence for predicting gas transfer was lacking.

INTERPRETATION

The evidence suggests using CT volume and density is the preferred technique in the prediction of postoperative FEV1. Further studies are required to ensure that the methods and thresholds we propose are linked to patient reported outcomes.

FUNDING

Salary support for NKO, RM, PN, BN, and AMT was provided by University Hospitals Birmingham NHS Foundation Trust.

Gadolinium-Based Blood Volume Mapping From MRI With Ultrashort TE Versus CT and SPECT for Predicting Postoperative Lung Function in Patients With Non-Small Cell Lung Cancer

OBJECTIVE

The purpose of this study is to directly compare the capability of gadolinium-based blood volume (BV) mapping from MRI (BV-MRI) with ultrashort TE (UTE) with that of CT and perfusion SPECT in predicting the postoperative lung function of patients with non-small cell lung cancer (NSCLC).

SUBJECTS AND METHODS

Unenhanced and contrast-enhanced MRI with UTE, thin-section CT, and perfusion SPECT examinations and measurements of the percentage of forced expiratory volume in 1 second (FEV₁) before and after lung resection were performed for 29 patients with NSCLC (16 men [mean age, 66 years] and 13 women [mean age, 66 years]). BV-MRI with UTE was generated as a percentage of the signal change between unenhanced and contrast-enhanced MRI. The postoperative percentage of FEV₁ was predicted from perfusion fractions derived from BV-MRI with UTE and from SPECT. Quantitatively and qualitatively predicted postoperative percentages of FEV₁ from CT were calculated from the functional lung volumes and the number of segments. Each predicted postoperative percentage of FEV₁ was then correlated with the actual postoperative percentage of FEV₁, and the limits of agreement for each actual and predicted postoperative percentage of FEV₁ were evaluated by Bland-Altman analysis.

RESULTS

Correlations between actual and predicted postoperative percentages of FEV₁ for all methods were strong and significant (0.88 ≤ r ≤ 0.95). The limits of agreement (mean ± 1.96 × SD) for BV-MRI with UTE (4.2% ± 6.5%) and quantitatively assessed CT (4.1% ± 6.5%) were smaller than those for qualitatively assessed CT (4.2% ± 9.8%) and perfusion SPECT (5.7% ± 8.7%).

CONCLUSION

BV-MRI with UTE has the potential to predict the postoperative lung function of patients with NSCLC more accurately than qualitatively assessed CT and SPECT, and it can be considered to be at least as useful as quantitatively assessed CT.

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.

To Find a Better Dosimetric Parameter in the Predicting of Radiation-Induced Lung Toxicity Individually: Ventilation, Perfusion or CT based

This study aimed to find a better dosimetric parameter in predicting of radiation-induced lung toxicity (RILT) in patients with non-small cell lung cancer (NSCLC) individually: ventilation(V), perfusion (Q) or computerized tomography (CT) based. V/Q single-photon emission computerized tomography (SPECT) was performed within 1 week prior to radiotherapy (RT). All V/Q imaging data was integrated into RT planning system, generating functional parameters based on V/Q SPECT. Fifty-seven NSCLC patients were enrolled in this prospective study. Fifteen (26.3%) patients underwent grade ≥2 RILT, the remaining forty-two (73.7%) patients didn’t. Q-MLD, Q-V20, V-MLD, V-V20 of functional parameters correlated more significantly with the occurrence of RILT compared to V20, MLD of anatomical parameters (r = 0.630; r = 0.644; r = 0.617; r = 0.651 vs. r = 0.424; r = 0.520 p < 0.05, respectively). In patients with chronic obstructive pulmonary diseases (COPD), V functional parameters reflected significant advantage in predicting RILT; while in patients without COPD, Q functional parameters reflected significant advantage. Analogous results were existed in fractimal analysis of global pulmonary function test (PFT). In patients with central-type NSCLC, V parameters were better than Q parameters; while in patients with peripheral-type NSCLC, the results were inverse. Therefore, this study demonstrated that choosing a suitable dosimetric parameter individually can help us predict RILT accurately.

Predicting exercise capacity after lobectomy by single photon emission computed tomography and computed tomography

OBJECTIVES

This study compared the prediction of postoperative exercise capacity by employing lung perfusion scintigraphy images obtained with single photon emission computed tomography together with computed tomography (SPECT/CT) versus the common method of counting subsegments (SC method).

METHODS

In 18 patients scheduled for lobectomy, predicted postoperative maximum oxygen uptake per kilogram body weight ([Formula: see text]) was calculated by the SPECT/CT and SC methods. Correlations were examined between the [Formula: see text] predicted by SPECT/CT or the SC method, and the actual [Formula: see text] measured at 2 weeks (mean 15.4 ± 1.5 days) and 1 month (mean 29.1 ± 0.75 days) after surgery to determine whether SPECT/CT was more accurate than SC for predicting postoperative exercise capacity.

RESULTS

There was a significant positive correlation between the [Formula: see text] predicted by SPECT/CT and the actual value at 2 weeks (r = 0.802, p < 0.0001) or 1 month (r = 0.770, p < 0.0001). There was also a significant positive correlation between the [Formula: see text] predicted by SC and the actual value at 2 weeks (r = 0.785, p < 0.0001) or 1 month (r = 0.784, p < 0.0001).

CONCLUSIONS

This study showed that both SPECT/CT and the SC method were useful for predicting postoperative [Formula: see text] in the clinical setting.

Feasibility of Single Scan for Simultaneous Evaluation of Regional Krypton and Iodine Concentrations with Dual-Energy CT: An Experimental Study

Purpose To evaluate the feasibility of a simultaneous single scan of regional krypton and iodine concentrations by using dual-energy computed tomography (CT). Materials and Methods The study was approved by the institutional animal experimental committee. An airway obstruction model was first made in 10 beagle dogs, and a pulmonary arterial occlusion was induced in each animal after 1 week. For each model, three sessions of dual-energy CT (80% krypton ventilation [krypton CT], 80% krypton ventilation with iodine enhancement [mixed-contrast agent CT], and iodine enhancement [iodine CT]) were performed. Krypton maps were made from krypton and mixed-contrast agent CT, and iodine maps were made from iodine and mixed-contrast agent CT. Observers measured overlay Hounsfield units of the diseased and contralateral segments on each map. Values were compared by using the Wilcoxon signed-rank test. Results In krypton maps of airway obstruction, overlay Hounsfield units of diseased segments were significantly decreased compared with those of contralateral segments in both krypton and mixed-contrast agent CT (P = .005 for both). However, the values of mixed-contrast agent CT were significantly higher than those of krypton CT for both segments (P = .005 and .007, respectively). In iodine maps of pulmonary arterial occlusion, values were significantly lower in diseased segments than in contralateral segments for both iodine and mixed-contrast agent CT (P = .005 for both), without significant difference between iodine and mixed-contrast agent CT for both segments (P = .126 and .307, respectively). Conclusion Although some limitations may exist, it might be feasible to analyze regional krypton and iodine concentrations simultaneously by using dual-energy CT. ^© RSNA, 2016.

Influence of Pulmonary Rehabilitation on Lung Function Changes After the Lung Resection for Primary Lung Cancer in Patients with Chronic Obstructive Pulmonary Disease

Influence of physiotherapy on the outcome of the lung resection is still controversial. Study aim was to assess the influence of physiotherapy program on postoperative lung function and effort tolerance in lung cancer patients with chronic obstructive pulmonary disease (COPD) that are undergoing lobectomy or pneumonectomy. The prospective study included 56 COPD patients who underwent lung resection for primary non small-cell lung cancer after previous physiotherapy (Group A) and 47 COPD patients (Group B) without physiotherapy before lung cancer surgery. In Group A, lung function and effort tolerance on admission were compared with the same parameters after preoperative physiotherapy. Both groups were compared in relation to lung function, effort tolerance and symptoms change after resection. In patients with tumors requiring a lobectomy, after preoperative physiotherapy, a highly significant increase in FEV1, VC, FEF50 and FEF25 of 20%, 17%, 18% and 16% respectively was registered with respect to baseline values. After physiotherapy, a significant improvement in 6-minute walking distance was achieved. After lung resection, the significant loss of FEV1 and VC occurred, together with significant worsening of the small airways function, effort tolerance and symptomatic status. After the surgery, a clear tendency existed towards smaller FEV1 loss in patients with moderate to severe, when compared to patients with mild baseline lung function impairment. A better FEV1 improvement was associated with more significant loss in FEV1. Physiotherapy represents an important part of preoperative and postoperative treatment in COPD patients undergoing a lung resection for primary lung cancer.

Predicting postoperative exercise capacity after major lung resection

PURPOSE

This study investigates whether postoperative exercise capacity can be predicted from preoperative lung perfusion scintigraphy and the number of subsegments resected.

METHODS

We studied 315 patients, with 158 being assigned odd numbers and 157 being assigned even numbers. In the 158 patients assigned odd numbers, the predicted postoperative VO2 max/m2 (ppo VO2 max/m2) was obtained from the results of lung perfusion scintigraphy and the number of subsegments scheduled for resection. We then examined correlations with the actual values, 2 weeks and 1 month postoperatively, to obtain a regression equation (Series 1). In the 157 patients assigned even numbers, the ppo VO2 max/m2 corrected by the regression equation derived from Series 1 (corrected-ppo VO2 max/m2) was compared with the actual values, 2 weeks and 1 month postoperatively, to establish whether the postoperative VO2 max/m2 could be predicted.

RESULTS

The regression equation between the ppo VO2 max/m2 and its actual value was y = 0.83x + 103, 2 weeks postoperatively, and y = 0.923x + 82, 1 month postoperatively. The difference between the corrected-ppo VO2 max/m2 and the actual postoperative value was small.

CONCLUSIONS

Calculating the residual [Formula: see text]o2 max/m2 preoperatively from the results of lung perfusion scintigraphy and the number of segments scheduled for resection is useful for predicting postoperative exercise capacity.

Oxygen-enhanced MRI, thin-section MDCT, and perfusion SPECT/CT: comparison of clinical implications to patient care for lung volume reduction surgery

OBJECTIVE

The purpose of our study was to prospectively and directly compare capability of O2-enhanced MRI, MDCT, and perfusion SPECT/CT to clinical outcome measurements in candidates for lung volume reduction surgery (LVRS).

SUBJECTS AND METHODS

Twenty-five consecutive candidates for LVRS (20 men and five women; age range, 45-76 years) underwent MDCT, O2-enhanced MRI, and perfusion SPECT/CT before and after LVRS. Clinical outcomes for each candidate were evaluated in terms of differences between pre- and postoperative percentage forced expiratory volume in 1 second (%FEV1), Pao2, and 6-minute walking distance. Quantitatively assessed upper/lower lung ratios on O2-enhanced MRI, MDCT, and SPECT/CT were calculated from regional relative enhancement ratios, functional lung volumes, and radioisotope uptakes between upper and lower lungs. Qualitatively assessed upper/lower lung ratios on O2-enhanced MRI, MDCT, and SPECT/CT were estimated using visual scoring systems. To evaluate the correlation for individual upper/lower lung ratios and clinical outcomes, all upper/lower lung ratios were correlated with clinical outcomes. Improvements in mean relative enhancement ratio were directly correlated with clinical outcomes to assess the capability of O2-enhanced MRI to assess therapeutic effect.

RESULTS

All quantitatively (-0.63≤r≤-0.47, p<0.05) and qualitatively (0.41≤r≤0.57, p<0.05) assessed upper/lower lung ratios showed moderate and statistically significant correlation with clinical outcomes, and improvement in mean relative enhancement ratio showed moderate or good correlation, both statistically significant (-0.44≤r≤0.71, p<0.05).

CONCLUSION

O2-enhanced MRI shows potential for more accurate evaluation of postoperative clinical outcome for LVRS candidates than SPECT/CT and can be considered at least as reliable as MDCT.

Semiquantification and classification of local pulmonary function by V/Q single photon emission computed tomography in patients with non-small cell lung cancer: potential indication for radiotherapy planning

INTRODUCTION

Perfusion (Q) single photon emission computed tomography (SPECT) has been used to divert dose away from higher-functioning lung during radiation therapy (RT) planning. This study aimed to (1) study regional lung function through coregistered pulmonary ventilation/perfusion (V/Q)-SPECT-CT and (2) classify these defects for its potential value in radiation planning in patients with non-small cell lung cancer (NSCLC).

METHODS

Patients with stages I to III NSCLC requiring radiation-based therapy were eligible for this prospective study. V/Q-SPECT performed within 2 weeks before the start of radiation was interpreted by nuclear medicine physicians and then measured by a semiquantitative score. The potential mechanism of V and Q defects was analyzed; the potential impact of V/Q-SPECT over Q-SPECT alone was completed through classified applications (high-dose RT versus RT avoidance) during planning.

RESULTS

Images of 51 consecutive patients were analyzed. The V and Q defects were matched, reverse mismatched (V defect > Q defect), and mismatched (Q defect > V defect) in 61, 31, and 8% of patients, respectively. Tumor was the leading cause of the defects of ipsilateral lung in 73% of patients. The defect scores of the ipsilateral lung were greater in patients with central primaries than those with peripheral primaries for both V-SPECT (2.3 ± 1.1 versus 1.5 ± 0.8, p = 0.017) and Q-SPECT (2.2 ± 0.8 versus 1.4 ± 0.6, p = 0.000). The patients with chronic obstructive pulmonary disease had greater defect scores in contralateral lung for both V-SPECT (1.5 ± 0.7 versus 1.0 ± 0.8, p = 0.006) and Q-SPECT (1.4 ± 0.6 versus 1.0 ± 0.4, p = 0.010). On assessing the potential value of SPECT on RT plan, 39% of patients could have their RT plan when applying V/Q-SPECT rather than Q-SPECT alone.

CONCLUSIONS

V/Q-SPECT provides a more comprehensive functional assessment, may provide additional value over Q-SPECT alone in assessing local pulmonary function, and guide RT plan decisions in patients with NSCLC.

Combined subsegmentectomy: postoperative pulmonary function compared to multiple segmental resection

Background

For small peripheral c-T1N0M0 non-small cell lung cancers involving multiple segments, we have conducted a resection of subsegments belonging to different segments, i.e. combined subsegmentectomy (CSS), to avoid resection of multiple segments or lobectomy. Tumor size, location of tumor, and forced expiratory volume in 1 second (FEV₁) of each preserved lobe were compared among the CSS, resection of single segment, and that of multiple segments.

Methods

FEV₁ of each preserved lobe were examined in 17 patients who underwent CSS, 56 who underwent resection of single segment, and 41 who underwent resection of multiple segments, by measuring pulmonary function and lung-perfusion single-photon-emission computed tomography and computed tomography before and after surgery.

Results

Tumor size in the CSS was significantly smaller than that in the resection of multiple segments (1.4 ± 0.5 vs. 2.0 ± 0.8 cm, p = 0.002). Tumors in the CSS were located in the right upper lobe more frequently than those in the resection of multiple segments (53% vs. 5%, p < 0.001). Postoperative of FEV₁ of each lobe after the CSS was higher than that after the resection of multiple segments (0.3 ± 0.2 vs. 0.2 ± 0.2 l, p = 0.07). Mean FEV₁ of each preserved lobe per subsegment after CSS was significantly higher than that after resection of multiple segments (0.05 ± 0.03 vs. 0.03 ± 0.02 l, p = 0.02). There was no significant difference of these factors between the CSS and resection of single segment.

Conclusions

The CSS is effective for preserving pulmonary function of each lobe, especially for small sized lung cancer involving multiple segments in the right upper lobe, which has fewer segments than other lobes.

V/Q SPECT: utility for investigation of pulmonary physiology

Single-photon emission computed tomography (SPECT) is being increasingly used as a tool in respiratory research, in particular ventilation SPECT. Much of the basic understanding of pulmonary physiology has been derived from inhaled radioactive inert gases because, as the lung behaves in an asymmetric manner, the nature of regional differences in ventilation is ideally studied with the use of imaging. It is well known to clinicians that ventilation is patchy in patients who have airways disease. However, the relevance to the disease mechanisms itself only started to be studied with the use of 3-dimensional imaging and with advances in quantitative image analysis. The measurements of both ventilation distribution and nonventilation (airway closure) have become very topical in the study of asthma, and accurate quantification of those parameters is of relevance to disease mechanisms. In chronic obstructive pulmonary disease, the drive is towards better characterization of disease groups ("phenotypes") and, again, description of ventilation patterns may prove to be useful. This is a review, therefore, on pulmonary SPECT imaging in respiratory research which includes a focus on methodology in relation to respiratory physiology. There has been relatively little published in this area but there is great potential for advances in the understanding of airways disease to be gained from SPECT imaging.

A segmentectomy of the right upper lobe has an advantage over a right upper lobectomy regarding the preservation of the functional volume of the right middle lobe: analysis by perfusion single-photon emission computed tomography/computed tomography

PURPOSE

To evaluate the advantages of a segmentectomy of the right upper lobe (RUL) over a right upper (RU) lobectomy regarding the preservation of the functional volume of the right middle lobe (RML), the postoperative forced expiratory volume in one second (FEV(1)) of the RML was compared between an RU lobectomy and an RUL segmentectomy, by using a coregistered perfusion single-photon emission computed tomography and computed tomography (SPECT/CT).

METHODS

The pulmonary function tests and perfusion SPECT/CT were conducted before and after surgery (RU lobectomy: 7; RUL segmentectomy: 13). The FEV(1) of the RML before and after surgery was calculated from the data of the pulmonary function test and SPECT/CT.

RESULTS

In the RU lobectomy group, the percentage change of FEV(1) was 71% +/- 12%, which was significantly lower in comparison to 92% +/- 9% in the RUL segmentectomy group (P = 0.001). In the lobectomy group, the preoperative FEV(1) of the RML was 0.17 +/- 0.10 l, which decreased significantly to 0.06 +/- 0.06l after surgery (P = 0.009). In the segmentectomy group, FEV(1) of the RML before and after the surgery were 0.23 +/- 0.10 l and 0.20 +/- 0.111, of which the difference was not significant.

CONCLUSION

An RUL segmentectomy has an advantage over an RU lobectomy regarding the preservation of pulmonary function, due to a greater preservation of not only the lung tissue, but also the FEV(1) of the RML.

Quantification of the impact of segmentectomy on pulmonary function by perfusion single-photon-emission computed tomography and multidetector computed tomography

OBJECTIVE

The impact of segmentectomy for preservation of pulmonary function was quantified by using a co-registered perfusion single-photon-emission computed tomography and multidetector computed tomography (SPECT/CT).

METHODS

Pulmonary function tests and perfusion SPECT/CT were conducted before and after segmentectomy in 56 patients. Actual values of forced expiratory volume in 1 second (FEV(1)) after segmentectomy were compared with the FEV(1) after virtual lobectomy, which was calculated by SPECT/CT. The preoperative and postoperative FEV(1) of each lobe that had undergone segmentectomy was measured by SPECT/CT.

RESULTS

The mean percent of FEV(1) preserved after segmentectomy was significantly higher than the value after virtual lobectomy (88% +/- 9% vs 77% +/- 7%; P < .001). Whereas the mean value of the preoperative FEV(1) of each lobe that was undergoing segmentectomy was 0.51+/-0.21 L, segmentectomy could preserve 41% +/- 24% of it. The FEV(1) of each lobe after the resection of more than three segments (n = 4) was preserved in 17% +/- 12% of the preoperative values, which was significantly less than 49% +/- 23% and 35% +/- 22% after the resection of one (n = 29) and two (n = 23) segments (P = .02 and .08, respectively). The FEV(1) of the left upper lobe after the upper division segmentectomy (n = 8) was preserved in 21% +/- 11% of the preoperative values, which was significantly less than 35% +/- 12% after the lingular segmentectomy (n = 7) (P = .03).

CONCLUSION

Segmentectomy can preserve the pulmonary function more significantly than lobectomy, except for the resection of more than three segments or the left upper division segmentectomy.