Usability of the lateral decubitus position on four-dimensional ultra-low-dose computed tomography for the detection of localized pleural adhesion in the pulmonary apical region

Abstract

<jats:sec><jats:title>Background</jats:title><jats:p> Localized pleural adhesion (LPA) evaluation in the apical region is difficult even with four-dimensional ultra-low-dose computed tomography (4D-ULDCT) in the supine position due to smaller pleural movements. </jats:p></jats:sec><jats:sec><jats:title>Purpose</jats:title><jats:p> To assess usability of 4D-ULDCT in the lateral decubitus (LD) position for LPA detection in the apical region. </jats:p></jats:sec><jats:sec><jats:title>Material and Methods</jats:title><jats:p> Forty-seven patients underwent 4D-ULDCT of a single respiration cycle with 16-cm coverage of body axis in supine and LD positions with the affected lung uppermost. Intraoperative thoracoscopic findings confirmed LPA presence. A pleural point and a corresponding point on costal outer edge were placed in identical axial planes at end-inspiration. Pleuro-chest wall distance between two points (PCD) was calculated at each respiratory phase. In the affected lung, average change in amount of PCD (PCD<jats:sub>ACA</jats:sub>) was compared between patients with and without LPA in total and two sub-groups (non-COPD and COPD, non-emphysematous and emphysematous patients) in supine and non-dependent (ND) LD positions. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal thresholds in PCD<jats:sub>ACA</jats:sub> for differentiating patients with LPA from those without. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> In COPD/emphysematous patients and total population, PCD<jats:sub>ACA</jats:sub> with LPA was smaller than in those without in the supine and NDLD positions for overall, lateral, and dorsal regions. For the lateral region in COPD patients, area under ROC curve (AUC) increased from supine (0.64) to NDLD position (0.81). For the dorsal region in emphysematous patients, AUC increased from supine (0.76) to NDLD position (0.96). </jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p> 4D-ULDCT in LD position may be useful for LPA detection in apical regions for COPD and/or emphysematous patients. </jats:p></jats:sec>

Area-Detector Computed Tomography for Pulmonary Functional Imaging

“…This system has been clinically tested as an upright CT system at our institution (Figure 5). 70,[113][114][115][116][117][118][119][120][121][122][123]. Regarding the use of ADCT for the evaluation of lung biomechanics, the ACTIve study group has published in vitro and in vivo studies of the capability of dynamic 4D ADCT to evaluate regional lung biomechanics and pleural invasion in lung cancer patients as well as air trapping or air flow limitations [115][116][117][118][119][120][121][122][123].…”

“…Pulmonary functional imaging has been recommended as having the potential to estimate lung compliance by tracking voxel motion at full inspiration (total lung capacity) and at full expiration (residual volume) by means of inspiratory/expiratory CT or MRI [67][68][69][70]112]. Moreover, lung compliance estimates derived from free-breathing and static-volume 4D CT and 4D MRI can be obtained by using deformable image registration [67][68][69][70][113][114][115][116][117][118][119][120][121][122][123]. Regarding the use of ADCT for the evaluation of lung biomechanics, the ACTIve study group has published in vitro and in vivo studies of the capability of dynamic 4D ADCT to evaluate regional lung biomechanics and pleural invasion in lung cancer patients as well as air trapping or air flow limitations [115][116][117][118][119][120][121][122][123].…”

“…Moreover, lung compliance estimates derived from free-breathing and static-volume 4D CT and 4D MRI can be obtained by using deformable image registration [67][68][69][70][113][114][115][116][117][118][119][120][121][122][123]. Regarding the use of ADCT for the evaluation of lung biomechanics, the ACTIve study group has published in vitro and in vivo studies of the capability of dynamic 4D ADCT to evaluate regional lung biomechanics and pleural invasion in lung cancer patients as well as air trapping or air flow limitations [115][116][117][118][119][120][121][122][123]. Moreover, it is now possible to generate whole lung 4D ADCT images with a proprietary software provided by Canon Medical Systems and, in the near future, to begin to evaluate the efficacy of 4D ADCT as a new system for pulmonary functional imaging.…”

Right main pulmonary artery distensibility on dynamic ventilation CT and its association with respiratory function

“…Some study subjects have been previously included in one of our previous studies [ 15 , 16 , 20 , 21 , 24 ] in the following way. In the selection process for the study population in the present study, 32 patients were identified among 72 patients who were enrolled between July 2015 and May 2016 in our previous study for different purposes: assessment of the detectability of localized benign pleural adhesion [ 15 , 16 , 24 ], continuous measurement of the main bronchial dimensions and lung density in the lateral position for smokers [ 20 ], and evaluation of the association of respiratory functional indices and smoking with pleural movement [ 21 ].…”