Quantitative CT Analysis for Fissure Completeness in Bronchoscopic Lung Volume Reduction

Objectives: The absence of collateral ventilation (CV) is crucial for effective bronchoscopic lung volume reduction (BLVR) with an endobronchial valve (EBV). Here, we assessed whether CT can predict the ChartisTM results and substitute it in part of patients. Methods: Patients who undertook CT to evaluate eligibility for BLVR between 2012 and 2013 were retrospectively reviewed. The ChartisTM system was used to check CV. Experienced thoracic radiologists independently determined the completeness of fissures on volumetric CT images using in-house software. Results: A total of 69 patients (mean age: 70.9±6.6 years; 66 [95.7%] male) underwent CT to assess BLVR eligibility. The comparison between the visual and quantitative analyses revealed that 5% defect criterion showed good agreement. The ChartisTM assessment was performed for 129 lobes; 11 (19.6%) of 56 lobes with complete fissures on CT showed positive CV, while this rate was significantly higher (35 of 44 lobes, i.e., 79.5%) for lobes with incomplete fissures. The size of the fissure defect did not affect the rate of CV. Of the patients who underwent BLVR, 22 of 24 patients (91.7%) with complete fissures and three of four patients with incomplete fissures (75%) achieved target lobe volume reduction (TLVR). Conclusions: The quantitative analysis of fissure shows that incomplete fissures increased the probability of CV on ChartisTM, while the defect size did not affect the overall rates. CT cannot substitute ChartisTM completely, because TLVR could be achieved even in some patients with relatively large fissure defect, if they showed negative CV on ChartisTM.