Pulmonary Fissure Integrity and Collateral Ventilation in COPD Patients

Abstract

PurposeTo investigate whether the integrity (completeness) of pulmonary fissures affects pulmonary function in patients with chronic obstructive pulmonary disease (COPD).Materials and MethodsA dataset consisting of 573 CT exams acquired on different subjects was collected from a COPD study. According to the global initiative for chronic obstructive lung disease (GOLD) criteria, these subjects (examinations) were classified into five different subgroups, namely non-COPD (222 subjects), GOLD-I (83 subjects), GOLD-II (141 subjects), GOLD-III (63 subjects), and GOLD-IV (64 subjects), in terms of disease severity. An available computer tool was used to aid in an objective and efficient quantification of fissure integrity. The correlations between fissure integrity, and pulmonary functions (e.g., FEV1, and FEV1/FVC) and COPD severity were assessed using Pearson and Spearman's correlation coefficients, respectively.ResultsFor the five sub-groups ranging from non-COPD to GOLD-IV, the average integrities of the right oblique fissure (ROF) were 81.8%, 82.4%, 81.8%, 82.8%, and 80.2%, respectively; the average integrities of the right horizontal fissure (RHF) were 62.6%, 61.8%, 62.1%, 62.2%, and 62.3%, respectively; the average integrities of the left oblique fissure (LOF) were 82.0%, 83.2%, 81.7%, 82.0%, and 78.4%, respectively; and the average integrities of all fissures in the entire lung were 78.0%, 78.6%, 78.1%, 78.5%, and 76.4%, respectively. Their Pearson correlation coefficients with FEV1 and FE1/FVC range from 0.027 to 0.248 with p values larger than 0.05. Their Spearman correlation coefficients with COPD severity except GOLD-IV range from −0.013 to −0.073 with p values larger than 0.08.ConclusionThere is no significant difference in fissure integrity for patients with different levels of disease severity, suggesting that the development of COPD does not change the completeness of pulmonary fissures and incomplete fissures alone may not contribute to the collateral ventilation.

Lung imaging

“…These findings were supported by another study looking at 573 CT examinations in COPD patients [3]. While the above-mentioned study relied on a visual assessment, PU et al [3] used an automatic tool for assessment of fissure integrity. The integrities of the right major fissure and the left major fissure were similar (∼82%), irrespective of COPD severity, and the integrity of the right minor fissure was relatively low (∼62%).…”

“…Accessory fissures were found in 16% of patients, with the left horizontal being the most common location [2]. These findings were supported by another study looking at 573 CT examinations in COPD patients [3]. While the above-mentioned study relied on a visual assessment, PU et al [3] used an automatic tool for assessment of fissure integrity.…”

Prevalence of incomplete interlobar fissures of the lung

“…For assessment on CT, the authors usually state criteria for incomplete fissures, with several using four types accord-ing to the varying presence of vessels, including the situation when a fissure is simply missing. Data from various CT methods were mostly obtained from hundreds of patients 1,[12][13][14][15][16][17][18][19][20][21][22][23] . Only Frija et al 12 used healthy volunteers.…”

“…Hereafter, scans of patients indicated for this examination with no pathological finding on the chest CT (selected retrospectively) were used, as during CT examination irradiation cannot be avoided and it would not be ethical to perform such a study on healthy population. Pu et al 22 also included COPD patients. The prevalence of incomplete fissures ranged from 19.2% to 77% (mean 48.7), 17.4% to 87% (mean 55.4), and 48.3% to 89% (mean 69.8) for left oblique, right oblique, and horizontal fissures, respectively.…”

Emphysema: Imaging for Endoscopic Lung Volume Reduction

“…A computer-assisted analysis of 573 CT-examinations recently showed that roughly 90 % of all examined persons have incomplete fissures regardless of whether COPD is present or not [56]. For the individual fissures, integrity was around 82 % for the oblique fissures (bilateral) and 62 % for the horizontal fissure, regardless of severity of COPD.…”