N-Phase Local Expansion Ratio for Characterizing Out-of-Phase Lung Ventilation.

ABSTRACT: Out-of-phase ventilation occurs when local regions of the lung reach their maximum or minimum volumes at breathing phases other than the global end inhalation or exhalation phases. This paper presents the N-phase local expansion ratio (LER _N ) as a surrogate for lung ventilation. A common approach to estimate lung ventilation is to use image registration to align the end exhalation and inhalation 3DCT images and then analyze the resulting correspondence map. This 2-phase local expansion ratio (LER₂) is limited because it ignores out-of-phase ventilation and thus may underestimate local lung ventilation. To overcome this limitation, LER _N measures the maximum ratio of local expansion and contraction over the entire breathing cycle. Comparing LER₂

SUBMITTER: Shao W 

PROVIDER: S-EPMC7316305 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature