PURPOSE To quantify the contributions of individual lobes to lung volume and to characterize quantitative morphological metrics associated with these volumes. METHOD AND MATERIALS 17 healthy volunteers underwent spirometrically monitored volumetric chest CT at total lung capacity (TLC), functional residual capacity (FRC), and mean inspiratory capacity (MIC), measured half-way between TLC and FRC. Dedicated software (Pulmo3D, MeVis, Germany) was used to measure lobar volume, lobar mean lung density (MLD) and the standard deviation of lobar MLD (MLD-SD), as a surrogate parameter for parenchymal heterogeneity. Differences between groups were tested by t-test and analyses of variance. RESULTS The biggest contributors to lung volume at TLC were RLL (27%) and LLL (27%), at MIC RLL (26%) and LLL (26%), and at FRC LUL (25%) and RLL (24%). The smallest contributor in all three respiratory capacities was the RML (TLC 8%, MIC 9%, FRC 11%). Relative volumes of lower lobes decreased from TLC to FRC (RLL 27 to 24%; LLL 27 to 23%), whereas relative volumes of middle (RML 8 to 11%) and upper lobes (RUL 17 to 18%; LUL 21 to 25%) increased. All CT lung volume changes between TLC, MIC, and TRC were statistically significant (p<0.001). Lobar MLD density was higher in lower lobes, at any lung volume (p<0.001). MLD-SD increased from TLC to FRC, in all lobes (p<0.001), again with different pattern of variation between upper and lower lobes. Lower lobes showed substantial increase in MLD-SD from TLC to MIC and to FRC. Otherwise, MLD-SD of upper lobes and right middle lobe were near-identical at any lung volume. CONCLUSION Our study provides normative data on absolute and relative lobar contribution to lung volume and lung heterogeneity in normals. The findings confirm the major contribution of the lower lobes to lung volume changes and reveal that substantial physiological heterogeneity throughout all lobe is a normal finding in healthy lungs. CLINICAL RELEVANCE/APPLICATION Our data provide normative reference values for lobar contribution to lung volume and lung heterogeneity, and can be used as quantitative benchmark for the evaluation of these parameters.
Lung volume and heterogeneity: CT quantification of lobar contribution / Silva, Mario; Nemec, Sf; Heidinger, Benedikt H; Occhipinti, Mariaelena; Dufresne, Valerie; Molinari, Francesco; Bankier, Alexander A.. - (2014). (Intervento presentato al convegno 100th Meeting of the Radiological Society of North America (RSNA) tenutosi a Chicago (IL) nel November 30 - December 4, 2014).
Lung volume and heterogeneity: CT quantification of lobar contribution
SILVA, Mario;
2014-01-01
Abstract
PURPOSE To quantify the contributions of individual lobes to lung volume and to characterize quantitative morphological metrics associated with these volumes. METHOD AND MATERIALS 17 healthy volunteers underwent spirometrically monitored volumetric chest CT at total lung capacity (TLC), functional residual capacity (FRC), and mean inspiratory capacity (MIC), measured half-way between TLC and FRC. Dedicated software (Pulmo3D, MeVis, Germany) was used to measure lobar volume, lobar mean lung density (MLD) and the standard deviation of lobar MLD (MLD-SD), as a surrogate parameter for parenchymal heterogeneity. Differences between groups were tested by t-test and analyses of variance. RESULTS The biggest contributors to lung volume at TLC were RLL (27%) and LLL (27%), at MIC RLL (26%) and LLL (26%), and at FRC LUL (25%) and RLL (24%). The smallest contributor in all three respiratory capacities was the RML (TLC 8%, MIC 9%, FRC 11%). Relative volumes of lower lobes decreased from TLC to FRC (RLL 27 to 24%; LLL 27 to 23%), whereas relative volumes of middle (RML 8 to 11%) and upper lobes (RUL 17 to 18%; LUL 21 to 25%) increased. All CT lung volume changes between TLC, MIC, and TRC were statistically significant (p<0.001). Lobar MLD density was higher in lower lobes, at any lung volume (p<0.001). MLD-SD increased from TLC to FRC, in all lobes (p<0.001), again with different pattern of variation between upper and lower lobes. Lower lobes showed substantial increase in MLD-SD from TLC to MIC and to FRC. Otherwise, MLD-SD of upper lobes and right middle lobe were near-identical at any lung volume. CONCLUSION Our study provides normative data on absolute and relative lobar contribution to lung volume and lung heterogeneity in normals. The findings confirm the major contribution of the lower lobes to lung volume changes and reveal that substantial physiological heterogeneity throughout all lobe is a normal finding in healthy lungs. CLINICAL RELEVANCE/APPLICATION Our data provide normative reference values for lobar contribution to lung volume and lung heterogeneity, and can be used as quantitative benchmark for the evaluation of these parameters.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
