title: Quantification of Pathologic Air Trapping in Lung Transplant Patients Using CT Density Mapping: Comparison with Other CT Air Trapping Measures.
abstract: To determine whether density mapping (DM) is more accurate for detection and quantification of pathologic air trapping (pAT) in patients after lung transplantation compared to other CT air trapping measures. One-hundred forty-seven lung and heart-lung transplant recipients underwent CT-examinations at functional residual capacity (FRC) and total lung capacity (TLC) and PFT six months after lung transplantation. Quantification of air trapping was performed with the threshold-based method in expiration (EXP), density mapping (DM) and the expiratory to inspiratory ratio of the mean lung density (E/I-ratio MLD). A non-rigid registration of inspiration-expiration CT-data with a following voxel-to-voxel mapping was carried out for DM. Systematic variation of attenuation ranges was performed for EXP and DM and correlated with the ratio of residual volume to total lung capacity (RV/TLC) by Spearman rank correlation test. AT was considered pathologic if RV/TLC was above the 95th percentile of the predicted upper limit of normal values. Receiver operating characteristic (ROC) analysis was performed. The optimal attenuation range for the EXP method was from -790 HU to -950 HU (EXP(-790 to -950HU)) (r = 0.524, p<0.001) to detect air trapping. Within the segmented lung parenchyma, AT was best defined as voxel difference less than 80 HU between expiration and registered inspiration using the DM method. DM correlated best with RV/TLC (r = 0.663, p<0.001). DM and E/I-ratio MLD showed a larger AUC (0.78; 95% CI 0.69-0.86; 0.76, 95% CI 0.67-0.85) than EXP(-790 HU to -950 HU) (0.71, 95% CI 0.63-0.78). DM and E/I-ratio MLD showed better correlation with RV/TLC and are more suited quantitative CT-methods to detect pAT in lung transplant patients than the EXP(-790HU to -950HU).
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Solyanik
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Kantonsspital, Aarau, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Hollmann
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Dettmer
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Kaireit
authors.affiliation: Radiologie, Meander Medisch Centrum, Amersfoort, the Netherlands; Radiologie - DIAG, UMC St Radboud, Nijmegen, the Netherlands.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Schaefer-Prokop
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Wacker
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Vogel-Claussen
authors.affiliation: Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany; Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hanover, Germany.
authors.forename: Hoen-oh
authors.initials: HO
authors.lastname: Shin
mesh_terms: D000328:Adult; D000388:Air; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology*; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D014057:Tomography, X-Ray Computed