title: Computer-assisted detection of pulmonary nodules: evaluation of diagnostic performance using an expert knowledge-based detection system with variable reconstruction slice thickness settings.
abstract: The purpose of this study was to evaluate the performance of a computer-assisted diagnostic (CAD) tool using various reconstruction slice thicknesses (RST). Image data of 20 patients undergoing multislice CT for pulmonary metastasis were reconstructed at 4.0, 2.0 and 0.75 mm RST and assessed by two blinded radiologists (R1 and R2) and CAD. Data were compared against an independent reference standard. Nodule subgroups (diameter >10, 4-10, <4 mm) were assessed separately. Statistical methods were the ROC analysis and Mann-Whitney U test. CAD was outperformed by readers at 4.0 mm (Az = 0.18, 0.62 and 0.69 for CAD, R1 and R2, respectively; P<0.05), comparable at 2.0 mm (Az = 0.57, 0.70 and 0.69 for CAD, R1 and R2, respectively), and superior using 0.75 mm RST (Az = 0.80, 0.70 and 0.70 and sensitivity = 0.74, 0.53 and 0.53 for CAD, R1 and R2, respectively; P<0.05). Reader performances were significantly enhanced by CAD (Az = 0.93 and 0.95 for R1 + CAD and R2 + CAD, respectively, P<0.05). The CAD advantage was best for nodules <10 mm (detection rates = 93.3, 89.9, 47.9 and 47.9% for R1 + CAD, R2 + CAD, R1 and R2, respectively). CAD using 0.75 mm RST outperformed radiologists in nodules below 10 mm in diameter and should be used to replace a second radiologist. CAD is not recommended for 4.0 mm RST.
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technical University Munich, Ismaningerstrasse 22, 81675, Munich, Germany. katharina.marten@roe.med.tu-muenchen.de
authors.forename: Katharina
authors.initials: K
authors.lastname: Marten
authors.forename: Andreas
authors.initials: A
authors.lastname: Grillhösl
authors.forename: Tobias
authors.initials: T
authors.lastname: Seyfarth
authors.forename: Silvia
authors.initials: S
authors.lastname: Obenauer
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.forename: Christoph
authors.initials: C
authors.lastname: Engelke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005103:Expert Systems; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed