title: Do diagnostic algorithms always produce a uniform lung scan interpretation?
abstract: Several algorithms have been devised to assist in the interpretation of ventilation-perfusion (V/Q) scans performed to diagnose pulmonary embolism. The degree to which adherence to a single algorithm facilitates diagnostic homogeneity among different readers, however, has been little investigated. We evaluated the individual variability in V/Q lung scan interpretation in a large, academic nuclear medicine division to determine the degree of interpretive heterogeneity among a group of physicians all using the same image interpretation algorithm. Ventilation-perfusion scan interpretive patterns and the diagnostic accuracy of individual physicians were evaluated using quantitative parameters to establish group norms and to detect variations from these norms. The performance of each reader was tracked over a 4 yr period. There was a significant variation in V/Q interpretive patterns and diagnostic accuracy between readers despite the attempted use of a uniform diagnostic algorithm. Subgroups of interpretive styles could be defined based on the percentage of intermediate (including both indeterminate and intermediate categories) scans read. Although there was significant variation in diagnostic accuracy among readers, there was no obvious correlation between accuracy and reading style except that the most nonstandard diagnostic patterns were associated with the most variable diagnostic accuracy. These data show a measurable variation in interpretive patterns and accuracy among multiple readers of V/Q scans despite attempted group adherence to an established diagnostic algorithm.
authors.affiliation: Division of Nuclear Medicine, Massachusetts General Hospital, Boston 02114.
authors.forename: J A
authors.initials: JA
authors.lastname: Scott
authors.forename: E L
authors.initials: EL
authors.lastname: Palmer
mesh_terms: D000465:Algorithms; D006801:Humans; D015994:Incidence; D008168:Lung / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio / Q000502:physiology