OBSERVER AGREEMENT AND ACCURACY FOR LUNG SCINTIGRAPHY - A COMPARISON WITH PULMONARY ANGIOGRAPHY

This study investigated whether the moderate observer agreement rate f or lung scintigraphy, when using the PIOPED criteria, reflects signifi cant variations in accuracy. In a prospective study, 170 patients were investigated with lung scintigraphy and pulmonary angiography. The lu ng scintigrams were read according to the PIOPED criteria by three ski lled observers from different hospitals who had no experience of conse nsus interpretation. The scintigrams were reinterpreted 6 months later . The inter-observer agreement rates were moderate and fair, with kapp a values of 0.49 (0.44-0.54) for the first reading and 0.36 (0.31-0.41 ) for the second reading. The intra-observer agreement rates were good and moderate, with kappa values of 0.62 (0.51-0.73), 0.52 (0.42-0.62) and 0.54 (0.44-0.64). There were no significant differences between t he observers in the areas under the ROC curves. However, one observer showed a significant difference between his first and second reading ( P = 0.02). All three observers showed good accuracy. Although there we re substantial variations in the inter- and intra-observer agreement r ates, this was only reflected to a minor degree in the accuracy.