INTEROBSERVER VARIABILITY IN THE INTERPRETATION OF CHEST ROENTGENOGRAMS OF PATIENTS WITH POSSIBLE PNEUMONIA

Background: Previous studies have found considerable interobserver var iability in the roentgenographic diagnosis of pneumonia. In this study we determined the impact of experience on interobserver variability i n the interpretation of chest roentgenograms of patients with pneumoni a and defined the characteristics of chest roentgenograms interpreted as pneumonia by all groups. Methods: The chest roentgenograms of 15 co nsecutive patients with a clinical and roentgenographic diagnosis of p neumonia were read by a convenience sample of 10 first-year and 20 fou rth-year medical students, 21 medical residents, and 21 staff physicia ns from the department of medicine. Three board-certified radiologists served as the gold standard. The majority rule decision and logistic regression analysis were used to analyze agreement among the various g roups of observers. Results: Agreement with the majority decision of t he gold-standard radiologists on the presence or absence of pneumonia for all observations of the various groups were as follows: original r adiologist, 87%; first-year medical students, 59%; fourth-year medical students, 54%; medical residents, 66%; and attending staff, 72%. Ches t roentgenograms with dense lobar or segmental opacities were generall y interpreted as pneumonia by all observers. Patchy opacities caused m ajor disagreements and were usually read as not being due to pneumonia . Bronchopneumonia was not diagnosed by any of the observers. Air bron chograms, atelectasis, and chronic obstructive lung disease were usual ly not recognized by the nonradiologists. Conclusions: There is consid erable interobserver variability in the roentgenographic diagnosis of pneumonia. This variability does not improve with increasing experienc e. Dense lobar or segmental opacities are uniformly recognized as pneu monia while patchy opacities result in a variety of interpretations.