[Interobserver agreement in the assessment of pulmonary infiltrates on chest radiography in community-acquired pneumonia].

PURPOSE

To assess interobserver agreement (IOA) in the diagnosis of pulmonary infiltrates on chest x-rays for patients with community-acquired pneumonia (CAP).

MATERIALS AND METHODS

From 7/2002 to 12/2005, 806 adults with CAP were included in the multicenter study "CAPNETZ" (7 hospitals). Inclusion criteria were clinical signs of pneumonia and pulmonary opacification on chest x-rays. Each x-ray was reevaluated by two radiologists from the university hospital in consensus reading against the interpreter at the referring hospital in regard to: presence of infiltrate (yes/no/equivocal), transparency (<or=/>50%), localization, and pattern of infiltrates (alveolar/interstitial). The following parameters were documented: digital or film radiography, hospitalization, fever, findings of auscultation, microbiological findings.

RESULTS

The overall IOA concerning the detection of infiltrates was 77.7% (n=626; CI 0.75-0.81), the infiltrates were not verified in 16.4% (n=132) by the referring radiologist with equivocal findings in 5.9% (n=48). The IOA of the different clinical centers varied between 63.2% (n=38, CI 0.48-0.78) and 92.3% (n=65, CI 0.86-0.99). The IOA for the diagnosis of infiltrates was significantly higher for inpatients with 82.6% (n=546; CI 0.80-0.85) than for outpatients with 55.2 % (n=80; CI 0.47-0.63), p<0.0001. The IOA of infiltrates with a transparency >50% was 95.1% (n=215; CI 0.92-0.98) versus 80.4% (n=403; CI 0.77-0.84) for infiltrates with a transparency >50% (p<0.0001). In patients with positive auscultation, the IOA was higher (p=0,034). Chest x-rays of patients with antibiotic therapy or an alveolar infiltrate showed more equivocal findings compared to patients without these features.

CONCLUSION

There is considerable interobserver variability in the diagnosis of pulmonary infiltrates on chest radiographs. The IOA is higher in more opaque infiltrates, positive auscultation and inpatients.