Background: CT is more sensitive and specific than CXR at finding infiltrates.
Four ED’s in France performed both CT and CXR, n = 308 adults with suspected CAP.
CXR 188 had infiltrates; CT excluded CAP in 56 of them.
CXR 120 had no infiltrates; CT found infiltrates in 40 of them.
So: nearly 1/3 of (+) CXRs were false positives, 1/3 of (-) CXR were false negatives.
CT changed antibiotic decision in 25% and hospitalization decision in 14%.
Conclusion: For the diagnosis of CAP, CT is better than CXR. But, we don’t know if using CT would change clinical outcomes, nor do we have a comparison of U/S with CT, which can be as accurate in experienced operators and has no radiation exposure (Am J Emerg Med 2015; 33:620).
Am J Respir Crit Care Med 2015 Oct 15; 192:974