Acute parenchymal lung disease in immunocompetent patients: Diagnostic accuracy of high-resolution CT

OBJECTIVE. The purpose of this study was to determine whether acute parench ymal lung diseases can be differentiated on the basis of the pattern and di stribution of abnormalities revealed on high-resolution CT. MATERIALS AND METHODS. High-resolution CT scans of 90 patients with acute p arenchymal lung diseases (19 with bacterial pneumonia, 13 with mycoplasmal pneumonia, 21 with acute interstitial pneumonia, 18 with hypersensitivity p neumonitis, 10 with acute eosinophilic pneumonia, and nine with pulmonary h emorrhage) were independently assessed by two observers who had no knowledg e of clinical or pathologic data. The observers recorded abnormalities, the ir first-choice diagnosis, and their degree of confidence in their first-ch oice diagnosis. RESULTS. The two observers made a correct first-choice diagnosis in an aver age of 55 (61%) of 90 cases. Correct first-choice diagnosis was made in 50% of cases of bacterial pneumonia, 62% of mycoplasmal pneumonia, 90% of acut e interstitial pneumonia, 72% of hypersensitivity pneumonitis, 30% of acute eosinophilic pneumonia, and 28% of pulmonary hemorrhage. CT findings allow ed distinction between infectious and noninfectious causes in 81 (90%) of 9 0 cases. CONCLUSION. High-resolution CT is helpful in the differential diagnosis of infectious from noninfectious acute parenchymal lung disease. However, high -resolution CT is of limited value in making a specific diagnosis.