DIAGNOSIS OF DISEASES OF THE TRACHEA AND MAIN BRONCHI - CHEST RADIOGRAPHY VS CT

OBJECTIVE. The purpose of this study was to compare the sensitivities and diagnostic accuracies of chest radiography and CT in the assessmen t of diseases of the trachea and main bronchi in regard to detection, evaluation of focal vs diffuse disease, separation of benign from mali gnant disease, and accuracy of diagnosis. MATERIALS AND METHODS. The c hest radiographs and CT scans of 35 patients with proved diseases of t he trachea and main bronchi and five control subjects were randomly as sessed by two independent observers in a blind study. The diagnoses in cluded 25 malignant and 1 0 benign conditions. The malignant lesions i ncluded 24 primary tumors and one metastatic melanoma. The benign lesi ons included two benign tumors, two tracheal stenoses, one focal amylo idosis, one tracheomalacia, and four miscellaneous diffuse abnormaliti es. The observers were asked to determine if an abnormality was presen t, to classify it as focal or diffuse and as benign or malignant, and to list the three most likely diagnoses. Sensitivities were compared b y using the McNemar test. RESULTS. The sensitivity of both observers i n detecting disease on the chest radiograph was 66%. The sensitivity o n the CT scan was 97% for the first observer and 91% for the second ob server (p < .01). Both observers were able to correctly classify the d etected abnormalities as either focal or diffuse in 91% of cases on th e chest radiographs and 97% of cases on the CT scans. The abnormalitie s were correctly classified as either benign or malignant in 78% of ca ses by both observers on the chest radiographs and in 85% and 78% of c ases on the CT scans by the first observer and the second observer, re spectively. The correct diagnosis was included in the list of the thre e most likely diagnoses in 61% of cases by both observers after review ing the radiographs and in 56% of cases by one observer and 63% of cas es by the other observer after reviewing the CT scans. CONCLUSION. CT is superior to chest radiography in allowing detection of abnormalitie s of the major airways. Both CT and chest radiography are accurate for differentiating focal from diffuse disease, but neither technique is accurate for distinguishing benign from malignant disease or for estab lishing a specific diagnosis.