Correlations between radiological and cytological findings in early development of bronchopulmonary dysplasia

Sequential chest radiographs from 40 newborn infants requiring assisted ventilation for respiratory distress syndrome or other conditions were evaluated with a new scoring system aiming at identifying abnormal expansion patterns and interstitial infiltrates representing an early stage of bronchopulmonary dysplasia (BPD). Age at examination ranged from 3 to 23 days. Tracheal effluent samples obtained from the babies during the same period of observation were examined cytologically for evidence of regenerating airway epithelium with squamous metaplasia, indicating BPD. According to the radiological scoring system 24 babies (60%) developed BPD, first diagnosed at a median age of 9 days. By cytological criteria 20 babies (50%) developed BPD, first diagnosed at a median age of 10.5 days. The results from radiological and cytological diagnosis of BPD were concordant in 16 babies (P < 0.05 by chi-square test). Using oxygen dependency at the age of 28 days as evidence of established BPD, the radiological scoring system alone had a sensitivity of 93% and a specificity of 53%. The corresponding figures for cytological assessment alone were 73% and 58%, respectively. By combining radiological and cytological findings, values for sensitivity and specificity were 67% and 68%, respectively.