HIGH-RESOLUTION CT IN THE ACUTE EXACERBATION OF CYSTIC-FIBROSIS - EVALUATION OF ACUTE FINDINGS, REVERSIBILITY OF THOSE FINDINGS, AND CLINICAL CORRELATION

OBJECTIVE. The aims of this study were threefold: to compare high-reso lution CT (HRCT) of adult patients with cystic fibrosis (CF) during ac ute exacerbations with asymptomatic patients with CF, to evaluate reve rsibility of HRCT abnormalities after exacerbations, and to correlate HRCT with clinical parameters. SUBJECTS AND METHODS. Nineteen symptoma tic and eight asymptomatic patients were prospectively evaluated by HR CT and pulmonary function tests (PFTs). Symptomatic patients were reas sessed 2 weeks after the exacerbation. Studies were independently revi ewed by two radiologists using a modified Bhalla scoring system, notin g the presence, extent, and severity of bronchiectasis, peribronchial thickening, mucus plugging, and atelectasis or consolidation. Modifica tions to the Bhalla system included evaluation of the presence and pro fusion of centrilobular nodules and air-fluid levels within bronchiect atic cavities. The highest possible score was 24 points. Higher scores indicated greater severity, Mosaic perfusion was noted but not includ ed in the modified Bhalla HRCT score. Total modified Bhalla HRCT score and components of the HRCT score were correlated with corresponding P FT parameters. RESULTS. Bronchiectasis, peribronchial thickening, mucu s plugging, centrilobular nodules, and mosaic perfusion were identifie d in symptomatic and asymptomatic patients. Air-fluid levels in bronch iectatic cavities, identified in two patients, represented the only fi nding limited to acute exacerbation, Reversible findings included air- fluid levels (100%), centrilobular nodules (36%), mucus plugging (33%) , and peribronchial thickening (11%), Total HRCT severity scores of sy mptomatic and asymptomatic patients correlated with forced vital capac ity (FVC) (r = .44, p = .01) and forced expiratory volume at 1 sec (FE V1) (r = .34, p = .04). Severity of bronchiectasis correlated with FVC (r = .50, p = .004) and FEV1 (r = .40, p = .02), Mucus plugging and c entrilobular nodules did not correlate with PFT parameters, In the sym ptomatic patients, improvement in HRCT score correlated with changes i n FEV1/FVC (r = .39, p = .049). CONCLUSION. Air-fluid levels in bronch iectatic cavities were the only parenchymal finding shown by HRCT that was limited to the acute exacerbation of CF in our study population. However, this finding was rare, being seen in two of 19 patients. Mucu s plugging, centrilobular nodules, and peribronchial thickening were p otentially reversible findings in symptomatic patients. HRCT accuratel y revealed disease severity in patients with CF. We also found that ch anges in HRCT scores correlated with clinical improvement as determine d by PFTs.