Pulmonary Abnormalities on High-Resolution CT Demonstrate More Rapid Decline Than FEV1 in Adults With Cystic Fibrosis: Patient Population

The CF radiology database was retrospectively searched from January 1997 to January 2005 by a single investigator (E.J.) for 39 consecutive patients with two HRCT scans (HRCT-1 and HRCT-2) > 18 months apart (19 males and 20 females; mean age, 22 years; range, 16 to 48 years). All patients had documented clinical, radiologic, or genotypic features of CF as well as abnormal sweat test results (sweat sodium and chloride > 60 mmol/L).
Clinical charts were reviewed and age, body mass index (BMI), spirometry, and sputum cultures were recorded at the time of the two HRCT scans. Only clinically stable patients at the time of a HRCT scan were included. Patients were excluded if they had the following: (1) only one HRCT (or two HRCTs < 18 months apart); (2) symptoms or signs of acute respiratory exacerbation at the time of HRCT or spirometry; (3) unstable spirometry results at the time of either HRCT (> 10% decrease in FEV1 compared with baseline values in the preceding 2 months); (4) required hospitalization for IV antibiotics in the 2 weeks prior to either HRCT for a respiratory tract infection; and (5) died before undergoing sequential HRCT. This resulted in approximately 210 patients being excluded from the study, leaving 39 in the final study group. The hospital ethics committee of out institution approved the study.
Images were obtained using spiral CT with patients in the supine position (Somatom Plus 4; Siemens; Erlangen, Germany). Inspiratory images were obtained in suspended deep inspiration with 1-mm slice thickness every 10 mm from the apices to the costophrenic angles. Expiratory images were obtained in full expiration at three levels: the top of the aortic arch, the carina, and 2 cm above the diaphragm. Scanning parameters were 140 kilovolt peak and 140 mA, with images reconstructed using a high spatial frequency bone algorithm and a 512 X 512 matrix. Lung windows with a width of 2,000 Hounsfield units and level of — 700 Hounsfield units were applied. Images were retrospectively, independently scored in random order by two chest radiologists (J.D., J.M.), who were blinded to patient identification, clinical severity of disease, spirometry, and date of all HRCT scans.

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