Abstract 2092 Pulmonary: Cystic Fibrosis Poster Symposium, Tuesday, 5/4

Purpose: There is a need for sensitive, reproducible noninvasive outcome measures for interventional studies in cystic fibrosis. The aims of this ongoing study were (1) to evaluate a new HRCT scoring system in CF patients before and after treatment for a pulmonary, (2) to correlate HRCT scores with clinical and pulmonary function parameters, and (3) to determine if HRCT scoring components are more sensitive than pulmonary function parameters for changes after therapeutic interventions. Methods: Sixteen symptomatic patients with mild to moderate CF pulmonary disease (9F:7M, [mean±SD] age: 17±7 years, FEV1: 65±15% pred, FEF25-75%: 41±22 % pred) were evaluated by spirometer-triggered electron beam CT scanning (1.5 mm collination) of the chest at specified and expiratory lung volumes for 6 anatomic levels of the lung, by pulmonary function tests, and by an acute change clinical score (ACCS) on exacerbation and at 15±1 days after treatment. HRCT scans were independently reviewed by three radiologists using a scoring system which incorporated irreversible (extent and severity of bronchiectasis and bronchial wall thickening) and reversible (mucus plugging [MP], atelectasis/consolidation [atel/cons], and air trapping [AT]) components. For atel/cons. and AT sub-components, HRCT images were scored as follows: 1=absent; 2 <25% lobar surface area; 3=25-50% lobar surface area; 4 > 50% lobar surface area. Test sensitivity for different HRCT and FEV1 parameters were assessed by effect size analysis. Results: In 16 subjects there was improvement in ACCS (17±4 [Test], 9±3 [Test2], p<0.0001), and selected PFT parameters (e.g. FVC 2.68±0.81 L [Test1], 2.90±0.85 L [Test2], p<0.01, FEV1 1.93±0.65 L [Test1], 2.16±0.76 L [Test2], p<0.01, FEFmax 6.00±1.93 L/s [Test1], 6.77±2.14 L/s [Test2], p<0.01). In interim analysis of 12 of 18 planned subjects, there was a significant decrease in the reversible subscore components MP and atel/cons.(p=0.02). The AT subscore did not improve significantly (p=0.58). In addition there was a correlation between change in FEV1 and change in ACCS (r=0.65, p=0.02), and change in total HRCT score (r=-0.44). Effect size analysis for different HRCT & FEV1 parameters revealed a rank order as follows: reversible component score w/o air-trapping =0.8 > reversible component score w/ air trapping =0.5 > total HRCT score =0.33 > FEV1 = 0.20 = air trapping subcomponent score of 0.20 > irreversible component score = 0.00. Conclusions: Improvements were noted in FEV1 and other pulmonary function parameters as well as the ACCS. Reversible HRCT component subscores w/o the air trapping component were sensitive in detecting short term changes. Air trapping as defined in this scoring system is insensitive in demonstrating short-term changes.

Funded by Cystic Fibrosis Research, Incorporated.