Areas of hyperlucency with hypovascularity defined mosaic perfusion on inspiratory scans. Areas of hyperlucency on expiratory images defined air trapping. The total score was derived by adding the scores for each abnormality, and ranged from 0 to 37. For scoring purposes, the average of the two observers’ individual scores were calculated. Absolute total scores were converted to percentages of the potential total maximum score. The extent and severity of abnormalities were scored as in Table 1.
Pulmonary function testing (PFT) [Masterscope; Vivaysis/Jaeger; Wurzburg, Germany] was performed within 1 month before or after HRCT, with the majority (61 of 78 scans) being performed on the same day. Comparisons at time 1 and time 2 for FEV1 and FVC were available in all patients; comparisons at time 1 and time 2 were available for forced expiratory flow between 25% and 75% of expiratory vital capacity (FEF25-75%) in 28 patients, diffusion capacity of the lung for carbon monoxide (Dlco) in 21 patients, and residual volume (RV) and total lung capacity (TLC) in 16 patients. Measurements were obtained using described techniques, and predicted normal values were used to calculate percentage of predicted values. Spirometry results were expressed as percentage of predicted. “Stable” spirometry results were defined as a change of < 1% over the time period for each patient (median ± SD time interval, 42 ± 7 months; range, 20 to 73 months).
Patients were also subgrouped into mild, moderate, and severely impaired lung function groups based on FEV1 percentage of predicted values. Patients in the mild group had FEV1 > 80% of predicted, patients in the moderate group had FEV1 from 50 to 80% of predicted, and patients in the severe group had FEV1 < 50% of predicted.
Sputum samples were collected following spontaneous expectoration at time 1 and time 2 and were processed by the microbiology laboratory at our CF center using standardized methodology. Samples were plated onto selective media using standard techniques, and pathogen colony morphotypes were identified visually.
Table 1—Modified Bhalla CT Scoring System
|Severity of bronchiectasis||Absent||Lumen slightly greater than adjacent vessel||Lumen 2 to 3 X adjacent vessel||Lumen > 3 X adjacent vessel|
|Peribronchial thickening||Absent||Airway wall thickness equal to adjacent vessel||Airway wall thickening < 2 X adjacent vessel||Airway wall thickening > 2 X adjacent vessel|
|Extent ofbronchiectasis (BPS)||Absent||1-5||6-9||> 9|
|Extent of mucous plugging (BPS)||Absent||1-5||6-9||> 9|
|Sacculations/abscesses (BPS)||Absent||1-5||6-9||> 9|
|Generations of bronchial divisions||Absent||Up to fourth generation||Up to fifth generation||Up to sixth generation|
|No. of bullae||Absent||Unilateral||Bilateral||> 4|
|Emphysema (BPS)||Absent||1-5||> 5|
|Mosaic perfusion*||Absent||1-5||> 5|
|Air trapping*||Absent||1-5||> 5|
|Thickening of intralobular septae*||Absent||Subsegmental/segmental||Lobar||Diffuse (> 1 lobe)|
|Ground glass*||Absent||Subsegmental/segmental||Lobar||Diffuse (> 1 lobe)|