Fibrosing alveolitis associated with systemic sclerosis (FASSc) is considered to be histologically and radiologically indistinguishable from lone cryptogenic fibrosing alveolitis (CFA). To date, the natural history of the two diseases has not been compared directly in large groups of patients followed at a single institution. We evaluated the survival of 205 patients with CFA and 68 patients with FASSc. Deaths during the follow-up period were reported in 142 patients with CFA (70%) and in 11 patients with FASSc (16%). Unadjusted survival from the onset of dyspnea was less in CFA than in FASSc (odds ratio, 3.3; p < 0.001); this difference persisted after adjustment for age of onset of dyspnea and smoking history. Survival from presentation was less in CFA (odds ratio approximately 3.3) after adjustment for age of presentation, smoking history, and initial pulmonary function indices. These differences persisted when analysis was confined to patients with histologic confirmation of fibrosing alveolitis and after adjustment for treatment. In patients undergoing computed tomography (CT) of the lungs, survival was less in CFA after adjustment for extent of abnormal lung on CT and CT pattern of disease (odds ratio, 3.9; p < 0.001). These findings indicate that despite their histologic and radiologic similarities, lone CFA and FASSc have different courses.

Serial CT in FibrosingAlveolitis: Prognostic Significance of the Initial Pattern OBJECTIVE.In patients with fibrosing alveolitis, a reticular pattern on CT scans of the lungs correistes with histologic findings of fibrosis, whereas a ground-glass pattern has been reported to correlate with reversible inflammatory disease. The majority of patients with fibrosing alveolitis have a ground-glass component visible on CT scans, but response to therapy is infrequent. The aim of this study was to evaluate the prognostic significance of the relative extents of ground-glass and reticular patterns by analyzing serial changes in these CT appearances. SUBJECTS AND METHODS. Serial CT scans were analyzed in 56 patients (21 withidiopathic pulmonary fibrosis and 35 with fibrosing alveolitis associated with systemic sclerosis). The relative extents of ground-glass and reticular patterns were assessed on the initial CT scan. Overall extent of abnormal lung and distribution of disease on initial CT scans were also categorized.Changes in extent and appearance of disease were evaluated in paired anatomically comparable CT sections and assessed Independently by two observers; the median interval between scans was 16 months. Serial changes on CT were examined in relation to the initial pattern, extent, and distribution of disease seen on CT scans and in relation to trends In results of concurrent pulmonary function tests.RESULTS. Changes in the extent of disease were due to regression of a groundglass pattern in 18 patients, an increase in a reticular pattern in nine patients, and an increase in a ground-glass pattern in five patients. A reticular pattern did not regress in any patient. In treated patients, diminution in extent of disease, shown as regression of a ground-glass pattern, was seen most frequently when a ground-glass pattern was the most extensive abnormality at initial scanning (p < .002), independent of extent or distribution of disease seen on CT scans and the type of fibrosing alveolitis. When a ground-glass pattern was associated with an equally extensive reticular pattern, the extent of disease diminished with therapy in a minority of patients (5/13). Improvement in results of pulmonary function tests was associated with regression of a ground-glass pattern in the majority of patients (5/11). CONCLUSION.These findings indicate that the prognostic significance of a ground-glass pattern depends on the extent of an associated reticular pattern and is independent of the extent and distribution of disease.

In most clinical series of patients with cryptogenic fibrosing alveolitis (CFA), disease severity is staged using lung function indices. However, many physiologic indices are measured in routine clinical practice; the choice of variable to evaluate functional severity is contentious. Computed tomography (CT) provides a reproducible means of quantifying the morphologic extent of disease. The aim of this study was to evaluate the functional consequences of smoking-related lung damage in CFA and to identify functional measures best reflecting the extent of fibrosing alveolitis on CT. Sixty-eight patients with CFA were studied. Fourteen patients with emphysema on CT were characterized by relative preservation of FVC and TLC (p < 0.005) and relative depression of DLCO (p < 0.05) and KCO (p < 0.00005). On multivariate analysis, the extent of fibrosing alveolitis and the presence of emphysema were independent determinants of functional impairment; there was no independent relationship between smoking history and functional abnormalities. In patients without emphysema on CT, percent predicted DLCO (r = -0.68), oxygen desaturation on exercise (r = 0.64), and the physiologic component of the clinical-radiographic-physiologic (CRP) score (r = 0.62) correlated much better with the extent of disease on CT than spirometric and plethysmographic volumes. A composite functional index was generated against the extent of disease on CT, using multivariate analysis; comparison with the CRP score suggested that the relationship between morphologic disease extent and the CRP score would be improved by the inclusion of DLCO and by the use of negative weighting for depression of FEV1. These findings indicate that in CFA, the presence of concurrent emphysema on CT has a more profound influence upon functional measures than the smoking history, and underline the importance of both the measurements of DLCO and exercise testing in the assessment of the severity of CFA.

Background: This study was designed to measure inter-observer variation between thoracic radiologists in the diagnosis of diffuse parenchymal lung disease (DPLD) using high resolution computed tomography (HRCT) and to identify areas of difficulty where expertise, in the form of national panels, would be of particular value. Methods: HRCT images of 131 patients with DPLD (from a tertiary referral hospital (n = 66) and regional teaching centres (n = 65)) were reviewed by 11 thoracic radiologists. Inter-observer variation for the first choice diagnosis was quantified using the unadjusted kappa coefficient of agreement. Observers stated differential diagnoses and assigned a percentage likelihood to each. A weighted kappa was calculated for the likelihood of each of the six most frequently diagnosed disease entities. Results: Observer agreement on the first choice diagnosis was moderate for the entire cohort (k = 0.48) and was higher for cases from regional centres (k = 0.60) than for cases from the tertiary referral centre (k = 0.34). 62% of cases from regional teaching centres were diagnosed with high confidence and good observer agreement (k = 0.77). Non-specific interstitial pneumonia (NSIP) was in the differential diagnosis in most disagreements (55%). Weighted kappa values quantifying the likelihood of specific diseases were moderate to good (mean 0.57, range 0.49-0.70). Conclusion: There is good agreement between thoracic radiologists for the HRCT diagnosis of DPLD encountered in regional teaching centres. However, cases diagnosed with low confidence, particularly where NSIP is considered as a differential diagnosis, may benefit from the expertise of a reference panel.

Areas of decreased attenuation on expiratory CT scans are common in severe bronchiectasis. Such areas in lobes without overt bronchiectasis suggest that small airways disease may precede the development of bronchiectasis.