Lone cryptogenic fibrosing alveolitis: a functional-morphologic correlation based on extent of disease on thin-section computed tomography

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.

Cryptogenic fibrosing alveolitis and the fibrosing alveolitis of systemic sclerosis: morphological differences on computed tomographic scans

BACKGROUND

The purpose of this study was to identify morphological differences on the computed tomographic (CT) scan between cryptogenic fibrosing alveolitis (CFA) and the fibrosing alveolitis associated with systemic sclerosis (FASSc), and to examine their biological relevance.

METHODS

One hundred and seven patients with CFA (n = 55) or FASSc (n = 52) who had undergone thin section CT scanning were included. Multivariate analysis was used to identify morphological differences on the CT scans between lone CFA and FASSc, and to determine whether the pattern and distribution of disease on the CT scans were functionally significant (as judged by the lung transfer factor (TLCO), forced vital capacity (FVC), and arterial oxygen tension (PaO2)) or predictive of survival (independent of the type and extent of fibrosing alveolitis, age, sex, and smoking history).

RESULTS

Increasingly extensive disease on CT scans was associated with a coarser reticular pattern (increase in reticular score per percentage increase in disease extent = 0.06, 95% confidence interval (CI) 0.03 to 0.09, p < 0.0005) and increasing upper zone involvement (increase in ratio of upper zone to total disease per percentage increase in disease extent = 0.002, 95% CI 0.000 to 0.003, p < 0.04). Patients with CFA were characterised by a higher upper zone ratio (difference = 0.08, 95% CI 0.02 to 0.13, p < 0.004) and a weak trend towards a coarser reticular pattern (p = 0.09), independent of disease extent. Smokers with CFA had more upper zone involvement (difference = 0.11, 95% CI 0.05 to 0.16, p < 0.0005) and a coarser reticular pattern (difference in reticular score = 1.92, 95% CI 0.27 to 3.55, p < 0.02) than smokers with FASSc. The extent of disease on the CT scan was predictive of lung function impairment and survival but the pattern and distribution of disease were not.

CONCLUSIONS

Patients with CFA have relatively more upper zone involvement than those with FASSc independent of the extent of disease on the CT scan. This finding may result from smoking related damage but is not functionally significant.

Effects of airway infection by Pseudomonas aeruginosa: a computed tomographic study

BACKGROUND

Pseudomonas aeruginosa commonly infects the airways of patients with bronchiectasis. A study was undertaken to examine the relationship between infection of the airways with this pathogen, the morphological pattern of bronchiectasis on thin section computed tomographic (CT) scanning, symptom duration, smoking habits of the patients, and the presence of airflow obstruction.

METHODS

Thin section CT scans of 22 adult patients with bronchiectasis and concurrent sputum infected by P aeruginosa (Pa +ve) and those of 45 randomly selected patients not infected by P aeruginosa (Pa -ve) were analysed independently by two thoracic radiologists. Patients with cystic fibrosis were excluded. Each scan was scored at a lobar level for extent of bronchiectasis, severity of bronchial wall thickening and dilatation, predominant pattern of bronchiectasis, presence of mucus plugging, and degree of decreased attenuation of the lung parenchyma.

RESULTS

The Pa +ve group had more extensive bronchiectasis and a greater degree of bronchial wall thickening and dilatation on the CT scan than the Pa -ve group; more extensive decreased attenuation was seen in the Pa +ve group. These findings were robust on multivariate analysis; decreased attenuation was also independently related to the duration of sputum production.

CONCLUSION

Patients with bronchiectasis infected by P aeruginosa have more extensive and severe bronchiectasis on thin section CT scanning than those without P aeruginosa infection. The bronchi and small airways are both involved, reflecting the end result of complex interactions between host airways and the numerous virulence factors produced by P aeruginosa.

Functional impairment in fibrosing alveolitis: relationship to reversible disease on thin section computed tomography

Thin-section computed tomography (CT) provides a reproducible method of quantifying global disease extent and can also discriminate between fibrotic disease, with predominance of reticular abnormalities, and reversible inflammatory cell infiltration, shown as ground-glass attenuation. The aim of this study was to determine whether functional impairment varied according to the presence of ground-glass attenuation on CT, independently of extent of disease on CT, demographic factors, smoking history, therapeutic status, and the type of fibrosing alveolitis (lone cryptogenic fibrosing alveolitis (CFA) versus fibrosing alveolitis associated with systemic sclerosis (FASSc)). Patients with concurrent emphysema on CT (n = 16) and FASSc patients with end-stage pulmonary hypertension (n = 5) were excluded. One hundred and eleven patients were studied (CFA, n = 54; FASSc, n = 57). The severity of functional impairment did not vary independently with the presence of predominant ground-glass attenuation, mixed appearance and predominant reticulation on CT. In 34 treated patients undergoing serial CT scanning, the severity of functional impairment did not differ independently between patients with and without regression of ground-glass attenuation at follow-up. We conclude that the severity of functional impairment does not discriminate between inflammatory and fibrotic disease in fibrosing alveolitis, as judged by initial and serial computed tomographic scanning, after adjustment for the morphological extent of disease on computed tomography.

Comparison of Doppler echocardiography and right heart catheterization to assess pulmonary hypertension in systemic sclerosis

Pulmonary hypertension (PHT) is an important complication of systemic sclerosis (SSc). Echocardiography can be used to detect PHT and, with Doppler echocardiography, the pulmonary arterial systolic pressure (PASP) can often be estimated. We have undertaken a study to compare echocardiographic assessment with right heart catheterization (RHC) in 33 SSc patients in whom clinical assessment [including ECG, chest X-ray, lung function tests and high-resolution computed tomography (HRCT) had raised strong suspicion of PHT. The mean (S.D.) interval between echocardiography and RHC was 1.8 (2.3) months. Twenty-one patients (64%) had PHT (PASP > or = 30 mmHg) on RHC, and echocardiography correctly identified 19 of these (sensitivity 90%). Of the 12 patients without PHT on RHC, nine were correctly identified by echocardiography (specificity 75%). The five incorrectly classified patients all had PASP in the borderline normal/abnormal range. The presence of tricuspid regurgitation allowed Doppler measurement of PASP in 20 patients (61%) and this correlated significantly with RHC values (r = 0.83, P < 0.001). We conclude that echocardiography is a reliable method for detecting PHT and it may be particularly useful for the early detection and monitoring of this potentially fatal complication in SSc.

Bronchiectasis: a neglected cause of respiratory morbidity and mortality

Bronchiectasis is a progressive condition characterized by irreversible destruction and dilation of airways generally associated with chronic bacterial infections. Although in Western countries, the morbidity and mortality from bronchiectasis is considered to have declined markedly in the modern era, the condition continues to cause significant morbidity and mortality in the south-west Pacific and probably also in South-East Asia. There is a high prevalence in indigenous populations in the region and factors such as poverty, substandard housing, malnutrition, barriers to medical care and inadequate education are all likely to have a major impact on prevalence and outcome of bronchiectasis. Although bronchiectasis has been viewed as a disease of medium and large airways, there is now increasing evidence of the importance of small airways disease in bronchiectasis and that it may play an integral role in pathogenesis. Chronic inflammation of the bronchial wall by mononuclear cells is common to all types of bronchiectasis. A vicious cycle of bacteria (mediated lung toxicity and bacteria) provoked, host-mediated inflammatory lung damage has been described. If progressive lung damage with its attendant morbidity and mortality is to be prevented, this vicious cycle needs to be broken. The two distinct therapeutic goals in bronchiectasis are to reduce morbidity and to prevent progression of underlying disease. It may be possible to modulate the host response directly and thus reduce tissue damage, but the precise role of immuno-modulatory therapy in bronchiectasis is still unclear. The management of this hitherto neglected disease, which reaches almost epidemic proportions in some ethnic groups and is an ongoing source of considerable morbidity and mortality, requires a comprehensive, multidisciplinary approach, which can be modelled on the successful management of chronic asthma in New Zealand.

Changes in cross-sectional area of the lungs on end expiratory computed tomography in normal individuals

With the increasing use of expiratory computed tomography (CT) for the detection of air-trapping, and specifically the diagnosis of small airways disease, information about the range of excursion of the chest wall in normal individuals is needed. CT was performed, in full inspiration and end expiration, in 78 individuals (age range 17-70 years) with no demonstrable lung disease. The area of the lungs was measured at the level of the carina, in inspiration and end expiration, and the percentage change in area was calculated. In normal subjects there is, on average, a 55% (SD 8.7%) change in cross-sectional area of the lungs at the level of the carina. Awareness of the normal change in area is of value in assessing the severity of air-trapping in patients undergoing CT for suspected obstructive lung disease.

Hypersensitivity pneumonitis: correlation of individual CT patterns with functional abnormalities

PURPOSE

To correlate the pattern and extent of abnormalities on thin-section computed tomographic (CT) scans with pulmonary function test results in subacute and chronic hypersensitivity pneumonitis.

MATERIALS AND METHODS

Thin-section scans (1-3 mm collimation) obtained in 22 patients were assessed for pattern of abnormality and extent of disease. CT scores were correlated with functional parameters by using Spearman rank correlation and forward stepwise regression analysis.

RESULTS

The most common CT patterns were decreased attenuation and mosaic perfusion (n = 19), ground-glass opacification (n = 18), small nodules (n = 12), and a reticular pattern (n = 8). Areas of decreased attenuation correlated with severity of air trapping indicated by residual volume (r = .58, P < .01), whereas ground-glass opacification and reticulation correlated independently with restrictive lung function.

CONCLUSION

Areas of decreased attenuation and mosaic perfusion are an important ancillary CT finding in hypersensitivity pneumonitis, and obstructive functional abnormalities indicate that this phenomenon is caused by bronchiolitis.

CT evaluation of fibrosing alveolitis--applications and insights

The clinical management of patients with fibrosing alveolitis has traditionally been empirical; without lung biopsy, a definitive diagnosis may be impossible and decisions about treatment are often arbitrary. With the advent of high-resolution computed tomography (CT), the proportion of patients needing lung biopsy for confirmation of the diagnosis of fibrosing alveolitis has declined. There is now much evidence that CT provides an accurate guide to disease activity, and more recent work has shown the important role of CT in providing new insights into the biologic behaviour and pathogenesis of fibrosing alveolitis.

CT findings in bronchiectasis: limited value in distinguishing between idiopathic and specific types

OBJECTIVE

The purpose of this study was to determine whether the pattern and distribution of bronchiectasis shown on CT scans can be used to discriminate between idiopathic cases and those with an identifiable cause.

MATERIALS AND METHODS

The CT scans of 168 patients with chronic purulent sputum production and who were suspected of having bronchiectasis were analyzed (117 patients with idiopathic bronchiectasis, 15 with allergic bronchopulmonary aspergillosis, 15 with hypogammaglobulinemia, 15 with impaired mucociliary clearance, and seven with cystic fibrosis diagnosed in adult life). The scans were analyzed in random order by two observers. The extent, site, type, and lobar distribution of bronchiectasis and the severity of bronchial dilatation and bronchial wall thickening were scored. The frequency of these features in the known-cause groups was compared with that in the idiopathic group to identify any significant differences.

RESULTS

Compared with idiopathic bronchiectasis, no significant lobar predominance was seen in any of the known-cause groups, apart from a higher frequency of lower lobe involvement in the patients with syndromes of impaired mucociliary clearance (p < .02). The bronchiectasis of allergic bronchopulmonary aspergillosis and adult cystic fibrosis was more often widespread (five or six lobes involved (p < .001 and p < .01, respectively) than idiopathic bronchiectasis. Central bronchiectasis was more common in allergic bronchopulmonary aspergillosis (p < .005), although the sensitivity when this was used as a diagnostic feature was only 37%. In all groups, cylindrical bronchiectasis was the most common type, with varicose and cystic bronchiectasis occurring more frequently in allergic bronchopulmonary aspergillosis (p < .01). On multiple regression analysis, allergic bronchopulmonary aspergillosis and adult cystic fibrosis showed more extensive disease than idiopathic bronchiectasis (p < .0005 and p < .001, respectively), independent of other CT features. In hypogammaglobulinemia, dilatation of the bronchial lumen was less than in idiopathic bronchiectasis (p < .02) independent of disease extent and bronchial wall thickness.

CONCLUSION

Although differences in distribution and morphology of bronchiectasis may be seen on CT scans in groups of patients with bronchiectasis of different causes, CT findings applied to individual patients are of limited value in discriminating between idiopathic bronchiectasis and bronchiectasis of various known causes.

Elevated levels of exhaled nitric oxide in bronchiectasis

Bronchiectasis is characterized by chronic inflammation in one or more bronchi, but the extent of inflammation is difficult to monitor. The concentration of nitric oxide (NO) in exhaled air is increased in asthmatic patients, possibly as a result of the chronic inflammatory process. We have measured exhaled NO in patients with documented bronchiectasis and investigated whether the concentration of exhaled NO is related to the extent of disease as defined by computed tomography (CT) and lung function. In 20 patients with bronchiectasis who were not taking inhaled steroids, the peak concentration of NO in exhaled air, measured by a modified chemiluminescence analyzer, was significantly elevated (285 +/- 49.0 ppb) as compared with values for 79 normal subjects (89 +/- 2.7 ppb, p < 0.01) and 19 patients with bronchiectasis treated with inhaled steroids (88 +/- 13.4 ppb, p < 0.01). Thin-section CT was used to quantify the extent of bronchiectasis in the 19 patients. There was a significant correlation between the CT score and FEV1 (r = 0.73, p < 0.01). In patients not treated with inhaled steroids there was a significant relationship between CT score and peak exhaled NO (r = 0.81, n = 12, p < 0.02), but this was not the case for patients treated with regular inhaled steroids (n = 7). We conclude that untreated bronchiectasis is associated with an increase in exhaled NO, and that this is correlated with disease severity, whereas patients treated with inhaled steroids have levels of exhaled NO within the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance scanning in cystic fibrosis: comparison with computed tomography

Comparison has been made between two different spin-echo sequence MR scans and CT scans of the lungs in 17 patients with cystic fibrosis. Scans were assessed for bronchial dilation, bronchial wall thickening and mucus plugging. The resolution of MR does not, at present, compare with CT. TE7 ms matched with CT for demonstrating the extent of bronchiectasis whereas TE30 ms scans were inferior to CT. Stronger background lung signal and less artefact was seen on TE7 ms scans compared with TE30 ms scans. MR is a developing technology that does not involve ionizing radiation which, with further refinement, may prove to be useful in imaging lung pathology in cystic fibrosis.

Fibrosing alveolitis in systemic sclerosis: increase in memory T-cells in lung interstitium

Despite the large numbers of T-cells present in the lungs in fibrosing alveolitis, their pathogenetic role is poorly understood. If these cells are involved in pathogenesis, they are more likely to express the CD45RO+ memory phenotype. To test this hypothesis, open lung biopsies from patients with fibrosing alveolitis associated with systemic sclerosis (FASSc) were compared with grossly normal lung taken from the periphery of lobes resected for lung cancer. Biopsies from eight patients with FASSc were compared with tissue from seven cancer controls. Paraffin sections were stained with a polyclonal anti-CD3 antibody for T-lymphocytes, monoclonal anti-CD45 antibody for leucocyte common antigen, and monoclonal anti-CD45RO antibody for primed T-lymphocytes. Staining was assessed quantitatively by computerized image analysis: in each case, the number of immunopositive cells was related to alveolar wall area and alveolar wall length. Mean alveolar wall thickness was increased in patients with FASSc (60.7 +/- 24.0 microns) compared with cancer controls (15.7 +/- 5.3 microns). Patients with FASSc had greater numbers of CD45+, CD3+ and CD45RO+ cells.mm-1 alveolar wall length compared with the controls. CD45RO+ cells made up 77% (median) of the CD3+ cells in FASSc, and their numbers per unit alveolar wall length were positively associated with alveolar wall thickness (r = 0.61). In conclusion, in fibrosing alveolitis of systemic sclerosis, most interstitial T-lymphocytes express the phenotype of memory cells; these cells are likely to be involved in the persistent inflammatory process.

Effective use of cyclosporin in sarcoidosis: a treatment strategy based on computed tomography scanning

Cyclosporin was used successfully in a patient with severe pulmonary sarcoidosis, a poor response and unacceptable side-effects from corticosteroid therapy. Computed tomography (CT) scanning initially suggested reversible disease, and subsequently detected improvement earlier than other indices of disease activity. This information was critical in the decision to commence and to continue cyclosporin. The literature on the use of cyclosporin in sarcoidosis is reviewed.

Bronchiectasis: functional significance of areas of decreased attenuation at expiratory CT

PURPOSE

To characterize areas of decreased attenuation on expiratory computed tomographic (CT) scans in patients with bronchiectasis.

MATERIALS AND METHODS

CT scans were obtained at full inspiration and end expiration in 70 patients with chronic purulent sputum production. Inspiratory scans were scored at a lobar level for the extent of bronchiectasis, and inspiratory and expiratory scans were scored for the presence and extent of areas of decreased attenuation. Total lobar observations were analyzed (n = 840).

RESULTS

Bronchiectasis was identified in 434 of 840 lobar observations. The total decreased attenuation score was related to extent of bronchiectasis (r = .49; P < .001), independent of functional indexes. Negative correlations were found between forced expiratory volume in 1 second (FEV1) and total decreased attenuation score (P < .002) and FEV1 to forced vital capacity ratio (P < .004) but not with indexes of gas transfer.

CONCLUSION

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.

Fibrosing alveolitis in systemic sclerosis. Bronchoalveolar lavage findings in relation to computed tomographic appearance

Fibrosing alveolitis in systemic sclerosis is histologically identical to lone cryptogenic fibrosing alveolitis (CFA) (idiopathic pulmonary fibrosis). The inflammatory cell content of bronchoalveolar lavage (BAL) samples has been used as a guide to prognosis and treatment in CFA. In this study, the relationship was explored between BAL findings and the extent and pattern of disease within the lavaged lobe, as judged by thin-section computed tomography (CT), in systemic sclerosis. Thirty-eight nonsmoking patients were studied; none had been treated with corticosteroids or immunosuppressive agents, and 11 had no evidence of fibrosing alveolitis on CT. BAL neutrophils were markedly increased in association with extensive disease on CT compared with less extensive disease (p < 0.001) and normal appearances (p < 0.001); the extent of a reticular pattern on CT (denoting fibrosis) correlated with the neutrophil percentage count (p < 0.005) and total neutrophil count/ml (p < 0.01). BAL eosinophils were increased in less extensive as well as in extensive disease when compared with lobes with a normal CT appearance (p < 0.01); eosinophil percentage counts but not total eosinophil counts/ml correlated with the extent of a ground-glass pattern on CT (through to denote inflammation) (p < 0.05). These findings indicate that in systemic sclerosis a BAL neutrophilia is generally associated with extensive fibrotic disease, whereas a BAL eosinophilia is often seen in less advanced disease, particularly when CT appearances suggest lung inflammation.

Fibrosing alveolitis associated with systemic sclerosis has a better prognosis than lone cryptogenic fibrosing alveolitis

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.

Observer variation in pattern type and extent of disease in fibrosing alveolitis on thin section computed tomography and chest radiography

In fibrosing alveolitis the pattern type on thin section computed tomography (CT) predicts histological appearances at open lung biopsy and the likelihood of response to treatment. To test the level of inter- and intra-observer variability on CT and chest radiography (CXR), the pattern type and extent of disease were assessed by four observers (two experienced, two inexperienced). A total of 126 CT examinations and 108 concurrent postero-anterior chest radiographs were scored on two occasions, at least 8 weeks apart. A confidence rating was assigned to each observation. Three out of four observers agreed on pattern type in 81% of cases on CT compared with 54% on CXR (kappa coefficient 0.48 and 0.16 for CT and CXR, respectively). Inter-observer variability in categorizing pattern type on CT was lowest in patients with the highest confidence scores (kappa = 0.63). Confident observations were associated with extensive or moderately extensive disease (P < 0.001), and with a predominantly reticular pattern (P < 0.0001). Intra-observer variability for pattern type on CT was less for the experienced observers (kappa = 0.78 and 0.70) than for the inexperienced group (kappa = 0.50 and 0.37). Inter-observer variability for extent of disease was significantly less on CT than on CXR (standard deviations 7.8% and 9.2% respectively, P < 0.001). This study shows that observer variability using a clinical grading system is lower with CT than with chest radiography in fibrosing alveolitis.

The reproducibility of bronchial circumference measurements using computed tomography

Objective measurement of bronchial damage in patients with bronchiectasis is needed to identify progressive disease. This study evaluates the inter- and intraobserver variation in computed tomography (CT) measurements of bronchial wall circumference and examines the precision with which CT measurements of the bronchi can be repeated in patients with bronchiectasis. Twelve patients were scanned and the circumferences of 61 subsegmental bronchi were measured independently on two occasions, by three observers, using a tracing facility on the CT console. To determine the accuracy with which previously acquired sections could be repeated, five patients were scanned on two separate occasions. The mean bronchial circumference measured by the three observers was 16.1 +/- 8.3 mm. The standard deviations of differences between first and second measurements of bronchial circumference for the three observers (intraobserver variability) were: 0.60 mm, 0.67 mm and 0.40 mm. The standard deviation of readings for interobserver variability was 0.71 mm. The standard deviations of differences (and coefficients of variation) for measurements of bronchial circumference following rescanning were: 1.82 mm, 1.40 mm and 1.74 mm (9.9%, 7.6% and 9.3%, respectively). The reproducibility of measurements of wall circumference, between and within observers and between examinations, indicates that such measurements may be clinically useful in demonstrating the progression of bronchiectasis.

Bronchiolitis in association with connective tissue disorders

In general, lung involvement in connective tissue disorders has not been as well defined as has isolated interstitial lung disease; this applies particularly to bronchiolitis, which occurs infrequently. The low prevalence of bronchiolitis may reflect difficulties in making the diagnosis in mild to moderate disease; at present, most reported disease is severe. This is likely to account for the lack of therapeutic success in obliterative bronchiolitis and in many patients with follicular bronchiolitis. There is a need for earlier intervention if treatment is to be effective, and thus there is a need to refine the noninvasive diagnosis of bronchiolitis. This goal is unlikely to be achieved without the systematic noninvasive evaluation and surveillance of large groups of patients with connective tissue diseases. The role of the pulmonary function laboratory in identifying early bronchiolitis remains entirely uncertain; whether silent "small airways disease," defined physiologically, predicts the eventual development of bronchiolitis is unclear. The reversibility of this asymptomatic lesion with inhaled steroid therapy and the role of inhaled treatment in bronchiolitis, in general, have not been evaluated. More work needs to be done to determine the predictive value of CT appearances and BAL findings, to try to identify a subgroup of patients at greater risk of developing severe bronchiolitis. Further histocompatibility studies may serve as a basis for the selection of patients with an increased likelihood of developing airways disease. The role of open lung biopsy requires further clarification. Better noninvasive evaluation should reduce the need for this invasive procedure; in some patients, however, including those with concomitant interstitial lung disease, histologic assessment will remain an essential component of management. In recent years, in contrast to early reports, it has become apparent that organizing pneumonia has a better prognosis than fibrosing alveolitis in the connective tissue diseases; overall, stability or regression of disease, usually with corticosteroid therapy, was documented in 28 of 39 reported cases. In these patients, a tissue diagnosis serves to identify the need for aggressive therapeutic intervention. Finally, the compilation of larger clinical series would improve our understanding of severe bronchiolitis. This is likely to require multicenter collaboration, which often is impracticable; without this approach, however, the description of bronchiolitis will remain anecdotal.

Serial CT in fibrosing alveolitis: prognostic significance of the initial pattern

OBJECTIVE

In patients with fibrosing alveolitis, a reticular pattern on CT scans of the lungs correlates 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 with idiopathic 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 ground-glass 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 (8/11).

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.

The predictive value of appearances on thin-section computed tomography in fibrosing alveolitis

Fibrosing alveolitis, a condition characterized by a poor prognosis and a limited response to treatment, is readily identified by thin-section computed tomography (CT). Fibrotic and inflammatory histologic results, obtained at open lung biopsy, both have characteristic CT patterns. To evaluate whether CT could predict prognosis and response to therapy, we examined the CT appearances of 76 patients with lone cryptogenic fibrosing alveolitis and 66 patients with fibrosing alveolitis associated with systemic sclerosis. CT abnormalities were categorized as predominantly a ground-glass pattern (Grade 1), mixed (Grade 2), or predominantly a reticular pattern (Grade 3). In cryptogenic fibrosing alveolitis, 4-yr survival was highest in association with CT Grade 1 and higher with CT Grade 2 than with CT Grade 3, independent of the extent of abnormal lung on CT, duration of dyspnea, or severity of depression of DLCO or FVC, p < 0.001. A response to therapy in previously untreated cryptogenic fibrosing alveolitis was seen most frequently with CT Grade 1 and more frequently with CT Grade 2 than with CT Grade 3, p < 0.025. In systemic sclerosis, CT appearances were not predictive of 4-yr survival; a response to therapy was seen more frequently with CT Grade 2 (three of seven patients) than with CT Grade 3 (zero of six patients). These data have shown that CT appearances are of prognostic value in fibrosing alveolitis and that they are likely to play an increasing role in disease-staging in this condition.

Clearance of inhaled 99mTc-DTPA predicts the clinical course of fibrosing alveolitis

The aim of this study was to determine whether the speed of technetium-labelled diethylene-triamine-pentacetate (99mTc-DTPA) clearance from the lung is predictive of disease progression in fibrosing alveolitis, as judged by changes in respiratory function tests. 82 nonsmoking patients with fibrosing alveolitis were studied (progressive systemic sclerosis, n = 53; lone cryptogenic fibrosing alveolitis, n = 29). Normal 99mTc-DTPA clearance at initial measurement predicted stable disease; rapid 99mTc-DTPA clearance identified patients at risk of deterioration. Repeat measurement of clearance, approximately 12 months later, enabled the definition of a subgroup at higher risk, with persistently abnormal 99mTc-DTPA clearance, and a smaller subgroup in whom reversion of clearance to normal was associated with a sustained improvement in respiratory function indices. These findings were not attributable to differences in treatment between subgroups. We conclude that the speed of 99mTc-DTPA clearance discriminates between stable and progressive disease in fibrosing alveolitis.

Clearance of inhaled 99mTc-DTPA predicts the clinical course of fibrosing alveolitis

The aim of this study was to determine whether the speed of technetium-labelled diethylene-triamine-pentacetate (99mTc-DTPA) clearance from the lung is predictive of disease progression in fibrosing alveolitis, as judged by changes in respiratory function tests. 82 nonsmoking patients with fibrosing alveolitis were studied (progressive systemic sclerosis, n = 53; lone cryptogenic fibrosing alveolitis, n = 29). Normal 99mTc-DTPA clearance at initial measurement predicted stable disease; rapid 99mTc-DTPA clearance identified patients at risk of deterioration. Repeat measurement of clearance, approximately 12 months later, enabled the definition of a subgroup at higher risk, with persistently abnormal 99mTc-DTPA clearance, and a smaller subgroup in whom reversion of clearance to normal was associated with a sustained improvement in respiratory function indices. These findings were not attributable to differences in treatment between subgroups. We conclude that the speed of 99mTc-DTPA clearance discriminates between stable and progressive disease in fibrosing alveolitis.