Chronic hypersensitivity pneumonitis: high-resolution CT and radiographic features in 16 patients.

Abstract

To evaluate the manifestations of chronic hypersensitivity pneumonitis at radiography and high-resolution computed tomography (HRCT), findings in 16 patients with this disease were reviewed. To ensure objectivity, 50 patients with other chronic infiltrative lung diseases (fibrosing alveolitis [n = 29], sarcoidosis [n = 16], and miscellaneous conditions [n = 5]) were included. All patients had chronic disease with evidence of fibrosis at HRCT, as indicated by irregular linear areas and architectural distortion. Radiographs and HRCT scans were reviewed separately, in random order, and without knowledge of diagnosis. On radiographs and HRCT scans, the fibrosis in cases of hypersensitivity pneumonitis was situated predominantly in the middle lung zones or showed no zonal predominance. Lung apices and bases were relatively spared in all cases. The distribution of fibrosis in the transverse plane was random in seven cases, subpleural in six, and peri-bronchovascular in three. The distribution of fibrosis can allow distinction of chronic hypersensitivity pneumonitis from other causes of fibrosis in many cases.

Pathology of Chronic Hypersensitivity Pneumonitis What Is It? What Are the Diagnostic Criteria? Why Do We Care?

“…Honeycombing, which is a requirement for a diagnosis of UIP/IPF, has been reported in 16% to 69% of CHP cases, 12,15,16 and in contrast to the honeycombing in patients with UIP/IPF, honeycombing in patients with CHP seldom has a basal predominance. The reticulation in CHP can be patchy, random or peribronchovascular or have a predominantly subpleural distribution, mimicking UIP/IPF.…”

“…Fibrosis may be predominantly mid or upper zonal with basal sparing (Figure 1, A through D) but is often predominantly in the lower zone and is sometimes evenly distributed. 12,15,17,18 Commonly, superimposed findings of subacute HP are encountered, including patchy ground-glass opacities usually affecting less than 50% of the lung parenchyma. Lobular areas of decreased attenuation and vascularity ( Figure 1, E and F) are described in approximately 80% of patients, with poorly defined centrilobular nodules in approximately 50% of patients.…”

Chronic Hypersensitivity Pneumonitis Caused by Aspergillus Complicated with Pulmonary Aspergilloma

“…Adler et al reported that on HRCT scan, the fibrosis in cases of CHP was situated predominantly in the middle lung zones or showed no zonal predominance, so they concluded that the distribution of fibrosis could allow the distinction of CHP from other causes of fibrosis in many cases (11). Lynch et al reported that patients with IPF were more likely to have honeycombing and peripheral or lower lung zone predominance of the disease, and less likely to have micronodules, than were patients with CHP (9).…”

Chronic Hypersensitivity Pneumonitis

“…In some cases, the findings are similar to those seen in IPF-lower lobe predominance, with subpleural honeycombing. 63 ACIF has, in many cases, a peribronchovascular distribution on HRCT.…”