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Figure 7–10. Chest x-ray of a patient with IPF. Note the relatively small lung volumes and the diffuse reticulonodular infiltrates, most apparent in the lung bases (arrow).
Table 7–2. Mimics of diffuse parenchymal lung disease Pulmonary edema Chronic bronchitis with prominent pulmonary vasculature Bronchiectasis Diffuse infectious pneumonia (nongranulomatous; ie, viral, Pneumocystis jiroveci, and atypicals)
other diagnoses of DPLDs such as sarcoid, hypersensitivity pneumonitis, lymphangioleiomyomatosis (LAM), and Langerhans cell histiocytosis or another idiopathic interstitial pneumonia. A confident radiologic diagnosis of UIP is based on classic findings of a bilateral, subpleural, basal-predominant, reticular pattern associated with subpleural cysts (honeycombing), and traction bronchiectasis. When based on these findings, a radiologic diagnosis of UIP is correct in more than 90% of cases. HRCT may help guide the location of biopsy to increase the yield. Ideally multiple lung biopsies should be obtained from more than one lobe of the lung and should include the full spectrum of the gross disease appearance. Based on the specificity of the clinical evaluation and the HRCT findings, the American Thoracic Society and the European Respiratory Society have developed criteria for the diagnosis of IPF without a surgical biopsy. Unfortunately, although the HRCT findings are specific they are not sensitive, and atypical HRCT findings may reveal UIP on biopsy. Therefore, if the