Cryptogenic fibrosing alveolitis (CFA) is characterized by interstitial fibrosis and parenchymal inflammation. Eleven patients with CFA (10 proved by lung biopsy) were followed over 2 yr using clinical symptoms, radiographic change, and pulmonary function tests to adjust their treatment. Lung lavage, positron camera (PET) measurements of regional extravascular lung density (Dev), pulmonary blood volume (Vb), and the metabolic rate for ¹⁸F-deoxyglucose (MRglc), clearance of ^99mTc-diethylenetriaminepentacetate (^99mTc-DTPA) aerosol, and lung uptake of ⁶⁷Ga were measured initially and at the end of the first year to give a profile of the inflammatory response. Compared with normal subjects, there was an increased percentage of neutrophils and eosinophils in the lung lavage, increased Dev (p < 0.002) with no significant difference in Vb, increased MRglc (p < 0.02), ^99mTc-DTPA clearance (p < 0.002), and ⁶⁷Ga uptake (p < 0.02). The smallest increases in Dev were seen in the two patients with most destruction shown by lung biopsy. There were inverse correlations between Dev and both FVC and TLC, but a direct correlation between Vb and transfer factor. ^99mTc-DTPA clearance changed concordantly with clinical status and radiographic and respiratory function changes during the first year. If glucose utilization (MRglc) remained in the normal range between the initial and first yearly assessment, the patient improved or remained stable during the second year as shown by clinical status and radiographic and respiratory function measurements. If it rose or remained high, the patient's condition deteriorated. This pilot study suggests that clearance of ^99mTc-DTPA and glucose utilization are useful additional measures of the parenchymal inflammation in CFA.