Semiquantitative 67Ga scintigraphy as an indicator of response to and prognosis after corticosteroid treatment in idiopathic interstitial pneumonia.

The prognosis in some forms of idiopathic interstitial pneumonia (IIP), especially idiopathic pulmonary fibrosis (IPF) and fibrotic nonspecific interstitial pneumonia (NSIP), is still poor. A minority of patients will respond to immunosuppressive treatment. In patients with IPF or fibrotic NSIP, pulmonary (67)Ga scintigraphy may be useful for predicting response to therapy and prognosis. The objective of the present study was to evaluate whether semiquantitative (67)Ga scintigraphy can be used to predict responsiveness to therapy with high-dose corticosteroids in a well-defined population of patients with IIP (IPF and fibrotic NSIP). This study was performed in a tertiary referral center. We prospectively performed (67)Ga scintigraphy in 23 consecutive patients previously diagnosed with IIP (IPF and fibrotic NSIP) before and after treatment with 3 monthly courses of high-dose methylprednisolone. Lung function tests and bronchoalveolar lavage (BAL) were performed before and after these 3 courses, and patients were monitored for 1 y after the start of the treatment. During follow-up, 5 patients died, none during the first 3 mo. Although pulmonary (67)Ga uptake significantly decreased after treatment (P = 0.001), there was no correlation between either initial (67)Ga uptake or change in (67)Ga uptake on treatment and 1-y prognosis. This finding was independent of prior immunosuppressive treatment, diagnosis of IPF or NSIP, or whether initial (67)Ga uptake was elevated or not. BAL cellularity was correlated with neither pulmonary (67)Ga uptake nor response to treatment. Pulmonary (67)Ga uptake cannot be used to predict response to corticosteroid treatment or prognosis in patients with IIP. Apparently, the (inflammatory) process influenced by treatment with methylprednisolone does not determine the progression of disease. This finding supports the hypothesis that although inflammation is present in IPF and fibrotic NSIP, it is neither the hallmark of the disease nor the major factor determining prognosis.