Octreoscan perspectives in sarcoidosis and idiopathic interstitial pneumonia

Clinical, radiological, and serological tests have been proven to be unsatisfactory as markers of activity in sarcoidosis and idiopathic interstitial pneumonia (IIP). We investigated 111In-Octreotide (Octreoscan) scintigraphy as a tool for classifying and assessing disease activity in sarcoidosis and IIP, in comparison of the radiological imaging and dyspnea symptom scores.

Thirty-three patients (pts) of which 16 with sarcoidosis (mean age 43.6, range 30-58 years) and 17 with histologically diagnosed IIP (mean age 62.2, range 35-79 years), were enrolled in the study. Clinical history was taken as well as, physical examination, chest X-ray and pulmonary function tests were assessed. A high-resolution computed tomography scan (HRCT) was carried out in-patients affected by sarcoidosis, who had a normal chest X-ray, and in IIP patients. Both groups were evaluated with the Octreoscan uptake index (U.I.; normal value: < or = 10).

In patients affected with sarcoidosis, the Octreoscan U.I. was significantly higher than in patients with IIP (16.35 +/- 3.1 and 10.06 +/- 0.8, respectively; p < 0.01) and was correlated with the radiographic staging (p < 0.01) and with the degree of dyspnea (p < 0.01). In-patients with IIP the Octreoscan uptake index was slightly above the normal limit (range 10.3-11.7) in non-specific interstitial pneumonia (NSIP) and desquamative interstitial pneumonia (DIP), whereas in usual interstitial pneumonia (UIP) Octreoscan uptake index was always within normal limit (< or = 10 U.I.). A negative correlation was observed with histological findings (p < 0.01) and with HRCT appearance (p < 0.01).

Octreoscan U.I. is correlated with the degree of dyspnea in patients affected by sarcoidosis and can quantify more accurately the degree of pulmonary involvement, as compared to radiological assessment. Further studies are necessary to evaluate Octreoscan as an early test for predicting disease progression. Octreoscan U.I. could be helpful in monitoring IIP in specific histological subsets (NSIP and DIP) and substitute HRCT in the assessment of UIP for its excellent accuracy.