Usefulness of quantitative Tc-99m HMPAO and Ga-67 citrate lung scans in detecting pulmonary vascular endothelium damage and lung inflammation in patients with systemic lupus erythematosus: a preliminary report.

Pulmonary vascular endothelium damage in 34 patients with systemic lupus erythematosus (SLE) was measured by technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan. The degree of damage was represented as lung/liver uptake (L/L) ratio. The patients were divided into two subgroups according to the following criteria: (a) clinical features, separated as stable or flare stage and (b) chest X-ray findings separated as positive or negative results. Meanwhile, quantitative gallium-67 citrate (Ga-67) lung scan was performed as Ga-67 uptake index (GUI) to evaluate the severity of inflammation in the SLE lungs. The results show (a) no significant statistical differences in the degree of pulmonary vascular endothelium damage (the L/L ratio on Tc-99m HMPAO lung scan) between the two subgroups according to clinical features or chest X-ray findings and (b) no good correlation between the degree of pulmonary vascular endothelium damage and lung inflammation (GUI on Ga-67 lung scan). In conclusion, the change in pulmonary vascular endothelium damage in SLE may be unrelated to the clinical presentation or chest X-ray findings, and its degree is not related to the severity of pulmonary inflammation.