Pulmonary involvement in Behçet's disease: evaluation of 123 I-MIBG retention

Pulmonary involvement in Behçet's disease (BD) is reported to indicate poor prognosis and high mortality. Our aim was to evaluate the pulmonary vascular status in BD. As 123I-meta-iodobenzylguanidine (123I-MIBG) shares the same uptake, storage and release mechanisms as norepinephrine, associated with the functional state of pulmonary endothelium, it may reflect endothelial injury. Twenty-five patients (13 males, 12 females; mean age, 36.44 years) and 12 age-matched controls were included. After intravenous injection of 123I-MIBG, thorax images were taken at 15 min and 4 h. Appropriate regions of interest were drawn, and heart to mediastinum (H/M) ratios and lung retention indices (LRI) were calculated. The difference between the LRI of controls (75.6+/-4%) and patients (87.7+/-10%) was found to be extremely significant (P<0.005). The LRIs of active (92.85+/-12%) and inactive (83.65+/-5%) states of BD were significantly different (P<0.05) from each other. There was no significant difference between the H/M ratios of controls (2.4+/-0.27) and patients (2.39+/-0.31) or between patients in active and inactive disease states. Our study revealed prolonged lung retention of 123I-MIBG in BD, probably reflecting the severity of the disease. In conclusion, 123I-MIBG lung retention is a valuable finding in the evaluation of pulmonary vascular status and may be a potential marker of prognosis in BD.