68 Gallium DOTA-NOC PET/CT as a predictor of disease activity in sarcoidosis

Introduction: It is hypothesized that granulomas in sarcoidosis, as like other somatostatin receptor expressing pathologies will show increased uptake of tracer on 68Ga-DOTA-NOC. However, role of 68Ga-DOTA-NOC PET/CT has not been studied in this disease till now. Aims: To evaluate the role of gallium- 68 (68Ga) labelled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-Nal3-octreotide (DOTA-NOC) PET/CT in assessing disease activity in sarcoidosis. Methods: 39 sarcoidosis patients were divided on the presence/absence of disease manifestations and underwent 68Ga-DOTA-NOC PET/CT. Maximum standardized uptake value (SUVmax) at the pathological site and in the descending thoracic aorta (reference standard, SUVmed) was assessed. SUVmax/SUVmed ratio [disease activity score (DAS)] of more than one was taken as a marker of active disease. DAS was compared with clinical symptoms and other parameters like serum angiotensin converting enzyme (SACE) and CT scan. Study was repeated in 13 patients who were started on treatment after six-nine months Results: 35 patients (88%) in this study had thoracic involvement. Increased disease activity was present in symptomatic than asymptomatic patients (92% vs 16%). In extrathoracic disease, parotid gland and lymph nodes demonstrated increased uptake. A positive correlation was observed between the DAS with SACE (p Conclusion: 68Ga-DOTA-NOC PET/CT emerged as a useful tool to detect clinical activity, treatment response in sarcoidosis patients with thoracic involvement.