Diagnostic performance of 68Ga-DOTANOC PET/computed tomography in cardiac sarcoidosis: comparison with 18F-fluorodeoxyglucose PET/computed tomography and cardiac magnetic resonance

Introduction Cardiac MRI (CMR) and PET aid in early diagnosis and follow-up of cardiac sarcoidosis. 18 F-fluorodeoxyglucose ( 18 F-FDG) PET/computed tomography (CT) is a major criterion in diagnosing cardiac sarcoidosis disease activity and therapy response; however, requires stringent dietary modifications for suppressing myocardial uptake. 68 Ga-DOTANOC, targeting somatostatin receptors in sarcoid granulomas, maybe an alternative, showing minimal physiological myocardial uptake and not needing dietary modifications to suppress myocardial radiotracer activity. Methodology This prospective study enrolled 23 patients, either biopsy-proven pulmonary sarcoidosis with suspected cardiac involvement or primary cardiac abnormalities with clinical and histopathological diagnosis from a systemic site. Patients underwent CMR, 13 N-NH 3 18 F-FDG PET/CT (post-low-carbohydrate, high-fat, high-protein diet), and 68 Ga-DOTANOC PET/CT. Patient-wise and cardiac-segment-wise analysis was done using Cohen’s κ to assess intermodality agreement among three modalities. Mean maximum standardized uptake value (SUV max ) and target-to-background blood pool ratio (TBR) were calculated for positive lesions on 68 Ga-DOTANOC and 18 F-FDG PET/CT. Results 68 Ga-DOTANOC and CMR showed almost perfect segment-wise agreement Cohen’s κ : 0.88, 95% confidence interval (CI): 0.84–0.92, P = 0.004 and moderate patient-wise agreement (Cohen’s κ : 0.51, 95% CI: 0.29–0.73, P = 0.003). 18 F-FDG PET/CT and CMR showed almost perfect segment-wise agreement (Cohen’s κ : 0.80, 95% CI: 0.76–0.84, P = 0.004) and substantial patient-wise agreement (Cohen’s κ : 0.77, 95% CI: 0.58–0.96, P = 0.001). Mean lesion SUV max and TBR were similar for 68 Ga-DOTANOC (6.6 ± 2.8 and 3.4 ± 1.4) and 18 F-FDG (9.0 ± 5.4 and 3.6 ± 1.2) (unpaired t -test, P = 0.16 for SUV max , P = 0.68 for TBR). Conclusion 68 Ga-DOTANOC PET/CT shows promise as a complementary imaging modality for cardiac sacoidosis, with diagnostic performance comparable in many aspects to 18 F-FDG PET/CT and CMR. Further prospective studies are warranted to validate its role.