A dual tracer Ga-68-DOTANOC PET/CT and F-18-FDG PET/CT pilot study for detection of cardiac sarcoidosis

作者：Gormsen Lars C^*; Haraldsen Ate; Kramer Stine; Dias Andre H; Kim Won Yong; Borghammer Per

来源：EJNMMI Research, 2016, 6(1): 52.

DOI：10.1186/s13550-016-0207-6

• Cardiac sarcoidosis
• PET/CT
• Somatostatin receptor imaging
• Inflammation
• Heart failure

Background: Cardiac sarcoidosis (CS) is a potentially fatal condition lacking a single test with acceptable diagnostic accuracy. F-18-FDG PET/CT has emerged as a promising imaging modality, but is challenged by physiological myocardial glucose uptake. An alternative tracer, Ga-68-DOTANOC, binds to somatostatin receptors on inflammatory cells in sarcoid granulomas. We therefore aimed to conduct a proof-of-concept study using Ga-68-DOTANOC to diagnose CS. In addition, we compared diagnostic accuracy and inter-observer variability of Ga-68-DOTANOC vs. F-18-FDG PET/CT.
Methods: Nineteen patients (seven female) with suspected CS were prospectively recruited and dual tracer scanned within 7 days. PET images were reviewed by four expert readers for signs of CS and compared to the reference standard (Japanese ministry of Health and Welfare CS criteria).
Results: CS was diagnosed in 3/19 patients. By consensus, 11/19 F-18-FDG scans and 0/19 Ga-68-DOTANOC scans were rated as inconclusive. The sensitivity of F-18-FDG PET for diagnosing CS was 33 %, specificity was 88 %, PPV was 33 %, NPV was 88 %, and diagnostic accuracy was 79 %. For Ga-68-DOTANOC, accuracy was 100 %. Inter-observer agreement was poor for F-18-FDG PET (Fleiss' combined kappa 0.27, NS) and significantly better for Ga-68-DOTANOC (Fleiss' combined kappa 0.46, p = 0.001).
Conclusions: Despite prolonged pre-scan fasting, a large proportion of F-18-FDG PET/CT images were rated as inconclusive, resulting in low agreement among reviewers and correspondingly poor diagnostic accuracy. By contrast, Ga-68-DOTANOC PET/CT had excellent diagnostic accuracy with the caveat that inter-observer variability was still significant. Nevertheless, Ga-68-DOTANOC PET/CT looks very promising as an alternative CS PET tracer.

• 出版日期2016-6-17