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

Abstract

BackgroundCardiac sarcoidosis (CS) is a potentially fatal condition lacking a single test with acceptable diagnostic accuracy. 18F-FDG PET/CT has emerged as a promising imaging modality, but is challenged by physiological myocardial glucose uptake. An alternative tracer, 68Ga-DOTANOC, binds to somatostatin receptors on inflammatory cells in sarcoid granulomas. We therefore aimed to conduct a proof-of-concept study using 68Ga-DOTANOC to diagnose CS. In addition, we compared diagnostic accuracy and inter-observer variability of 68Ga-DOTANOC vs. 18F-FDG PET/CT.MethodsNineteen 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).ResultsCS was diagnosed in 3/19 patients. By consensus, 11/19 18F-FDG scans and 0/19 68Ga-DOTANOC scans were rated as inconclusive. The sensitivity of 18F-FDG PET for diagnosing CS was 33 %, specificity was 88 %, PPV was 33 %, NPV was 88 %, and diagnostic accuracy was 79 %. For 68Ga-DOTANOC, accuracy was 100 %. Inter-observer agreement was poor for 18F-FDG PET (Fleiss’ combined kappa 0.27, NS) and significantly better for 68Ga-DOTANOC (Fleiss’ combined kappa 0.46, p = 0.001).ConclusionsDespite prolonged pre-scan fasting, a large proportion of 18F-FDG PET/CT images were rated as inconclusive, resulting in low agreement among reviewers and correspondingly poor diagnostic accuracy. By contrast, 68Ga-DOTANOC PET/CT had excellent diagnostic accuracy with the caveat that inter-observer variability was still significant. Nevertheless, 68Ga-DOTANOC PET/CT looks very promising as an alternative CS PET tracer.Trial registrationCurrent Controlled Trials NCT01729169.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0207-6) contains supplementary material, which is available to authorized users.

Hybrid Magnetic Resonance Imaging and Positron Emission Tomography With Fluorodeoxyglucose to Diagnose Active Cardiac Sarcoidosis

“…Although our use of a control group that underwent CT/PET rather than CMR/PET was a potential limitation, the fact that we consistently observed this apparent failure of myocardial suppression across both modalities serves to reinforce this as a limiting factor with FDG. Although hybrid CMR/PET imaging can improve the differentiation of this false-positive uptake from true myocardial inflammation, ultimately, more specific tracers for inflammation or improved methods for myocardial suppression are required (19). Finally, not all patients fulfilled conventional diagnostic criteria for cardiac sarcoidosis, such as those proposed in 2014 by the Heart Rhythm Society (6) (Table 5).…”

Somatostatin receptor based PET/CT in patients with the suspicion of cardiac sarcoidosis: an initial comparison to cardiac MRI

“…Additionally, whereas a recent study comparing 68 Ga-DOTANOC and 18 F-FDG PET/CT has demonstrated encouraging diagnostic accuracy for SSTR-directed PET [24], the prognostic value of 68 Ga-DOTATOC PET/CT, especially in comparison to 18 F-FDG has to be clarified in future trials. Whereas higher quantitative 18 F-FDG uptake in CS patients with ventricular tachycardia than in those with atrioventricular block and asymptomatic controls and a higher risk of death or ventricular tachycardia as compared to JMHWG criteria or the ejection fraction have been reported for 18 F-FDG [9, 25], nothing is known about patient prognostication by SSTR-PET/CT so far.…”

Cardiac PET/MRI—an update

“…An alternative approach may be the assessment of the inflammatory granulomas in the myocardium using radiotracers targeting the somatostatin receptor (e.g., Ga-68 DOTANOC). While first reports using this approach are available for PET/CT, there is no clinical experience with simultaneous PET/MRI (Slart et al 2017;Gormsen et al 2016). Imaging post-ischemic inflammatory processes in the myocardium…”