Optimizing Acquisition Parameters and Interpretive Methods of FDG-PET/CT With Rb-82
Optimizing Acquisition Parameters and Interpretive Methods of FDG-PET/CT With Rb-82
In this this investigation, 15 subjects with a high probability of cardiac sarcoidosis based
 on clinical criteria and abnormal cardiac FDG uptake on initial, clinically indicted FDG PET
 study will be considered for this study. The study will test the following Aims:

 Aim 1. Effect of FDG incubation time on visual and quantitative interpretation of FDG uptake.

 Changes in incubation time can affect imaging target:background ratios and study
 sensitivity/specificity. For the study-directed exam, all patients will undergo sequential
 cardiacfocused FDG-PET imaging at 90 and 120 minutes after injection of FDG. Imaging
 variables will be evaluated as below.

 Aim 2. Reproducibility of FDG and Rb82 PET findings on sequential imaging. It is unknown
 whether FDG-positive imaging findings in cardiac sarcoidosis are reproducible. All patients
 will undergo study-directed FDG-PET/CT with MPI imaging within approximately 2 weeks from
 initial clinical scan.
Sarcoidosis is a systemic disease of unknown etiology characterized by non-caseating
 granulomatous inflammation. The pathophysiologic features of cardiac sarcoidosis include
 macrophage-induced, T-cell mediated non-caseating granulomatous inflammation, followed by
 myocardial scarring/fibrosis with clinical sequelae including arrhythmias, conduction
 abnormalities, and contractile dysfunction. These lead to high event rates in patients with
 cardiac sarcoidosis, with several studies reporting a prevalence of ventricular tachycardia
 ranging from 23% to 38% and an ~ 20% rate of clinical congestive heart failure.

 FDG-PET/CT with Rb82 myocardial perfusion imaging (FDG-PET with MPI) is becoming the gold
 standard imaging technique for evaluating the degree of inflammation and the response to
 immunosuppressive treatment in patients with cardiac sarcoidosis. FDG PET imaging allows for
 evaluation of inflammatory macrophage infiltration, while Rb82 MPI allows for determination
 of myocardial scar burden. Despite emerging data from our center and others on the clinical
 utility of this technique in predicting prognosis, there is little consensus on the
 reproducibility of this technique or optimal imaging acquisition techniques and
 interpretative strategies.

 In this study, patients with a high clinical likelihood of cardiac sarcoidosis will undergo a
 study-directed FDG PET/CT with Rb82 myocardial perfusion imaging study approximately 2 weeks
 following an initial clinically-directed examination.

 The two FDG PET with MPI examinations will be examined for reproducibility of imaging
 findings, including: SUVmax, SUVmean, distribution of FDG uptake, extra cardiac FDG uptake,
 SUVvolume, SUVvolume:intensity, perfusion defect size/severity/location, LV ejection
 fraction, myocardial blood flow.

 Strict attention will be paid to ensure patients undergo the same metabolic preparation prior
 to the two examinations.
Inclusion Criteria:

 Symptoms

 -  Palpitations/presyncope/syncope

 -  Heart failure symptoms Signs

 -  Abnormal ECG or Holter

 -  RBBB, LBBB, LAFB

 -  Abnormal Q waves in ≥2 leads

 -  1st degree AVB > 240 msec, 2nd/3rd deg. AVB

 -  Frequent PVCs

 -  VT (sustained/non-sustained)

 -  LVEF < 50%

 -  Cardiac Regional Wall Motion Abnormality

 Exclusion Criteria:

 -  Low likelihood of CS/Other explanation for symptoms

 -  Inability to consent

 -  Pregnancy