IJCS | Volume 33, Nº4, July and August 2020

398 because of the reduced cost of personnel and reduced risk of complications. 55 For the patient, it would mean a single visit to the imaging department, and less time spent in the hospital. The MRI would play the role of the CT for attenuation correction, anatomic reference and evaluation of extracardiac findings and will add value of tissue characterization, mainly for scar and edema. 56 The combination of both imaging techniques improves spatial relationship between the findings of scar and inflammation, making it useful to patient’s management and understanding of the phases of the disease (mismatching, scarring or inflammation alone). CHASM CS-RCT Due to the lack of previous clinical trials to evaluate treatment strategies in CS, the Cardiac Sarcoidosis Multi-Center Randomized Controlled Trial (CHASM CS-RCT; NCT-03593759) is an ongoing multicenter randomized controlled trial aiming to evaluate the optimal initial treatment strategy for patient with active CS. 57 The inclusion criteria are: patients with clinically manifest CS with at least one finding such as advanced conduction systemdisease, significant node dysfunction, non-sustained or sustained ventricular arrythmia, LV dysfunction or RV dysfunction. The primary hypothesis is that a lowdose prednisone/ methotrexate combination will havenon-inferior efficacy to standarddoseprednisone and will result in a significantly better quality of life due to less side-effects when compared to the standard therapy. The subject are randomized in a 1:1 ratio to high dose prednisone (0.5mg/kg/day for sixmonths, with maximumdose of 30mg/day) or to prednisone 20mg/day for one month, 10mg/day for one month, then 5mg/day for onemonth, followed by discontinuation of prednisone and initiation of methotrexate 15-20mg once weekly for six months. This study uses PET imaging (perfusion and metabolism with FDG) to evaluate the presence of scar and inflammation. Showing the non-inferiority of the low-dose steroidwill be enough to guide therapy toward a highly-effective treatment with less adverse effects and better quality of life for the patient. Conclusion CS can be difficult to diagnose and often requires multiple tools to reach timely diagnosis. Cardiac MR and FDG PET are advanced imaging techniques that can be used a complementary fashion for diagnosis, Table 4 – Use of 18F-FDG PET in the management of Cardiac Sarcoidosis Indication Significant findings Technical aspects References Diagnosis Normal or decreased perfusion in the involved region of the myocardium, with increased 18F-FDG uptake Inadequate preparation can severely impair the accuracy for the diagnosis of CS 58 Prognosis Perfusion defect or focal 18F-FDG uptake in left ventricle, increased uptake in right ventricle, extensive and severe uptake in the myocardium Up to 25% of qualitative 18F-FDG PET exams may not be reproducible (90-120 minutes of 18F-FDG uptake improves reproducibility) 42, 52, 59 Assessment of Treatment Response Decreased or resolved 18F-FDG uptake in the myocardium can support the decision to wean prednisone Increased costs and radiation exposure. Limit to 3-4 scans in a year. Caution should be taken concerning the effect of steroid on false-positive 18F-FDG-PET results 60 Diagnosis of extra-cardiac sarcoid disease activity or findings to guide a biopsy from an extracardiac location of 18F-FDG uptake 18F-FDG avid lymph nodes or other accessible area to guided biopsy can provide a definitive diagnosis or exclude malignancy in uncertain cases The whole body 18F-FDG PET as well as the CT transmission (on hybrid scanners) images need to be reviewed and reported in conjunction with a physician credentialed to supervise and interpret body PET/CT 47 CS: cardiac sarcoidosis; PET: positron emission tomography; CT: computed tomography; 18F-FDG: 18F-fluorodeoxyglucose Wiefels et al. 18F-FDG PET/CT and cardiac sarcoidosis Int J Cardiovasc Sci. 2020; 33(4):389-400 Review Article