Complementary Value of Cardiac Magnetic Resonance Imaging and Positron Emission Tomography/Computed Tomography in the Assessment of Cardiac Sarcoidosis

Abstract

Background-Although cardiac magnetic resonance (CMR) and positron emission tomography (PET) detect different pathological attributes of cardiac sarcoidosis (CS), the complementary value of these tests has not been evaluated. Our objective was to determine the value of combining CMR and PET in assessing the likelihood of CS and guiding patient management. Methods and Results-In this retrospective study, we included 107 consecutive patients referred for evaluation of CS by both CMR and PET. Two experienced readers blinded to all clinical data reviewed CMR and PET images and categorized the likelihood of CS as no (<10%), possible (10%-50%), probable (50%-90%), or highly probable(>90%) based on predefined criteria. Patient management after imaging was assessed for all patients and across categories of increasing CS likelihood. A final clinical diagnosis for each patient was assigned based on a subsequent review of all available imaging, clinical, and pathological data. Among 107 patients (age, 55±11 years; left ventricular ejection fraction, 43±16%), 91 (85%) had late gadolinium enhancement, whereas 82 (76%) had abnormal F18-fluorodeoxyglucose uptake on PET, suggesting active inflammation. Among the 91 patients with positive late gadolinium enhancement, 60 (66%) had abnormal F18-fluorodeoxyglucose uptake. When PET data were added to CMR, 48 (45%) patients were reclassified as having a higher or lower likelihood of CS, most of them (80%) being correctly reclassified when compared with the final diagnosis. Changes in immunosuppressive therapies were significantly more likely among patients with highly probable CS. Conclusions-Among patients with suspected CS, combining CMR and PET provides complementary value for estimating the likelihood of CS and guiding patient management. (Circ Cardiovasc Imaging. 2018;11:e007030.

Advanced cardiovascular imaging for the evaluation of cardiac sarcoidosis

“…In addition, a number of LGE-positive/FDG-negative patients had neither typical LGE pattern nor clinical history of sarcoidosis; thus, it is possible that some of these cases may represent cardiomyopathies other than sarcoidosis. While limited in size, this study, together with the findings of Vita et al, 44 suggests that CMR may have a larger contribution than FDG PET when assessing prognosis.…”

“…A final adjudicated diagnosis (including imaging, clinical data, and pathology) was ascertained by consensus and used as Reference. 44 In total, 85% had LGE on CMR, whereas 76% had abnormal FDG on PET. Among those with LGE, 66% had abnormal FDG uptake, supporting the notion that LGE cannot be reliably used to identify patients who may benefit from anti-inflammatory therapies.…”

“…42 While the presence of myocardial LGE is common in a number of nonischemic cardiomyopathies, there are certain patterns of myocardial involvement that are considered typical for sarcoidosis. 43,44 …”

Establishing an Evidence-Based Method to Diagnose Cardiac Sarcoidosis

“…Other important contributions of this report are its concise descriptions and examples of imaging patterns for both CMR and FDG-PET that correspond to the probabilistic likelihood assignments (Figure 2 of Vita et al 4 ). The nuanced description of imaging patterns is this report are commendable.…”

“…In this regard, the study by Vita et al 4 reported in this issue of Circulation: Cardiovascular Imaging is an important step forward in our understanding of how to approach the diagnosis of CS.…”