Advances in PET Imaging of Sarcoidosis
Purpose of Review
The purpose of this paper is to provide an updated review of recent advances in protocols for positron emission tomography (PET) or PET/computed tomography (PET/CT) imaging in patients with sarcoidosis.
There has been more research focused on developing newer and improved PET imaging modalities to diagnose and follow-up cardiac sarcoidosis (CS). Fluorine-18-fluorodeoxyglucose (18F- FDG)-PET are widely used to diagnose CS, with or without concurrent rest nuclear myocardial perfusion study. There have been various patient preparation strategies for FDG PET/CT in CS. Interpretation criteria for cardiac FDG PET/CT in diagnosing CS also varies. There are emerging data utilizing new PET radiotracers (i.e., 68Ga-DOTATATE, 18F-Flurpiridaz) and PET/MRI imaging for CS diagnosis.
Based on published imaging data, patient preparation with a 72-h high-fat, high-protein, and very-low-carbohydrate diet protocol generates the most promising results in suppression of physiological myocardial FDG uptake in cardiac PET/CT. The “focal-on-diffuse uptake” pattern on myocardial uptake is not convincing and should not be interpreted as active CS. Nuclear myocardial perfusion test might not be needed to diagnose CS if optimal suppression of myocardial background uptake of FDG is achieved. FDG PET/MRI with optimal patient preparation may increase diagnostic confidence. More data will be needed for new tracers to be used for CS diagnosis.
KeywordsCardiac sarcoidosis Sarcoidosis PET; PET/CT
Compliance with Ethical Standards
Conflict of Interest
Yang Lu and Homer A. Macapinlac declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
For the retrospective studies involve human participants performed by the authors, informed consent is not required. No animal research involved.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
- 5.Cooper LT, Baughman KL, Feldman AM, Frustaci A, Jessup M, Kuhl U, et al. The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology. Endorsed by the Heart Failure Society of America and the Heart Failure Association of the European Society of Cardiology. J Am Coll Cardiol. 2007;50(19):1914–31.CrossRefGoogle Scholar
- 16.• Chareonthaitawee P, Beanlands RS, Chen W, Dorbala S, Miller EJ, Murthy VL, et al. Joint SNMMI-ASNC expert consensus document on the role of (18)F-FDG PET/CT in cardiac sarcoid detection and therapy monitoring. J Nucl Med. 2017;58(8):1341–53 It is the latest expert consensus from SNMMI-ASNC, but one should be aware that it is not a scientific data-based conclusion. Additional comments about this expert consensus can be found in reference no. 43. CrossRefGoogle Scholar
- 25.Atterton-Evans V, Turner J, Vivanti A, Robertson T. Variances of dietary preparation for suppression of physiological (18)F-FDG myocardial uptake in the presence of cardiac sarcoidosis: a systematic review. J Nucl Cardiol. 2018.Google Scholar
- 26.Manabe O, Yoshinaga K, Ohira H, Masuda A, Sato T, Tsujino I, et al. The effects of 18-h fasting with low-carbohydrate diet preparation on suppressed physiological myocardial (18)F-fluorodeoxyglucose (FDG) uptake and possible minimal effects of unfractionated heparin use in patients with suspected cardiac involvement sarcoidosis. J Nucl Cardiol. 2016;23(2):244–52.CrossRefGoogle Scholar
- 30.Wykrzykowska J, Lehman S, Williams G, Parker JA, Palmer MR, Varkey S, et al. Imaging of inflamed and vulnerable plaque in coronary arteries with 18F-FDG PET/CT in patients with suppression of myocardial uptake using a low-carbohydrate, high-fat preparation. J Nucl Med. 2009;50(4):563–8.CrossRefGoogle Scholar
- 32.•• Lu Y, Grant C, Xie K, Sweiss NJ. Suppression of myocardial 18F-FDG uptake through prolonged high-fat, high-protein, and very-low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis. Clin Nucl Med. 2017;42(2):88–94 This is so far the largest reported CS FDG PET/CT patient data with minimal variance. The paper provided a thorough description of an effective and simple patient preparation protocol, and straightforward interpretation criteria for CS FDG PET/CT. CrossRefGoogle Scholar
- 34.Tezuka D, Terashima M, Kato Y, Toriihara A, Hirasawa K, Sasaoka T, et al. Clinical characteristics of definite or suspected isolated cardiac sarcoidosis: application of cardiac magnetic resonance imaging and 18F-Fluoro-2-deoxyglucose positron-emission tomography/computerized tomography. J Card Fail. 2015;21(4):313–22.CrossRefGoogle Scholar
- 43.Lu Y, Sweiss N. Role of (18)F-FDG PET/CT in cardiac sarcoid detection and therapy monitoring: addition to the expert consensus. J Nucl Med. 2018.Google Scholar
- 47.• Patel DC, Gunasekaran SS, Goettl C, Sweiss NJ, Lu Y. FDG PET-CT findings of extra-thoracic sarcoid are associated with cardiac sarcoid: a rationale for using FGD PET-CT for cardiac sarcoid evaluation. J Nucl Cardiol. 2017. https://doi.org/10.1007/s12350-017-0962-4 The largest case series with same patient preparation protocol showed extra-thoracic sarcoid and CS occur with significant frequency, thus a PET/CT with field-of-view from the skull to upper thigh is necessary to the full extent of disease.
- 50.Ohira H, Birnie DH, Pena E, Bernick J, Mc Ardle B, Leung E, et al. Comparison of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) and cardiac magnetic resonance (CMR) in corticosteroid-naive patients with conduction system disease due to cardiac sarcoidosis. Eur J Nucl Med Mol Imaging. 2016;43(2):259–69.CrossRefGoogle Scholar