Impact of carbohydrate restriction with and without fatty acid loading on myocardial 18F-FDG uptake during PET: A randomized controlled trial

Abstract

BackgroundLow-carbohydrate (LC) and high-fat, low-carbohydrate (HFLC) dietary preparations may enhance 18F-FDG-PET-based imaging of small, inflamed structures near the heart by suppressing myocardial FDG signal. We compared myocardial 18F-FDG uptake in patients randomized to LC, HFLC, and unrestricted (UR) preparations prior to 18F-FDG-PET.Methods and ResultsWe randomized 63 outpatients referred for oncologic 18F-FDG-PET to LC, HFLC, or UR dietary preparations (1:1:1 allocation) starting the evening before PET. After eating dinner according to instructions, UR and LC patients fasted until FDG injection (mean time 745 minutes for UR, 899 minutes for LC), and HFLC patients drank a fatty drink 60-70 minutes prior to FDG injection. Attenuation-corrected PET imaging was performed 60 minutes after FDG administration. Maximal myocardial standard uptake values (MyoSUVmax) were systematically measured in axial view and compared between the three groups. Using UR patients as reference, mean MyoSUVmax was lower in LC patients (3.3 ± 2.7 vs 6.2 ± 5.2, P = .03) but not in HFLC patients (5.5 ± 4.2, P = .63). Ratios of MyoSUVmax to liver SUVmax, calculated to control for background uptake, were not significantly different amongst the groups (1.9 ± 2.1 LC, 2.6 ± 2.3 HFLC, 3.6 ± 3.5 UR).ConclusionIn this small randomized controlled trial using UR diet as reference, LC dietary preparation followed by extended fasting resulted in significant myocardial uptake suppression.

Joint SNMMI–ASNC expert consensus document on the role of 18F-FDG PET/CT in cardiac sarcoid detection and therapy monitoring

“…56 Despite these studies, the optimum amount of fat or carbohydrate in these dietary manipulations has not been clearly defined or standardized, though one study did specify that the evening meal before the PET study should include more than 35 g of fat and less than 5 g of carbohydrates. 57 A strategy of adding a high-fat beverage to the high-fat, low-carbohydrate diet just before administering the 18 F-FDG has also been explored but does not appear to have additive benefit. [57][58][59][60] On the basis of our clinical experience and the available literature, nonspecific myocardial uptake may be observed in up to 20% of patients despite various dietary preparations.…”

“…57 A strategy of adding a high-fat beverage to the high-fat, low-carbohydrate diet just before administering the 18 F-FDG has also been explored but does not appear to have additive benefit. [57][58][59][60] On the basis of our clinical experience and the available literature, nonspecific myocardial uptake may be observed in up to 20% of patients despite various dietary preparations. 52 Table 3 provides dietary recommendations for patients before undergoing 18 F-FDG PET for CS.…”

Imaging moving heart structures with PET

“…In the case of coronary 18 F-FDG imaging, an additional complication is presented by myocardial activity, which may overlap with plaque activity due to arterial/myocardial motion. 20 Heart motion could be one reason why 18 F-FDG studies investigating coronary plaques have not been strongly conclusive. 18 To partially mitigate blurring due to cardiac motion during Figure 1.…”

Optimizing myocardial metabolism for fluorine-18 fluorodeoxyglucose positron emission tomography imaging of cardiac inflammation

“…8 A number of studies that have been carried out either compared different methods of patient preparation-mostly dietary and to a lesser extent pharmacologic-5,9-20 or report suppression rates of a single protocol in patients under evaluation for cardiac sarcoidosis 21,22 or undergoing imaging of vulnerable coronary plaques. 23 Only three of them are randomized, 5,10,15 and small to moderate in size (N range 36 to 153), while the remainder are nonrandomized.…”