Frankel Cardiovascular Center, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
Division of Cardiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
J Nucl Cardiol. 2023 Jun;30(3):928-937. doi: 10.1007/s12350-023-03209-3. Epub 2023 Feb 23.
F-FDG PET/CT is used to diagnose cardiac sarcoidosis and endocarditis. It requires myocardial glucose utilization (MGU) suppression to avoid false positives, which occur in up to 20% of patients. Serum beta-hydroxybutyrate (BHB) levels may help identify incomplete suppression of MGU. We determined the optimal timing and diagnostic thresholds to identify incomplete suppression of MGU.
We retrospectively identified 114 patients referred for F-FDG PET/CT for endocarditis, wherein myocardial uptake outside of paravalvular regions is not related to pathology and can be confidently ascribed as being due to inadequate suppression of MGU. Patients followed a high-fat, low-carbohydrate diet and received heparin. Serum BHB, insulin, glucose and hemoglobin A1c were measured. Maximum standardized uptake value (SUV) of left ventricle (LV) and mean SUV (SUV) in LV blood pool (LVBP) was measured. Logistic regression and area under the receiver-operating characteristic analyses were used to quantify the relationship between biomarkers and MGU suppression. A threshold of BHB ≥ 0.35 mmol·L to detect suppression resulted in sensitivity of 88% and specificity of 61%. A threshold of BHB ≥ 0.95 mmol·L resulted in sensitivity of 45% and specificity of 100%. AUC was 0.87. BHB measured ~ 4 hours prior to F-FDG injection performed similarly to or better than later timepoints.
Serum BHB levels are useful for assessing suppression of MGU and could simplify interpretation of F-FDG PET/CT inflammation studies.
氟代脱氧葡萄糖正电子发射断层扫描（FDG PET/CT）用于诊断心脏结节病和心内膜炎。为了避免高达 20%的患者出现的假阳性，需要抑制心肌葡萄糖利用（MGU）。血清β-羟基丁酸（BHB）水平可能有助于识别 MGU 抑制不完全。我们确定了识别 MGU 抑制不完全的最佳时间和诊断阈值。
我们回顾性地确定了 114 例因心内膜炎接受 FDG PET/CT 检查的患者，其中瓣周区域外的心肌摄取与病理学无关，可以确信是由于 MGU 抑制不完全所致。患者遵循高脂肪、低碳水化合物饮食并接受肝素治疗。测量血清 BHB、胰岛素、葡萄糖和糖化血红蛋白。测量左心室（LV）的最大标准化摄取值（SUV）和 LV 血池（LVBP）的平均 SUV（SUV）。使用逻辑回归和受试者工作特征曲线下面积分析来量化生物标志物与 MGU 抑制之间的关系。BHB≥0.35mmol·L 作为检测抑制的阈值，其敏感性为 88%，特异性为 61%。BHB≥0.95mmol·L 的阈值导致敏感性为 45%，特异性为 100%。AUC 为 0.87。BHB 在 FDG 注射前约 4 小时测量与稍后时间点测量的效果相似或更好。
血清 BHB 水平可用于评估 MGU 的抑制情况，并可简化 FDG PET/CT 炎症研究的解释。
