IJCS | Volume 33, Nº1, January / February 2019

91 Table 3 - Preparations for fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography described in the studies included in the review Author N pts Diet Heparin Specific preparation Van Riet et al. 25 no no 4-hour fasting Ozcan et al. 72 no no 6-hour fasting (4-hour for diabetic patients) Saby et al. 72 yes no HFLW (only one meal) diet, 12-hour fasting Kouijzer et al. 72 no no 6-hour fasting Rouzet et al. 39 yes no HFLW (only one meal) diet, 12-hour fasting Ricciardi et al. 27 yes yes HFLW diet, 6-hour fasting Pizzi et al. 92 no yes 12-hour fasting, 50 IU/Kg heparin bolus 15 min before FDG Jimenez-Ballvè et al. 41 yes yes 48-hours HFLC diet, 12-hour fasting, 50 IU/Kg heparin bolus 15 min before FDG Granados et al. 51 no yes 12-hour fasting, 50 IU/Kg heparin bolus 15 min before FDG Fagman et al. 30 no no 18-hour fasting Kokalova et al. 13 no no 6-hour fasting Guenther et al. 26 yes no HFLW diet, 12-hour fasting Salomaki et al. 23 yes no 24-hour HFLW diet, 10-hour fasting Kouijzer et al. 88 yes no 24-hour HFLW diet, 6-hour fasting de Camargo et al. 303 yes no 24-hour HFLW diet, 8-hour fasting El-Dalati et al. 14 yes yes 36-hour HFLC diet, 30 IU/kg of heparin administered in three boluses (10 IU/kg) at 10 min before FDG and 5 and 20 min after FDG MS: myocardial suppression; HFLW: High-fat low-carbohydrate; NR: not reported. Albano et al. PET and SPECT in endocarditis Int J Cardiovasc Sci. 2020;33(1):87-93 Review Article preparation for PET/CT, with different time of fasting or diet for myocardial suppression (Table 3). Pooled sensitivity of PET/CT was 47% (95%CI 18-81) in patients without specific protocol and 78% (95% CI 45-99) in patients who performed specific preparation (myocardial suppression diet and/or heparin injection). Pooled sensitivity of PET/CT was 76% (95% CI 64–88) and 72% (95% CI 46–99) in patients with and without specific preparation, indicating a high heterogeneity. Also, a pooled specificity of 93% (95% CI 70-100) was observed in the first group and 91% (95% CI 85-94) in the second group. Discussion An accurate diagnosis of IE is critical for clinical decisionmaking and represents a challenge for clinicians; in the latest update of the European Society of Cardiology Guideline, 26 nuclear medicine imaging was integrated in the diagnostic flow-chart of IE. Although blood cultures and echocardiography continue to play a crucial role in the diagnosis and the subsequent clinical management of IE, they have limitations, with a significant number of doubtful reports. Also, ultrasound may have difficulties to study prosthetic valves and inconclusive results have been reported in up to 30% of cases. 27 In this context, WBC SPECT and 18F-FDG PET/ CT studies have demonstrated a significant impact on the study of both PVE and NVE. In particular, in case of suspected PVE, abnormal 18F-FDG PET/CT and WBC SPECT/CT uptake should be considered as a pathological finding. In this systematic review we included 19 studies, with a total of 1,115 patients. Overall, 18F-FDG PET/CT had good specificity (86%) and low sensitivity (68%), with high heterogeneity among papers, while WBC SPECT had high specificity (98%) and good sensitivity (80%) but a small number of patients evaluated. Our results are similar to those reported in previous reviews and meta-analysis. 4,5