Afzelius Pia, Nielsen Ole L, Alstrup Aage Ko, Bender Dirk, Leifsson Páll S, Jensen Svend B, Schønheyder Henrik C
Department of Diagnostic Imaging, North Zealand Hospital Hillerød, Denmark.
Department of Veterinary Disease Biology, University of Copenhagen Copenhagen, Denmark.
Am J Nucl Med Mol Imaging. 2016 Jan 28;6(1):42-58. eCollection 2016.
Approximately 5-7% of acute-care patients suffer from bacteremia. Bacteremia may give rise to bacterial spread to different tissues. Conventional imaging procedures as X-ray, Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and ultrasound are often first-line imaging methods for identification and localization of infection. These methods are, however, not always successful. Early identification and localization of infection is critical for the appropriate and timely selection of therapy. The aim of this study was thus; a head to head comparison of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) to PET with tracers that potentially could improve uncovering of infectious lesions in soft tissues. We chose (11)C-methionine, (11)C-PK11195, and (68)Ga-citrate as tracers and besides presenting their bio-distribution we validated their diagnostic utility in pigs with experimental bacterial infection. Four juvenile 14-15 weeks old female domestic pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of S. aureus using a sequential scanning protocol with (18)F-FDG, (11)C-methionine, (11)C-PK11195 and (68)Ga-citrate. This was followed by necropsy of the pigs consisting of gross pathology, histopathology and microbial examination. The pigs primarily developed lesions in lungs and neck muscles. (18)F-FDG had higher infection to background ratios and accumulated in most infectious foci caused by S. aureus, while (11)C-methionine and particularly (11)C-PK11195 and (68)Ga-citrate accumulated to a lesser extent in infectious foci. (18)F-FDG-uptake was seen in the areas of inflammatory cells and to a much lesser extent in reparative infiltration surrounding necrotic regions.
约5%-7%的急症护理患者患有菌血症。菌血症可能导致细菌扩散至不同组织。传统的成像检查方法，如X射线、计算机断层扫描（CT）、磁共振成像（MRI）和超声，通常是用于感染识别和定位的一线成像方法。然而，这些方法并非总能成功。感染的早期识别和定位对于恰当且及时地选择治疗方案至关重要。因此，本研究的目的是对（18）F-氟脱氧葡萄糖（（18）F-FDG）正电子发射断层扫描（PET）与可能有助于更好地发现软组织感染性病变的示踪剂PET进行直接比较。我们选择了（11）C-蛋氨酸、（11）C-PK11195和（68）Ga-柠檬酸盐作为示踪剂，除了展示它们的生物分布外，我们还在患有实验性细菌感染的猪身上验证了它们的诊断效用。对4只14-15周龄的幼年雌性家猪在右股动脉进行动脉内接种猪源金黄色葡萄球菌菌株7天后，使用（18）F-FDG、（11）C-蛋氨酸、（11）C-PK11195和（68）Ga-柠檬酸盐的序贯扫描方案进行扫描。随后对猪进行尸检，包括大体病理学、组织病理学和微生物检查。猪主要在肺部和颈部肌肉出现病变。（18）F-FDG具有更高的感染与背景比值，并在大多数由金黄色葡萄球菌引起的感染灶中积聚，而（11）C-蛋氨酸，特别是（11）C-PK11195和（68）Ga-柠檬酸盐在感染灶中的积聚程度较低。在炎症细胞区域可见（18）F-FDG摄取，而在坏死区域周围的修复性浸润中摄取程度要小得多。
