Chacko T K, Zhuang H, Stevenson K, Moussavian B, Alavi A
Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA 19802, USA.
Nucl Med Commun. 2002 Sep;23(9):851-5. doi: 10.1097/00006231-200209000-00008.
Ten per cent of patients with hip replacement will eventually complain of significant pain after surgery, often requiring a revision arthroplasty. The majority of these patients experience aseptic loosening rather than infection. Despite significant advances made in diagnostic imaging, distinguishing infection from aseptic loosening remains a significant challenge. Imaging using fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to have excellent sensitivity in detecting infections associated with hip prostheses. However, in some studies, a high rate of false positive results has been reported, especially when increased tracer uptake adjacent to the prosthesis (which is not surrounded by bone) is used as the sole criterion for diagnosing infection. The objective of this investigation was to determine the optimal criteria for diagnosing periprosthetic infection, thereby avoiding false positive results in this setting. A total of 41 total hip arthroplasties from 32 patients and for whom complete clinical follow-up was available were included in this analysis. The location and intensity of FDG uptake were determined for each scan. Final diagnosis was made by microbiology, histopathology, surgical findings and clinical follow-up. Patients who did not undergo surgery were followed up to at least 9 months. Twelve patients were proven eventually to have periprosthetic infection. Images from 11 of these patients displayed increased tracer uptake along the interface between bone and prosthesis. The intensity of the increased tracer uptake varied from mild to moderate, with standardized uptake values less than 2. In contrast, images from uninfected, loose hip prostheses revealed very intense uptake around the head or neck of the prosthesis with standardized uptake values as high as 7. It is concluded that the intensity of increased FDG uptake is less important than the location of increased FDG uptake when FDG PET is used to diagnose periprosthetic infection in patients with hip arthroplasty. Using increased uptake as the sole criterion for diagnosing infection will result in false positive results in this setting.
10%的髋关节置换患者最终会在术后主诉严重疼痛，通常需要进行关节置换翻修手术。这些患者中的大多数经历的是无菌性松动而非感染。尽管诊断成像技术取得了重大进展，但区分感染与无菌性松动仍然是一项重大挑战。据报道，使用氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）成像在检测与髋关节假体相关的感染方面具有出色的敏感性。然而，在一些研究中，报道了较高的假阳性结果率，特别是当假体周围（未被骨包围）示踪剂摄取增加被用作诊断感染的唯一标准时。本研究的目的是确定诊断假体周围感染的最佳标准，从而避免在此情况下出现假阳性结果。本分析纳入了32例患者的41例全髋关节置换术，且均有完整的临床随访资料。对每次扫描确定FDG摄取的位置和强度。最终诊断通过微生物学、组织病理学、手术发现和临床随访做出。未接受手术的患者随访至少9个月。最终证实12例患者存在假体周围感染。其中11例患者的图像显示沿骨与假体界面示踪剂摄取增加。示踪剂摄取增加的强度从轻度到中度不等，标准化摄取值小于2。相比之下，未感染的松动髋关节假体的图像显示假体头部或颈部周围摄取非常强烈，标准化摄取值高达7。得出的结论是，当使用FDG PET诊断髋关节置换患者的假体周围感染时，FDG摄取增加的强度不如其位置重要。在这种情况下，将摄取增加作为诊断感染的唯一标准会导致假阳性结果。
