74 Part I Chapter 3 Table 2 Best Evidence Literature Overview of SPECT/CT in Postoperative Pain After TKA Author, Year No. of Patients Key Findings and Comparator Technique Hirschmann, et al, 2015 [34] 100 Prospective study, proven diagnostic benefits of SPECT/CT in patients after TKA, and typical pathology-related BTO patterns identified. Because of the benefits in establishing the correct diagnosis, SPECT/CT should be part of the routine diagnostic algorithm for patients with pain after TKA. Hirschmann et al, 2010 [48] 18 SPECT/CT localization algorithm is reliable and useful in patients with painful TKA, combining biomechanical loading and bone turnover. Huellner and Strobel, 2014 [41] Review SPECT/CT arthrography of the knee, visualizing the cartilage, menisci, synovial structures, and loose bodies [49]. SPECT/CT is more sensitive to mechanical bone overload compared with MRI [50]. Filippi and Schillaci, 2006 [51] 28 SPECT/CT improves imaging with 99mTc-HMPAO-labeled leukocytes suspected of osteomyelitis by providing accurate anatomical localization and precise definition of the extent of infection, compared with planar. Graute, et al, 2010 [52] 31 SPECT (±CT) substantially improved imaging with 99mTc-labeled antigranulocyte antibodies for diagnosis and localization of suspected joint infections compared with planar scintigraphy. van der Bruggen, et al, 2010 [45] Review SPECT/CT with WBC and bone marrow seems to be the best imaging technique for diagnosis of PJI. FDG-PET may have acceptable specificity for diagnosis of PJI, depending strongly on the localization of the implant and developing criteria used to diagnose infection. Gemmel, et al, 2012 [47] Review Combined in vitro labeled WBC and bone marrow scintigraphy, with an accuracy of about 90%, is currently the imaging modality of choice for diagnosing PJI. Role of PET may increase using new radiotracers, such as 68Ga and 64Cu. Normal SPECT/CT characteristics after knee surgery Three-phase BS displays perfusion, bloodpool and osteoblastic activity after knee surgery. Bone-SPECT/CT enables combined assessment of bone remodeling around the prosthesis, mechanical alignment, component position and structural changes [1]. In particular, the combination of 3D analysis of component position, mechanical and anatomical axes as well as distribution and intensity of SPECT tracer uptake values is beneficial for the orthopedic surgeon [1]. When interpreting bone-SPECT/CT, the duration between surgery and imaging is important as BTO generally remains physiologically increased for approximately 6-12months after knee joint replacement. Moreover, some mild uptake around both components, especially below the tibial component, may persist as long as 4 years after replacement, and still reflecting physiological reaction of the bone to the used materials or nonpathologically altered biomechanics [41]. To our experience, diagnostic certainty of bone-SPECT/CT is