137 Review of the role of bone-SPECT/CT in tarsal coalitions Table 2. (continued) Non-osseous Partly ossified Completely ossified MRI Optimal soft tissue characterization Generalized edema in the area No bone edema. Useful to detect surrounding soft tissue abnormality Plain radiograph Low sensitivity, talar beaking C-sign on lateral view C-sign on lateral view Imaging findings before and after treatment including metal in situ Postoperative foot pain is a frequent clinical challenge, with often multifactorial etiology as the foot and ankle exhibit complex anatomy and function, and therefore difficulties in finding the pain generator are common [15]. In a non-operated patient, with no prior anatomical changes and no metallic osteosynthesis material, plain radiographs combined with MRI will often be successful with the considerations and limitations above. Bone-SPECT/CT is not only very helpful in primary surgical planning, but also has favorable characteristics in follow-up of patients after surgery, with SPECT not being affected by metallic implants artifacts. In patients with TC therefore, pre-operative bone-SPECT/CT might be considered for both primary surgical planning as well as for follow-up. Still, a major limitation of bone-SPECT to assess post-surgery bone is nonspecific tracer uptake at the site of surgery secondary to physiological remodeling [26]. The amount of this physiological bone reaction causing increased radionuclide uptake varies per exact type of surgery as well as the anatomical site within the foot and ankle. After arthrodesis in the hind foot, complete osseous union is achieved on average in 3.5 to 4 months in the subtalar joint, 6 months in the ankle joint, and up to 7.5 months after triple arthrodesis [15, 27]. Pre-operative bone-SPECT/CT may clearly pinpoint increased bone turnover in a TC, to support to ascertain the indication for surgery. In patients that underwent surgery, including metallic implants, post-operative MRI will often not be performed because of hampered adequate visualization of the joints and relevant surrounding tissues as result of metal hardware susceptibility artifacts. Bone-SPECT on the other hand, is much less hampered and will usually be able to precisely pinpoint the location of the possible pain generator. Quality of CT can be impaired by hardware-induced artefacts, which might be (partly) overcome using metal artefact reduction (iMAR) [28]. BoneSPECT/CT performance before and after arthrodesis is illustrated by a 35-year-old 5