130 Part I Chapter 5 Partly ossified CNC Although MRI is generally useful in patients with partly ossified CNC, MRI (Figure 5) might not always delineate the ossified fragment as clearly as on bone-SPECT/ CT (Figure 6 and 7), with just generalized edema in this area (Figure 5, green circle). The increased bone turnover on SPECT combined with the more precise anatomic information of the CT part of the bone-SPECT/CT might therefore be advantageous in surgical planning. Figures 6 and 7 demonstrate the value of bone-SPECT/CT in adequately combining the pathophysiological information with precise anatomical localization in a patient with CNC. Bone-SPECT/CT pinpoints the pain generator and excludes other osseous painful sites which allows improved planning for diagnostic or therapeutic injections and surgical procedures, such as resection of a partly ossified calcaneonavicular coalition (Figure 8). Figure 6. SPECT/CT with 3D volume rendering with maximum intensity projection was of incremental value as the low-dose CT depicted the partially ossified coalition, with increased bone turnover at the calcaneonavicular articulation on SPECT. Also note the increased bone-turnover on the dorsal side of the left ankle joint as an additional finding (blue arrow), caused by an os trigonum, on this projection optimized for the calcaneonavicular the os trigonum is obscured by the fibula, however.