145 Review of the role of bone-SPECT/CT in tarsal coalitions Additionally, blood pool bone-SPECT/CT has recently been described as a proof of concept [37], but evidence for clinically added value for using blood pool boneSPECT/CT images for TCs is non-existent until now, as far as we know. Quantification in bone-SPECT/CT may add objectivity and certainty in primary diagnosis, and could especially be of value in follow-up situations to depict change more objectively, in our experience. The accuracy of bone-SPECT/CT-quantification does depend on many factors: use of a collimator, the detector trajectory, the need for more complicated correction for scatter and attenuation than in PET, and reconstruction algorithms [38]. Corrections for photon attenuation and scatter, collimator modeling and reconstruction, have improved reconstruction, thus enabling absolute SPECT quantification [38]. However, the evidence for added clinical value of quantitative bone-SPECT/CT over visual assessment in both primary diagnosis and in follow-up of benign diseases is still very limited, and more research is needed to precisely correlate (changes) in measured SUVmax to (change in) clinical findings [22, 25, 28]. Conclusion This illustrated review demonstrates added clinically useful information of boneSPECT/CT over plain radiographs and MRI in suspected TCs (both CNC and TCC). MRI is known to be especially advantageous in depicting the soft tissues, whereas bone-SPECT/CT excels in fast and accurate characterization of the bone pathology and confidently excluded any synchronous lesion elsewhere in the foot and ankle. Secondly, bone-SPECT/CT is being utilized by our orthopedic surgeons for surgery planning because of optimal insight in structure of the bones and 3D localization of bone metabolism and especially post-operatively bone-SPECT/CT pinpoints the culprit site from where the pain originates. Moreover, bone-SPECT/CT is of extra value in postoperative patients where MRI is either contra-indicated or considerably hampered to pinpoint the possible pain generator by depicting the bone turnover, especially in the presence of osteosynthesis material. Declaration None of the authors reported any potential conflicts of interest. 5