Relevance of SPECT-CT in Complex Cases of Foot and Ankle Surgery: A Comparison With MRI

Background. Finding the right diagnoses in patients with complex foot and ankle disorders can be challenging. Single-photon emission computed tomography and computed tomography (SPECT-CT) has shown to be feasible in foot and ankle surgery. The aim of this study was to evaluate the reliability and accuracy of SPECT-CT and thereby its impact on final treatment decision compared with magnetic resonance imaging (MRI). Methods. A retrospective study was performed on 49 patients treated at our institution. Experienced foot and ankle surgeons independently, and blinded, analyzed clinical data and radiographs together with MRI, SPECT-CT, or a combination of both. Based on the determined final treatment decision Cohen’s kappa values were calculated to illustrate interrater and intrarater reliability. Results. The kappa values for interrater reliability were higher for SPECT-CT at .68 and MRI + SPECT-CT at .71 compared to 0.38 for MRI alone (P < .05). The kappa values for intrarater reliability of MRI + SPECT-CT were higher at .75 compared with SPECT-CT alone at .67 (P < .05) and MRI at .35 (P < .01). Conclusion. We found a higher interrater and intrarater reliability for SPECT-CT compared with MRI alone for diagnosing complex foot and ankle pathologies. SPECT-CT has a high impact on final treatment decision. The main indications are bony pathologies with diagnostic uncertainty especially in closely adjacent structures as the joints of the midfoot, occult coalitio, stress fractures, verification or exclusion of nonfusion, periprosthetic disorders after total ankle replacement and osteochondral lesion in cases of combined pathologies. Levels of Evidence: Level IV: Retrospective study