Utility of (99m)Tc-MDP hybrid SPECT-CT for diagnosis of skull base osteomyelitis: comparison with planar bone scintigraphy, SPECT, and CT.

Objective: To evaluate single photon emission tomography-computed tomography (SPECT-CT) for diagnosis of skull base osteomyelitis (SBO) and to compare this technique with planar bone scintigraphy (BS), SPECT, and CT.

Methods: Data from 13 patients with known/suspected SBO were retrospectively analysed. Planar BS and SPECT images were evaluated by an experienced nuclear medicine physician, CT by and experienced radiologist, and SPECT-CT by the nuclear medicine physician and radiologist in consensus. On the basis of diagnostic confidence a score of 1-5 was given, with 1 being definitely osteomyelitis, 2 being probably osteomyelitis, 3 being equivocal, 4 being probably normal, and 5 being definitely normal. ROC analysis areas under the curves (AUC) were calculated. For diagnostic values a score of ≤2 was taken as positive. Clinical/imaging follow-up/microbiology was taken as reference standard.

Results: AUC was largest for SPECT-CT (0.977) followed by SPECT (0.909), CT (0.886), and planar BS (0.614). However, no significant difference was found between the techniques except for borderline significance between planar BS with SPECT-CT (P = 0.071) and CT (P = 0.072). Accuracy was 46% for planar BS, 85% for SPECT, 77% for CT and 92% for SPECT-CT.

Conclusions: SPECT-CT seems to be useful, but not superior to planar BS, SPECT, or CT, for diagnosis of SBO.