Comparison of planar bone scintigraphy and single photon emission computed tomography in patients suspected of having unilateral condylar hyperactivity

Abstract

A comparison is made of single photon emission computed tomography (SPECT) and planar bone scintigraphy in the diagnosis of patients with suspected unilateral condylar hyperactivity (UCH). The subjects comprised 56 patients with suspected UCH who underwent SPECT and regular planar bone scans. Accuracy of SPECT and planar scintigraphy were compared using left-right condylar activity. Of the 56 patients, 29 were diagnosed with active UCH and 27 without UCH. The mean relative activity of the hyperactive condylar region in the planar scans was 53.5% (SD +/- 2.3%), which was significantly higher in the SPECT scan with a mean value of 60.5% (SD +/- 5.4%), P < .005 (t = 8.951). Receiver operating curves (ROC) were clearly in favor of SPECT over the planar bone scan. The area under the curve (AUC) of the planar ROC was 0.87 +/- 0.049 while that of the SPECT ROC was 0.97 +/- 0.024. The optimal cut-off value for planar scanning was 52%, yielding a sensitivity of 67% and a specificity of 85%. For SPECT scanning, the optimal cut-off was 56%, resulting in a sensitivity of 93% and a specificity of 96%. It can be concluded that in patients with a clinically suspected active UCH, SPECT scanning is the preferred diagnostic tool rather than planar bone scanning. However, treatment planning should be done in combination with clinical assessment of progressive mandibular asymmetry as well as taking into account the patient history.