Quantitative bone single-photon emission computed tomography imaging for uninfected nonunion: comparison of hypertrophic nonunion and non-hypertrophic nonunion.

Background: Recently, a standardized uptake value (SUV) has been used to evaluate bone single-photon emission computed tomography (SPECT). The aim of this study was to investigate quantitative SPECT imaging of uninfected nonunion to compare hypertrophic nonunion and non-hypertrophic nonunion using volume-based parameters.

Methods: We evaluated 23 patients with uninfected nonunion who underwent SPECT acquisition 3 h after an injection of Tc-hydroxymethylene diphosphonate or Tc-methylene diphosphonate from April 2014 to November 2019. We reconstructed the acquired data and performed voxel-based quantitative analysis using the GI-BONE software. Quantitative parameters, maximum SUV (SUV), peak SUV (SUV), and mean SUV (SUV) in the high and low uptake areas of nonunion were compared between hypertrophic nonunion and non-hypertrophic nonunion. The contralateral limb was used as a control, and the ratios of the quantitative parameters were calculated.

Results: The values for the quantitative parameters (high uptake area/low uptake area, respectively), SUV control ratio (12.13 ± 4.95/6.44 ± 4.71), SUV control ratio (11.65 ± 4.58/6.45 ± 4.64), and SUV control ratio (11.94 ± 5.03/6.28 ± 4.95) for hypertrophic nonunion were higher than those for non-hypertrophic nonunion (7.82 ± 4.76/3.41 ± 2.09 (p = 0.065/0.12), 7.56 ± 4.51/3.61 ± 2.23 (p = 0.065/0.22), and 7.59 ± 5.18/3.05 ± 1.91 (p = 0.076/0.23)).

Conclusions: SUV, SUV, and SUV control ratios obtained from bone SPECT images can quantitatively evaluate the biological activity of nonunions and may be an effective evaluation method for treatment decisions, especially the necessity of autologous bone grafting.