Feasibility study of SPECT/CT bone quantitative analysis using PET/CT post-processing workstation

Objective To investigate the consistency of SPECT/CT and PET/CT post-processing workstations for quantitative analysis of SPECT/CT bone quantitative data, and compare the similarities and differences of the maximum standardized uptake value (SUV_max), the average standardized uptake value (SUV_ave), volume and average CT value of the lesions measured by different workstations.

Methods Forty patients who underwent whole-body bone scintigraphy and quantitative SPECT/CT imaging, and had no more than two hot spots within SPECT/CT imaging range were retrospectively analyzed. A total of 50 lesions were obtained. Three-dimensional (3D) isocontour volume of interest (VOI) method of "SyngoMI VB10B" SPECT/CT workstation was used to obtain the SUV_max, SUV_ave, volume, and average CT value of the lesions. Then the data were imported into the "uWS-MI" medical image processing software of PET/CT post-processing workstation. The above parameters were measured by 3D ellipsoid VOI method, adaptive threshold segmentation method, and fixed threshold segmentation method, respectively. The SUV_max, SUV_ave, volume, and average CT value measured by the three processing methods of "uWS-MI" workstation and 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation were compared respectively to see if the difference was statistically significant.

Results The SUV_max measured by the 3D ellipsoid VOI method of "uWS-MI" workstation and the 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation were completely consistent, but SUV_ave (t=9.841, P < 0.001), lesion volume (t=-4.314, P < 0.001) and average CT value (t=12.554, P < 0.001) were significantly different. The adaptive threshold segmentation method and the fixed threshold method of "uWS-MI" workstation can not accurately segment two adjacent lesions of the lumbar spine and sacrum in one patient. Comparing with the 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation, the SUV_max of 48 lesions in 39 other patients was completely the same. Comparing the adaptive threshold segmentation method of "uWS-MI" workstation with the 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation, the SUV_ave (t=-0.723, P=0.473), lesion volume (t=-1.407, P=0.166), and average CT value (t=-0.735, P=0.466) of the 48 lesions were not statistically different. Comparing the fixed threshold measurement method of "uWS-MI" workstation with the 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation, the SUV_ave (t=2.947, P=0.473) and lesion volume (t=-2.003, P=0.051) of 48 lesions were not statistically different, while the difference in average CT value (t=-4.71, P < 0.001) was statistically significant.

Conclusions "uWS-MI" medical image processing software of PET/CT post-processing workstation has good compatibility with the quantitative data of SPECT/CT bone imaging. The three methods of PET/CT post-processing workstation can obtain consistent results for the measurement of SUV_max. However, the adaptive threshold segmentation method and fixed threshold measurement method of "uWS-MI" workstation have certain limitations for extracting the corresponding parameters for the segmentation of adjacent lesions. The values of SUV_ave, volume, and average CT value will be affected by different measurement methods. There is no significant difference between the adaptive threshold segmentation method of "uWS-MI" workstation and the 3D isocontour VOI method of "SyngoMI VB10B" SPECT/CT workstation.