Comparison of SUVr calculations in amyloid PET brain imaging

Objectives The aim of our study was to compare two methods for SUVr calculations in amyloid PET brain imaging.

Methods In a continuing study, 19 patients were imaged on a GE STE 16 slice PET/CT system with 370 kBq of ¹⁸F florbetapir. The data were reconstructed using the vendor’s reconstruction software. Corresponding MRI data were retrieved from the PACS system and matched PET and MRI data was transferred to a common platform. Two methods for calculation of the ratio of cortical to cerebellar signal (SUVr) were used. One was based on the MIM Software Inc., Version 6.1 software and only uses PET data. The second approach used the PMOD NEURO tool (version 3.501). This approach utilizes PET and corresponding MRI data (preferably T1 weighted) for better brain segmentation.

Results For amyloid negative subjects, average SUVr ± SD values were 0.95±0.01 and 1.00±0.12, for MIM and PMOD applications, respectively. For amyloid positive patients, average SUVr values were 1.30±0.19 and 1.28±0.25. SUVr values from the two methods were compared by Bland-Altman analysis. The 95% limits of agreement were calculated by mean ± 1.96 standard deviation and were 0.04 ± 0.29. Linear fitting yielded a slope and intercept of 0.87 and 0.16, respectively, and the correlation coefficient was 0.81.

Conclusions Our results indicated that the SUVr values derived using MIM and PMOD are effectively interchangeable and well correlated.