The aim of the present study was to compare two methods for standardized uptake value ratio calculations in amyloid florbetapir 18 F PET brain imaging.
Amyloid positron emission tomography ( PET ) imaging with florbetapir 18 F ( 1 8 F-AV-45 ) allows in vivo assessment of cerebral amyloid load and can be used in the evaluation of progression of Alzheimer's disease (AD) and other dementias associated with b -amyloid
However, cortical amyloid deposition can occur in healthy cases, as well as in patients with AD and quantification of cortical amyloid burden can improve the 18 F-AV-45 PET imaging evaluations. The quantification is mostly performed by cortical-to-cerebellum standardized uptake value ratio ( SUVr ).
In amyloid florbetapir 18 F PET brain imaging study, we imaged 42 cases with the mean age of 72.6 ± 9.9 (mean ± standard deviation). Researchers were imaged on different PET / computed tomography systems with 369.0 ± 34.2 kBq of 18 F florbetapir.
Data were reconstructed using the vendor's reconstruction software. Corresponding magnetic resonance imaging (MRI) data were retrieved, and matched PET and MRI data were transferred to a common platform.
Two methods were used for the calculation of the ratio of cortical-to-cerebellar signal (SUVr). One method was based on the MIM Software Inc., Version 6.4 software and only uses PET data.
The second approach used the PMOD Neuro tool (version 3.5). This approach uses PET and corresponding MRI data (preferably T1-weighted) for better brain segmentation.
For all the 42 cases, the average SUVr values ??for MIM and PMOD applications were 1.24 ± 0.26 and 1.22 ± 0.25, respectively, with a mean difference of 0.02 ± 0.15.
The repeatability coefficient was 0.15 (12.3% of the mean). The Spearman's rank correlation coefficient was very high, r = 0.96. For amyloid-negative cases, the average SUVr values ??were lower than all group SUVr average values, 0.96 ± 0.07 and 1.00 ± 0.09, for MIM and PMOD applications, respectively.
A mean difference was 0.04 ± 0.12, the repeatability coefficient was 0.12 (12.9% of the mean) and the Spearman's rank correlation coefficient was modest, r = 0.55.
For amyloid-positive patients, the average SUVr values ??were higher than the same for all grou P values, 1.34 ± 0.16 and 1.35 ± 0.20, respectively, with a mean difference of 0.01 ± 0.16.
The repeatability coefficient was 0.16 (11.9% of the mean). The Spearman's rank correlation coefficient was high, r = 0.93. Our results indicated that the SUVr values ??derived using MIM and PMOD are effectively interchangeable and well correlated.
However, PET template-based quantification (MIM approach) is clinically friendlier and easier to use. MRI template-based quantification (PMOD Neuro) better delineates different regions of the brain, can be used with any tracer, and therefore is more suitable for research.