Abstract
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Objectives: With the latest SPECT scanners, it is possible to quantitate radioisotope activity precisely. We report SUV quantification of 123I-Ioflupane data in patients investigated for suspected neurodegeneration of the nigro-striatal pathway, as compared with the standard reference of striatal binding ratios (SBR) and rSUV.
Methods: In total, 7 individuals were scanned (Symbia Intevo, Siemens Healthcare) and images were reconstructed using iterative reconstruction (Flash 3D) and the xSPECT algorithm, providing SUV values. Three were scored as normal on visual rating and four as abnormal. Data were analyzed using Scenium (Siemens Healthcare). The software coregisters the individual tomographic data to a reference template and subsequently applies a standard set of volumes of interest (VOI), extracting in a fully automated way mean regional counts and SUV values for the left and right caudate and striatum, as well as for the occipital region, taken as reference region for the calculation of striatal binding ratios (SBR) and rSUV. We compared SUVmean and rSUV in normal and abnormal subgroups.
Results: SUVmean and rSUV in striatum and caudate nucleus calculated based on XSPECT reconstruction were significantly different between normal vs. abnormal subgroups (3.83±0.49 vs. 2.17±0.09 g/mL [p=0.002], 3.06±0.34 vs. 2.25±0.14 [p=0.03], 4.11±0.31 vs. 2.5±0.17 [p<0.001], and 3.08±0.43 vs. 2.58±0.19 [0.27], respectively. The difference was more apparent when using absolute quantitation as compared to normalized striatal binding ration rSUV.
Conclusion: Preliminary quantitative data showed a clear difference in normal and pathologic subgroups between SUVmean and rSUV in the striatum and SUVmean in caudate nucleus, but not for rSUV in the caudate nucleus. The knowledge of absolute quantitation of SUVmean may help to increase the accuracy of deafferentiation between normal and pathologic areas. Research Support: none