Abstract
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Objectives: Firstly, the comparison of quantitative values between the new reconstruction algorithms, xSPECT Bone (xB) and xSPECT Quant (xQ), in a group of patients. Secondly, image quality qualitative assessment in a subset of patients, comparing the new reconstruction algorithms with the classic Flash3D method.
Methods: 48 patients referred for a bone scintigraphy due to musculoskeletal, oncological and internal medicine pathologies were assessed using a Symbia IntevoBold SPECT-CT (Siemens). Images were reconstructed using the ordered subset conjugate gradient maximization algorithm, xB and xQ, selecting for each of them the reconstruction predefined by the manufacturer, best and the standard. SUVmax and SUVmean values were measured in pathological uptake regions as well as in healthy bone, subsequently comparing the variability between the measurements (ANOVA). In a subset of 6 patients, a double acquisition protocol, Flash3D and xSPECT, was performed with the obtention of 6 reconstructions: corrected and uncorrected Flash3D, best and standard xB and best and standard xQ. Five specialists in nuclear medicine evaluated the reconstructions quality using a 4 categories scale (excellent, good, poor, not interpretable).
Results: There were no significant differences among SUVmean values when comparing the measurements performed in healthy bone: xB-Best vs. xB-Standar, xQ-Best vs. xQ-Standar, xB-Best vs. xQ-Best, xB-Standar vs. xQ-Standard. In the pathological uptake regions, SUVmean behavior was more heterogeneous, as there were no significant differences among the groups xB-Best vs. xQ-Best, xB-Best vs. xQ-Standard, xB-Standard vs. xQ-Standard, xQ-Best vs. xQ-Standard.SUVmax values showed statistically significant differences between the different reconstructions (p <0.001), except for the reconstructions xQ-Best vs. xQ-Standard, in the pathological uptake regions as well as in healthy tissue.In the qualitative assessment, xB-Best and standard reconstructions were considered in most cases of excellent visual quality (73.3% and 90% respectively), whereas xQ-Best and standard were rated as good quality (93,3% and 73.3% respectively). However, Flash3D was considered poor in 86.7% of corrected reconstructions, in the 66.7% of uncorrected ones and not interpretable in 26.7%.
Conclusions: Regarding quantitative values, SUVmax showed statistically significant differences when comparing different reconstructions. However, SUVmean values appear to be more stable.With reference to image quality, it is better in the xB reconstruction than in xQ or Flash3D and there were no large differences when comparing the reconstructions xB-Best Vs. xB-standard and xQ Vs. Flash3D.