Fig 1.
SPECT/CT images of the homogeneous cylindrical phantom.
The top row shows CT images of the homogeneous phantom in A) coronal, B) sagittal and C) transaxial sections, together with D) VOI location used for texture analysis. The second and third rows show reconstructed SPECT images of the central slice of the phantom for E) 5S and F) 10S, and different I values.
Table 1.
Texture features analized with CGITA software.
Fig 2.
Spatial configurations used for statistical analysis.
A) Gravity configuration: the horizontal black dashed line defines the midplane of the phantom, dividing it into two halves. B) Radial configuration: the location of the VOIs is the same as in A), but they are grouped in inner (dotted line), middle (dashed line) and fringe (continuous line) rings. The VOIs crossed by the aforementioned lines were considered for statistical analysis.
Fig 3.
Workflow adopted for the statistical analysis.
Table 2.
fANOVA results of the gravity configuration.
Corrected p-values obtained from the statistical analysis on texture features performed for 5S that rejected H0. For completeness, the corrected p-values for 10S are also reported.
Table 3.
fANOVA results of the radial configuration for 5S.
Corrected p-values obtained from the statistical analysis on texture features that rejected H0.
Table 4.
fANOVA results for the radial configuration for 10S.
Corrected p-values obtained from the statistical analysis on texture features that rejected H0.
Table 5.
Post-hoc analysis results of the radial configuration for 5S.
Table 6.
Post-hoc analysis results of the radial configuration for 10S.
Fig 4.
Texture features for VOIs in radial configuration for 5S.
A) NC-correlation, B) TFC-coarseness and C) TFCC-code similarity. Dots represent individual texture values inside the VOIs in the considered rings, while thick lines are their average values. Colors indicate spatial groupings of the VOIs (inner, middle and fringe). Box plots are reported under each plot.
Fig 5.
Texture features for VOIs in radial configuration for 10S.
A) NID-busyness, B) TFC-coarseness, C) TFCC-homogeneity and D) TFCC-code similarity. Dots represent individual texture values inside the VOIs in the considered rings, while thick lines are their averaged values. Colors indicate spatial groupings of the VOIs (inner, middle and fringe). Box plots are reported under each plot.
Fig 6.
Heat-maps of cross-correlation coefficients between texture features rejecting H0 in the radial configuration.
In each heat-map the horizontal and vertical axes refer to the value of the texture features obtained at a specific I for A) 5S and B) 10S. The legend reported in both maps refers to the Pearson’s correlation coefficient, and the color associated with a legend value is reported on the square regions of the maps, representing the level of correlation between the texture features.