TABLE 1

Attenuation Coefficients Based on Pseudo-CT and CT for Each ROI

	Attenuation coefficient
ROI	Pseudo-CT–based	CT-based	Absolute difference	P
Cerebellar white matter	0.094554 ± 0.000324	0.094557 ± 0.000556	0.000004 ± 0.000570	0.7969
Cerebellar gray matter	0.094910 ± 0.002787	0.094919 ± 0.003018	0.000009 ± 0.002358	0.6289
Brain white matter	0.094501 ± 0.000244	0.094468 ± 0.000512	0.000033 ± 0.000530	0.0938
Brain gray matter	0.094982 ± 0.004226	0.094942 ± 0.004577	0.000040 ± 0.003724	0.1211
Cerebrospinal fluid	0.094201 ± 0.006186	0.093993 ± 0.002647	0.000208 ± 0.005549	0.1406
Bone	0.171169 ± 0.039059	0.174073 ± 0.034212	0.002904 ± 0.028846	0.2383
Fat	0.096634 ± 0.013912	0.096558 ± 0.004161	0.000076 ± 0.012901	0.7969
Muscle	0.087851 ± 0.016329	0.087132 ± 0.004444	0.000719 ± 0.015747	0.1563
Skin	0.081767 ± 0.022670	0.087893 ± 0.009935	0.006126 ± 0.021313	0.0039

Data are mean ± SD pseudo-CT–based attenuation coefficient, CT-based attenuation coefficient, and absolute difference as obtained from Wilcoxon signed-rank test.