CT texture analysis: a potential tool for prediction of survival in patients with metastatic clear cell carcinoma treated with sunitinib

Table 3 Imaging parameters as predictors of PFS

Variable	P-value	Hazard ratio	95% CI
Mean positive pixel intensity prior to treatment	0.61	1.01	0.98 – 1.04
Mean positive pixel intensity following treatment	0.72	1.00	0.99 – 1.02
SD prior to treatment	0.71	0.99	0.97 – 1.02
SD following treatment	0.33	0.99	0.97 – 1.01
Entropy prior to treatment	0.25	1.84	0.64 – 5.32
Entropy following treatment	0.08	2.23	0.91 – 5.49
nSD prior to treatment	0.01	0.01	0.000 – 0.31
nSD following treatment	0.003	0.01	0.001 – 0.22
Kurtosis prior to treatment	0.21	1.28	0.87 – 1.87
Kurtosis following treatment	0.34	1.12	0.89 – 1.41
Skewness prior to treatment	0.32	1.66	0.62 – 4.41
Skewness following treatment	0.65	1.20	0.55 – 2.61
Percent change in size	0.14	0.98	0.96 – 1.01
Mean pixel intensity change	0.36	0.99	0.98 – 1.01
SD change	0.51	0.70	0.25 – 2.02
Entropy change	0.21	15.12	0.21 – 1096.9
nSD change	0.06	0.02	0.00 – 1.21
Kurtosis change	0.92	1.06	0.37 – 3.04
Skewness change	0.81	0.94	0.56 – 1.58

Entries in bold were significant
Abbreviations: SD standard deviation, nSD size normalized standard deviation, PFS progression free survival

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