Radiomics Feature Extraction from Ultrasound B-Mode Images and Radio-Frequency Signals of the Carotid Arterial Wall: A Feasibility Study

Table 4 Results of reproducibility of features across frames

Frame No	Roi size (mm)	Model	Train MSE	Train R²	Test MSE	Test R²	Feature selected	Feature Name (Feature class)	Feature Type
1	Var	Lasso L1	34.36	0.09	40.28	0.05	4	Busyness and complexity (NGLDM), Gray-Level Nonuniformity (GLRLM), SdVett_5 (Wavelet transform)	B-mode higher order and Wavelet transform
2	Var	Lasso L1	32.31	0.14	38.31	0.13	10	Standard Deviation (First order), Entropy (GLDM), Contrast (NGTDM), Mean entropy (Avg features), Gray-Level Variance (GLRLM), meanVett_3, SdVett_5, SdVett_9 (Wavelet transform), and RF First order: Median (DEA) and Median (SSD)	B-mode first order, higher order, wavelet and RF first order
3	Var	Lasso L1	33.73	0.112	42.32	0.11	2	Gray-Level Nonuniformity (GLRLM), SdVett_9(Wavelet transform)	B- mode Higher order and Wavelet transform
Med	Var	Lasso L1	33.86	0.13	30.79	0.11	3	Complexity (NGTDM), Gray-Level Nonuniformity (GLRLM), SdVett_9 (Wavelet transform)	B- mode Higher order and Wavelet transform

Dependent Variable: Chronological age. The Mean square Error (MSE) is represented in years
DEA Direct Energy attenuation map, GLDM Grey Level Distance Matrix, GLRLM Grey Level Run Length Matrix, NGLDM Neighboring Grey Level Dependence Matrix, SSD Skewness of spectrum difference Map

ISSN: 1876-4401