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Table 2 Noise and CNR values of polychromatic and VMIs with different DRIs, body sizes, and energy

From: Value of virtual monochromatic spectral image of dual-layer spectral detector CT with noise reduction algorithm for image quality improvement in obese simulated body phantom

Body size

 

DRI

Polychromatic image

VMI (keV)

40

45

50

55

60

65

70

75

80

90

100

110

120

140

160

180

200

S

Noise

16

8.99

9.30

8.78

8.38

8.18

8.02

7.90

7.85

7.78

7.75

7.67

7.65

7.63

7.63

7.63

7.62

7.62

7.63

19

7.66

8.20

7.67

7.37

7.20

7.07

6.95

6.93

6.90

6.88

6.85

6.87

6.80

6.83

6.83

6.77

6.78

6.80

22

6.81

7.20

6.63

6.27

5.98

5.77

5.62

5.58

5.52

5.47

5.38

5.37

5.37

5.33

5.35

5.33

5.33

5.37

25

5.98

6.78

6.00

5.40

5.05

4.80

4.68

4.55

4.47

4.47

4.37

4.38

4.37

4.35

4.38

4.42

4.43

4.42

CNR

16

6.78

17.00

14.82

12.96

11.27

9.95

8.86

7.96

7.23

6.63

5.78

5.15

4.71

4.40

3.96

3.70

3.53

3.41

19

8.39

17.72

15.82

13.95

12.29

10.98

9.96

9.05

8.29

7.72

6.85

6.23

5.85

5.51

5.11

4.90

4.73

4.64

22

9.33

20.76

18.68

16.63

14.91

13.44

12.24

11.07

10.15

9.45

8.37

7.59

6.99

6.61

6.04

5.71

5.50

5.34

25

10.90

21.48

20.15

18.85

17.27

15.86

14.37

13.35

12.32

11.38

10.24

9.19

8.53

8.04

7.33

6.83

6.56

6.40

L

Noise

16

12.36

11.43

11.27

10.90

10.62

10.50

10.28

10.22

10.18

10.12

9.98

9.98

9.98

9.93

9.92

9.87

9.88

10.10

19

10.59

10.18

9.70

9.35

9.12

8.93

8.85

8.73

8.68

8.67

8.60

8.57

8.52

8.53

8.47

8.48

8.42

8.45

22

9.44

8.47

7.98

7.68

7.42

7.33

7.18

7.15

7.05

7.07

6.97

6.92

6.92

6.95

6.90

6.90

6.85

6.90

25

4.32

6.82

6.37

6.15

6.03

5.90

5.82

5.78

5.78

5.75

5.73

5.73

5.72

5.72

5.70

5.75

5.68

5.73

CNR

16

4.41

11.56

9.82

8.63

7.67

6.83

6.23

5.71

5.25

4.92

4.44

4.07

3.80

3.62

3.38

3.23

3.12

2.99

19

5.46

14.69

12.69

11.00

9.56

8.40

7.44

6.73

6.07

5.55

4.82

4.30

3.94

3.66

3.31

3.11

2.95

2.87

22

6.30

17.78

15.63

13.68

12.12

10.67

9.64

8.72

8.02

7.38

6.52

5.94

5.50

5.13

4.73

4.46

4.39

4.87

25

7.82

20.87

18.56

16.21

14.20

12.69

11.38

10.35

9.45

8.73

7.69

6.97

6.51

6.13

5.63

5.25

5.09

4.98

  1. Note – CNR contrast to noise ratio, DRI Dose Right Index, VMI virtual monochromatic spectral image, S small, L large