Table 1: The neuroradiologist’s image quality parameters scores of low dose- and standard dose head CT protocols.

 

220 (n = 22)

Image quality category

p-value

SDa = LDb

SD = LD

SD > LD

LD > SD

(score 1)

(score 2)

(score 1 vs. 2)

(score 1 vs. 2)

visual impression

0.0005**

8 (36.4%)

2 (9.1%)

12 (54.5%)

0

outer CSFc

1

22 (100%)

0

0

0

GMd/WMe differentiation

0.0002**

4 (18.2%)

5 (22.7%)

13 (59.1%)

0

size of bleeding

1

22 (100%)

0

0

0

ventricles

1

22 (100%)

0

0

0

edema

0.006*

7 (31.8%)

3 (13.6%)

11 (50%)

1 (4.5%)

postoperative changes

1

22 (100%)

0

0

0

basal cisterns

1

22 (100%)

0

0

0

240 (n = 31)

Image quality category

p-value

SD = LD

SD = LD

SD > LD

LD > SD

(score 1)

(score 2)

(score 1 vs. 2)

(score 1 vs. 2)

visual impression

0.0005**

15 (48.4%)

4 (12.9%)

12 (38.7%)

0

outer CSF

1

30 (96.8%)

0

0

1 (3.2%)

GM/WM differentiation

0.001*

12 (38.7%)

8 (25.8%)

11 (35.5%)

0

size of bleeding

1

28 (90.4%)

1 (3.2%)

1 (3.2%)

1 (3.2%)

ventricles

1

30 (96.8%)

0

0

1 (3.2%)

edema

0.004*

17 (54.8%)

5 (16.1%)

9 (29%)

0

postoperative changes

0.6

27 (87.1%)

0

3 (9.7%)

1 (3.2%)

basal cisterns

0.6

27 (87.1%)

1 (3.2%)

2 (6.5%)

1 (3.2%)

 

aSD = standard dose

bLD = low dose

cCSF = cerebrospinal fluid spaces

dGM = gray matter

eWM = white matter

**significance level with p < 0.001 and *p < 0.05