Application of different tube voltage-current protocol in combination with KARL iterative reconstruction in CT chest scanning for novel coronavirus pneumonia screening

doi:10.16150/j.1671-2870.2020.02.016

Abstract

Abstract:

Objective: To explore application of different tube voltage-tube current scanning protocol in combination with KARL iterative reconstruction in CT chestscanning for coronavirus pneumonia screening. Methods: The study prospectively enrolled 120 patients with fever subjected to CT chest scanning, who were randomly assigned to groups exa-mined with different scanning protocols: 120 kV tube voltage and automatic tube current modulation with 60 mAs effective tube current (Group A); 120 kV tube voltage and 30 mA fixed tube current (Group B); 100 kV tube voltage and automatic tube current modulation with 60 mAs effective tube current (Group C); 100 kV tube voltage and 30 mA fixed tube current (Group D). The traditional FBP algorithm reconstruction and KARL iterative reconstruction were adopted in the study. The comprehensive image quality was evaluated subjectively based on noise and artifacts. Images reconstructed with FBP algorithm and KARL iterative reconstruction were compared by Wilcoxon test and Kruskal-Wallis test. The image noise within the regions of interest was measured, and the radiation dosage of each protocol in different groups was calculated. Radiation dosage and image noisefor each group were compared with t-test and ANOVA analysis. Results: The radiation dosage of group A, B, C, D were 2.5±0.4, 1.2±0.1, 1.6±0.2 and 0.8±0.1 mSv respectively. The lower tube voltage and tube current decreased the radiation dosage significantly (F=256.316, P<0.001). Image processed with KARL iterative reconstruction had lower noise and better subjective image quality than those treated with FBP reconstruction (P<0.05). At lower radiation dosage, the image acquired with tube voltage of 100 kV and a fixed tube current of 30 mA and processed by KARL iterative reconstruction achieved a score of 4.0 for overall subjective image quality. Conclusion: Compared with FBP reconstruction, KARL iterative reconstruction might reduce noise and improve image quality. With lower radiation dosage, the CT chest scanning protocol with a tube voltage of 100 kV and a fixed tube current of 30 mA in combination of KARL iterative reconstruction is optimum choice for novel coronavirus pneumonia screening.

Key words: Tomography, X-raycomputed, Iterativereconstruction, Imagequality, Radiationdosage

CLC Number:

R733.3

CHANG Rui, YANG Yanzhao, KONG Deyan, XU Jiaxu, CAO Qiqi, YANG Wenjie, YAN Fuhua, DONG Haipeng. Application of different tube voltage-current protocol in combination with KARL iterative reconstruction in CT chest scanning for novel coronavirus pneumonia screening[J]. Journal of Diagnostics Concepts & Practice, 2020, 19(02): 182-187.

Figures/Tables 5

References 11

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组别	管电压	管电流	病例数（n）	年龄（岁）	身高（m）	体重（kg）	BMI（kg/m²）	DLP(mGy·cm)	ED（mSv）
A	120 kV	自动调控	30	43±15	1.65±0.1	62.0±10.2	22.6±3.1	182.6±31.5	2.5±0.4
B	120 kV	30 mA	30	49±19	1.67±0.1	63.4±11.9	22.6±3.5	88.5±6.6	1.2±0.1
C	100 kV	自动调控	30	41±15	1.66±0.1	62.8±12.5	22.6±3.4	114.7±17.7	1.6±0.2
D	100 kV	30 mA	30	44±18	1.69±0.1	64.4±11.2	22.5±3.0	55.6±3.0	0.8±0.1
F值	-	-	-	1.219	1.165	0.240	0.007	256.706	256.316
P值	-	-	-	0.306	0.326	0.868	0.999	<0.001	<0.001

重建方法	A组	B组	C组	D组	F值	P值
FBP	57.8±11.5	67.7±13.4	78.7±10.3	86.0±12.9	31.568	<0.001
KARL	43.4±8.0	48.1±7.7	58.9±6.4	61.6±9.8	34.915	<0.001
t值	16.135	11.866	14.696	14.819	-	-
P值	<0.001	<0.001	<0.001	<0.001	-	-

主观评分	FBP重建	KARL迭代重建	Z值	P值
图像噪声
A组	2.0(1.0)	1.0(0)	-4.119	<0.001
B组	2.0(0.25)	1.0(1.0)	-4.939	<0.001
C组	3.0(1.0)	2.0(1.0)	-5.014	<0.001
D组	3.5(1.0)	2.0(1.0)	-5.260	<0.001
χ²值	63.497	70.116
P值	<0.001	<0.001
伪影
A组	1.0(1.0)	1.0(0)	-2.449	0.014
B组	1.0(1.0)	1.0(0)	-3.162	0.002
C组	2.0(1.0)	1.0(0.25)	-4.000	<0.001
D组	2.0(0)	2.0(1.0)	-3.162	0.002
χ²值	41.073	40.906
P值	<0.001	<0.001
图像总体质量
A组	5.0(1.0)	5.0(0)	-2.714	0.007
B组	4.0(0)	5.0(0.25)	-4.359	<0.001
C组	4.0(0)	4.0(1.0)	-5.500	<0.001
D组	4.0(1.0)	4.0(0)	-4.000	<0.001
χ²值	37.191	36.149
P值	<0.001	<0.001