Effect of different reconstruction algorithms on the image quality of low dose CT scan of elbow joint in children

ObjectiveTo explore the effects of low parameter setting and improved posture on the image quality and radiation dose of CT scanning of elbow joints in preschool children.

MethodsThe clinical data of elbow CT examination in 137 children aged 1-5 years were prospectively and continuously collected.The children were divided into the group A(n=48), group B(n=45) and group C(n=44) using the random number table method.The tube voltage in three groups was set as 80 kV.In group A, the affected limbs were placed on the side of the spine, the arms were straightened as far as possible, and the DoseRight technique was adopted.In group B, the affected limbs were raised about 45° by self-made sponge pad, the affected limbs were not in the same plane as the spine and sternum, and the DoseRight technique was adopted.In group C, the scanning position was the same as the B group, and the fixed tube current was 50 mAs.The CT volume dose index(CTDIvol) and dose length product(DLP) were recorded, the images were reconstructed using the iDose⁴ and IMR algorithms, and the image quality in three groups were subjectively and objectively scored.

ResultsThe results of comparison between groups showed that the subjective and objective scores of iDose⁴ images in three groups were the group B >group A>group C(P < 0.05), and the objective scores of IMR images were the group B >group A >group C(P < 0.05).The results of intra-group comparison showed that the subjective and objective scores of IMR images in group A and group C were higher than those of iDose⁴ images, while the differences of the subjective and objective scores between IMR and iDose⁴ images in group B were not statistically significant(P>0.05).The CTDIvol and DLP in three groups were the group A>group B>group C(P < 0.05).

ConclusionsThe CT scan of elbow in children is feasible under the affected limb is raised about 45° with self-made sponge pad, the affected limb is not in the same plane as the spine and sternum, the fixed tube current is 50 mAs, and the tube voltage is 80 kV.The IMR reconstruction algorithm can further improve the image quality.