| Objective:To explore the feasibility of low-dose radiation scanning technology and low-dosecontrast medium used in gemstone CT contrast-enhanced scan,by establishing an in-vitromodel test and using the adaptive statistical iterative reconstruction (ASiR) technology ofgemstone CT.Methods:Eight hard plastic tubes were placed2ml different concentrations of iodinesolution(2.50,3.00,3.62,4.34,5.23,6.25,7.50,9.00mgI/ml) in each, and were numbered byconcentration from low to high(①～⑧).Another hard plastic tube was used as a controltube (containing saline2ml). Respectively, two of the test tube were embedded in a freshpork package each time(including a test tube and the control tube) and were fixed in a tankfull of water. The tank was scanned by gemstone spectral CT (GE Discovery CT750HD),with different value of noise index (NI):15,17,19, and21,which were set to A, B, C, Dfour groups. ASiR right were set to10%～100%respectively to of reconstruct the image.To record CT dose index volumes (CTDIvol), dose-length product (DLP), and calculateeffective dose(ED),CNR,SNR and SD. The image quality was evaluated by3experiencedradiologist through the sharpness of tube wall, the clarity of soft tissue and SD, all dataabove were statistically analyzed.Results:1, The radiation dose: the NI value had a negative effect on the radiation dose. Therewas a statistically significant difference between A and B(P <0.05),while the differenceamong B,C and D was not significant(P>0.05).2, ASiR%: as with the increasing of ASiR%, SD gradually decreased, while CNR, SNR increased; image quality score had reached a peak in the range of50%to70%ASiR,the image quality score decreased gradually after70%.3. CNR,SNR and SD: the NI value had a negative effect on CNR and SNR, in whichthe difference was not statistically significant between A, B (P>0.05), while between B, Cthe result was statistically significant (P <0.05); the NI value had a positive effect on SD,the differences among all groups (A, B, C, D) were statistically significant (P <0.05). Thevariation of iodine solution concentration has a positive effect on CNR and SNR, but has nosignificant influence on SD.4. Image quality score: compared with groups A and B, the score of groups C and Dhad significantly decreased, and there was no statistically significant difference (P>0.05)between A and B. As with the increasing of iodine solution concentration, the Image qualityscore became higher, and there was no statistically significant difference between groups⑥to⑧(P>0.05),which represented the concentration of6.25,7.50and9.00mgI/ml.Conclusions:1, As with the increasing of NI value, the radiation dose, CNR and SNR decreases,while SD value increases. The variation of iodine solution concentration has a positiveeffect on CNR and SNR, but has no significant influence on the radiation dose and SD.2, The radiation dose can be reduced significantly by using the adaptive statisticaliterative reconstruction (ASiR) technology of gemstone CT, and17is thought to be anappropriate value of NI.3, The image quality has been improved significantly after reconstruction withdifferent ASiR%, and the value of50%～70%is thought to be the most appropriate.4, In this experiment, the image qualities of three low-dose contrast mediumgroups(5.23,6.25,7.50mgI/ml) are able to meet the diagnostic requirements, the two ofwhich(7.50,6.25mgI/ml) can reach the same level with the common-dose group(9.00mgI/ml). Experiments show that it is available to use the "double-low" proposal—low-dose radiation and low-dose contrast medium in contrast-enhanced scanning ofgemstone CT. 5, The results of this experiment have certain clinical prompt effect, and furtherclinical validations are needed, for there would be a manifest difference between the humanbody and in-vitro model. |
PDF Full Text Request