| Part 1 Evaluation of CT perfusion in the response to concurrent radiochemotherapy for middle-advanced cervical squamous carcinoma.Objective:To explore the value of Toshiba 320-detector-row dynamic volume CT perfusion imaging in evaluating the response of concurrent radiochemotherapy for middle-advanced cervical squamous carcinoma.Methods:From January 2017 to August 2018,forty-five patients with cervical squamous carcinoma later than stage II b were included in this study in our hospital.All the patients were treated with concurrent radiochemotherapy.After informed consent,pelvic perfusion scan was performed with Toshiba 320-detector-row dynamic volume CT before and after treatment with the same conditions.The perfusion data of patients were post-processed to obtain the perfusion curve,perfusion pseudo-color maps and perfusion parameters of cervical carcinoma.According to the response evaluation criteria in solid tumors(RECIST),the patients after treatment were divided into effective group and ineffective group.General clinical data and perfusion parameters of patients with different clinical effects before and after treatment were compared,and the perfusion parameters that might affect treatment effect were analyzed by using ROC curve.The correlation between tumor size and perfusion parameters was analyzed by Pearson correlation analysis.Perfusion parameters and perfusion curves of patients before and after concurrent radiochemotherapy were compared.Results:The arterial blood flow(AF),blood volume(BV)and clearance(CL)of patients with cervical carcinoma in the effective group were higher than those in the ineffective group,and the diameter of tumors in the effective group was smaller than that in the ineffective group.In evaluating the effect of concurrent radiochemotherapy for middle-advanced cervical squamous carcinoma,the area under the ROC curve of BV was the largest,so the diagnostic efficiency of BV was better than that of AF and CL.Small tumors usually had higher BV and CL values,and thus had a good treatment response.After concurrent radiochemotherapy,the values of AF,BV and CL of patients were significantly lower than those before therapy.The rising trend of perfusion curve is slower,the amplitude is smaller,the time to peak is longer and the peak value is obviously lower than before.Conclusion:CT perfusion imaging can evaluate the response of concurrent radiochemotherapy for middle-advanced cervical squamous carcinoma,and provide an imaging reference for clinical in the judgement of prognosis and adjustment of treatment plan.Part 2 Feasibility study on limit optimization of CT perfusion imaging scan sequence for cervical carcinomaObjective:By analyzing the influence of selectively decreasing the number of CT perfusion imaging scans and shortening the scan time on the perfusion parameters and the perfusion curve for cervical carcinoma,the CT perfusion scan sequence was gradually optimized to minimize the number of scans and the scan time,so as to minimize the radiation dose.Methods:CT perfusion data of twenty patients diagnosed with stage II b cervical squamous carcinoma were retrospectively analyzed.The original perfusion date contained 25 volume data packets,with a scan time of 90 seconds,and the perfusion curves,perfusion pseudo-color maps and perfusion parameters were obtained by image post-processing as the control group.Firstly,the number of perfusion scans was optimized.Removed the first volume data packet to get the first experimental group,removed the second volume data packet to get the second experimental group...removed the twenty-fifth volume data packet to get the twenty-fifth experimental group.The perfusion data of each experimental group were processed respectively by image postprocessing to obtain the perfusion curve,perfusion pseudo-color images and perfusion parameters which were compared with the control group.When any perfusion parameters value of one experimental group were not statistically significant different from those of the control group,it showed that the removal of the scan time point had no effect on the perfusion parameters,and the scan time point should be removed in all subsequent experimental groups;when any perfusion parameters of one experimental group were significantly different from those of the control group,it indicated that the removed scan time point was a key point,which should be retained in all subsequent experimental groups.The experimental group with no significant difference in perfusion parameters compared with the control group and the least number of scans was the preliminary optimization group.Secondly the perfusion scan time was optimized.To further shorten the scanning time of the preliminary optimization group,the scan time points of 83 s,76s,69 s,62s,55 s and 48 s were respectively used to replace the last 90 s scan time point of the preliminary optimization group to obtain the new experimental groups.After image post-processing,perfusion curves,perfusion pseudo-color maps and perfusion parameters of each new group were obtained and compared with those of the control group respectively.Finally,the new experimental group with no significant difference compared with the control group and the shortest scanning time was the limit optimization group that did not affect the diagnostic efficiency of cervical carcinoma.Results:There was no statistically significant difference in perfusion parameters between the 24 th experimental group and the control group,and the number of scans in the 24 th group were the least,which was the preliminary optimization group.When the scanning time of the preliminary optimization group was shortened to 55 s,the perfusion parameters of the new experimental group still showed no statistical significance compared with those of the control group,which was the limit optimization group that did not affect the diagnostic efficiency of cervical carcinoma in our study.The radiation dose of the patients in the limit optimization group was theoretically only 2/5 of that of the control group and the scanning time points of perfusion sequence scanning were 0s,16 s,22s,24 s,27s,30 s,36s,39 s,42s and 55 s.Conclusion:Decreasing the number of CT perfusion scans and shortening the scanning time for cervical carcinoma will lead to corresponding changes in perfusion curve and perfusion parameters.Without affecting the diagnostic efficiency of cervical carcinoma,the fewer the number of CT perfusion scans,the shorter the scanning time,and the lower the radiation dose the patient receives.CT perfusion imaging limit optimization scanning sequence of cervical carcinoma meets the requirements of medical ethics,and its application prospect is worth looking forward to. |
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