The Value Of Rectal MR In Re - Evaluation Of Neoadjuvant Therapy For Rectal Cancer

Section I:Comparison of Image Quality of High-resolution DWI and Conventional EPI DWI for Evaluation of Rectal CancerOBJECTIVE:To compare image quality of RESOLVE DWI and EPI DWI for evaluation of rectal cancer.MATERIAL and METHODS:Image of rectal cancer patients, who received MR scan by 3. OT MR scanner both before and after CRT, was evaluated retrospectively. Image quality was assessed by subjective and objective evaluation methods. SNR, CNR and rADC value were measured objectively. Five-level image quality was used to evaluate geometric distortion and motion artifacts, imaging blurring. Comparative statistical analysis was performed for comparing RESOLVE DWI and EPI DWI. SNR, CNR, rADC, geometric distortion and motion artifacts, image blurring of the same DWI befor and after CRT were also cpmpared.RESULTS:There were 37 patients enrolled into this study, including 28 male and 9 female, with a mean age of 60.11±12.73years (range 32-83years). Compared with EPI DWI, RESOLVE DWI showed better image quality in SNR, rADC, geometric distortion and motion artifacts, image blurring befor CRT, and SNR, geometric distortion and imaging blurring after CRT. For the same DWI, CNR and rADC had statistically difference between MR image before and after CRT, while the others had not.CONCLUTION:Compared with EPI DWI, RESOLVE DWI had better image quality both befor and after CRT, and can be used as a routine scan sequence.Section II:Value of High-resolution DWI in Reassessment of Rectal Cancer after CRTOBJECTIVE:To compare accuracy of T staging of RESOLVE DWI and EPI DWI for Rectal Cancer after CRT.MATERIAL and METHODS:Image data of rectal cancer patients who underwent MR scan after CRT were retrospectively analysed. Firstly, T2WI image was used only to assess T stage, and calcuting its accuracy. For those who cannot be staged correctly by T2WI only, T2WI combined RESOLVE DWI or EPI DWI was used respectively for staging, and to compare their accuracy.RESULTS:62 patients were enrolled in this study, including 46 male and 16 female, with a mean age of 57.19±12.80years (range 25-85years). For the 62 patients, there were 28 patients who were staged correctly by T2WI only, and the accuracy was 45.16%. For the 34 patients who cannot be assessed correctly only by T2WI, there were 11 patients and 6 patients who were staged correctly by T2WI combined RESOLVE DWI and EPI DWI respectively.CONCLUTION:For those who cannot be staged by T2WI only, compared with EPI DWI, RESOLVE DWI can improve the accuracy of rectal cancer after CRT highly.Section III:Reassessment of Rectal Cancer after Neoadjuvant Chemoradiotherapy:a Comparative Study of MR and PathologyOBJECTIVE:To evaluate MR restaging accuracy of rectal cancer after N-CRT, and to investigate influence factors of T restaging.MATERIAL and METHODS:Prospectively and consectively enrolled rectal cancer patients who underwent MR scan after CRT from 2015-06-01 to 2015-12-31. Data of MR image was reviewed by two radiologists independently, and pathological sections were reassessed by two pathologists together. Carefully compare preoperate MR image and pathological components, in order to find reasons for wrong assessment. Application SAS9.2 software for analysis, kappa test was used to evaluate consistency of staging of the two readers, Fisher exact probability was used to compare accuracy of T staging of the two groups, who contained different size of residual cancer. P<0.05 was considered statistically significant.RESULTS:35 patients were enrolled in this study, including 25 male, and 10 female, with a mean age of 57.03+11.99. Kappa value of the two readers of T staging was 0.707. Accuracy of T staging of the two was 48.6%,51.3%, respectively. Among the 8 patients with ypTO,3 patients had mucus, and all of the three were proved to be over-staged. For the 7 mucinous adenocarcinoma patients, there were 4 who were under-staged. Between the 8 patients with residual cancer more than 5% and the 19 patients with residual cancer more than 5%, there was significant difference (P<0.05) about T staging, indicating that size of residual cancer had relationship with T staging.CONCLUTION:YpTO stage with mucus, mucinous adenocarcinoma, and patients with residual caner not more than 5% were main reasons about wrong restaging of rectal cancer after N-CRT.