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Rectal cancer is one of the most common gastrointestinal malignancies in China. Accurate and reasonable assessment of the preoperative staging of rectal cancer can significantly enhance treatment outcomes and improve patient prognosis. Magnetic resonance imaging is the technique of choice for local staging of rectal cancer and has significant advantages in the diagnosis of rectal primary tumors (T) and peri-intestinal lymph nodes (N). In this review paper, the research ideas and progress of traditional radiomics and deep learning methods for preoperative TN staging prediction of rectal cancer were reviewed around multimodal magnetic resonance images, with the aim of providing new ideas for realizing fully automated TN staging algorithms for rectal cancer.
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Objective To investigate the impact of prescribed adaptive statistical iterative reconstruction V (Pre-ASiR-V) on imaging quality and radiation dosage of pure ground glass nodules (pGGN) in chest phantom,in order to obtain the optimal level of Pre-ASiR-V.Methods CT scanning for a chest phantom containing 4 artificial pGGNs was performed with Revolution CT,and the Pre-ASiR-V level was set as 0,20％,40％,60％,80％ and 100％ group,respectively.The mean noise,effective dose (ED) and the subjective scores of pGGN imaging were recorded and compared.Results The mean noise of groups (Pre-ASiR-V 0,20％,40％,60％,80％ and 100％) was (17.93±2.20)HU,(17.30±3.68)HU,(18.20± 3.44)HU,(18.80±0.20)HU,(19.87±2.56)HU and (15.90±4.56)HU,respectively (F=0.568,P=0.723).ED of these groups was 7.40 mSv,5.16 mSv,3.36 mSv,1.97 mSv,0.97 mSv and 0.33 mSv,respectively.Compared with imaging of PreASiR-V 0,the reduction percentage of ED was 30.27％,54.59％,73.38％,86.89％ and 95.54％,respectively.The subjective score of the image quality evaluated by the 2 observers had high agreement (Kappa=0.778,P=0.003),and all the scores were greater than 3.The subjective score of Pre-ASiR-V 80％ and 100％ group was slightly lower than those in other groups.Conclusion Different Pre-ASiR-V level slightly impacts the noise of high-resolution CT images of chest phantom,while reduces radiation dosage significantly.Pre-ASiR-V level of 60％ is the optimal protocol.
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Objective To access the value of three dimensional gradient echo two-point Dixon water-fat separation sequence (3 D-DIXON) in quantitative diagnosis of non-alcoholic fatty liver disease(NAFLD) by comparing with in-phase/opposed-phase (IN/OPP)and proton magnetic resonance spectroscopy (1 H-MRS).Methods A total of 69 patients with NAFLD diagnosed by CT were divided into two groups by the ratio of liver spleen in CT (group A,low-grade fatty liver,n=32;group B,moderate and severe fatty liver,n=37).All patients underwent MR 3D-DIXION,1H MRS and IN/OPP examination twice within 1 week after CT examination.Fat fraction(FF) was evaluated and analyzed respectively.Results Pearson linear correlation analysis showed significant positive correlation between group A and group B about FF3D-DIXON,FFMRs and FFIN/OPP.Area under ROC curve (AUC) was different:AUCsYNTHESIZE＞AUCMRs＞AUCIN/OPP＞AUC3D-DIXON.Kruskal-Wallis H revealed significant difference among the three sequences no matter in group A or group B (P＜0.05).FF values of the three sequences (FF3D-DIXON,FFMRs and FFIN/OPP) were negatively correlated with CT liver/ spleen ratio in each group.The cut-off value of 3D-DIXON,IN/OPP and 1 H-MRS to diagnose presence or absence of fatty liver was 4.9 3 9 ％,5.2 8 4 ％ and 10.4 6 0 ％.Conclusion FF values measured by MRI methods might significantly vary based on different sequences.1 H-MRS is also the main method for quantitative assessment of fatty liver,3D-DIXON showed significant advantage in quantifying moderate and severe fatty liver.
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Objective To study the accuracy,clinical value and limit in assessing the vessels surrounding pancreas involved by pancneutic carcinoma with low field MRI.Methods MRI scanning was performed in 55 patients with pancreatic carcinoma.We prospectively evaluated the MRI findings of vascular involvement by pancreatic carcinoma,and compared with the surgical results.Results Of total 55 cases,50(91%)cases were correctly diagnosed on MRI .MRI carries an accuracy of 86% for prediction of resectility,and accuracy of 93% for unresectility.Conclusion Low field MRI can accurately assess the peripancreative vessels ,but it has limited value in the patients with pancreatic carinomaⅠa orⅠb.