A new radiomics approach combining the tumor and peri-tumor regions to predict lymph node metastasis and prognosis in gastric cancer

Objective The development of non-invasive methods for evaluating lymph node metastasis(LNM)preoperatively in gastric cancer(GC)is necessary.In this study,we developed a new radiomics model combining features from the tumor and peritumor regions for predicting LNM and prognoses.Methods This was a retrospective observational study.In this study,two cohorts of patients with GC treated in Zhongshan Hospital Fudan University(Shanghai,China)were included.In total,193 patients were assigned to the internal training/validation cohort;another 98 patients were assigned to the independent testing cohort.The radiomics features were extracted from venous phase computerized tomography(CT)images.The radiomics model was constructed and the output was defined as the radiomics score(RS).The performance of the RS and CT-defined N status(ctN)for predicting LNM was compared using the area under the curve(AUC).The 5-year overall survival and progression-free survival were compared between different subgroups using Kaplan–Meier curves.Results In both cohorts,the RS was significantly higher in the LNM-positive group than that in the LNM-negative group(all P<0.001).The radiomics model combining features from the tumor and peri-tumor regions achieved the highest AUC in predicting LNM(AUC,0.779 and 0.724,respectively),which performed better than the radiomics model based only on the tumor region and ctN(AUC,0.717,0.622 and 0.710,0.603,respectively).The differences in 5-year overall survival and progression-free survival between high-risk and low-risk groups were significant(both P<0.001).Conclusions The radiomics model combining features from the tumor and peri-tumor regions could effectively predict the LNM in GC.Risk stratification based on the RS was capable of distinguishing patients with poor prognoses.

临床5.0 T超高场MRI评估脑动脉及其分支的价值

目的探讨5.0 T超高场MR评估脑动脉及其分支的价值。方法本研究为前瞻性研究。收集复旦大学附属中山医院2021年9月1日至11月30日招募的健康成年人40名,采用完全随机设计将其分为3.0 T MR组和5.0 T MR组,每组20名。对所有受检者进行时间飞跃MR血管成像(TOF-MRA),采用主观Likert5量表评分和信噪比(SNR)、对比噪声比(CNR)对图像质量进行评估,采用3分量表法对脑动脉显示质量[大脑中动脉(MCA)及其3段、大脑前动脉(ACA)及其3段、大脑后动脉(PCA)及其3段、豆纹动脉(LA)、脑桥动脉(PA)]进行评估。2组间定量指标的比较采用独立样本t检验和Mann-WhitneyU检验。结果40名受检者中男29名、女11名,年龄20~69(50±12)岁。5.0 T MR组图像的SNR值(187±9)和CNR值(156±7)高于3.0 T MR组(分别为91±4、70±4),差异有统计学意义(t分别为31.59、31.45,P<0.001),但5.0 T MR组、3.0 T MR组图像质量主观评分差异无统计学意义[分别为5.0(4.0,5.0)、5.0(5.0,5.0)分,Z=-1.23,P=0.218]。对脑动脉的评估上,3.0 T MR组与5.0 T MR组TOF-MRA在MCA、ACA和PCA近段及中段的显示均较好,评分差异无统计学意义(P>0.05),而在远段血管的显示上5.0 T MR组图像均明显优于3.0 T MR组图像(P<0.05)。在穿支动脉的评估中也可发现5.0 T MR组对LA和PA的显示均显著高于3.0 T MR组图像(P<0.001)。结论5.0 T超高场强MR扫描对远段脑血管及穿支动脉显示较佳,可用于脑血管疾病的诊断和鉴别诊断。