胃癌区域淋巴结转移的CT征象分析

目的探讨胃癌区域淋巴结转移的CT征象。方法收集165例胃癌术前平扫及三期增强资料,对CT发现的991枚淋巴结与手术病理、术后CT复查对比,回顾性分析胃癌区域淋巴结径线和CT值等对转移的诊断价值。根据淋巴结短径大小分为5级,1级短径≥2mm、2级≥4mm、3级≥6mm、4级≥8mm、5级≥10mm。结果165例胃癌发现区域淋巴结共991枚,平均淋巴结数目为6.01±3.73枚,区域淋巴结转移的比例为45.9%,区域淋巴结短径大小与转移正相关,r=0.436,P<0.001,提示不同短径级别的淋巴结转移比例差异有统计学意义,X^2=200.924,P<0.001;以短径6mm为阈值诊断有无淋巴结转移的阳性预测值81.8%,阴性预测值64.6%。178枚转移淋巴结平均短径(10.00±5.08)mm,平均长径(13.99±6.81)mm,与阴性淋巴结均存在差异(P<0.001)。转移淋巴结的平扫及增强各期CT值均高于阴性淋巴结,差异具有统计学意义(P<0.05),平扫、动脉期、门脉期、延迟期的平均CT值分别为(28.96±15.16)HU、(55.94±22.23)HU、(72.37±25.25)HU、(69.65±22.12)HU。以平扫平均CT值>20HU诊断转移的阳性预测值为92.6%,阴性预测值35.5%。结论以淋巴结短径6mm及平扫CT值>20HU为阈值对诊断胃癌区域淋巴结转移有临床应用价值。

Analysis of CT Signs of Gastric Cancer with Extraserosal Infiltration

Objective To investigate the CT features of regional lymph node metastasis in gastric cancer.Methods Preoperative plain scan and phase iii enhanced data of 165 patients with gastric cancer were collected,and 991 lymph nodes detected by CT were compared with surgical pathology and postoperative CT reexamination.The diagnostic value of lymph node diameter line and CT value of regional lymph nodes in gastric cancer for metastasis was retrospectively analyzed.The lymph nodes were divided into 5 grades according to their short diameter:grade 12 mm,grade 24 mm,grade 36 mm,grade 48 mm and grade 510 mm.Results A total of 991 regional lymph nodes were found in 165 cases of gastric cancer,with an average number of 6.013.73.The proportion of regional lymph node metastasis was 45.9%.The positive predictive value and negative predictive value of lymph node metastasis were 81.8%and 64.6%respectively.The mean short diameter of 178 metastatic lymph nodes was 10.005.08 mm,and the mean long diameter was 13.996.81 mm,which was different from the negative lymph nodes(P<0.001).The mean CT values of plain scan,arterial phase,portal phase and delayed phase were(28.96±15.16)HU,(55.94±22.23)HU,(72.37±25.25)HU,(69.65±22.12)HU,respectively.The positive predictive value and the negative predictive value were 92.6%and 35.5%respectively.Conclusion Lymph node short diameter of 6 mm and plain CT value of>20 HU as the threshold for the diagnosis of gastric cancer regional lymph node metastasis has clinical value.