【作者】 蓝美红；

【导师】 牛金亮；

【作者基本信息】 山西医科大学 ， 影像医学与核医学， 2012， 硕士

【摘要】 目的：建立新西兰大白兔头颈部良恶性肿大淋巴结的动物模型,以病理学为金标准,比较相对表观弥散系数(rADC)和钆喷酸葡胺增强MR诊断兔头颈部转移淋巴结的准确性。材料和方法：20只新西兰大白兔雌雄不限,2-3个月龄,平均体重(2±0.5)kg。随机分成两组,每组10只。炎症组：用生鸡蛋黄与生理盐水按1：1体积比混合制成蛋黄乳胶,10只实验兔于右耳根部(外侧耳廓边缘和耳中央动脉之间,耳的下三分之一入颅处)每只注射3m1,3天后重复注射,每天观察兔子的日常情况,触摸头颈部淋巴结是否肿大,约1周建立炎性肿大淋巴结模型。荷瘤组：切取VX2荷瘤兔肿瘤边缘生长旺盛的鱼肉样组织,制成浓度为1×107个/ml的单细胞悬液；10只实验兔以3%戊巴比妥钠(30mg/kg)经耳缘静脉麻醉,于右耳根部(具体位置同上)注射瘤细胞悬液共0.5ml,接种后连续3天每天注射青霉素40万U,每天观察兔子的日常情况,触摸头颈部淋巴结是否肿大,约4周建立转移淋巴结模型。使用GE1.5T signal HDT MR扫描仪,膝关节线圈,实验兔采用3%戊巴比妥钠(30mg/kg)经耳缘静脉麻醉。兔颈部拉直、仰卧位、足先进。扫描范围从双耳根部连线至胸廓入口。扫描序列包括：横断面FSE T1W1.横断面FSE T2W1.横断面DWI序列,其中b值为1000s/mm2。注射钆喷酸葡胺(Gd-DTPA)80s后行T1WI序列扫描。测量淋巴结、同层肌肉的ADC值,计算淋巴结/肌肉的rADC值,测量增强前、后T1WI序列淋巴结/同层肌肉的信号强度值(SI),计算增强后/增强前信号强度比值(SIr),并进行统计学分析。最后取出淋巴结,测淋巴大小,进行组织病理学HE染色,确定淋巴结的性质。结果：经病理证实,炎症组取出淋巴结26枚,肿瘤组取出转移淋巴结14枚。转移淋巴结的长径为12.29±3.80mm,短径为7.95±2.10mm；炎性肿大淋巴结的长径为9.40±1.90mm,短径为5.60±2.10mm。转移淋巴结有9枚短径<l0mm,3枚长径/短径≥2；炎性肿大淋巴结2枚短径>l0mm,有15枚长径/短径≤2,3枚发生中央坏死。炎症组反应增生淋巴结的rADC值为1.05±0.09,肿瘤转移组淋巴结的rADC值为0.78±0.10；反应增生淋巴结平均SIr值为1.34±0.25,肿瘤组转移淋巴结的SIr值为1.78±0.33。炎症组、肿瘤转移组淋巴结的rADC值、SIr值差异均具有统计学意义(t值分别为-8.30、4.76,p均<0.05)。利用rADC值鉴别良、恶性淋巴结ROC曲线下的面积(AUC)是0.93,阈值0.88,灵敏度92.3%,特异度92.9%；SIr值的AUC是0.81,阈值是1.66,灵敏度78.6%,特异度88.5%。结论：经兔右耳根部注射蛋黄乳胶、VX2肿瘤细胞可以建立头颈炎性、肿瘤转移性淋巴结模型；转移淋巴结与炎性淋巴结直径大小、长径／短径值重叠较大；炎症组肿大淋巴结、肿瘤转移组淋巴结的rADC值、SIr值具有差异性；rADC值比钆剂增强扫描SIr值鉴别转移性淋巴结具有较高的准确性。更多还原

【Abstract】 [Objective]:To establish animal modes of benign and malignant lymph nodes with New Zealand white rabbits. To compare the diagnostic accuracy of the relative apparent diffusion coefficient(rADC) with gadolinium-enhanced MR in differentiating the metastatic lymph nodes in head and neck rabbit models,by using histologic analysis as the reference standard.[Materials and Methods]:20New Zealand white rabbits,male or female, age3to4months, body weight2.0-2.5kg, were randomly divided into two groups with10rabbits in each group.Established model of inflammation group:Making blend of egg yolk emulsion with raw egg yolk and saline1:1volume.The emulsion was inoculated concentrically between the lateral auricle edge and the central auricular artery into the cranial section of the lower third of right auricles by injecting3ml of blend of egg yolk emulsion.The same procedure was repeated after three days.From the first day after inoculation,growth and the head and neck lymph node enlargement were observed every day.Established model of VX2carcinoma malignant group:Cut the Vigorous growth strong fish-like organization of tumor edge in VX2tumor-bearing rabbit, made into tumor cell suspension of1×10ml;10rabbits Were anesthetized with3%sodium pentobarbital (30mg/kg) via marginal ear vein,VX2carcinoma was inoculated concentrically between the lateral auricle edge and the central auricular artery into the cranial section of the lower third of right auricles by injecting tumor cell suspension0.5ml.Intramuscular injection (4×105U/day) of penicilin was administered for the three consecutive days to prevent infection. From the first day after inoculation,growth and the head and neck lymph node enlargement were observed every day.All subjects were examined with GE1.5T signal HDT MR scanner using knee coil. Rabbits were anesthetized with3%sodium pentobarbital (30mg/kg) via the marginal ear vein Straighten rabbits neck, Supine position, feet first. Scan range was from the ears roots connect to the thoracic inlet.Scanning sequences included cross sectional FSE T1-weighted image(TlWI), cross sectional FSE T2-weighted image(T2WI),and cross sectional diffusion weighted imaging (DWI) sequence scan were performed on each model, After80seconds administration of Gd-DTPA FSE T1WI were acquired. lymph nodes, the same level of muscle’s ADC values were measured and lymph node/muscle rADC value were calculated.lymph nodes/the same level of muscle’s standardized signal intensities (SI) values were measured before and after Gd-DTPA enhanced T1WI sequences, the SIpost/SIpre value (SIr)were calculate and analyzed statistically. Finally get the lymph nodes, measuring the size of lymph nodes, and diagnose the nature of lymph node by histopathology HE staining.[Results]:Confirmed by pathology, the number of lymph nodes from inflammation group were26, the number of lymph nodes from tumor group were14. The long diameter of metastasis lymph node is12.29±3.80mm, short diameter is7.95±2.10mm;the long diameter of inflammatory lymph nodes is9.40±1.90mm, short diameter is5.60±2.10mm. The number of the metastasis lymph nodes short diameter<10mm is9, the number of long diameter/short diameter≥2is3; inflammatory lymph nodes2short diameter>10mm, the number of long diameter/short diameter≤2is15,3lymph nodes has central necrosis.The rADC value of inflammation group lymph nods is1.05±0.09, the rADC value of malignant group lymph nods is0.78±0.10;the SIr value of inflammation group lymph nods is1.34±0.25, the SIr value of malignant group lymph nods is1.78±0.33.Independent-Samples T Test were conducted to compare the differences of benign and malignant lymph nodes.rADC value, Sir value,both were statistically significant (t value were-8.30、4.76respectively,all P <0.05).A receiver operating characteristic analysis was conducted to compare the diagnostic value of rADC value and SIr value,when using rADC value area under the ROC curve (AUC) was0.93, and the threshold value of rADC was0.88, while the sensitivity, specificity was92.3%,92.9%respectively; when using SIr value the AUC area was0.81, the threshold was1.66, the sensitivity, specificity was78.6%,88.5%respectively.[Conclusion]:The diameter of malignant lymph node and inflammatory lymph node, long diameter/short diameter values overlap larger. There is a difference of rADC value and SIr value of lymph nodes between Inflammation and neoplasms metastasis groups. rADC value can be more accurate than SIr value in differentiating benign and malignant lymph nodes in rabbit models.更多还原