兔VX2舌癌前哨淋巴结CT间接淋巴造影观察

Sentinel lymph node localization by indirect CT lymphography in VX2 tongue cancer rabbits

目的探讨间接淋巴造影CT定位兔荷瘤VX2舌癌前哨淋巴结可行性。方法新西兰白兔9只,于左舌腹黏膜下接种VX2瘤,在接种VX2瘤后第21天于每兔舌腹黏膜下注射0.5ml欧乃派克(omnipaque)进行间接淋巴造影。于造影前及造影后1、5、15、20分钟行CT轴位扫描。扫描后再常规饲养24小时后在注射造影剂相同部位注射欧乃派克与亚甲蓝1:1混合液0.5ml,5分钟后处死动物,解剖颈淋巴结,将蓝染的淋巴结行CT扫描,全部淋巴结行组织病理学观察。结果在间接淋巴造影CT扫描指导下,位于喉、气管旁的增强淋巴结很容易被定位、发现,并与蓝染淋巴结位置相一致。肿瘤兔双侧颈淋巴结经病理学检查发现9只兔VX2舌癌的同侧颈深淋巴结均发生转移,但对侧颈深淋巴结无转移。颈浅和下颌下淋巴结无转移。同侧转移淋巴结横断面最大平均直径为(0.82±0.03)cm。在间接淋巴造影后1分钟,淋巴结增强最为明显,此后明显减弱,间接淋巴造影后1、5、15分钟的CT值分别为(687.4±55.6)Hu、(535.1±86.6)Hu和(282.3±19.4)Hu。转移性淋巴结增强显影后表现为不同程度的充盈缺损、周边凹凸不平,正常颈深淋巴结表现为圆形或椭圆形,周边光滑,无充盈缺损。所有兔在造影整个过程中未见下颌下淋巴结、颈浅淋巴结和颈部血管显影。结论间接淋巴造影CT可定位兔VX2舌癌前哨淋巴结。

OBJECTIVE To evaluate the feasibility of the sentinel lymph node （SNL） localization of tongue cancer by indirect computed tomography lymphography （CT-LG） . METHODS The VX2 carcinoma cells were transplanted into the left ventral submucosa of the tongue in 9 rabbits by injecting carcinoma mass suspension. Indirect CT-LG was performed on the 9 rabbits with injection of undiluted Iohexol into the submucosa of the tongue 21 days after transplantation. CT images were acquired before and at 1, 5, 15 and 20 minutes after contrast injection. Methylenc blue which mixed with Iohexol was injected into the same tongue areas 24 hours after indirect CT-LG, followed by SNL identification and histopathological examination. RESULTS The excellent enhancement of the tongue SLNs in 9 rabbits was demonstrated. The locations of SLNs identified under the guidance of CT lymphographic images were overlapped well with those observed by mixed blue dye method. VX2 tongue carcinomas were found and confirmed with pathological examination in all rabbits. Histological analysis revealed metastases in the ipsilateral （left） SLNs in all the 9 carcinoma-bearing rabbits. No metastasis was found in the contralateral SLNs, parotid lymph nodes and submandibular lymph nodes. The diameter of the metastatic SLNs was （0.82±0.03） cm in average. The peak enhancement of cervical lymph nodes was obtained at one minute after Iohexol injection and then the intensity decreased significantly on the subsequent CT lymphographic images with time. The average maximum CT attenuation of the cervical lymph nodes were （46.8±5.2） Hu on the precontrast CT images, （687.4±55.6） Hu, （535.1±86.6） Hu and （282.3±19.4） Hu at 1, 5 and 15 minutes after contrast agent administration respectively. CONCLUSION Indirect CT-LG is feasible in localization of the SLNs in the tongue carcinoma model.