Development of Endoscopic CT Lymphography for Mapping Sentinel lymph node in esophageal cancer

目的探讨胃镜CT淋巴造影(CTLG)技术结合黏膜下注射广泛使用的造影剂碘帕米多直接显示狗和可手术食道癌患者引流淋巴通路的可行性。在该机构动物委员会的批准下，在9只麻醉犬中，使用柔性内窥镜将2ml未稀释的异丙咪醇注射到食道(n=6)或胃(n=3)的粘膜下层。在注射对比剂前和注射后10min分别进行1.25 mm厚的多排螺旋CT扫描。这些动物被安乐死以检查淋巴解剖。在伦理委员会批准和患者知情同意的情况下，9例可手术食道癌患者接受了类似的CTLG，但瘤周注射2ml碘帕咪醇，然后在CTLG指导下进行食道切除术和区域淋巴清扫。对包括SLN在内的切除的结节进行组织病理学检查。CTLG在所有受试者注射对比剂后5分钟内即可显示引流淋巴管与强化/非强化结节[即前哨淋巴结(SLN)]的直接连接，观察者间一致。在CT-LG导引下，13枚犬SLN(1.4枚/只)和18枚SLN(2枚/只)均能在正确的位置被发现和解剖。组织病理学检查提示CTLG引导下SLN活检成功的可能性；仅3例术前确诊的SLN中的一个转移阳性，2例SLN和邻近淋巴结转移阳性，其余4例所有切除的SLN转移均为阴性。内窥镜下CTLG对SLN和引流淋巴管的直接连接和精确解剖定位是可行的。

To evaluate the feasibility of endoscopic computed tomographic lymphographic (CTLG) technique with submucosal injection of a widely-available contrast agent iopamidol for direct visualization of drainage lymphatic pathways in dogs and in patients with operable esophageal cancer. With approval by the institution's animal committee, a total of 2 ml undiluted iopamidol was injected into esophageal (n = 6) or gastric (n = 3) submucosa in 9 anesthetized dogs, using a flexible endoscopy. The 1.25-mm thick multidetector-row CT images were obtained prior to contrast injection and during 10 min after injection. These animals were euthanized to examine lymphatic anatomy. With approval by ethical committee and informed consent from patients, 9 patients with operable esophageal cancer similarly underwent CTLG, but with peritumoral injection of 2 ml iopamidol, followed by esophagotectomy and regional lymph node dissection under CTLG guidance. Histopathology of dissected nodes including SLNs was examined. CTLG visualized the direct connection of the drainage lymphatic vessels and enhanced/unenhanced nodes [i.e., sentinel lymph nodes (SLNs)] as early as within 5 min after contrast injection in all subjects, with an interobserver consistency. All 13 SLNs in dogs (1.4 nodes per animal) and 18 SLNs in patients (2 nodes per patient) could be found and dissected at the correct location under CT-LG guidance. In patients, histopathological examination indicated successful probability of CTLG-guided SLN biopsy; metastasis was positive only in one of the preoperatively identified SLNs in 3 patients and in both SLNs and adjacent nodes in 2 patients, and negative in all resected nodes in the remaining 4 patients. Endoscopic CTLG is feasible for visualizing direct connection and accurate anatomic location of SLNs and drainage lymphatic vessels.