乳腺癌前哨淋巴结CT淋巴管造影的可行性分析

The feasibility of breast cancer sentinel lymph node mapping at CT lymphography

目的 初步评价CT淋巴管造影（LG）显示早期乳腺癌前哨淋巴结（SLN）的可行性.方法 选取25例穿刺证实且腋窝触诊为阴性的乳腺癌患者行CT-LG检查.自注射部位指向腋窝方向的引流淋巴管上最先显像的1个或数个淋巴结为SLN,与前哨淋巴结活检（SLNB）结果相对照,数目相等者为符合,多于和少于分别为高估和低估.显像质量根据容积重组后有无淋巴管显像分为Ⅰ和Ⅱ级;并以体质量指数（BMI）≥25时为肥胖.对所得结果行Fisher精确检验.结果 （1）25例患者中,5例有局部切除手术史;BMI＜25者20例,≥25者5例.（2）25例患者CT-LG均见SLN显像,其中84.0%（21例）患者图像质量为Ⅰ级,16.0%（4例）为Ⅱ级.肥胖患者CT-LG显像质量较差,两者差异有统计学意义（P＜0.05）.（3）25例患者共显示56枚SLN和45条淋巴管.与SLNB对照,36.0%（9例）患者两种结果符合,而高估和低估者分别为28.0%（7例）和36.0%（9例）.造成两种结果不一致的原因主要与肥胖因素和局部切除手术有关,两者差异均有统计学意义（P＜0.05）.（4）SLNB证实18例（52枚）阴性SLN,7例（15枚）阳性SLN,对应CT-LG共56枚SLN显像,其中阴性43枚,阳性13枚.形状为圆形在阴性和阳性SLN的比例分别为32.6%（14/43）和76.9%（10/13）,二者差异有统计学意义（P＜0.05）.中央区出现充盈缺损在阴性和阳性SLN中的比例分别为9.3%（4/43）和23.1%（3/13）,但边缘区表现为不规则充盈缺损只在30.8%（4/13）的阳性SLN中出现.3枚（2例）SLN周围伴有多发小淋巴结,组织学显示有癌细胞浸润.结论 CT-LG可有效显示乳腺癌的SLN,但其准确性易受患者肥胖因素及患侧乳房手术的影响.SLN为圆形,边缘出现虫蚀样充盈缺损,以及伴有多发小淋巴结者均可提示痛细胞浸润.

Objective To evaluate the feasibility of sentinel lymph node（SLN） mapping with CT lymphography （CT-LG）. Methods Twenty-five patients with confirmed breast cancer and no palpably axillary lymph node underwent CT-LG examination. The first one or more lymph nodes along the lymph duct draining from the injection sites to axilla were defined as SLNs, and then the LG results were compared with sentinel lymph node biopsy （SLNB）. The over- and underestimation of LG were evaluated. The quality of LG imaging was classified Grade Ⅰ and Ⅱ according to lymph duct appearance on volume rendering （VR）. The body mass index （BMI） 〉 25 was considered obesity. Fisher exact test was used for the statistics. Results （1）Of 25 patients, 5 had local mastectomy history. BMI 〈 25 was found in 20 cases, and ≥25 was in 5 cases. （2） All SLNs were showed by CT-LG, and Grade Ⅰ and Ⅱ imaging quality were achieved in 21 cases （ 84. 0% ） and 4 cases （ 16. 0% ）, respectively. The obese patient tended to have a poor imaging quality （ P 〈 0. 05 ）. （3） Fifty-six SLNs and 45 lymph ducts in all 25 patients were identified on CT-LG. Compared with the results of SLNB, 7 cases （ 28. 0% ） and 9 cases （ 36. 0% ） were over- and underestimated respectively by CT-LG due to obesity and local mastectomy （ P 〈 0. 05 ）. （4） Fifty-two negative SLNs in 18 patients and 15 positive SLNs in 7 patients were confirmed by pathology through SLNB, while 56 SLNs were delineated on CT-LG with 43 negative and 13 positive. The shape in 32. 6% of the negative SLNs （14/43） and 76. 9% of the positive SLNs （10/13） was round,the difference was significant （P〈0. 05）. The filling defect on the center in 9.3% of negative SLNs （4/43） and 23. 1% of positive SLNs （3/13） was demonstrated, and irregular filling defect on the margin was found only in 30.8% of positive SLNs （4/13）. 3 SLNs in 2 patients combined with small satellite lymph nodes on CT-LG were also confirmed to have tumor infiltration. Conclusion CT-LG can clearly demonstrate the breast lymphatic pathway and may potentially be used for breast SLN mapping, while the imaging quality can be influenced by the obesity and local mastectomy.