PET-CT诊断免鼻咽VX2移植癌颈部转移淋巴结的价值

Value of PET-CT in Diagnosing Neck Lymph Node Metastasis of Rabbit Nasopharyngeal VX2 Carcinoma

目的:探讨Biograph Sensation 16 PET-CT一体大型机在诊断兔鼻咽VX2肿瘤颈部转移淋巴结性质上的价值。方法:建立兔鼻咽VX2肿瘤模型,利用Biograph Sensation 16 PET-CT一体大型机完成^(18)F-FDG PET-CT扫描,测量淋巴结最大标准摄取值。解剖清扫双侧颈部淋巴结,分别标记,测量淋巴结最短径,获得病理结果。将PET-CT诊断结果与病理结果比较。结果:1)30只移植成功并存活的鼻咽VX2肿瘤兔,解剖检出颈部淋巴结共53枚,病理证实转移淋巴结42枚。28只兔发现颈部淋巴结转移,转移率93.3%。2)^(18)F-FDG PET-CT诊断真阳性的28枚淋巴结SUV为3.820±1.658,其淋巴结最短径为0.83±0.37cm,大于PET-CT诊断假阴性的14枚淋巴结最短径(0.38±0.15cm),两者差异有统计学意义(t=5.599,P=0.000)。3)^(18)F-FDG PET-CT对淋巴结最短径<0.5cm及≥0.5cm两组诊断的敏感性分别为0.250、0.833,相比较差异有统计学意义(t=13.125,P=0.000)。准确性分别为0.571、0.844,相比较差异有统计学意义(t=4.837,P=0.028)。4)在转移淋巴结较小,仅结内侵犯时或被膜下侵犯时,PET-CT能发现部分病灶,但假阴性高。结论:Biograph Sensation 16 PET-CT一体大型机能很好显示中型动物的兔VX2鼻咽移植癌颈部淋巴结;对于最短径≥0.5cm的颈部转移淋巴结,^(18)F-FDG PET-CT的诊断敏感性、准确性高,特异性为100%,是有价值的影像检查;对于仅结内侵犯或被膜下侵犯的小淋巴结,^(18)F-FDG PET-CT能发现部分病灶,但假阴性高。

Objective： To study the value of Biograph Sensation 16 positron emission tomography - computed tomography （PET-CT） in diagnosing neck lymph node （LN） metastasis of rabbit nasopharyngeal VX2 carcinoma. Methods： After the establishment of 30 rabbit nasopharyngeal VX2 carcinoma models, ^18F-deoxyglucose （18F- FDG） PET-CT was performed on the Biograph Sensation 16 PET-CT machine and standard uptake value （SUV） was measured. Then anatomical and pathological diagnoses were completed. Neck LN images were observed and compared with the results of the anatomical and pathological findings. Results： （1） A total of 53 neck LNs were collected from 30 nasopharyngeal VX2 carcinoma rabbits and 42 neck LNs were pathologically confirmed with metastasis. Twenty-eight rabbits had neck lymph node metastasis and the metastatic rate was 93.3% （28/30）. （2） SUVs of 28 positive LNs diagnosed by ^18F-FDG PET-CT were 3.820± 1.658. Short diameter of positive LNs was significantly longer than that of false negative LNs （t=5.599, P=-0.000）, 0.83±0.37 cm and 0.38±0.15 cm, respectively. （3） The diagnostic sensitivity of 18F-FDG PET-CT was 0.250 and 0.833 for LNs with the short diameter 〈0.5cm and ≥ 0.5cm, respectively, with a significant difference （t=13.125, P=-0.000）. The diagnostic accuracy for LNs with short diameter 〈0.5cm was significantly different from that for LNs with short diameter ≥.5cm （t=4.837, P=- 0.028）. The accuracy was 0.571 and 0.844, respectively （t=4.837,≥=-0.028）. （4） When there were micro-metastases only inside LNs or subcapsular invasion, PET-CT could find some metastatic LNs but with more false negative LNs. Conclusion： Biograph sensation 16 PET-CT is a useful tool to detect the neck LN metastasis of rabbit nasopharyngeal VX2 carcinoma. The diagnostic sensitivity and accuracy were high and the specificity was 100%. 18F-FDG PET-CT was reliable to detect the neck LNs with short diameter ≥0.5cm. ^18F-FDG PET-CT could find micro-metastases only inside LNs or subcapsular invasion.