CT增强鉴别胰腺神经内分泌癌与胰腺癌

Differential diagnosis of pancreatic neuroendocrine carcinoma and pancreatic ductal adenocarcinoma by CT enhancement

目的分析PNEC与PDAC的临床及影像学特点,寻找具有鉴别价值的临床或影像学征象,以期提高术前诊断准确率。方法回顾性分析经病理证实的11例PNEC与20例PDAC患者的临床及影像学资料,观察病变位置、大小、形态、边界,测量病灶、周围正常胰腺组织平扫及增强扫描各期CT值,计算并采用两样本T检验方法比较两组相对密度指数;另外观察分析胰管、胆管扩张情况及远端胰腺萎缩、邻近组织受侵或远处转移等征象。结果 PNEC组病灶边界相对PDAC更为清晰;PNEC病灶于各期CT值均高于PDAC,且二者动脉期及静脉期相对密度指数有明显的差异,但平扫及延迟期病灶相对密度指数接近,不易区分两组病灶;PDAC组出现胰腺萎缩的概率高于PNEC,差异有统计学意义;胰、胆管扩张、淋巴结转移、局部侵犯或远处转移等征象对于区分两者无显著意义。结论 PNEC与胰腺癌可出现不同程度的影像重叠征象,容易误诊,但PNEC相对于PDAC边界较清,动脉期及静脉期相对密度指数高于PDAC,以及较少出现胰腺萎缩等征象有助于鉴别诊断。

Objective To describe imaging and clinical findings of pancreatic neuroendocrine carcinoma （PNEC） and to de- termine imaging features differentiating them from pancreatic duct adenocarcinoma （PDAC） , so as to improve the accuracy of pre- operative diagnosis. Methods The CT unenhanced, parenchymal phase, venous phase and delayed phase enhanced images of 11 PNEC and 20 PDAC patients were retrospectively analyzed, including tumor location, size, boundary, involvement of the pancre- atic duct and bile duct, changes of adjacent artery and vein, and other organs lesions. CT values of pancreatic lesion, surrounding normal pancreatic parenchyma and relative density index in unenhancement and enhancement images were measured or calculated. PNEC group and PDAC group were compared. Results Boundaries were more poorly defined in PDAC than PNEC. PNEC and PDAC CT values were lower than those of normal pancreatic parenchyma. Hyper-/isointensity was more common in PNEC than PDAC. Relative density index was higher in PNEC than PDAC on the arterial and portal phases. Pancreatic atrophy more often oc- curs in PDAC patients. However, the difference about Lymph node metastasis and local invasion/distant metastasis showed no sig- nificant difference. Conclusion PNEC can mimic PDAC due in part to a characteristic hypoenhanced pattern. Well-defined mar- gins, high relative density index, and less pancreatic atrophy may be useful for differentiating PNEC from PDAC.