超声内镜对胰腺小肿瘤的诊断价值

The role of endoscopic ultrasound in detection of small pancreatic tumors

胰腺癌的早期诊断极为困难,多数患者确诊时均为局部进展期或已出现远处转移。直径大于2 cm的胰腺癌在诊断明确时多已有微转移发生,故早期诊断、早期手术是治愈胰腺癌的唯一手段,也是改善预后的关键。目前,体表超声、CT和MRI等临床常用的影像学诊断技术对直径小于2 cm的胰腺病变仍存在一定的漏诊率。超声内镜(endoscopic ultrasound,EUS)技术借助其高分辨率超声探头及近距离探查等优势,可提供实时的、清晰的胰腺实质回声特征,甚至可显示直径小至5 mm的胰腺病灶,被认为是诊断胰腺肿瘤最敏感的方法。近年来,随着EUS设备及技术的普及,使得胰腺实质性小肿瘤的发现率得到了提高;尤其是超声弹性成像技术(elastography)、对比增强谐波成像技术(contrast-enhanced harmonic endoscopic ultrasonography,CEH-EUS)及EUS引导下细针抽吸活组织检查(EUS-guided fine needle aspiration biopsy,EUS-FNAB)等技术的应用,进一步提高了EUS对胰腺小肿瘤的诊断与鉴别诊断的能力。

Early detection of pancreatic cancer is difficult and most of patients with pancreatic cancer present with locally advanced stage disease or distant metastasis on diagnosis. Micrometastasis occurs in the majority of pancreatic cancers larger than 2 cm in diameter and making early diagnosis and treatment essential to improve the prognosis. Small pancreatic tumors less than 2 cm in diameter can be missed on transcutaneous ultrasound, CT and MRI. Endoscopic ultrasound （EUS） has been considered the most sensitive modality in evaluation of pancreatic lesions. It can be placed in close proximity to the pancreas and provide real-time, high resolution imaging using a high frequency ultrasound probe to find lesions as small as 5 mm. Recently, small pancreatic tumors have been increasingly detected with the widely used EUS. The development of new techniques such as EUS elastography, contrast-enhanced harmonic EUS （CEH-EUS） and fine needle aspiration biopsy （EUS-FNAB） have enhanced the ability of EUS in detection of small solid pancreatic tumors as well as in differentiation of malignancies from benign tumors.