Restaging Locally Advanced Rectal Cancer with MR Imaging after Chemoradiation Therapy
Restaging Locally Advanced Rectal Cancer with MR Imaging after Chemoradiation Therapy
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DOI：
10.1148/rg.303095085
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发表时间：
2010-05-01
期刊：
影响因子：
5.5
通讯作者：
Bonomo, Lorenzo
中科院分区：
文献类型：
--
作者：
Barbaro, Brunella;Vitale, Renata;Bonomo, Lorenzo
近年来，术前治疗已成为局部进展期直肠癌的标准治疗方法。由于术前化疗-放射治疗(CRT)导致的肿瘤缩小现在已经成为现实，病理完全反应并不少见。一些研究人员现在正致力于器官保护，从而增加了对CRT反应的功能和形态放射学评估的需求，以区分有效和无反应的肿瘤。在磁共振(MR)图像上，CRT后肿瘤的形态特征和体积变化对评估疗效具有较高的阳性预测值和较低的阴性预测值。初步结果表明，扩散加权磁共振成像，特别是在高b值时，对于预测治疗结果和早期检测肿瘤反应将是有效的。一些作者报告说，表观弥散系数值与其他磁共振成像标准的结合使用显著改善了对恶性和良性淋巴结的鉴别。在正电子发射断层扫描/计算机断层扫描中连续测定氟脱氧葡萄糖摄取已被证明在CRT中和结束时区分有反应和无反应的肿瘤是有用的。然而，放射性核素技术具有空间分辨率低、成本高等局限性。需要大量的研究来验证直肠癌CRT术后再分期的最有效的形态和功能成像方式。有关补充材料，请访问http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.303095085/-/DC1.(C)RSNA，2010.Radiogics.rsna.org
In recent years, preoperative therapy has become standard procedure for locally advanced rectal cancer. Tumor shrinkage due to preoperative chemotherapy-radiation therapy (CRT) is now a reality, and pathologically complete responses are not uncommon. Some researchers are now addressing organ preservation, thus increasing the demand for both functional and morphologic radiologic evaluation of response to CRT to distinguish responding from nonresponding tumors. On magnetic resonance (MR) images, post-CRT tumor morphologic features and volume changes have a high positive predictive value but a low negative predictive value for assessing response. Preliminary results indicate that diffusion-weighted MR imaging, especially at high b values, would be effective for prediction of treatment outcome and for early detection of tumor response. Some authors have reported that the use of apparent diffusion coefficient values in combination with other MR imaging criteria significantly improves discrimination between malignant and benign lymph nodes. Sequential determination of fluorodeoxyglucose uptake at positron emission tomography/computed tomography has proved useful in differentiating responding from nonresponding tumors during and at the end of CRT. However, radionuclide techniques have limitations, such as low spatial resolution and high cost. Large studies will be needed to verify the most effective morphologic and functional imaging modalities for post-CRT restaging of rectal cancer. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.303095085/-/DC1. (C) RSNA, 2010 .radiographics.rsna.org