直肠癌MRI研究进展

MRI是目前直肠癌诊断、分期的首选影像学方法。在判断肿瘤对邻近器官、结构的浸润程度上具有明显优势,尤其是对有较高复发风险的低位肿瘤。常规MRI尤其是高分辨MRI能够清晰显示直肠相关解剖,结合扩散加权成像(Diffusion weighted imaging,DWI)通过确定肿瘤边界,直肠系膜有无受侵,淋巴结及远处转移情况,可以准确有效的进行术前诊断、分期;DWI有助于鉴别辅助治疗后失活与存活组织、筛选出辅助治疗有效的患者,在评估治疗后疗效、提示患者预后方面发挥重要作用,也为临床制定治疗方案提供依据。同时也发现准确进行淋巴结分期、鉴别复发仍然存在困难,需要在以后进一步探讨,提高评估的准确性。本文就近年来MRI在直肠癌术前评价、术后疗效评估、复发监测及表观弥散系数(Apparent diffusion coefficient,ADC)的应用做一综述。

Research Progress of Magnetic Resonance Imaging of Rectal Cancer

MRI is currently the imaging modality of choice for the detection, characterization, and staging of rectal cancer. It is superior for assessing invasion to adjacent organs and structures, especially low tumors that carry a high risk of recurrence. Conventional MRI, in particular, high-resolution MRI and diffusion weighted image are accurate and sensitive imaging method delineating tumor margins, mesorectal involvement, nodes, and distant metastasis. DWI have proven benefit not only for tumor detection/characterization but also for monitoring treatment response. MRI is also helpful in estimating prognosis. It can be difficult to identify of metastatic lymph nodes and distinguish recurrent tumors from postsurgical/radiation changes. It needs to be further explored in the future, to improve the accuracy of the assessment. The latest research progress of MRI of rectal cancer and ADC value were reviewed in this article.