DWI术前评价直肠腺癌侵袭能力的应用价值研究

The value of diffusion-weighted imaging in the preoperative assessment of aggressiveness of rectal adenocarcinoma

目的通过分析表观扩散系数(apparent diffusion coefficient,ADC)值与直肠腺癌病理学特征之间的相关性,探讨磁共振扩散加权成像(diffusion-weighted imaging,DWI)术前评价直肠腺癌侵袭能力的应用价值。方法收集48例直肠癌患者的影像学资料,所有患者均经肠镜活检证实为直肠腺癌并手术治疗。术前均行MRI常规及DWI检查,并测量肿瘤组织ADC值。分析直肠腺癌不同病理学特征(肿瘤分化程度,T分期,N分期,淋巴结外肿瘤种植,脉管癌栓,直肠系膜筋膜状态、增值指数Ki-67)与ADC值之间的相关性。结果直肠腺癌在不同分化程度、T3期固有肌层外浸润深度及有无结外肿瘤种植的ADC值,差异均有显著统计学意义(P<0.01),而对于不同T分期、N分期、有无脉管癌栓、直肠系膜筋膜状态的ADC值,差异均无统计学意义(P>0.05)。ADC值越低,直肠腺癌分化程度越低,浸润深度越大,越有可能伴有淋巴结转移、脉管癌栓或直肠系膜筋膜阳性。ADC值与T3期固有肌层外浸润深度、增值指数Ki-67均呈负相关(r=-0.577,P=0.001;r=-0.630,P=0.000)。结论 ADC值与直肠腺癌分化程度、T3期固有肌层外浸润深度、结外肿瘤种植及ki67均有一定相关性。ADC值越低,反映了肿瘤的侵袭性越强,预后越差。ADC值有利于对术前评价直肠腺癌侵袭性提供更多的辅助信息。

Objective To explore the value of diffusion-weighted imaging（ DWI） in the preoperative assessment of aggressiveness of rectal adenocarcinoma by analyzing the relationship between tumoral apparent diffusion coefficient（ ADC） and pathological features. Methods The clinical data and images of 48 patients with rectal adenocarcinoma pathologically proven were collected and analyzed. All patients underwent plain MR scan and diffusion weighted imaging before surgery. ADC values were measured and compared between subgroups according to histological differentiation grade,T-stage,N-stage,extranodal tumor deposits,lymphovascular invasion,mesorectal fascia status or Ki-67. Results ADC value of rectal adenocarcinoma was significantly different when comparing groups stratified by histological differentiation grades,extramural depths of tumor invasion,extranodal tumor deposits（ P〈0. 01）. There was no significant difference in ADC value when stratifying patients according to T-stage,N-stage,presence of lymphangiovascular invasion or mesorectal fascia status（ P〉0. 05）. A significant negative correlation between ADC values and extramural depth of tumor invasion（ r =-0. 577,P = 0. 001）,Ki-67（ r =-0. 630,P = 0. 000） was found. The overall trend was that higher T stage correlated with lower ADC values. Rectal adenocacinoma with lymph nodes involved,lymphangiovascular invasion,or positive mesorectal fascia status had lower ADC values. Conclusion Significant correlations were found between ADC values and differentiation grade,extramural depth of tumor invasion,extranodal tumor deposits,and Ki-67.Lower ADC values were associated with a more aggressive tumor profile and poor outcome. ADC may be useful for providing additional information in the preoperative assessment of aggressiveness for rectal cancer.