高分辨T2WI结合T1WI增强扫描诊断直肠癌区域转移淋巴结的价值探讨

目的比较高分辨二维快速自旋回波T2加权成像(简称平扫)及平扫结合各向同性高分辨三维梯度回波T1加权成像脂肪抑制增强扫描(简称增强扫描)诊断直肠癌不同短径范围的区域转移淋巴结的价值。方法纳入直接行全直肠系膜切除术且术前接受直肠高分辨MRI检查的直肠癌患者80例。两名放射科医师分别根据平扫及平扫结合增强扫描独立评价区域淋巴结性质。以短径5 mm和10 mm为界,将区域淋巴结分为三个亚组。以术后病理结果为金标准,计算平扫及平扫结合增强扫描诊断不同亚组区域转移淋巴结的敏感性、特异性及受试者工作特征曲线的曲线下面积(AUC)。结果影像与病理匹配的淋巴结共592枚。对于短径≤5 mm及短径>5 mm且≤10 mm的区域淋巴结,平扫结合增强扫描诊断区域转移淋巴结的敏感性均高于平扫(52.94%vs. 82.35%,P=0.002;65.28%vs. 97.22%,P<0.01),但特异性不如平扫(99.28%vs. 96.15%,P<0.01;98.36%vs. 67.21%,P<0.01)。两者诊断这两个亚组的价值均中等(AUC为0.761~0.893)。9枚短径> 10 mm的区域淋巴结均为恶性,平扫结合增强扫描均判定为转移,而平扫将其中1枚误判为良性。结论平扫结合增强扫描诊断直肠癌区域转移淋巴结的价值优于平扫,具有更高的敏感性。

Differential diagnosis of metastasis from non-metastatic lymph nodes in cervical cancers： pilot study of diffusion weighted imaging with background suppression at 3T magnetic resonance

Background Diffusion weighted imaging with background suppression （DWIBS） is potentially useful in detecting metastatic lymph nodes. This study aimed to evaluate the efficacy of DWIBS at 3T magnetic resonance （MR） for diagnosing metastatic lymph nodes in cervical cancer.Methods This retrospective study included 25 patients with cervical cancer who underwent MR examination and were treated by hysterectomy and lymphadenectomy. The metastatic and non-metastatic lymph nodes were histologically proven by operation. Apparent diffusion coefficient （ADC） values, long-axis diameters, short-axis diameters, ratio of short- to long-axis diameters of all the identifiable lymph nodes were measured and compared.Results Twenty-five primary tumor lesions, 17 metastatic lymph nodes and 140 non-metastatic lymph nodes were pathologically confirmed in 25 cases with cervical cancer. The difference of ADC values between primary tumor lesions,metastatic and non-metastatic lymph nodes were statistically significant （F=7.93, P=0.001）. There was no statistically significant difference between primary tumor lesions of cervical cancer and metastatic lymph nodes （t=-0.75, P=-0.456）,and the difference between primary tumor lesions and non-metastatic lymph nodes was statistically significant （t =4.68, P〈0.001）. The ADC values, long-axis diameters, short-axis diameters, ratio of short- to long-axis diameters of metastatic and non-metastatic lymph nodes were （0.86±0.36）×10-3 mm2/s vs. （1.12±0.34）×10-3 mm2/s, （1.51±0.41） cm vs.（1.19±0.36） cm, （1.16±0.35） cm vs. （0.77±0.22） cm, 0.78±0.17 vs. 0.68±0.19 respectively, and statistically significant difference existed between two groups.Conclusions DWIBS at 3T MR has the distinct advantages in detecting pelvic lymph nodes of cervical cancer.Quantitative measurement of ADC values could reflect the degree of restriction of diffusion of metastatic and non-metastatic lymph nodes. The combination of size and ADC value would be useful in the accurate diagnosis of metastatic lymph nodes.