3.0T MR ADC值和相对ADC值对颈部转移性淋巴结的诊断价值

Apparent diffusion coefficient and relative apparent diffusion coefficient in the dignosis of cervical metastatic lymph nodes with 3.0T MR

目的探讨3.0T MR ADC值和相对ADC值(rADC值)对颈部转移性淋巴结的诊断价值。方法对23例颈部淋巴结转移患者(病例组)和40名健康志愿者(对照组)行MR检查,测量对照组脊髓、肌肉、颌下腺和腮腺的ADC值并对比分析,为rADC选取最佳参照部位。测量所有受检者淋巴结ADC值,并计算其rADC值,比较转移性淋巴结与正常淋巴结ADC值与rADC值有无差异。结果①头半棘肌的变异系数最低,腮腺的观察者间一致性最好;②转移性淋巴结(n=28)ADC值和rADC值均低于正常淋巴结(n=57,P均<0.05);③b=600s/mm2时,DWI鉴别诊断转移性淋巴结与正常淋巴结的ADC阈值为0.924×10-3 mm2/s,敏感度90.9%,特异度86.4%;以头半棘肌为参照的rADC阈值为0.489,敏感度86.4%,特异度86.4%;以腮腺为参照的rADC阈值为0.944,敏感度86.4%,特异度81.8%。结论 ADC值及rADC值均有助于区分颈部转移性淋巴结与正常淋巴结;rADC值的诊断价值未较ADC值提高。

Objective To observe the value of ADC and relative apparent diffusion coefficient （rADC） in the diagnosis of cervical metastatic lymph nodes with 3.0T MR. Methods Totally 23 patients with cervical lymph nodes metastasis （case group） and 40 healthy volunteers （control group） underwent MR examination. ADC of the spinal cord, muscle, submandibular gland and parotid gland in control group were measured, and then the reference site was determined. ADC value of Lymph nodes were measured, and rADC were calculated in all subjects. ADC and rADC of metastatic lymph nodes and nonmetastatic lymph nodes were compared. Results ①Variation coefficient of semispinalis capitis was the lowest, while interobserver consistency of submandibular gland was the best. ②ADC and rADC of metastatic lymph nodes （n=28） were less than those of nonmetastatic lymph nodes （n=57, P〈0.05）. ③When b value was 600 s/m^m2 , the threshold value of ADC in the differential diagnosis of metastatic lymph nodes and normal lymph nodes was 0. 924 × 10-a mm^2/s, the sensitivity and specificity was 90.9% and 86.4%, the threshold value of rADC referred to semispinalis capitis was 0. 489, the sensitivity and specificity was 86.4G and 86.4%, threshold value of rADC refered to suhmandibular gland was 0. 944, the sensitivity and specificity was 86.4% and 81.8%, respectively. Conclusion ADC and rADC are helpful to discriminating metastatic and nonmetastatic cervical lymph nodes. However, compared to ADC, the diagnostic value of rADC is not improved.