扩散加权成像诊断鼻咽癌放疗后颅底斜坡复发

目的 探讨DWI诊断鼻咽癌颅底斜坡复发瘤价值。方法 收集经病理活检或随访证实的22例鼻咽癌放疗后颅底斜坡复发瘤患者和48例无复发患者，分析其常规MRI以及DWI特征，比较二者ADC值的差异，绘制ROC曲线，确定ADC诊断鼻咽癌颅底斜坡复发瘤的阈值。结果 MR平扫示复发与无复发患者的病灶均呈稍长T1稍长T2信号，增强后呈无强化至明显强化。复发患者中，77.27%（17/22）病灶DWI呈高信号，18.18%（4/22）呈等信号，其中21例（21/22，95.45%）病灶ADC图像均呈低或稍低信号；1例（1/22，4.55%）病灶DWI呈等信号、ADC图像呈稍高信号。无复发患者中，91.67%（44/48）病灶DWI呈高信号、ADC图像呈等或稍高信号，8.33%（4/48）病灶DWI呈等或稍低信号，ADC图像呈等或稍低信号。复发患者与无复发患者病灶ADC值差异有统计学意义（0.78±0.17）]×10^-3mm²/s vs（1.67±0.34）×10^-3mm²/s， P=0.002）。以1.018×10^-3mm²/s为ADS诊断复发瘤阈值，其诊断敏感度和特异度分别为95.45%（21、22）和91.67%（44、48），ROC曲线下面积为0.984。结论 DWI诊断鼻咽癌颅底斜坡复发瘤效能较高，具有重要临床应用价值。

Diffusion-weighted imaging in diagnosing clivusrecurrence of nasopharyngeal carcinoma

Objective To explore the diagnostic value of DWI on clivus recurrence of nasopharyngeal carcinoma. Methods Totally 22 patients of clivus recurrent of nasopharyngeal carcinoma after radiotherapy and 48 non-recurrent patients confirmed by biopsy or follow-up were collected. The characteristics of routine MRI and DWI were analyzed, and ADC values were compared between recurrent patients and non-recurrent patients. ROC curves were drawn to determine the threshold of ADC value in diagnosing clivus recurrence of nasopharyngeal carcinoma. Results Recurrent and non-recurrent lesions both showed slightly hypo-intense signal on T1WI, slightly hyper-intense signal on T2WI in plain scanning, no enhancement to obvious enhancement after administration of contrast agent. Among patients with recurrent nasopharyngeal carcinoma, lesions in 17 patients (17/22, 77.27%) showed hyper-intense signal, while in 4 patients (4/22, 18.18%) showed iso-intense signal on DWI, in 21 patients 95.45% (21/22) showed hypo-intense signal on ADC images. The lesion of one recurrent patient (1/22, 4.55%) showed iso-intense signal on DWI and slightly hyper-intense signal on ADC images. Among non-recurrent patients, lesions in 44 patients (44/48, 91.67%) showed hyper-intense signal on DWI and iso-intense or slightly hyper-intense signal on ADC images, in 4 patients (4/48, 8.33%) showed iso-intense or slightly hypo-intense on DWI and iso-intense or slightly hypo-intense on ADC images. There were significant differences of ADC values between recurrent and non-recurrent patients (0.78±1017]×10^-3mm²/s vs1.67±0.34]×10^-3mm²/s, P=0.002). Taken 1.018×10^-3mm²/s as the diagnostic threshold, the diagnostic sensitivity and specificity of ADC was 95.45% (21/22) and 91.67% (44/48), and the area under ROC curve was 0.984. Conclusion DWI is able to diagnose clivus recurrence of nasopharyngeal carcinoma therefore having great clinical application value.