扩散加权成像诊断鼻咽癌放疗后颅底斜坡复发

Diffusion-weighted imaging in diagnosing clivus recurrence of nasopharyngeal carcinoma

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)×10-3 mm2/s vs(1.67±0.34)×10-3 mm2/s;P=0.002)。以1.018×10-3 mm2/s为ADC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。

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±0.17]×10^-3mm^2/s vs[1.67±0.34]×10^-3mm^2/s, P=0.002）. Taken 1.018×10^-3mm^2/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.