Signal intensity changes of dentate nucleus on plain MR T1WI innasopharyngeal carcinoma patients after radiotherapy andmultiple injections of gadolinium-base contrast agent

鼻咽癌患者经放射治疗及多次注射钆对比剂后平扫MRT1WI齿状核信号强度变化

Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(GBCA).Methods Fifty patients with pathologically confirmed nasopharyngeal carcinoma and received intensity-modulated radiotherapy were retrospectively enrolled as the nasopharyngeal carcinoma group,and 50 patients with other malignant tumors and without history of brain radiotherapy were retrospectively enrolled as the control group.All patients received yearly GBCA enhanced MR examinations for the nasopharynx or the head.T1WI signal intensities of the dentate nucleus and the pons on same plane were measured based on images in the year of confirmed diagnosis(recorded as the first year)and in the second to the fifth years.T1WI signal intensity ratio of year i(ranging from 1 to 5)was calculated with values of dentate nucleus divided by values of the pons(ΔSI i),while the percentage of relative changes of year j(ranging from 2 to 5)was calculated withΔSI j compared toΔSI 1(Rchange j).The values of these two parameters were compared,and the correlation ofΔSI and GBCA injection year-time was evaluated within each group.Results No significant difference of gender,age norΔSI 1 was found between groups(all P>0.05).The second to the fifth yearΔSI and Rchange in nasopharyngeal carcinoma group were all higher than those in control group(all P<0.05).Within both groups,ΔSI was positively correlated with GBCA injection year-time(both P<0.05).Conclusion Patients with nasopharyngeal carcinoma who underwent radiotherapy and multiple times of intravenous injection of GBCA tended to be found with gradually worsening GBCA deposition in dentate nucleus,for which radiotherapy might be a risk factor.

目的观察鼻咽癌患者经放射治疗(放疗)及多次静脉注射钆对比剂(GBCA)后平扫MR T1WI中齿状核信号强度的变化。方法回顾性纳入50例经病理确诊并接受调强放疗的鼻咽癌患者(鼻咽癌组),以同期50例无颅脑放疗史的其他恶性肿瘤患者为对照组,均每年接受鼻咽部或头颅GBCA增强MR检查。分别测量确诊当年(记为第1年)及第2~5年轴位齿状核及同层脑桥T1WI信号强度,计算并比较第i年(范围第1~5年)2组齿状核/脑桥T1WI信号强度比值(ΔSIi)及第j年(范围第2~5年)ΔSIj相对ΔSI1变化百分比(Rchangej),评估组内ΔSI与GBCA注射年次的相关性。结果组间患者性别、年龄及ΔSI1差异均无统计学意义(P均>0.05)。第2~5年鼻咽癌组ΔSI及Rchange均高于对照组(P均<0.05)。2组内ΔSI均与GBCA注射年次呈正相关(P均<0.05)。结论鼻咽癌患者经放疗及多次静脉注射GBCA后易出现逐渐加重的齿状核GBCA沉积;放疗可能为其危险因素。