磁共振成像平扫和扩散加权成像预测脑转移瘤的价值

The value of MRI plain scan and DWI in the diagnosis of brain metastases

目的探讨磁共振成像(MRI)平扫和扩散加权成像(DWI)预测脑转移瘤的临床价值。方法回顾性分析2016年6月至2018年12月就诊于中国医学科学院肿瘤医院深圳医院、经增强MRI检查和临床诊断为脑转移瘤和非脑转移瘤患者的MRI平扫的影像学表现,对比分析105例脑转移瘤(转移组)和103例非脑转移瘤(非转移组)患者的常规T1加权成像(T1WI)、T2加权成像(T2WI)、T2液体衰减反转恢复(T2WI/FLAIR)、DWI和表观扩散系数(ADC)值。结果转移组患者中T1WI低信号、等信号、高信号和混杂信号分别为54、23、9和19例,非转移组患者中T1WI低信号和等信号分别为52和51例,差异有统计学意义(P<0.001)。转移组中T2WI低信号、等信号、高信号和混杂信号分别为1、9、72和23例,非转移组中T2WI等信号和高信号分别为11和92例,差异有统计学意义(P<0.001)。转移组中DWI低信号、高信号和混杂信号分别为4、31、65例;非转移组中DWI高信号4例,其余均呈等信号,差异有统计学意义(P<0.001)。转移组中T2WI/FLAIR低信号、等信号、高信号和混杂信号分别为4、5、60和36例,非转移组中T2WI/FLAIR均为高信号,差异有统计学意义(P<0.001)。转移组患者病灶周围伴水肿69例,高于非转移组(0例),差异有统计学意义(P<0.001)。转移组患者的ADC值为(0.919±0.019)×10-3 mm^(2)/s,低于非转移组[(1.098±0.012)×10-3 mm^(2)/s,P<0.05]。结论对于伴有原发恶性肿瘤病史的患者,脑转移瘤与非转移瘤患者MRI平扫中的T1WI、T2WI、DWI和T2WI/FLAIR信号差异明显,混杂信号、病灶周围水肿和DWI扩散受限有助于诊断脑转移瘤,以上参数联合应用可以提高预测脑转移瘤的诊断效能,必要时需进一步行MRI增强扫描以明确诊断。

Objective To investigate the clinical value of magnetic resonance imaging(MRI)plain scan and diffusion weighted imaging(DWI)in the diagnosis of brain metastases.Methods The MRI plain imaging findings of 105 cases with brain metastases and 103 cases without brain metastases confirmed by enhanced MRI examination and clinical diagnosis were retrospectively analyzed.The comparisons of plain MRI findings including T1 weighted image(T1WI),T2WI,T2/fluid attenuated inversion recovery(T2/FLAIR),DWI and apparent diffusion coefficient(ADC)values were made between brain metastases and non-brain metastases.Results The numbers of hypo-intensity,iso-intensity,hyper-intensity and heterogeneous signal intensity of T1WI in the brain metastatic group were 54,23,9 and 19,respectively,while the numbers of hypo-intensity and iso-intensity in the non-brain metastatic group were 52 and 51,respectively,with statistically significant difference(P<0.001).The numbers of hypo-intensity,iso-intensity,hyper-intensity and heterogeneous signal intensity of T2WI in the brain metastatic group were 1,9,72 and 23,respectively,while the numbers of iso-intensity and hyper-intensity in the non-brain metastatic group were 11 and 92,respectively,with statistically significant difference(P<0.001).The numbers of hypo-intensity,hyper-intensity and heterogeneous signal intensity of DWI in the brain metastatic group were 4,31 and 65,respectively,while the number of hyper-intensity in the non-brain metastatic group was 4 and others were iso-intensity,respectively,with statistically significant difference(P<0.001).The numbers of hypo-intensity,iso-intensity,hyper-intensity and heterogeneous signal intensity of T2WI/FLAIR in the brain metastatic group were 4,5,60 and 36,respectively,while all cases in the non-brain metastatic group were hyper-intensity,with statistically significant difference(P<0.001).The number of lesion accompanied with peripheral edema in the brain metastatic group were 69 cases,significantly higher than 0 cases in the non-brain metastatic group(P<0.001).The mean ADC value in the brain metastatic group were(0.919±0.019)×10^(-3) m㎡/s,significantly lower than(1.098±0.012)×10^(-3) m㎡/s of non-brain metastatic group(P<0.05).Conclusions For patients with a history of primary malignancy,the MRI plain scan signals of T1WI,T2WI,T2WI/FLAIR and DWI are significantly different between brain metastatic tumor and non-metastatic tumor.The mixed signal,peripheral edema and the restriction of DWI diffusion indicate brain metastases.The combined application of the above parameters can improve the diagnostic efficacy of predicting brain metastases,and contrast enhancement MRI examination should be performed for the confirmation of diagnosis.