扩散张量成像对脑脓肿与坏死囊变性胶质瘤的鉴别诊断价值

The Differential Diagnosis of Brain Abscess and Necrotic Cystic Glioma with DTI

目的探讨磁共振扩散张量成像(DTI)对脑脓肿与坏死囊变性胶质瘤的鉴别诊断价值。资料与方法回顾性分析2例经手术病理、3例经临床复查证实的脑脓肿和10例经手术病理证实的坏死囊变性胶质瘤。所有病例均行常规MR平扫、增强及DTI检查。构建表观扩散系数(ADC)图和各向异性分数(FA)图。测量病灶的坏死囊变区及其周围水肿区的ADC和FA值,计算其平均值,并行组间统计学分析。结果脑脓肿脓腔扩散加权图像(DWI)表现为高信号者4例,低信号1例;胶质瘤坏死囊变区DWI表现为高信号者1例,混杂信号1例,低信号8例。脓腔、胶质瘤坏死囊变区ADC平均值分别为(0.79±0.11)×10-3mm2/s、(2.38±0.28)×10-3mm2/s,二者之间ADC值差异有统计学意义(t=6.45,P<0.01)。胶质瘤与脑脓肿周围水肿区ADC值分别为(1.65±0.13)×10-3mm2/s、(1.94±0.17)×10-3mm2/s,二者之间差异有统计学意义(t=1.98,P<0.05)。在FA图上,脓腔、胶质瘤坏死囊变区均表现为低信号,FA值分别为0.17±0.06、0.11±0.03,二者差异有统计学意义(t=2.42,P<0.05),二者周围水肿区FA值分别为0.21±0.04、0.19±0.08,二者之间差异无统计学意义(t=1.13,P>0.05)。结论DTI通过构建DWI图、ADC图和FA图能有效反映脓肿与坏死囊变性胶质瘤的不同液态性质。绝大多数脑脓肿的脓腔在DWI图上表现为高信号,ADC图上为低信号,而胶质瘤坏死囊变区则与之相反;脑脓肿周围水肿ADC值高于胶质瘤瘤周水肿。DTI对脑脓肿与坏死囊变性胶质瘤的鉴别诊断具有重要价值。

Objective To evaluate the value of diffusion tensor imaging （DTI） in differential diagnosis of brain abscess and necrotic cystic gliomas. Materials and Methods 5 brain abscesses, 10 gliomas confirmed clinically or pathologically underwent conventional MRI and DTI. Average diffusion coefficient（ADC） value, fractional anisotropy（FA） value and maps were measured in the portion and surrounding edema regions, then statistical analysis was made. Result On the DWI maps, 4 cases of brain abscesses showed hypefintensity signal, 1 cases showed hypointensity; 1 case of glioma displayed hypefintensity signal, 1 case showed mixed signal, 8 cases showed hypointensity signal. Significant differences of ADC value （ t = 6.45, P 〈 0.01 ） were found in the portion between abscess [ （0.79 ± 0. 11 ） ×10^-3mm^2/s ] and glioma [ （2.38 ±0.28） ×10^-3mm^2/s]. Significant differences ofADC value（t =2. 42,P 〈0.05） were also found in surrounding edema regions between abscess[ （ 1.65 ± 0.13） ×10^-3mm^2/s] and glioma[ （ 1.94 ± 0. 17） ×10^-3mm^2/s]. On FA maps, the portion of them displayed hypointensity. Significant differences of FA value （ t = 1.98 ,P 〈 0.05 ） were found in necrotic regions between abscess （0. 17 ± 0.06 ） and glioma （0.11 ± 0.03 ）. No significant differences of FA value （ t = 1.13, P 〉0.05） were found in the surrounding edema between abscess （0.21 ± 0.04） and glioma （0. 19 ± 0.08 ）. Conclusion DTI can reflect efficiently the character of the liquid state between brain abscess and necrotic cystic glioma. Most of abscess display hypefintensity signal on DWI and hypointensity signal on ADC map, but it is opposite in glioma; The ADC value of edema in abscess is higher than that of glioma. DTI has significant diagnostic value between brain abscess and necrotic cystic glioma.