DWI及增强扫描对幕下原发淋巴瘤的应用价值

The application value of DWI and enhanced scan in the case of the primary lymphoma

目的探讨MR扩散加权成像(DWI)及增强扫描在原发性小脑淋巴瘤中的诊断及鉴别诊断价值。方法对5例经临床手术病理证实的小脑淋巴瘤患者,行常规MR、DWI及增强扫描,回顾性分析各病例的平扫、DWI及增强扫描特征,并定量测定肿瘤实质区表观扩散系数(ADC)值;同时选取经手术病理证实的幕下实质型血管母细胞瘤4例,髓母细胞瘤8例,脑膜瘤10例进行DWI及增强扫描对比分析。结果 5例淋巴瘤,单发3例,多发2例,共计病灶数8个,T1WI呈等或稍低信号,T2WI以等或稍高信号为主,其中1例2个病灶表现为T_2WI低信号;DWI上2个病灶呈低信号,1个病灶为等信号,余病灶呈高信号表现,增强后,所有病灶均明显强化,1个病灶强化欠均质,余强化均匀,DWI与增强对照,测得肿瘤实质区的平均ADC值为(0.66±0.10)×10-3mm2/s,其中有3个病灶累及邻近脑膜,致脑膜增厚、强化;实质型血管母细胞瘤明显强化,DWI上呈低信号,实质区的平均ADC值为(1.93±0.13)×10-3mm2/s;髓母细胞瘤呈中-明显强化,DWI上呈高信号,实质区的平均ADC值为(0.71±0.11)×10^(-3)mm^2/s;脑膜瘤呈中-明显强化,6例出现脑膜尾征,DWI上5例为等信号,3例为稍低信号,2例为稍高信号,实质区的平均ADC值为(1.07±0.22)×10-3mm^2/s。淋巴瘤的ADC值最低,其次是髓母;强化程度上实质型血管母细胞瘤最高,其次是淋巴瘤。结论应用DWI结合增强扫描对幕下淋巴瘤的诊断及鉴别诊断有重要价值,能够明显提高淋巴瘤的诊断准确率。

Objective To explore the value of MR diffusion weighted imaging（ DWI） and contrast-enhanced scan in the diagnosis and differentiative diagnosis of primary cerebellar lymphoma. Methods The characteristic of conventional MRI,DWI and enhanced scanning in 5 cases with cerebellar lymphoma which were confirmed by surgery and pathology were retrospectively analyzed. Quantitative determination of tumor parenchyma of apparent diffusion coefficient（ ADC） value of all cases were analyzed as well. We selected 4 cases of solid hemangioblastomam,8 cases of medulloblastoma,10 cases of meningothelioma to analyze the character of DWI and contrast-enhanced scan which were confirmed by surgery and pathology,as a comparison. Results There were 3 cases with signal lesion and 2 cases with multiple lesions in 5 cases of lymphoma. A total of 8 lesions were included research. MR scan showed iso-or hypo-intense signal on T1WI and slightly hyperintense signal on T2WI,in which 2 lesions in one case showed hypointense signal on T2WI. 2 lesions on DWI showed hypo-intense signal,1 lesion showed iso-intense,the remainder lesions showed hyperintense signal. A majority of lesions in contrast-enhanced scan showed homogeneous intense enhancement,1 lesion showed heterogeneous intense enhancement. By comparing with DWI and contrast-enhanced scan,average ADC value of tumor was（ 0. 66 ± 0. 10） × 10^-3 mm^2/s. 3 lesions involved the adjacent meninges which showed thickening and enhancement of meninges in contrast-enhanced scan. Solid hemangioblastoma showed an intense enhancement and hypointense signal on DWI. Average ADC value of parenchyma area was（ 1. 93 ± 0. 13） × 10^-3mm^2/s; Medulloblastoma showed a moderate or intense enhancement and hyperintense signal on DWI. Average ADC value of parenchyma area was（ 0. 71 ± 0. 11） × 10-3 mm2/s. Meningothelioma showed a moderate or intense enhancement,dural tail sign was shown in 6 cases. On DWI sequence,5 cases showed iso-intensity signal,3 cases showed slightly hypointense signal,2 cases showed slightly hyperintense signal. Average ADC value of parenchyma area was（ 1. 07 ± 0. 22） × 10-3 mm2/s. ADC values of lymphoma tend to be the minimum which followed by Solid hemangioblastoma. Solid hemangioblastoma showed a high degree of enhancement which followed by lymphoma. Conclusion Application of DWI combined with contrast-enhanced scan in the diagnosis and differentiative diagnosis of screen lymphoma is of great value,which can significantly improve the diagnostic accuracy of lymphoma.