Dynamic susceptibility contrast enhanced MRI in differential diagnosis of glioblastoma, solitary cerebral metastasis and cerebral lymphoma

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(1.Graduate School of Tianjin Medical University, Tianjin 300060, China; 2.MRI Division, Tianjin Huanhu Hospital, Tianjin 300350, China)

Dynamic susceptibility contrast enhanced MRI in differential diagnosis of glioblastoma, solitary cerebral metastasis and cerebral lymphoma

LUHao1，2,FENGQuanzhi1,CHENGQiansheng2,DINGYan2,LIDaibin2,LIYuge2,HANBihui2,HANTong2*

(1.GraduateSchoolofTianjinMedicalUniversity,Tianjin300060,China; 2.MRIDivision,TianjinHuanhuHospital,Tianjin300350,China)

Objective To investigate the value of the dynamic susceptibility contrast enhanced MRI (DSC-MRI) in differential diagnosis of glioblastoma, solitary cerebral metastatic tumors and cerebral lymphoma. Methods Seventeen patients with glioblastoma, 15 cases with solitary cerebral metastatic tumor and 17 cases with cerebral lymphoma were analyzed retrospectively. All patients underwent conventional MR imaging, contrast-enhancement and DSC-MRI preoperatively. Pseudo color pictures of cerebral blood volume (CBV) and the time signal intensity curve were obtained from the raw data of DSC-MRI. The relative CBV (rCBV ) were measured from regions of enhanced solid parts of the tumors, peritumoral region and contralateral normal white matter regions respectively. The percentage of signal intensity recovery (PSR) of enhanced solid parts of the tumors were measured. ROC curve analysis was performed to determine optimum indicator in differential diagnosis of three types of tumors, and the sensitivity and specificity were calculated. Results Three types of tumors all showed enhancement of solid area with obvious peritumoral edema. Besides the no difference between glioblastoma and metastasis in rCBV of solid parts of the tumors, there were statistically significant differences in comparisons of two types of tumors (allP<0.05). Besides the no difference between single brain metastases and lymphoma in rCBV of peritumoral regions, there were statistically significant differences in comparisons of two types of tumors (allP<0.05). The PSR of the solid parts of the tumors had no difference between glioblastoma and single brain metastases, while there were statistically significant differences in comparisons of two types of tumors (allP<0.05). ROC curve analysis showed sensitivity and specificity of the PSR values of solid parts of the tumors in differentiating lymphoma and non lymphoma were 100% and 81.3%. The rCBV of peritumoral regions was the optimum indicator for differentiating glioblastoma and solitary brain metastasis, the sensitivity and specificity were respectively 94.1% and 86.7%. Conclusion The combination of rCBV and PSR can improve the efficiency for diagnosing the three types of brain tumors.

Glioblastoma; Single brain metastases; Lymphoma; Magnetic resonance imaging

胶质母细胞瘤、脑转移瘤为颅内常见恶性肿瘤，脑淋巴瘤的发生率也越来越高，三者在影像上虽各有特点，但互有重叠，尤其病史不详时诊断困难。由于其医学分期、外科计划及治疗手段各不相同，故临床上区分3种肿瘤尤为重要。动态磁敏感对比增强磁共振成像(dynamic susceptibility contrast enhanced MRI, DSC-MRI)已成熟应用于临床，对肿瘤的诊断及鉴别诊断有重要意义，本研究旨在分析DSC-MRI鉴别诊断3种肿瘤的价值。

1 资料与方法

1.1 一般资料 收集2014年11月—2016年1月经活检或术后病理证实的脑肿瘤患者49例，其中胶质母细胞瘤17例，男9例、女8例，年龄30～68岁，平均(53.3±8.2)岁；单发脑转移瘤15例(原发肿瘤均为肺癌)，男11例、女,4例，年龄41～86岁，平均(63.6±7.3)岁，其中低分化腺癌9例、小细胞癌4例、鳞癌2例；淋巴瘤17例，男8例、女9例，年龄24～80岁，平均(58.1±15.6)岁，其中弥漫大B细胞淋巴瘤15例、滤泡性淋巴瘤1例、套细胞淋巴瘤1例。所有患者均接受常规MRI和DSC-MRI扫描，且检查前均未接受过放化疗、激素治疗及手术。

1.2 仪器与方法 采用Siemens Trio A Tim 3.0T MR扫描仪。常规平扫包括轴位SE序列T1WI(TR 195.0 ms，TE 4.8 ms)，轴位FSE序列T2WI(TR 4 000 ms，TE 98.0 ms)，轴位FLAIR序列(TR 8 200 ms，TE 84.0 ms)，矢状位SE序列T1WI(TR 550.0 ms，TE 8.4 ms)，T1WI增强扫描(TR 550.0 ms，TE 8.4 ms)。T2*DSC灌注扫描采用SE-EPI序列，层面选择同增强前T1WI轴位扫描，成像时间1 min 39 s，TR 1 840 ms，TE 32 ms，层厚6 mm，层数17层，FOV 230 mm×230 mm，矩阵128×128，带宽1 346 Hz/Px，翻转角90°，NEX 1次，扫描至第5个时相时以高压注射器经肘前静脉团注Gd-DTPA (0.2 mmol/kg体质量)，注射速率3 ml/s，共扫描50个时相，获得850幅灌注原始图。

1.3 图像处理及数据分析 在工作站应用Perfusion MR软件处理DSC-MRI的原始数据，获取脑血容量(cerebral blood volume， CBV)伪彩图。将肿瘤实质最高灌注区定义为瘤体区；将对比剂强化T1WI勾勒的强化肿瘤边界以外、长T2高信号水肿区且距肿瘤强化边缘1 cm范围内定义为瘤周区。……