脑转移瘤的磁共振序列优化

目的探讨MR常规序列及T1加权三维成像(3D-T1WI)诊断脑转移瘤的价值,优化脑转移瘤MR扫描方案。方法收集原发灶经病理证实的35例脑转移瘤患者,均行MR常规序列及3D-T1WI平扫和增强扫描,分析各序列对脑转移瘤的检出率,并对比常规扫描方案与优化扫描方案的扫描时间。结果 35例共检出609个病灶;平扫T1WI、T2WI、T2-FLAIR、DWI(b=0)、3D-T1WI分别检出病灶101个(101/609,16.58%)、155个(155/609,25.45%)、235个(235/609,38.59%)、176个(176/609,28.90%)、228个(228/609,37.44%);增强T1WI、3D-T1WI分别检出病灶427个(427/609,70.11%)、609个(609/609,100%)。增强及平扫3D-T1WI对脑转移瘤的检出率明显高于增强及平扫T1WI(P均0.05);DWI(b=0)与T2WI对脑转移瘤检出率差异无统计学意义(P0.05)。常规方案MR扫描共用时638s,优化方案为575s。结论 3D-T1WI序列可明显提高MR对脑转移瘤的检出率。以3D-T1WI替代常规T1WI、DWI(b=0)替代T2WI的优化扫描方案可提高脑转移瘤检出率,缩短扫描时间。

Optimization of MR sequences for brain metastases

Objective To explore the value of conventional MR sequences and three-dimensional T1-weighted imaging (3D-T1WI) in diagnosis of brain metastases, and to optimize the scanning program. Methods Totally 35 patients with brain metastases underwent conventional MR and unenhanced and enhanced 3D-T1WI, and the primary tumors had been confirmed by pathology. The detection rates of brain metastases in all the sequences were analyzed, and then the time between conventional and three-dimensional scanning programs were compared. Results A total of 609 lesions were detected in 35 cases. For plan scan sequences, 101 lesions (101/609, 16.58%) were detected in T1WI, 155 lesions (155/609, 25.45%) lesions in T2WI, 235 lesions (235/609, 38.59%) in T2-FLAIR, 176 lesions (176/609, 28.90%) in DWI (b=0), 228 lesions (228/609, 37.44%) in 3D-T1WI. For enhanced scan sequences, 427 lesions (427/609, 70.11%) were detected in enhanced T1WI and 609 lesions (609/609, 100%) in enhanced 3D-T1WI. The detection rate of 3D-T1WI enhanced and plan scans for brain metastases was significantly higher than those of T1WI (both P<0.05). No significant difference of detection rate was found between DWI (b=0) and T2WI (P>0.05). Conventional program took 638 s, while optimize program took 575 s for scanning. Conclusion Using 3D-T1WI, the detection rate of brain metastases increased obviously. Taking 3D-T1WI for replacement of conventional T1WI, DWI (b=0) for replacement of T2WI can improve the detection rate of brain metastases and shorten scanning time.