Abstract: Objective To study the value of source images of three dimensional time-of-flight magnetic resonance angiography(3D-TOF MRA) in detecting cerebral microbleeds(CMBs) in brain parenchyma.Methods Two hundred and eighty patients who were suspected to have microbleeding lesions were recruited. T2* gradient recall echo(GRE) sequence and 3D-TOF MRA sequences were performed after routine magnetic resonance(MR) head imaging were performed. Numbers, location, and scales of CMBs on 3D-TOF MRA axial source images and T2*GRE images were compared.Results Seven-five cases were proved to have CMBs by T2*GRE sequence. Nine cases which could not be compared were excluded. On T2*GRE images, three hundred and thirty eight CMBs were found with 50 cases as grade 1, 10 cases as grade 2, and 6 cases as grade 3. On 3D-TOF MRA source images, two hundred and forty two CMBs were found with 11cases as grade 0, 40 cases as grade 1, 12 cases as grade 2, and 3 cases as grade 3. Paired-sample t test showed that there were significant difference between CMBs found by two methods at cortical/subcortical area(P=0.000), thalami(P=0.001), and cerebellum(P=0.039), while no significant difference were found between CMBs found by two methods at basal ganglia(P=0.581) and brain stem(P=0.211). Consistency of two different sequences showed Kappa value was 0.494(P=0.092).Conclusion Source images of 3D-TOF MRA can be used to detect CMBs. Though CMBs on 3D-TOF MRA source images were not as clear as those on T2*GRE images, when T2*GRE images are absent, 3D-TOF MRA source images may be helpful to display microbleeds lesions and suggest further examination.

Key words: Three-dimensional time of flight; Magnetic resonance angiography; Microbleeds; brain

摘要： 目的 研究三维时间飞跃法磁共振血管成像（three dimensional time-of-flight magnetic resonance angiography，3D-TOF MRA）原始图像评估脑内微出血病灶的应用价值。方法 收集269例高血压、缺血性卒中、短暂性脑缺血或既往原发性脑出血病患者。分别进行T2*加权梯度回波（T2* weighted gradient echo，T2*GRE）序列及3D-TOF MRA序列扫描，评估T2*GRE图像及3D-TOF MRA原始轴位图像显示的微出血病灶数量、部位及分级。结果 75例患者脑实质内存在微出血病灶，排除9例不符合标准者，剩余66例。T2*GRE成像共发现微出血病灶338个，1级50例，2级10例，3级6例；3D-TOF MRA序列原始图像显示微出血病灶242个，0级11例，1级40例，2级12例，3级3例。两种序列发现微出血病灶的比较差异有显著性（皮质和皮质下P=0.000、丘脑P=0.001、小脑P=0.039）；对基底节（P=0.581）和脑干（P=0.211）发现的微出血病灶之间的差异无显著性。结论 3D-TOF MRA原始图像可显示脑微出血灶。在无T2*GRE图像的情况下，观察3D-TOF MRA原始图像有助于了解及初步观察脑微出血情况

关键词: 三维时间飞跃法; 磁共振血管成像; 微出血; 脑