运动引起心肌SPECT断层伪影的实验研究

An experimental study of myocardial tomography artifacts caused by motion

探讨心肌断层采集过程中体位移动的方向、幅度、时限对断层影像的影响。方法 在探头旋转到 45°、90°、135°时 ,将心脏模型依次沿x、y和z轴方向分别移动± 5mm、± 10mm、± 2 0mm。其图像分别与无移动者对比 ,并由 3名医师判别伪影。结果经统计学处理。结果 在移动 5mm时无伪影。移动 10mm以上出现伪影 ,且距离愈大愈明显。在短轴上呈典型的三角形分布且交替出现“冷”、“热”结节。在水平及垂直长轴上 ,表现为前间隔和前侧壁、前壁和下壁的对称性变薄内收 ,心尖拉长。结论 位移≥ 10mm时 。

Objective To determine the relationship between the phantom motion and the resultant image artifact Methods A myocardial phantom was filled with 99 Tc mO - 4solution During imaging,the phantom was moved ±5 mm, ±10 mm, ±20mm along the x, y and z axis, respectively at the angle of 45°, 90°, 135° sequentially Each image was compared with its counterpart image acquired from no motion imaging and assessed by three experienced observers without knowledge of presence or absence of phantom motion The results were analyzed by chi square test Results When the phantom was moved 5 mm, there was no significant motion artifact When the phantom was moved 10 mm or 20 mm, artifacts were obvious The more moved, the more remarkable the artifacts The artifacts showed unevenness of the radioactivity of the myocardial wall In the short axis slices, the triangular patterns composed of the “lumpy” and “defect” areas in the images rotated to certain extent in position In the horizontal and vertical long axis slices, the thickness of the lateral and septal wall, the anterior and inferior wall were decreased symmetrically Conclusions When the phantom was moved 10 mm or 20 mm, there were obvious motion artifacts The artifacts have their specifics and can be recognized