Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60612, USA.
IEEE Trans Biomed Eng. 2011 Sep;58(9):2566-73. doi: 10.1109/TBME.2011.2159383. Epub 2011 Jun 13.
This study describes and evaluates a semiautomated method for prescribing an optimal imaging plane that is located as close as possible to the skull base, and is simultaneously nearly perpendicular to the four arteries leading blood to the brain [internal carotid arteries (ICAs) and vertebral arteries (VAs)]. Such a method will streamline and improve reliability of the measurement of total cerebral blood flow and intracranial pressure by velocity encoding phase-contrast magnetic resonance imaging. The method first extracts the vessels' centerline from a 2-D time-of-flight magnetic resonance angiogram of the neck by performing distance transformations. An anatomical marker, the V2 segment of the VAs, is then identified to guide the imaging plane to be as close and below the skull base. An imaging plane that is nearly perpendicular to the ICAs and V2 segment of VAs is then identified by minimizing a misalignment value, estimated by a weighted mean of the angles between the plane's normal and the vessel axes at the vessel-plane intersections. The performance of the semiautomated method was evaluated by comparing manually selected planes to those found semiautomatically in nine magnetic resonance angiogram datasets. The semiautomated method consistently outperformed manual prescription with a significantly smaller misalignment value, 8.6° versus 20.7° (P < 0.001), respectively, and significantly improved reproducibility.
本研究描述并评估了一种半自动方法，用于选择尽可能靠近颅底且同时几乎垂直于向大脑供血的四条动脉（颈内动脉 [ICAs] 和椎动脉 [VA]）的最佳成像平面。这种方法将简化并提高速度编码相位对比磁共振成像测量全脑血流量和颅内压的可靠性。该方法首先通过执行距离变换从颈部 2D 时间飞跃磁共振血管造影中提取血管中心线。然后，识别椎动脉的 V2 段作为解剖学标记，以引导成像平面尽可能靠近颅底。然后通过最小化失准值来确定几乎垂直于 ICAs 和 VA 的 V2 段的成像平面，该失准值通过在血管-平面交点处平面的法向与血管轴之间的角度的加权平均值来估计。通过将手动选择的平面与在九个磁共振血管造影数据集半自动找到的平面进行比较，评估半自动方法的性能。半自动方法的失准值明显更小，分别为 8.6°和 20.7°（P < 0.001），且重现性明显提高，因此始终优于手动处方。
