Memorial Sloan-Kettering Cancer Center, New York, NY, USA,
Int J Comput Assist Radiol Surg. 2013 Jan;8(1):15-27. doi: 10.1007/s11548-012-0745-y. Epub 2012 May 27.
Liver motion due to respiration restricts targeting and needle placement accuracy during image-guided interventional procedures. Breath holds, imaging techniques, and navigation systems are used to improve targeting accuracy. Data of in-vivo liver behavior under respiration can enhance these approaches.
An experimental study was performed using the swine model to capture the dynamics of liver motion during respiration using needles tipped with electromagnetic sensors. The swine liver was segmented into four lobes (right lateral, right medial, left medial and left lateral), and two sensor-tipped needles were placed in each location to acquire representative displacement data.
Maximum displacement was found to occur in the left medial and left lateral lobes, in the anterior-posterior direction. Significant lobe-dependent variation in motion behavior was recorded, but a variation within a lobe was minimal and independent of needle approach. Magnitude of displacement in all lobes was found to be monotonically correlated to breathing volume. Displacement of liver was found to be out of phase with breathing by approximately 2 Hz. The positioning of the animal was also found to influence direction and magnitude of liver displacement in different lobes.
We have presented previously unavailable data and insight into the role of easily controllable parameters such as breathing volume, patient positioning, and lobe-specific heterogeneity in the displacement of liver due to respiration.
呼吸引起的肝脏运动限制了影像引导介入手术中靶向和针的放置精度。采用呼吸暂停、成像技术和导航系统来提高靶向准确性。呼吸下活体肝脏行为的数据可以增强这些方法。
采用猪模型进行了一项实验研究，使用带有电磁传感器的针尖针来捕获呼吸过程中肝脏运动的动力学。将猪的肝脏分为四个叶（右外侧、右内侧、左内侧和左外侧），在每个位置放置两个带有传感器的针以获取具有代表性的位移数据。
发现最大位移发生在前-后方向的左内侧和左外侧叶。记录到明显的叶依赖性运动行为变化，但一个叶内的变化最小且与针的进入方式无关。所有叶的位移幅度都与呼吸量呈单调相关。肝脏的位移与呼吸相比被发现有约 2Hz 的相位差。动物的定位也被发现会影响不同叶中肝脏位移的方向和幅度。
我们提出了以前未提供的数据和见解，了解了呼吸引起的肝脏位移中易于控制的参数（如呼吸量、患者体位和叶特异性异质性）的作用。
