Quantifying Post- Laser Ablation Prostate Therapy Changes on MRI via a Domain-Specific Biomechanical Model: Preliminary Findings.
Quantifying Post- Laser Ablation Prostate Therapy Changes on MRI via a Domain-Specific Biomechanical Model: Preliminary Findings.
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DOI：
10.1371/journal.pone.0150016
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Madabhushi A
中科院分区：
文献类型：
--
作者：
Toth R;Sperling D;Madabhushi A
局部激光消融通过激光对组织的热破坏来破坏癌细胞。热量被吸收，引起靶区热坏死。它结合了放射治疗（摧毁癌细胞）的积极好处，而没有有害的副作用（由于它的精确定位）。MRI通常用于治疗前确定目标区域，治疗后通过检测坏死组织或肿瘤复发来确定疗效。然而，目前尚无系统可以定量评价后处理对MRI形态学和结构的影响。为了量化这些变化，必须首先对处理前和处理后的MR图像进行空间对齐。目的是量化(a)激光诱导的基于形状的变化，以及(b)治疗后MRI参数的变化。基于形状的变化可能与治疗效果有关，而激光治疗随时间的定量效果目前尚不清楚。这项工作试图模拟激光治疗后腺体形态的变化，这是由于(1)患者对齐，(2)由于周围器官（如膀胱和直肠）的变化，以及(3)由于治疗本身的变化。为了分离处理引起的基于形状的变化，首先对(1)和(2)中的变化进行建模，并使用有限元模型（FEM）去除。有限元法模拟组织的物理性质。使用物理生物力学模型很重要，因为这项工作的既定目标是确定治疗对前列腺的物理形状变化，因此只允许物理真实变形。然后使用第二个FEM来隔离物理的、基于形状的、处理引起的变化。我们应用并评估了我们的模型来捕捉激光诱导的前列腺形态变化，8例患者在治疗后大约6个月获得3.0 Tesla， t2加权MRI。我们的研究结果表明，激光治疗导致前列腺体积的减少，这似乎主要表现在消融部位。在空间对齐图像后，可以清楚地看到消融部位的MRI强度值变化。我们的结果表明，我们的新方法能够捕获和量化激光诱导前列腺变化的程度。反映变形变化的定量测量可用于跟踪处理响应随时间的变化。
Focal laser ablation destroys cancerous cells via thermal destruction of tissue by a laser. Heat is absorbed, causing thermal necrosis of the target region. It combines the aggressive benefits of radiation treatment (destroying cancer cells) without the harmful side effects (due to its precise localization). MRI is typically used pre-treatment to determine the targeted area, and post-treatment to determine efficacy by detecting necrotic tissue, or tumor recurrence. However, no system exists to quantitatively evaluate the post-treatment effects on the morphology and structure via MRI. To quantify these changes, the pre- and post-treatment MR images must first be spatially aligned. The goal is to quantify (a) laser-induced shape-based changes, and (b) changes in MRI parameters post-treatment. The shape-based changes may be correlated with treatment efficacy, and the quantitative effects of laser treatment over time is currently poorly understood. This work attempts to model changes in gland morphology following laser treatment due to (1) patient alignment, (2) changes due to surrounding organs such as the bladder and rectum, and (3) changes due to the treatment itself. To isolate the treatment-induced shape-based changes, the changes from (1) and (2) are first modeled and removed using a finite element model (FEM). A FEM models the physical properties of tissue. The use of a physical biomechanical model is important since a stated goal of this work is to determine the physical shape-based changes to the prostate from the treatment, and therefore only physical real deformations are to be allowed. A second FEM is then used to isolate the physical, shape-based, treatment-induced changes. We applied and evaluated our model in capturing the laser induced changes to the prostate morphology on eight patients with 3.0 Tesla, T2-weighted MRI, acquired approximately six months following treatment. Our results suggest the laser treatment causes a decrease in prostate volume, which appears to manifest predominantly at the site of ablation. After spatially aligning the images, changes to MRI intensity values are clearly visible at the site of ablation. Our results suggest that our new methodology is able to capture and quantify the degree of laser-induced changes to the prostate. The quantitative measurements reflecting of the deformation changes can be used to track treatment response over time.