Pauly Kim Butts, Diederich Chris J, Rieke Viola, Bouley Donna, Chen Jing, Nau Will H, Ross Anthony B, Kinsey Adam M, Sommer Graham
Department of Radiology, Stanford University, Stanford, CA 94305-5488, USA.
Top Magn Reson Imaging. 2006 Jun;17(3):195-207. doi: 10.1097/RMR.0b013e31803774dd.
This paper describes our work in developing techniques and devices for magnetic resonance (MR)-guided high-intensity ultrasound ablation of the prostate and includes review of relevant literature.
Catheter-based high-intensity ultrasound applicators, in interstitial and transurethral configurations, were developed to be used under MR guidance. Magnetic resonance thermometry and the relevant characteristics and artifacts were evaluated during in vivo thermal ablation of the prostate in 10 animals. Contrast-enhanced MR imaging (MRI) and diffusion-weighted MRI were used to assess tissue damage and compared with histology.
During evaluation of these applicators, MR thermometry was used to monitor the temperature distributions in the prostate in real time. Magnetic resonance-derived maximum temperature thresholds of 52 degrees C and thermal dose thresholds of 240 minutes were used to control the extent of treatment and qualitatively correlated well with posttreatment imaging studies and histology. The directional transurethral devices are selective in their ability to target well-defined regions of the prostate gland and can be rotated in discrete steps to conform treatment to prescribed boundaries. The curvilinear applicator is the most precise of these directional techniques. Multisectored transurethral applicators, with dynamic angular control of heating and no rotation requirements, offer a fast and less complex means of treatment with less selective contouring.
The catheter-based ultrasound devices can produce spatially selective regions of thermal destruction in prostate. The MR thermal imaging and thermal dose maps, obtained in multiple slices through the target volume, are useful for controlling therapy delivery (rotation, power levels, duration). Contrast-enhanced T1-weighted MRI and diffusion-weighted imaging are useful tools for assessing treatment.
本文描述了我们在开发用于磁共振（MR）引导下高强度超声消融前列腺的技术和设备方面的工作，并对相关文献进行了综述。
开发了基于导管的高强度超声探头，包括间质和经尿道配置，以便在MR引导下使用。在10只动物的前列腺体内热消融过程中，评估了磁共振测温以及相关特征和伪影。使用对比增强磁共振成像（MRI）和扩散加权MRI评估组织损伤，并与组织学结果进行比较。
在这些探头的评估过程中，磁共振测温用于实时监测前列腺内的温度分布。磁共振得出的52摄氏度的最高温度阈值和240分钟的热剂量阈值用于控制治疗范围，并与治疗后成像研究和组织学结果在质量上具有良好的相关性。定向经尿道设备在靶向前列腺明确区域的能力方面具有选择性，并且可以以离散步骤旋转，以使治疗符合规定边界。曲线形探头是这些定向技术中最精确的。多节段经尿道探头具有加热的动态角度控制且无需旋转，提供了一种快速且不太复杂的治疗方法，轮廓选择较少。
基于导管的超声设备可在前列腺中产生空间选择性的热破坏区域。通过目标体积的多个切片获得的MR热成像和热剂量图，有助于控制治疗传递（旋转、功率水平、持续时间）。对比增强T1加权MRI和扩散加权成像有助于评估治疗效果。
