Shea Jill, de Bever Joshua, Kholmovski Eugene, Beal Hannah, Hadley J Rock, Minalga Emilee, Salama Mohamed E, Marrouche Nassir F, Payne Allison
Department of Surgery, University of Utah, 30 North 1900 East, Salt Lake City, UT 84132 USA.
Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, UT 84108 USA.
J Ther Ultrasound. 2017 Jun 12;5:16. doi: 10.1186/s40349-017-0094-y. eCollection 2017.
Past catheter-based and focused ultrasound renal denervation studies have indicated that procedure efficacy is related to the number of ablations performed or the amount of energy used for the ablation. This study extends those prior results and investigates energy level effects on the efficacy of MR guided focused ultrasound renal denervation performed in a porcine model.
Twenty-four normotensive pigs underwent unilateral denervation at three intensity levels. The applied intensity level was retrospectively de-rated to account for variability in animal size. Efficacy was assessed through evaluating the norepinephrine present in the kidney medulla and through histological analysis. The treatment was performed under MRI guidance including pre- and post-procedure T1-weighted and quantitative T1 and T2 imaging. During treatment, the temperature in the near field of the ultrasound beam was monitored in real time with MR temperature imaging. Energy delivery in the regions surrounding the renal artery was independently confirmed through an invasive fiberoptic temperature probe placed in the right renal artery.
Animals that underwent denervation at a de-rated acoustic intensity of greater than 1.2 kW/cm had a significantly lower norepinephrine concentration in the kidney indicating successful denervation. Images obtained during the treatment indicated no tissue changes in the kidneys as a function of the procedure but there were significant T1 changes present in the right lumbar muscles, although only one animal had indication of muscle damage at the time of necropsy.
While MR guided focused ultrasound renal denervation was found to be safe and effective in this normotensive animal model, the results indicated the need to incorporate patient-specific details in the treatment planning of MRgFUS renal denervation procedure.
以往基于导管和聚焦超声的肾去神经研究表明，手术疗效与消融次数或消融所用能量有关。本研究扩展了先前的结果，并研究了能量水平对猪模型中磁共振引导聚焦超声肾去神经疗效的影响。
24只血压正常的猪在三个强度水平下接受单侧去神经治疗。应用的强度水平进行了回顾性降额处理，以考虑动物大小的差异。通过评估肾髓质中去甲肾上腺素的含量和组织学分析来评估疗效。治疗在MRI引导下进行，包括术前和术后的T1加权成像以及定量T1和T2成像。在治疗过程中，用磁共振温度成像实时监测超声束近场的温度。通过放置在右肾动脉中的侵入性光纤温度探头独立确认肾动脉周围区域的能量传递。
在降额声强大于1.2kW/cm的情况下接受去神经治疗的动物，其肾脏中去甲肾上腺素浓度显著降低，表明去神经成功。治疗期间获得的图像显示，肾脏中未出现与手术相关的组织变化，但右腰大肌出现了显著的T1变化，不过尸检时只有一只动物有肌肉损伤迹象。
虽然在这个血压正常的动物模型中发现磁共振引导聚焦超声肾去神经是安全有效的，但结果表明在磁共振引导聚焦超声肾去神经手术的治疗规划中需要纳入患者的具体细节。
