使用磁共振引导的高强度聚焦超声进行肾脏消融：磁共振成像和组织病理学评估。
Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment.
作者信息
Saeed Maythem, Krug Roland, Do Loi, Hetts Steven W, Wilson Mark W
机构信息
Maythem Saeed, Roland Krug, Loi Do, Steven W Hetts, Mark W Wilson, Department of Radiology and Biomedical Imaging, School of Medicine, University of California San Francisco, San Francisco, CA 94107-5705, United States.
出版信息
World J Radiol. 2016 Mar 28;8(3):298-307. doi: 10.4329/wjr.v8.i3.298.
AIM
To use magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU), magnetic resonance imaging (MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue.
METHODS
Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication (n = 24) using a 3T-MRg-HIFU (1.1 MHz frequency and 3000J-4400J energies). T2-weighted fast spin echo (T2-W), perfusion saturation recovery gradient echo and contrast enhanced (CE) T1-weighted (T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically significant.
RESULTS
Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or non-CE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images in vivo (0.12-0.36 cm(3) for single sonication 3000J, 0.50-0.84 cm(3), for double 3000J, 0.75-0.78 cm(3) for single 4400J and 0.12-2.65 cm(3) for double 4400J) and at postmortem (0.23-0.52 cm(3), 0.25-0.82 cm(3), 0.45-0.68 cm(3) and 0.29-1.80 cm(3), respectively) were comparable. The ablated volumes on 3000J and 4400J double sonication were significantly larger than single (P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively.
CONCLUSION
Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.
目的
运用磁共振引导高强度聚焦超声（MRg-HIFU）、磁共振成像（MRI）及组织病理学对肾组织进行非侵入性消融、定量及特征分析。
方法
6只麻醉/机械通气的猪接受单/双侧肾脏超声处理（n = 24），使用3T-MRg-HIFU（频率1.1MHz，能量3000J - 4400J）。分别采用T2加权快速自旋回波（T2-W）、灌注饱和恢复梯度回波及对比增强（CE）T1加权（T1-W）序列进行治疗规划、温度监测、病灶可视化、特征分析及定量分析。对切除的肾脏进行组织病理学检查以量化及分析细胞和血管变化。采用配对学生t检验，P值<0.05认为具有统计学意义。
结果
在T2-W或非CE T1-W序列上，消融的肾实质无法与正常肾实质区分。在灌注及CE T1-W MRI序列上，消融的肾脏病灶表现为低增强区域，提示灌注不足及坏死。体内CE T1-W图像上消融的实质体积（单次超声处理3000J为0.12 - 0.36 cm³，双次3000J为0.50 - 0.84 cm³，单次4400J为0.75 - 0.78 cm³，双次4400J为0.12 - 2.65 cm³）与死后测量值（分别为0.23 - 0.52 cm³、0.25 - 0.82 cm³、0.45 - 0.68 cm³及0.29 - 1.80 cm³）具有可比性。3000J和4400J双次超声处理后的消融体积显著大于单次（P < 0.01），因此，消融组织的体积和深度取决于施加的能量及超声处理次数。大体及显微镜检查分别证实了凝固性坏死的位置及存在、血管损伤和间质出血。
结论
对比增强MRI可对MRg-HIFU肾消融进行评估。组织病理学显示了凝固性坏死、血管损伤，并证实了MRI上所见的损伤体积。
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