二维剪切波弹性成像评价肝肿瘤射频消融灶边界的临床研究

Assessment of the boundary of ablation zone in liver neoplasms using 2D shear-wave elastography

目的应用二维剪切波弹性成像（2Dshear—waveelastography，2DSWE）探究肝肿瘤射频消融灶的弹性临界值（cut-offvalueofSwE，Ecut—off）及弹性成像评估消融范围的最佳量程设定。方法选取进行肝肿瘤射频消融术的27例患者，共27个病灶。术前评估靶病灶SWE成像质量（分为Ⅰ级、Ⅱ级、Ⅲ级），测量靶病灶弹性平均值（meanvalueofSWE，Emean）及右肝肝实质Emean。术后分别于2h、1d及1个月对消融灶进行2DSWE及超声造影检查，以CEUS图像中门脉期无增强区为消融灶范围，测量弹性图中相对应消融灶边缘及紧邻消融灶边缘肝组织杨氏模量。以消融灶边缘弹性最小值（minimumvalueofSWE，Emin）及消融灶边缘肝组织弹性最大值（maximumvalueofSWE，Emax）构建R0c曲线获得消融灶Ecut-off值。以Ecut—off值为量程调整消融灶弹性图像后将弹性饱和区域与超声造影无增强区重合，弹性饱和区域边界与超声造影无增强区边界重合率达到80％认为重合度良好。结果术前靶病灶SWE成像质量Ⅰ级16例（60％），Ⅱ级11例（40％），病灶Emean为（66．0±47．0）kPa，右肝肝实质Emean为（10．7±5．4）kPa。术后2h消融灶Ecut-off值为48．25kPa，术后1d消融灶Ecut—off值为47．10kPa，术后1个月消融灶Ecut-off值为47．80kPa。以50kPa作为量程调整射频消融SWE图像所得弹性饱和区域与超声影无增强区图像重合度良好。结论射频消融灶Ecut—off值为47～49kPa。以50kPa作为量程调整消融灶SWE图像所得弹性饱和区域可以较准确地反映超声造影无增强区范围。

Objective To explore the cut-off value of elasticity（Ecut-off） of the ablative tissue and the optimum scale for shear-wave elastography（SWE） to best delineate the liver ablations. Methods A total of 27 patients with hepatic tumor（27 nodules） were studied. 2D ultrasound and SWE images for every target focal liver lesion and SWE images for the right liver parenchyma were taken pre-operation. SWE images and contrast-enhanced ultrasound（CUES） images of the ablation in the same plane were taken at 2 h, 1 d and 1 month post-ablation. The quality of SWE images was evaluated, Grade Ⅰ or Ⅱ were considered satisfied. The mena value of SWE（Emean） for both the target lesion and right liver parenchyma were measured. The non-enhanced area in the portal phase of CEUS image was considered as the ablation region. Young Modulus of corresponding region of the ablation area in SWE image were measured, which were boundary of the ablation zone and besides the boundary. ROC curve was made by minimum value of SWE （Emin） of the boundary and maximum value of SWE（Emax） of that besides the boundary to get the Ecut- off value of the ablative tissue. The Ecut-off was taken as the scale. The maturation region of SWE images and the non-enhanced regions of CEUS images were compared. An overlap above 80% was considered satisfied. Results Sixty percent （16 cases） of target lesions got I Grade SWE images and forty percent （11 cases） got Grade Ⅱ . Emean for lesions was （66.0 ±47.0）kPa and that for right liver parenchyma was（10.7 ± 5.4）kPa. The Ecut-off values for ablative tissues at 2 h, 1 d and 1 m postablation were （48.25, 47.10,47.80）kPa respectively. Maturation regions in SWE images with the scale of 50 kPa overlapped well with the corresponding non-enhanced areas of CEUS. Conclusions The Ecut-off values for ablative tissues are 47~50 kPa, SWE images with the scale of 50 kPa can well delineate the non-enhanced region of the corresponding CEUS images.