MRI T_2 WI信号强度与高强度聚焦超声消融子宫肌瘤疗效关系的研究

US-guided high-intensity focused ultrasound(HIFU)surgery for uterine fibroids:relationship between the therapeutic effects and signal intensity of preexisting T_2-weighted MR images

目的：通过研究消融前M RI T2 WI信号强度特点与高强度聚焦超声消融术（high intensity focused ultrasound ablation ，HIFU ）治疗子宫肌瘤消融疗效之间的关系，从信号方面探讨影响 HIFU 治疗子宫肌瘤疗效的因素。方法选择2011年10月～2013年7月经MRI诊断的子宫肌瘤患者50例，行超声引导下的 HIFU 治疗，共有子宫肌瘤56个，消融前根据M RI T2 WI信号强度将其分为四种类型：①高信号；②等信号；③低信号；④混杂信号，消融后次日及术后6个月行增强M RI扫描评估肌瘤体积的消融范围，计算消融率及术后6个月肌瘤体积的缩小率，分别作为早期和中期 HIFU疗效的指标，同时记录术中与消融有关的不良反应。结果所有患者顺利完成治疗，未出现显著并发症。消融前肌瘤的体积0.43～502．12cm3，平均（125．13±111．40）cm3，消融后次日增强M RI中无增强剂灌注区域体积0．38～316．63cm3，平均（87．09±78．05）cm3，消融率25．16％～97．92％，平均（70．61±15．62）％，且MRI T2WI不同信号强度之间疗效差异有统计学意义（P ＜0．05），低信号强度的肌瘤消融率最高，6个月后此类肌瘤体积进一步缩小，且此缩小率与术后次日消融率呈正相关（ r ＝0．67，P ＜0．05）。结论 M RI T2 WI低信号子宫肌瘤更易达到理想的消融疗效，且术后肌瘤体积缩小程度较大，可为选择患者提供依据。

Objective To investigate the relationship between the signal intensity of T 2-weighted magnetic resonance im-ages and the therapeutic effect of US-guided high-intensity focused ultrasound （HIFU ） ablation in the treatment of uterine fibroids .Methods Fifty patients with 56 uterine fibrcids were enrolled in the study from October 2011 to July 2013 .They underwent US-guided HIFU ablation ,which were classified into 4 types based on the signal intensity of T2-weighted mag-netic resonance images type 1 ,high intensity ;type 2 ,intermediate intensity ;type 3 ,low intensity ;type 4 ,mixed intensi-ty .The next day and 6 months after ablation ,the volume of the nonperfused fibroids and the volume reduction ratio were observed on contrast-enhanced MR .They were used as the indices of therapeutic effect .We noted the relevant adverse e-vents .Results All the patients were completed the treatment successfully .No major complications occurred .The pre-treatment fibroid volume ranged from 0 .43 to 502 .12 cm3 ,the mean （125 .13 ± 111 .40） cm3 ,the non-enhancer region vol-ume was 0 .38--316 .63 cm3 ,the mean （87 .09 ± 78 .05） cm3 measured in the enhanced MRI after the treatment .Myoma volume ablation rate was 25 .16% -97 .92% ,mean ablation ratio （70 .61 ± 15 .62）% .The treated area ratio of type 3 fi-broids was highest among the 4 types （ P 〈 0 .05） .During six-month follow-up ,the valume of this type fibroids were shrunk further .The volume reduction ratio was correlated with the treated area ratio （ r=0 .67 ,P〈0 .05） .Conclusion The efficacy of US-guided HIFU correlates with the signal intensity of T 2-weighted magnetic resonance images .Low sig-nal fibroids are suitable candidates for MRgFUS ,which can provide evidenle for choosing pations .