子宫肌瘤玻璃样变性及肿瘤内血管密度的MR-PWI研究

中文摘要

目的通过MRI灌注成像(MR perfusion imaging ,MR-PWI)检测子宫肌瘤患者，初步探讨子宫肌瘤玻璃样变性及肿瘤内血管密度与PWI强化特征SS max的相关性，为PWI 指导子宫肌瘤治疗方案提供理论依据。

方法对临床诊断为子宫肌瘤患者进行MR平扫及增强MRI灌注成像扫描，使用1.5T 磁共振成像扫描仪，采用稳态快速场回波序列（balance-turbo field echo,B-TFE），在肿瘤强化最显著的区域以及正常子宫肌层设定感兴趣区，通过后处理得出时间-信号曲线（灌注曲线），检查一周后均经手术后标本送病理检查分析玻璃样变性的程度及免疫组化测定肿瘤血管密度（medial intratumoral vessel density, MVD），计算分析时间-信号曲线的首过最大灌注斜率值（steepest slope ，SS max）并与术后病理及免疫组化测定的MVD结果做对照分析。

结果共对79例患者进行检查，年龄29-53岁，平均48岁。①MRI诊断结果：子宫肌瘤91个，子宫腺肌瘤8个，子宫内膜癌1个，术后均行病理结果证实，子宫肌瘤最大径1.1cm-16.0cm,平均直径5.6cm,其中未变性38个，轻度玻璃样变性16 个，中度玻璃样变性19个，重度玻璃样变性18个。玻璃样变性子宫肌瘤T2WI表现为等信号、低信号或混杂信号，T1WI均为低信号，包膜和结合带完整,MRI平扫表现无特异性。②灌注扫描显示：普通未变性的子宫肌瘤与正常子宫肌层同时强化，灌注曲线陡并逐渐上升，而正常子宫肌层在后期灌注曲线呈下降趋势；轻度玻璃样变的肌瘤灌注曲线较正常子宫肌层略平缓，早期曲线陡度相近，而后期子宫肌瘤灌注曲线缓慢上升，而肌层逐渐下降；中度玻璃样变肌瘤曲线逐渐上升，早期曲线陡度较正常子宫肌层略平缓，而后期子宫肌瘤灌注曲线缓慢上升，而肌层逐渐下降；重度玻璃样变肌瘤早期曲线平缓，后期缓慢上升。③直径小于3cm的肌瘤均为未变性子宫肌瘤。直径大于3cm的子宫肌瘤玻璃样变性的发生率为63.9%,变性程度与肌瘤的大小有关(X2=163.01,P<0.01),其中未变性子宫肌瘤的最大灌注斜率值SS max高于玻璃样变性子宫肌瘤，差异有显著性统计学意义（P﹤0.05）；其中轻度玻璃样变性早期强化最明显，SS max最大，MVD表达最高，中度次之，重度最小，差异有显著性统计学意义（P﹤0.05）；且SS max 与MVD 成正相关(r=0.657，p=0.0028，p﹤0.01)。

结论子宫肌瘤在其生长的过程中常伴发不同程度的玻璃样变性,玻璃样变性程度越轻，肌瘤内血供越丰富，SS max越大，MVD越高。PWI可用于评估子宫肌瘤玻璃样变性的程度，能够反映组织血液灌注情况及微血管分布，为子宫肌瘤术前治疗方案的选择提供了影像学依据。

关键词: 子宫肌瘤磁共振灌注成像玻璃样变性最大灌注斜率血管密度

Abstract

Objective To study the characteristics of MR perfusion imaging in various hyaline degeneration and intratumoral vessel density of uterine leiomyomas and priliminarily explore their correlation, to provide the theory accordance for making in therapeutic regimen in the uterine leiomyomas.

Methods Conventional MR imaging and enhanced MRI T1-weighted perfusion imaging were performed on clinical diagnosing uterine leiomyomas .A turbo fast low-angle shot sequence was performed in a 1.5-T MR scanner.An operator-defined region of interest （ROI）was placed in the maximal enhancement region of the tumor site and adjacent tumor-free parenchyma of all patients. A time– signal intensity（SI-T） curve was plotted and analyzed. The steepest slope （SS max） of the perfusion curve of the highest perfusion area were calculated, which was compared with the pathological and immunohistochemistry result medial intratumoral vessel density (MVD) after surgery.

Result Conventional MR imaging and enhanced MRI T1-weighted perfusion imaging were performed in 79 patients, aged 29-53years with a mean of 48years.It pathologically showed 91 masses of uterine leiomyoma、8 cases of endometrioma、1 case of endometrial cancer, the diameters were from 1.1cm-16.0cm,the medial value was 5.6cm, including 38cases of none –hyalinization(NH), 16cases of slight- hyalinization (SLH), 19 cases of intermediate-hyalinization(IH) and 18 cases of severe -hyalinization (SEVH). On plain scanning, various hyaline degenerated uterine leiomyomas appeared similarly with equal、low or mix signal on T2WI, low signal on T2WI，with the amicula and junctional zone integrated. PWI showed: NH and normal myometrium were enhanced simultaneously, perfusion curve of which was steep and gradually rising; and of SLH was a little gentle; of IH was gradually rising, lower than normal myometrium; while of SEVH was slowly rising . Uterine leiomyomas with the diameter lower than 3.0cm were wholely NH. The incidence rate of the hyalinization larger than 3.0cm was 63.9%,in which the SS max of NH was higher than H, with the difference was statistcally significant(P﹤0.05). Among the H, the SLV enhanced the most obviously,and the SS max was the highest, followed by the IH and the SEVH, with the difference was statistcally significant(P﹤0.05)，as same as the MVD . And a positive correlation was observed between MVD and the SS max (r=0.657，p=0.0028，p﹤0.01).

Conclusion Various hyaline degenerated uterine leiomyomas showed homoioplastic