孕囊型剖宫产瘢痕妊娠的经静脉超声造影特点及其诊断价值

The image features and diagnostic values of contrast-enhanced ultrasonography in bursa type of cesarean scar pregnancy

目的探讨孕囊型剖宫产瘢痕妊娠(CSP)的经静脉超声造影(CEUS)成像特点及诊断价值。方法选择2012年2月至2017年1月,于四川大学华西第二医院临床拟诊为孕囊型CSP的31例患者为研究对象。对其同时进行常规超声检查和经静脉CEUS检查。首先在常规超声检查中发现疑似CSP病灶,并确定造影检查时的观察切面;再经肘静脉团注超声微泡造影剂,并实时、动态观察疑似CSP病灶的CEUS成像表现。以患者自身子宫肌层为参照,观察孕囊部位造影剂首次出现位置、最早出现时间、增强强度、分布区域及消退情况等。以刮宫术术后清除病灶的组织病理学检查结果作为诊断疾病的金标准,分别计算常规超声检查与金标准、经静脉CEUS检查与金标准的诊断符合率,并采用Fisher确切概率法,比较二者诊断符合率的差异。本研究符合2013年修订的《世界医学会赫尔辛基宣言》的要求。结果(1)孕囊型CSP的经静脉CEUS图像特点:早增强、高增强、"半环征"及慢消退。在紧贴子宫瘢痕位置的孕囊处,首先出现造影剂增强,造影剂出现时间早于自身子宫肌层;造影剂在孕囊病灶处的增强强度,强于自身子宫肌层;在造影早期,可于孕囊着床的原子宫瘢痕部位见"半环状"弧形高增强;造影剂在孕囊病灶处廓清消退时间,晚于自身子宫肌层。(2)本组31例临床拟诊为孕囊型CSP的患者,经常规超声检查均被诊断为孕囊型CSP;而金标准与经静脉CEUS的检查结果相同,26例为孕囊型CSP,4例为孕囊位置低(非CSP),1例为难免流产。常规超声检查与金标准的诊断符合率为83.9%(26/31),经静脉CEUS检查与金标准的诊断符合率为100.0%(31/31),前者诊断结果与金标准符合率较后者低,并且差异有统计学意义(P=0.026)。结论孕囊型CSP的经静脉CEUS检查具有特征性图像特点,有助于确诊该病,以利于临床医师采取合理治疗措施,防止对孕妇盲目施行刮宫术时大出血。

Objective To investigate the image features and diagnostic values of transvenous contrast-enhanced ultrasonography（CEUS）in patients with bursa type of cesarean scar pregnancy（CSP）.Methods From February 2012 to January 2017,a total of 31 pregnant women with bursa type of CSP which suspicion diagnosed clinically in West China Second University Hospital,Sichuan University,were chosen as research objects.Conventional ultrasonography and transvenous CEUS were performed to all patients at the same time.First,conventional ultrasonography was performed to discover the suspected CSP lesion and determine the observation view at CEUS.Then,after ultrasound microbubble contrast agents were bolus intravenous injected via elbow vein,real-time dynamic imagings of CEUS were observed in suspicion lesion of CSP.Took patients＇ own myometrium as reference,to observe the first position,the earliest time,the intensity of contrast enhancement,the distribution area and the clearance of contrast agent in gestational sac.The histopathological examination results of dilatation and curettage postoperative cleared lesion were taken as the gold standard,and the diagnose accordance rates of conventional ultrasonography with gold standard,transvenous CEUS with gold standard were calculated respectively.Fisher′s exact test was used to compare the difference between these two diagnose accordance rates.This study met the requirements of the World Medical Association Declaration of Helsinki revised in 2013.Results（1）Image characteristics of transvenous CEUS in patients with bursa type of CSP were early enhancement,high enhancement, ＂semi-ring sign＂ and slow clearance.Specifically for contrast agents first appearing at the gestational sac close to uterine scar.The first appearing time of contrast agents in gestational sac was earlier than that in patients′ own myometrium.The intensity of contrast enhancement in gestational sac was higher than that in patients′ own myometrium. The ＂ semi-ring＂ arc hyperenhancement was observed at the early stage of CEUS at uterine scar where the gestational sac was implanted.The clearance and regression time of contrast agents at the lesions of gestational sac was later than that of patients′own myometrium.（2）The conventional ultrasonography results of 31 patients with clinical suspicion diagnosed as bursa type of CSP were all bursa type of CSP.Gold standard and transvenous CEUS results of these 31 patients were the same that 26 cases were bursa type of CSP,4 cases were low position of gestational sac（non-CSP）,and 1 case was inevitable abortion.The results showed that the diagnose accordance rate of conventional ultrasonography with gold standard was 83.9%（26/31）while the diagnose accordance rate of transvenous CEUS with gold standard was 100.0%（31/31）.The former has a lower diagnose accordance rate than the latter,and the difference was statistically significant（P=0.026）.Conclusions Transvenous CEUS for bursa type of CSP has characteristic image features to make a definite diagnosis so that the clinicians can take reasonable treatment measures to prevent pregnant women from hemorrhea during curettage.