探讨超声及磁共振成像在凶险型前置胎盘（PPP）诊断中的图像特征。

对2014年1月至2015年1月孕20~24周在南京大学医学院附属鼓楼医院行产前超声及磁共振（MRI）检查（17例）疑诊为胎盘植入的27例患者进行连续超声随访检查至分娩，并与MRI及手术病理检查结果对照分析。

27例患者产前超声显示胎盘增厚14例；子宫肌层与胎盘基底部分界不清，胎盘后间隙部分消失17例；胎盘内见胎盘陷窝及丰富血窦15例；彩色多普勒示胎盘后或胎盘实质内有丰富的血流，血流紊乱湍急21例。27例患者超声表现：（1）植入型PPP 24例，声像图示子宫浆膜层连续，肌层部分回声失落，与胎盘基底部分界不清，胎盘后间隙部分消失；（2）穿透性植入3例，声像图示子宫浆膜层不连续，肌层回声失落，膀胱壁肌层回声不连续，胎盘基底部与膀胱壁分界不清，彩色多普勒示低阻高速动脉血流。27例中17例MRI检查，其中2例子宫结合带信号连续，子宫肌层变薄，10例子宫结合带信号中断，子宫肌层变薄受侵或信号不规则，血管迂曲扩张，流空血管影穿过肌层；5例胎盘绒毛侵入并穿透子宫肌层达浆膜层，子宫肌层信号完全消失，胎盘位于子宫轮廓线外，3例膀胱壁浆膜层信号中断，胎盘基底与膀胱交接连续性消失，膀胱壁上见胎盘结节。27例分娩结局：17例行髂内动脉临时球囊阻断＋剖宫产术＋次全子宫切除术；9例行髂内动脉临时球囊阻断＋剖宫产术；1例行子宫动脉栓塞术＋刮宫术治疗。因超声与MRI诊断及时，27例手术治疗后均未发生大出血等严重产科并发症。与超声、MRI及手术病理诊断结果对照，产前超声诊断植入型PPP并连续追踪随访至分娩的10例患者最终证实超声诊断正确7例，其余3例产后综合分析及病理检查均诊断为胎盘粘连；产前超声与MRI联合检查正确诊断PPP 13例（13/17），其余4例超声与MRI诊断结果不一致，其中2例超声诊断植入型PPP，MRI及病理诊断为胎盘粘连；2例MRI诊断PPP穿透性植入，超声及手术病理诊断植入型PPP。

超声与MRI联合检查与产后病理诊断一致性好；PPP患者超声及MRI影像表现均有特征性，产前超声联合MRI检查互为补充和验证，可对PPP正确诊断及临床诊治提供重要的参考信息。

To describe the features of ultrasound (US) and magnetic resonance imaging (MRI) of pernicious placenta previa (PPP).

Twenty-seven patients (gestational weeks, 20-24) with probable placenta implantation diagnosed by prenatal US or MRI in Affiliated Drum Tower Hospital of Nanjing University from January 2014 to January 2015 were included in this study. Ultrasound follow-up were given to these patients until birth-giving. Their continual US/MRI results and pathological examination results were acquired for comparison.

Ultrasound exams were performed in twenty-seven patients, among which seventeen patients recieved both US and MRI examination. The common sonographic findings of PPP included placenta thickening (14 cases), partial echo loss in myometrium and loss of the normal hypoechoic retroplacental zone (17 cases), placenta pit and rich blood sinus (15 cases) and abundant blood flow in or behind the placenta and blood disorder (21 cases). The frequent sonographic presences of patients with placenta implantation included continuous uterine serosa layer, partial echo loss of muscle layer, obscure placenta base-myometrium interface and loss of the normal hypoechoic retroplacental zone (24 cases). Features of 3 patients with placenta through were discontinuity of uterine serosa layer, partial echo loss of muscle layer, discontinuity of the echo of bladder wall muscle layer, obscure bladder-myometrium interface, low resistance-high speed arterial blood flow and placenta penetration. The common MRI findings of PPP (a total of 17 cases) include continuous signal in uterine junction, myometrium thinning and placenta accreta (2 cases); uterine junction, myometrium thinning or invaded or irregular signal, blood vessels expand circuity, empty vessels through muscularis and placenta increta (10 cases); placental villi penetrates the myometrium of size film layer, completely disappearing myometrium and locating outside the uterus contour line and placenta penetration (5 cases), among which three cases featured interruption of the bladder wall and placental invasion into the bladder. Delivery results: among all patients delivered by caesarean section, seventeen patients underwent temporary occlusion balloon catheter of the internal iliac artery and cesarean section with hysterectomy. Nine patients underwent temporary occlusion balloon catheter of the internal iliac artery and cesarean section without hysterectomy. One patient underwent transcatheter uterine artery embolization and dilatation and curettage. No severe obstetric complications were found in all the 27 cases. The results were consistent among US, MRI and pathology in most of the patients (13/17). Two patients with adherent placenta (confirmed by pathology and MRI) were diagnosed as placenta implantation by US. And two patients with placenta implantation (confiremed by pathology and US) were diagnosed as placenta through by MRI. Ten patients received US examination only. The results were consistent with pathology in most cases (7/10). Three patients who were diagnosed as placenta implantation were confirmed as adherent placenta by pathology.

Ultrasound and magnetic resonance imaging of pernicious placenta previa (PPP) exhibit significant features, which can provide important reference for clinical treatments.