Zhenduanxue lilun yu shijian (Apr 2021)
Color Doppler ultrasound and magnetic resonance imaging in prenatal diagnosis of pernicious placenta previa and pernicious placenta previa with placenta accreta: clinic value and analysis of missed diagnosis
Abstract
Objective: To explore the detection efficacy of ultrasound(US) and magnetic resonance imaging(MRI) for pernicious placenta previa(PPP) and PPP with placenta accreta, and analyze the causes for missed diagnosis. Methods: A total of 134 pregnancies with pernicious placenta treated at the International Peace Maternity and Child Health Hospital Affiliated to Shanghai Jiao Tong University School of Medicine during January 2015 to December 2019 were enrolled. All the pregnancies underwent US and MRI, and image characteristics of both were retrospectively analyzed. Findings of US and MRI were compared with the results of intraoperative and postoperative pathological examination, and detection efficacy of US and MRI for PPP was assessed. Results: For PPP, US identified 124 out of 134 cases, with a detection rate of 92.5%, and 10 cases were missed because of obesity(2 cases), intestine gas interference(1 case), placenta position (placenta covering lateral or posterior wall of the uterus)(2 cases) and multi-causes(more than 2 causes, 2 cases). MRI recognized 126 out of 134 cases, with a detection rate of 94%, and 8 cases were missed because of placenta position and complicated surrounding structure. With combined use of US and MRI, 128 cases were recognized and 6 cases were missed. For PPP with placenta accreta, 73 cases were diagnosed by US in 80 patients, with a sensitivity of 91.25%, and 7 cases were missed for obesity (1 case), intestine gas interference (1 case), placenta position (1 case) and complicated surrounding structure (4 cases); 75 cases were diagnosed by MRI, and 5 cases were missed. US combined with MRI could recognized 75 out of 80 PPP with placenta accreta, and 5 cases were missed because of non-obvious placental thickening, lack of blood sinuses in posterior or inner of placenta, and complicated anatomical structure. US detection for PPP was in good consistency with that of MRI(Kappa>0.8). Conclusions: Color Doppler US and MRI have good diagnostic efficacy for PPP and PPP with placenta accreta, and US is still the preferred method for prenatal diagnosis because of its low costs and convenience. MRI can be used as a supplementary method when US diagnosis is not clear.
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