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Comparative Study
. 2019 Jan;41(1):17-23.
doi: 10.1055/s-0038-1675803. Epub 2018 Nov 14.

Assessment of Sensitivity and Specificity of Ultrasound and Magnetic Resonance Imaging in the Diagnosis of Placenta Accreta

Elisa Santos Lopes  1 , Francisco Edson de Lucena Feitosa  1 , Antonio Viana Brazil  1 , José Daniel Vieira de Castro  1 , Jesus Irajacy Fernandes da Costa  1 , Edward Araujo Júnior  2 , Alberto Borges Peixoto  3 , Francisco Herlânio Costa Carvalho  1
Affiliations
Comparative Study

Assessment of Sensitivity and Specificity of Ultrasound and Magnetic Resonance Imaging in the Diagnosis of Placenta Accreta

Elisa Santos Lopes et al. Rev Bras Ginecol Obstet. 2019 Jan.

Abstract
in English, Portuguese

Objective: To assess and compare the sensitivity and specificity of ultrasonography and magnetic resonance imaging in the diagnosis of placenta accreta in patients with placenta previa.

Methods: This retrospective cohort study included 37 women, and was conducted between January 2013 and October 2015; 16 out of the 37 women suffered from placenta accreta. Histopathology was considered the gold standard for the diagnosis of placenta accreta; in its absence, a description of the intraoperative findings was used. The associations among the variables were investigated using the Pearson chi-squared test and the Mann-Whitney U-test.

Results: The mean age of the patients was 31.8 ± 7.3 years, the mean number of pregnancies was 2.8 ± 1.1, the mean number of births was 1.4 ± 0.7, and the mean number of previous cesarean sections was 1.2 ± 0.8. Patients with placenta accreta had a higher frequency of history of cesarean section than those without it (63.6% versus 36.4% respectively; p < 0.001). The mean gestational age at birth among women diagnosed with placenta previa accreta was 35.4 ± 1.1 weeks. The mean birth weight was 2,635.9 ± 374.1 g. The sensitivity of the ultrasound was 87.5%, with a positive predictive value (PPV) of 65.1%, and a negative predictive value (NPV) of 75.0%. The sensitivity of the magnetic resonance imaging was 92.9%, with a PPV of 76.5%, and a NPV of 75.0%. The kappa coefficient of agreement between the 2 tests was 0.69 (95% confidence interval [95%CI]: (0.26-1.00).

Conclusion: The ultrasound and the magnetic resonance imaging showed similar sensitivity and specificity for the diagnosis of placenta accreta.

Objetivo: Avaliar e comparar a sensibilidade e especificidade da ultrassonografia e da ressonância magnética no diagnóstico do acretismo placentário em pacientes com placenta prévia. MéTODOS: Estudo de coorte retrospectivo com 37 mulheres, sendo 16 com acretismo placentário, realizado de janeiro de 2013 a outubro de 2015. Considerou-se padrão-ouro para o diagnóstico de acretismo placentário o exame anatomopatológico, sendo que, na sua ausência, a descrição do achado intraoperatório. As associações entre variáveis foram investigadas utilizando o teste qui-quadrado de Pearson e o teste U de Mann-Whitney.

Resultados: A idade média foi de 31,8 ± 7,3 anos, o número médio de gestações foi de 2,8 ± 1,1, o número médio da quantidade de partos foi de 1,4 ± 0,7, e o número médio de cesáreas prévias foi de 1,2 ± 0,8. O grupo do acretismo placentário apresentou antecedente de cesariana mais frequentemente do que o grupo sem acretismo (63,6% versus 36,4%, respectivamente; p < 0,001). A idade gestacional no parto em mulheres com diagnóstico de placenta prévia com acretismo foi de 35,4 ± 1,1 semanas. O peso ao nascer médio foi de 2.635,9 ± 374,1 g. A sensibilidade do ultrassom foi de 87,5%, com valor preditivo positivo (VPP) de 65,1%, e valor preditivo negativo (VPN) de 75,0%. Para a ressonância magnética, a sensibilidade foi de 92,9%, com VPP de 76,5% e VPN de 75,0%. O índice kappa para concordância entre os dois testes foi de 0,69 (intervalo de confiança de 95% [IC95%]: 0,26–1,00). CONCLUSãO: O ultrassom e a ressonância magnética apresentaram sensibilidade e especificidade semelhantes no diagnóstico do acretismo placentário.

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Conflict of interest statement

The authors have none to declare.

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