Diagnostic accuracy of ultrasound in detecting the depth of invasion in women at risk of abnormally invasive placenta: A prospective longitudinal study.

INTRODUCTION: The aim of this study was to assess the diagnostic accuracy of ultrasound in detecting the depth of abnormally invasive placenta in women at risk. MATERIAL AND METHODS: Prospective longitudinal study including women with placenta previa and at least one prior cesarean delivery or uterine surgery. Depth of abnormally invasive placenta was defined as the degree of trophoblastic invasion through the myometrium and was assessed with histopathological analysis. The ultrasound signs explored were: loss of clear zone, placental lacunae, bladder wall interruption, uterovesical hypervascularity, and increased vascularity in the parametrial region. RESULTS: In all, 210 women were included in the analysis. When using at least one sign, ultrasound had an overall sensitivity of 100% (95% CI 96.5-100) and overall specificity of 61.9 (95% CI 51.9-71.2) for all types of abnormally invasive placenta. Using two ultrasound signs increased the diagnostic accuracy in terms of specificity (100%, 95% CI 96.5-100) but did not affect sensitivity. When stratifying the analysis according to the depth of placental invasion, using at least one sign had a sensitivity of 100% (95% CI 93.7-100) and 100% (95% CI 92.6-100) for placenta accreta/increta and percreta, respectively. Using three ultrasound signs improved the detection rate for placenta percreta with a sensitivity of 100% (95% CI 92.6-100) and a specificity of 77.2% (95% CI 69.9-83.4). CONCLUSION: Ultrasound has a high diagnostic accuracy in detecting the depth of placental invasion when applied to a population with specific risk factors for anomalies such as placenta previa and prior cesarean delivery or uterine surgery.

3D power Doppler in the evaluation of abnormally invasive placenta.

The anomalies in placental insertion and invasion, such as placenta previa and the various forms of abnormally invasive placenta, are today a rising obstetric pathology. Two-dimensional (2D) ultrasonography is the gold standard in the diagnosis of abnormally invasive placenta (AIP), but the important feto-maternal impact of this pathology suggests the opportunity to employ all the available diagnostic techniques, such as three-dimensional (3D) power Doppler. This technique allows acquiring multiplanar images on coronal, axial and sagittal planes and with a rotational technique, it permits visualizing the placenta-bladder interface more accurately. Consequently, it allows a better study of the degree of bladder invasion, which is information that has a great impact on the subsequent counseling and management. Thus, 3D power Doppler represents an important technique complementary to 2D ultrasound in the diagnosis of AIP. The aim of this paper is to illustrate the possible applications of this procedure, referring to the main literature data.