Invasive placental disorders: a prospective US and MRI comparative analysis

Invasive placental disorders are potentially life-threatening. Its diagnosis and evaluation of degree of invasiveness is vital in surgical and treatment planning.

To compare the role of various imaging modalities used in current practice for evaluation of invasive placental disorders, and evaluate the validity of certain imaging signs for prediction of invasive placenta.

Twenty-two patients, which were clinically stratified as a risk group for underlying invasive placental abnormality, underwent Doppler sonography and magnetic resonance imaging (MRI). Abnormal placental invasiveness was assessed using various Doppler sonography and MRI signs described in the existing literature. We systematically evaluated the utility of each of these modalities and signs, and compared the roles played by them separately and in combination. All the cases were correlated with surgical and pathological findings.

Nine patients had surgical and pathological confirmation of placental adhesive disorders, of which eight were predicted correctly by MRI (true positive) while one was misdiagnosed as normal placenta (false negative). All the nine cases were correctly identified by Doppler sonography. MRI was more accurate in predicting bladder invasion, identifying 5/6 cases.

Both MRI and Doppler sonography are useful for detection of invasive placental disorders. However, MRI is a better predictor of bladder invasion.