Role of Fast MRI Pulse Sequences in Evaluation of Placental Adhesive Disease

Objective: The purpose of this study was to evaluate the diagnostic accuracy of fast, nearly motion free MRI pulse sequences (HASTE true FISP) in the prenatal assessment of placental adhesive disease (PAD) compared to US and Doppler. Patients and Methods: This prospective study included sixteen singleton pregnancies at risk of PAD, ten had actually PAD, all were investigated by transabdominal ultrasonography (gray scale color Doppler methods) and prenatal fast MRI (including: HASTE; half-Fourier acquisition single-shot turbo spin-echo [T2], true FISP; true fast imaging with steady-state precession [GRE] T1 weighted gradient-echo with fat suppression). Their gestational age ranged from 26 to 30 weeks. In each method placental location, appearance invasion topography were assessed. Ultrasound and MRI findings were compared with surgical pathological results. Results: All patients had placenta previa: 2 marginalis, 2 incomplete centralis and 12 complete centralis, ten patients from the later proved to have PAD as follows: 7 were placenta accreta, one was placenta increta and 2 were placenta percreta. US Doppler diagnosed 8 patients (diagnostic accuracy: 80%) with PAD; they showed lost retroplacental hypoechoic space, increased vascularity and vascular lacunes. Ultrasound misdiagnosed two patients with posterior placenta accreta. MRI successfully diagnosed all the patients with PAD. Fast, nearly motion free MRI techniques revealed 100% diagnostic accuracy compared to ultrasound findings. MRI allowed accurate evaluation of placental appearance invasion, vascularity, uterine contour evaluation extra uterine involvement. It also differentiated between venous lakes septae in normal placentas and lacunae dark bands in PAD. Conclusion: Fast, nearly motion free placental MR pulse sequences provides excellent characterization of the degree and extension of placental invasion allowing optimal coordination with obstetricians in managing this complex life threatening conditions.