This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following describes sonological findings of Placenta accreta? \nSelect and explain. \nA. Ring of fire appearance, B. Large intraplacental lacunae, C. Thickening of retroplacental myometrium with retroplacental clots, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Large intraplacental lacunae is a sonological finding of placenta accreta. Sonological findings suggestive of placenta accreta. The distance between the uterine serosa-bladder wall interface and the retroplacental vessels is <1mm Large intraplacental lacunae Hypervascularity of the uterine serosa-bladder wall interface Image: Sonography of abdomen revealed uterus to be enlarged with endomeytrial cavity, showing an echogenic mass of dimensions 8.1cm*5.8cm attached posteriorly, suggestive of placenta, with colour Doppler confirming it to be posterior, low-lying placenta accreta with no definite myometrial invasion. Ref: Williams Obstetrics 25th edition Pgno: 780', 'role': 'assistant'}]