This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Sonographic finding of spina bifida – a) Ventriculomegalyb) Obliteration of cisterna magnac) Small BPDd) Abnormal curvature of cerebellume) Club foot \nSelect and explain. \nA. acd, B. bcd, C. abc, D. abd', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sonographic findings of spina bifida \n\nMost common site is lumbosacral region.\nVentriculomegaly with hydrocephalus.\nBanana sign - cerebellum is stretched around the brain stem with effacement of cisterna magna.\nLemon sign - Flattening of frontal bones on transverse image.\nBony defect in spine: -\n\tV shaped profile due to outward flaring of two posterior ossification centres.\n\tPresence of intact sac on posterior aspect of spine.\n\tSac filled with fluid or solid tissue in meningocele or myelomeningocele.', 'role': 'assistant'}]