In depth ultrasound

Has anyone had an in depth ultrasound. Not like the regular ones, but the one where they can tell you if the baby has any deformities or if your cervix is shortening from the inside? This is my 3rd pregnancy and by far the hardest one ever! I had to take zofran from the beginning, [yes I know the risks]. I have taken it with all the pregnancies. But this one, I have been deathly ill. To the point that I throw up so much, I can't breathe and it bruises my ribs. I am currently 26 weeks and should technically be over the throwing up phase. This has also been causing Braxton Hicks contractions which has my Dr worried and he told me I have a 25% chance of delivering early. I just wanted to know if anyone has had a truly in depth ultrasound and what should I expect?