12 week vacuum abortion procedure done a week ago, will obgyn be able to detect on ultrasound or will it look like a miscarriage?

Like a miscarriage: As long as the abortion was performed correctly, the only thing visible on sonogram now should be some leftover blood clots (similar to a recent miscarriage). Your uterus will still be enlarged compared to a non-pregnant uterus. And there will still be pregnancy hormone (HCG) in your blood. Honestly, your OB/Gyn will not judge you for having an abortion if that's what you're worried about.