Hindi sila exactly same thing, pero pareho lang ang goal, checking baby para sa any abnormalities, kaya usually ginagamit ang terms na yan interchangeably na! The ideal time is usually between 18-22 weeks (ang detailed anatomy scan), pero some docs do it a bit later din depending sa situation, so don't worry na wala pang mention ng doc mo ngayon, baka iya lang timing niya or baka na-do na niya while checking baby sa previous ultrasounds! Definitely ask Dra mo on April 4 lang about it para sure, pero honestly marami sa amin first-time moms ang nag-overthink about this kaya better na clarify directly sa doctor mo para peace of mind mo na!