I recently had a hida scan and it took my gall bladder 3 hours to show up. It normally takes an hour or less. I had my gall bladder removed last week. They used the scope but had to also make a 2 inch incision due to a "bleeder vein" they had to repair.
Yes, you will need to have your gall bladder removed. The recovery was not that bad - I only took pain meds for 2 days.
Word of advice, if you have a recliner then sleep on it vs the bed for a few days after the surgery. Otherwise it will hurt when you first lay down and get back up.