I'm honestly a litltle confused by what your doctor has told you, as well as you are, so you're not alone. Everything that I read about this specific type of cholesystitis is that it should be treated right away, and you're waiting a whole month. That sounds odd to me! You don't have to have gallstones for this inflammation.
"pathophysiology: the main cause of this illness is thought to be due to bile stasis and increased lithogenicity of bile."
i'm not sure that they could see this bile stasis on an ultrasound. I just can't put two and two together with you. A non-functioning gallbladder is totally opposite from inflammation of the gallbladder. I guess you could have both at the same time, which would expalin why your hida scan was low, if your bile duct is not working exactly right.
I'm sorry I can't give you a clear cut answer. You may want to call the doctor and tell them you're kind of confused as to whats going on. And is your gall bladder just not functioing or do you have the cholesystitis as well.
Plain cholesystis is an inflammation just as you said and you can have perfect hida and ultrasounds and still have the infalmmation. It generally flares and most people opt to have it removed because it causes a great deal of pain, that is my situation. Anywhere from 15 percent of people and under can have this without having stones. I don't have any stones. You can also have tiny chrystals though, that cannot be seen until they open your gall bladder up after removing it. The ultrasound can't pick up everything.