Welcome to my world!
First question: What blood work did your vet do? There are a number of blood tests that are a prerequisite before you go into more invasive diagnoses. A dog can have a temporarily enlarged liver if they are coming off some kind of infection, or ate something really bad.
Here are the things that your vet should be testing for before getting into expensive ultrasounds:
Bile Acids - Should be tested both pre-fast and post-fast
Albumin
ALT
ALS
Total Protein
That's kinda the minimum to determine if more diagnosis is required.
My Bacca just had his bloodwork redone. His levels are bad enough to now warrant an ultrashound, and perhaps a biopsy.
Up to now, both the vet and I were satisifed with a slightly reduced protein and milk thistle supplements.
Now he's going on Zentinol, and like I said, the next round of diagostics. And btw....he is only 4.5 years old.
Liver and hypothyroidism is the biggest hidden disease in your dogs. It is there but not actually manifest until physical symptoms until later in life. By that time, the damage is often done.
At 11 years old, you face a tough choice. How much intervention is required to make knowledgeable decisions. And then deciding at that point if the cure is worse than the disease, given the age of the dog. Yeah, I know it sounds harsh when talking about our furkids.
Wishing you all the best and hope the best of all diagnoses! Hug