Hi emtredhead.
The dilation you mentioned could be due to an obstruction, caused commonly by gallstones which become dislodged from the gallbladder & travel down the bile duct where it drains into the small intestine, the most narrow part of the bile duct.
There are other reasons for the obstructions
The MRCP will hopefully help determine the cause of this, however, there are cases where the MRCP may not detect anything significant.
When allergic reactions to foods or medicines involve the bile ducts, there's internal tissue inflammation and swelling,causing the obstruction of bile flow.
An elimination diet will be warranted if your MRCP is negative or results are indeterminate.
While you are waiting for your MRCP, I suggest you look into Magnesium Oil transdermal supplementation (Mg Oil= 1/2 Mg Chloride flakes + 1/2 water) and also oral Magesium Chloride Hexahydrate (25 gr. diluted in 1L
water-dose is 125 ml every 6-8 hours, however tapering up to this dose
is recommended and also sipping it very slowly to avoid laxative issues).
This will help prevent gallstone formation.
Another factor in gallstone formation is low stomach acid.
You can do a Betaine HCL challenge. Just follow the label instructions and if you feel better after each meal consistently, then you have low stomach acid.
Best wishes,
Niko