I've just got the bill for an ambulance journey to Emerge which I expected but there's also charges for ultrasound and xray which I didn't expect and have never heard of. I'm covered by OHIP.

Any ideas?

My last time to Emergency I got a bil, basically the same as yours, with a sub-total after which was deducted the cost of the procedures, recorded on bill as under OHIP, leaving the cost of ambulance only, to be paid. Fortunately that was covered by my former employer health coverage, so my total cost $NIL.
Perhaps yours is a billing error.

ah, I've had another look at the bill and it could be interpreted that way, the total isn't exactly clear. Of course I'll check on Monday but I wondered what was up.