If you need an MRI post haste and don't want to endure the long wait times, consider shelling out $$$ and have it done immediately. Yes, Ontario does have a thriving two-tier healthcare system.
In Toronto, you can also book an MRI scan with a private imaging clinic. Doing so may speed up the process, but it can also be costly. For example, private clinics such as Ilumina, Axxess Imaging and MedCentra offer MRI services.
I tore up my knee playing sports. They did a CT in emerge and said I had in fact torn a ligament, somewhere between 5% and 49%. They said I may or may not require surgery but the CT can't determine the level of damage accurately enough. They said they could send me for an MRI but I would have to wait 4 months for it. I said 4 months? It would practically be healed by then. If I did need surgery, I wanted to know sooner than later so I could either start rehab or book surgery. So I paid $950 and had my MRI results in 3 days. I went back to the doctor with the results and he said, good news, no surgery required. You can start rehab/physio once the pain subsides.
There's not a chance in hell I'd wait a long time for a screening procedure if I was looking at a cancer diagnosis. I'd hit the private clinic immediately. The other benefit of going to a private clinic, is that it frees up a spot for someone waiting for an OHIP covered one.