I got a knee MRI at Salud Digna in Cancun for 2100 pesos. Very worthwhile. The ADO to Cancun Centro is like 100p each way and it was nice to spend the day in Cancun.I booked and paid online so all I had to do was scan a QR code when I showed up and verify my identity with an ID. I waited maybe 10-15 minutes before being taken back and left with the MRI on a CD and got a digital copy emailed the next day via a portal.