Hotjar.com is a brilliant tool for usability testing and user journey mapping.
It revealed a number of things people find confusing about Radiology Masters which over a couple of weeks of testing and iterating I have been able to crush.
The big remaining one (shock to me) is that people don't really get the swipe to scroll horizontal menu on mobile. I say this because not many click on far right options.
This will be a bigger job to change but it is on my TODO list to rewrite the header navigation to be a simple popover full screen menu on mobile.