You can't diagnose PCOS with ultrasound alone. Some women with PCOS don't have cysts, I have PCOS but I don't have the cysts. They're actually getting ready to change the name of PCOS http://news.yahoo.com/women-pcos-support-name-change-004312875.html
Just because you have follicles doesn't mean you'll ovulate. The follicles need to grow and be mature enough to ovulate. Sometimes the follicles don't grow or they stop growing.. Did you take Clomid or other fertility treatments this cycle?