I suppose it depends on when in your cycle the ultrasound was done and what type
of ultrasound. However, I had dozens
of ultrasounds at various times in my cycle and
the cysts always were very apparent. However, all of my ultrasounds were transvaginal, it may be harder to see them on an abdominal ultrasound...I never had an abdominal ultrasound of my ovaries. On a transvaginal scan, this website shows what your ovary would look like if you had PCOS: http://www.advancedfertility.com/pcos.htm.