It differes with the type of breast implants! If you have saline implants, then you can know the leak after an hour. One the other hand, It is hard to detect rupture with silicone implants. So in this case when you are doubtful about the rupture, do take a mammography. If scar lumpiness is found, then your implants hs ruptured. MRI scanning is also work for identifying the breast implants rupture. .