In DICOM you have the notion of a transfer syntax, so you can choose your compression scheme (from a list of Dicom supported transfer syntax), such as JPEG2000.

In DICOM you have the notion of a transfer syntax, so you can choose your compression scheme (from a list of Dicom supported transfer syntax), such as JPEG2000. You can also just leave the images uncompressed as well. That being said, any images of sufficient size are very likely to be compressed, J2K being one of the most popular. IMO, the flexibility provided by the container is not worth the development/support effort. It's better to do one or two things really well rather than have hundreds of edge cases.