The International Journal for Computer Assisted Radiology and Surgery (IJCARS) also contains a lot of work related with medical image processing. And since this year(early 2014), SPIE society will release its Medical Image Journal.
There are relatively many journals from the field, which you asking. I highly recommend: Medical Image Analysis (Elsevier), BMC Medical Imaging (BioMed Central Ltd) and Journal of Medical Imaging (SPIE). Sometimes an interesting issues related to using image processing and analysis in medical applications are presented in Journal of Electronic Imaging (SPIE).
From a wide range of open access journals covering above mentioned field you can consider publication in: International Journal of Biomedical Imaging (Hindawi),
Open Journal of Medical Imaging (Scientific Research Publishing Inc.),
International Journal of Medical Imaging and Graphics (Society for Science and Education) as well as Journal of Innovative Optical Health Sciences (World Scientific Publishing Co.).
Everything cannot be found in open access journals. Any how you need subscription of good journals mentioned above either from your university or self.