In the current era of technological development, medical imaging plays an important role in many applications of medical diagnosis and therapy. This requires more accurate images with much more details and information for correct medical diagnosis and therapy. Medical image fusion is one of the solutions for obtaining both high spatial and high spectral information in a single image. Multimodal medical image fusion provides a remarkable improvement in the fused image quality. This review paper covers the following items, the basic definition of the image fusion process, applications, advantages, and disadvantages of fusion procedures, A short summery of radiological imaging modalities, usage, applications, and observed advantages and disadvantages of each modality is introduced to provide a comprehensive view of medical imaging modalities. Through this, a hybrid imaging combinations are suggested for better Image visualization for different human organs. The paper ends with some novel trends in the medical image fusion topic.