Image Fusion of Diagnostic Ultrasound with Other Modalities

Image fusion between different “anatomic” imaging modalities such as CT or MRI with the “functional” radionuclide images (positron emission tomography, PET, or single photon emission tomography, SPECT) has been shown to give very useful clinical information. This image fusion technique is now implemented in several, commercially available PET-CT and SPECT-CT, and very recently also PET-MRI scanners. Involvement of ultrasound (US) in image fusion has obvious potential benefits compared with the other imaging modalities: real-time images, possible bedside examinations and ease of image-guided biopsies. However, two important challenges comprise the lack of a DICOM standard in US and the fact that being a real-time examination, it either means fusion of previously recorded static US images or live fusion, which has been applied to liver, prostate, brain and vessels. A review is presented of the current literature involving US in image fusion from peer-reviewed journals in English, to give an overview of the current and future possibilities with this technique.