Advances in Diagnostic Ultrasound: Fusion Ultrasound Imaging

Fusion imaging overlays multiple images of the same anatomy so clinicians can more easily interpret the data to enhance diagnosis, monitoring, and therapy. Fused images may be obtained using images from the same modality or from different modalities. Positron emission tomography/computed tomography (PET/CT) scanners, for example, are dedicated fusion imaging systems that acquire physiologic and anatomic data during a single examination. PET/CT is widely used in oncology for tumor staging and disease monitoring.

Fusion ultrasound (FUS), in comparison, allows previously acquired CT, magnetic resonance imaging (MRI), PET/CT, or ultrasound images to be fused with real-time ultrasound. The images from those modalities can be displayed in the same imaging plane and location, and are synchronized so that the CT, MRI, or PET/CT image updates as the ultrasound transducer is moved.

Needle-navigation capabilities employ FUS, in conjunction with position sensors that are placed on needles and other devices, to enhance interventional procedures. Advances in technology combined with greater clinical experience are driving increased use of FUS for a range of applications.

Because ultrasound provides real-time data, it is particularly useful for fusion with CT, MRI, or PET/CT, which produce static images that show more detail than is possible with ultrasound alone. Real time B-mode ultrasound, which depicts anatomy, and color Doppler modes, which are used to assess blood flow, can be used during FUS exams. Previously acquired three-dimensional ultrasound images can be fused with real-time two-dimensional ultrasound images for volume navigation; and contrast-enhanced ultrasound can be used for FUS applications to obtain additional diagnostic data.

Advantages of FUS over conventional ultrasound are:

1. Additional data provided by CT, MRI, or PET/CT helps users localize areas...