The present invention relates to contrast agent enhanced medical diagnostic ultrasound imaging. In particular, contrast agents are provided useful for cell imaging and cell therapy. More in particular, it provides a particle comprising a fluorinated organic compound and a metal. Such particles may be advantageously employed in qualitative or quantitative imaging such as acoustic imaging including photo acoustic and ultrasound imaging, MRI imaging, such as 19F imaging, 1H imaging including T1 and T2 weighted imaging, SPECT, PET, scintigraphy and fluorescence imaging. This may then be employed in cell labeling, microscopy, histology or for imaging vasculature or perfusion in vivo and in vitro.
