The present invention relates to the diagnosis of clinical conditions characterized by undesirable and/or abnormal selectin expression. In particular, the invention provides for the use of fucoidans for the detection of selectins using imaging techniques including ultrasonography, scintigraphy and MRI. Selectin-targeted imaging agents are provided that comprise at least one fucoidan moiety associated with at least one detectable moiety. Methods and kits are described for using these imaging agents in the diagnosis of clinical conditions such as thrombosis, myocardial ischemia/reperfusion injury, stroke and ischemic brain trauma, neurodegenerative disorders, tumor metastasis and tumor growth, and rheumatoid arthritis.
