A new method giving a two criteria diagnosis of venous occlusion using isotope imaging of 99mTc-labelled fibrinogen.

A new method for the diagnosis of venous occlusion involves three stages: first, injection of 99mTc-labelled fibrinogen into a distal vein in the suspected limb with a dynamic gamma scan of venous flow; second, a static pool scan of both limbs to show the anatomy of the veins seen in the dynamic scan and third, a later static scan showing 99mTc-fibrinogen associated with thrombus. In occlusion, absence of flow in the dynamic scan corresponds to the presence of isotope in thrombus in the second static scan. The test uses a low-volume, low-radioactivity injection and may be repeated many times.