Please, see the picture where the areas (1,2,3) look little yellow:
I think these areas are fat, platelets and/or air. I think 3 is fat/platelets while 1 is air/platelets. There also exists white thrombosis, which can explain something here. However, I do not it is that because those white areas do not contain thrombocytes or leucocytes (not sure, since I have no more closer picture; probably you can see it from this).
I think at the moment that these white areas are endothelium-lined spaces. However, I am not sure about (3).
What can these three areas be in the coronary thrombosis?