For dry gangrene, vascular surgeons normally do angiography (a radiologic review with dye that demonstrates arterial blood flow in tissues, also termed arteriogram) to begin to see the extent of ongoing or probable arterial blood decline to tissue. Moist gangrene (also termed moist gangrene) is easily the most risky form https://www.sgvascularctr.com/what-is-a-gangrene/