For dry gangrene, vascular surgeons often do angiography (a radiologic review with dye that shows arterial blood stream in tissues, also termed arteriogram) to see the extent of ongoing or probable arterial blood reduction to tissue. Soaked gangrene (also termed moist gangrene) is among the most unsafe form of gangrene https://www.sgvascularctr.com/what-is-a-gangrene/