Frostbite injury: prediction of tissue viability with triple-phase bone scanning

Triple-phase bone scans were obtained in seven patients within 48 hours of admission for frostbite injuries. Three patterns of perfusion imaging and delayed bone imaging were observed: hyperemic blood flow with normal early blood pool and normal delayed bone images; absent blood flow and absent early blood pool depiction, but depiction of bone in delayed images; and absent perfusion and absent blood pool depiction, with no bone uptake in the delayed images. The first pattern indicated mild ischemia that required no surgical treatment, the second indicated ischemia with occasional superficial tissue infarction that required minor debridement, and the third pattern indicated deep-tissue and bone infarction that required amputation. The triple-phase bone scan is a useful indicator of tissue viability as early as 2 days after cold injury and appears to have a clinical role in the evaluation of frostbite injuries. The perfusion and blood pool images demonstrate the ischemic tissue at risk, while the delayed bone scan images demonstrate the extent of deep-tissue and bone infarction.