The utility of bone scintigraphy with SPECT/CT in the evaluation and management of frostbite injuries

Abstract

Objective:: Frostbite is a localized cold-thermal injury resulting from prolonged exposure of flesh to freezing and near freezing temperatures. The depth and extent of frostbite injuries are not easily assessed, from a clinical standpoint, at the time of injury making it challenging to plan appropriate management and treatment.

Methods:: A review of the literature of management of cold-related injuries and retrospective case review of the imaging and clinical course of frostbite injury.

Results:: Bone scintigraphy with single photon emission computed tomography (SPECT)/CT was performed in the acute and subacute course of frostbite injuries, subsequently leading to earlier definitive management and shorter hospital stay.

Conclusion:: Multiphase technetium-99m-methylenediphosphonate (⁹⁹mTc-MDP) bone scintigraphy with SPECT/CT can expedite clinical management of frostbite injuries by determining the extent of injury and can accurately predict the level of amputation if needed.

Advances in knowledge:: SPECT/CT is underutilized at many facilities but can have a profound and immediate impact on clinical management of patients with frostbite when used in combination with physiological bone scan imaging.

Figure 1.

Multiphase [Tc⁹⁹m]-MDP bone scintigraphy and bilateral extremity angiogram following a severe frostbite injury. Delayed (A) and soft tissue phase (B) images with fingertip markers demonstrate absent radiotracer activity within the majority of the bilateral fingers. These findings mirror the digital subtraction angiogram, which demonstrates diminutive arteries in both the right (C) and left (D) hands with no significant arterial flow to the digits. MDP, methylene diphosponate.

Figure 2.

Multiphase [Tc⁹⁹m]-MDP bone scintigraphy with SPECT/CT after a severe frostbite injury of the bilateral feet. Plantar angiographic phase images (A) demonstrate absent uptake in the bilateral forefeet to the level of the metatarsal heads on the left and to the distal metatarsal shafts on the right. Planar soft tissue and delayed phase images in plantar, medial and lateral views (B) show focally increased radiotracer uptake involving the left first-5th metatarsal heads with absent radiotracer uptake at the left first-5th phalanges. There is increased radiotracer uptake involving the right fourth-5th metatarsal heads with absent radiotracer uptake in the right first-5th phalanges and right first-3rd distal metatarsals. Maximum intensity projection fused SPECT (C) and fused SPECT/CT (D) delayed phase images demonstrate absence of radiotracer uptake in the bilateral forefeet confirming these findings. Note that on planar images it is difficult to identify the precise location of tracer absence without markers. The areas of intense uptake represent the demarcation zone between viable and nonviable tissue. A bilateral transmetatarsal amputation was subsequently performed. MDP, methylene diphosponate; SPECT, single photon emission CT.

Figure 3.

Multi phase [Tc⁹⁹m]-MDP bone scintigraphy with SPECT/CT of the bilateral hands after a severe frostbite injury. Angiographic (A) and delayed phase images with fingertip markers (B) demonstrate absent radiotracer uptake within the bilateral hands. The SPECT (C) and fused SPECT/CT MIP images (D) demonstrate the precise anatomic location of non-viable tissue at the level of the metacarpal heads. The patient subsequently underwent bilateral transmetacarpal amputation 8 days after initial presentation. MDP, methylene diphosponate; SPECT, single photon emission computed tomography.