Macroscopic pulmonary fat embolism following cemented hemiarthroplasty for pathological femoral fracture: A case report with dual-energy CT spectral analysis

Macroscopic pulmonary fat embolism is an uncommon complication of cemented arthroplasty, and its occurrence after fixation of a pathological femoral fracture is rarely documented. We report the case of a 73-year-old woman with metastatic nonsmall cell lung cancer who developed severe hemodynamic instability during cement pressurization for hemiarthroplasty of a pathological right proximal femoral lesion, consistent with bone cement implantation syndrome but not fulfilling the criteria for fat embolism syndrome, and who recovered with supportive care. Dual-energy CT pulmonary angiography showed a 30 × 15 mm filling defect in the right main pulmonary artery and smaller left lower lobe segmental defects, with a mean attenuation of −86.6 HU within the main defect, CT numbers becoming progressively more negative at lower photon energies in contrast to a paraspinal muscle reference, and persistence of the defect on virtual noncontrast images. This case illustrates that attenuation measurement within any postoperative intraluminal filling defect is a simple and potentially decisive step, and that dual-energy spectral analysis may provide complementary support for the fatty nature of an embolus.