Calcified Lymph Nodes Causing Clinically Relevant Attenuation Correction Artifacts on PET/CT Imaging

There are several artifacts unique to PET/CT imaging, with CT-based attenuation correction (AC) artifacts being among the most commonly reported. AC artifacts from calcified lymph nodes represent clinically significant and easily misinterpreted PET/CT artifacts that have received little attention in the literature. In this case series, we report three cases of calcified lymph nodes causing an AC artifact and one case of a highly calcified lymph node without an AC artifact. All three cases of calcified lymph nodes causing an AC artifact would have resulted in a change in patient staging, and likely management, if the nodes had been misinterpreted as malignant nodes. In PET/CT imaging, this artifact needs to be considered as a potential cause of apparent FDG activity when calcified lymph nodes are present on the CT portion of a PET/CT study in order to avoid misinterpretation and potential patient mismanagement.