Dual-energy CT of the bone marrow in multiple myeloma: diagnostic accuracy for quantitative differentiation of infiltration patterns

ObjectivesBone marrow imaging patterns in patients with multiple myeloma possess prognostic and potential therapeutic relevance. We aim to evaluate whether different magnetic resonance imaging (MRI) patterns also result in different bone marrow dual-energy computed tomography (DECT) virtual non-calcium (VNCa) attenuation values.MethodsThe institutional review board approved this study. Written informed consent was obtained from all participants. 53 patients with plasma cell disorders (24 with normal imaging pattern, 24 with focal infiltration, 5 with diffuse infiltration) and 21 control subjects sequentially underwent DECT and MRI of the axial skeleton. MRI served as reference standard for imaging pattern assessment. Bone marrow VNCa attenuation numbers were obtained according to pattern allocation. Generalised estimating equations and a receiver operating characteristic (ROC) analysis were performed.ResultsMean VNCa attenuation numbers in patients with normal, focal and diffuse imaging patterns were - 65.8 HU, 3.3 HU and - 13.3 HU, respectively. We found significant differences between diffuse vs. normal (p < 0.001), diffuse vs. focal (p = 0.002) and normal vs. focal (p < 0.001) patterns. A cut-off of - 35.7 HU showed a sensitivity of 100% (24/24) and specificity of 97% (116/120) for the identification of a diffuse pattern vs. normal pattern, with an area under the ROC curve of 0.997.ConclusionsBone marrow VNCa attenuation numbers of various imaging patterns in patients with plasma cell disorders differ significantly and a diffuse imaging pattern can be determined confidently using DECT, when ROIs are carefully selected on the basis of MRI findings.Key Points center dot DECT allows for imaging pattern allocation similar to MRI.center dot Bone marrow VNCa attenuation numbers differ significantly depending on the imaging pattern.center dot A diffuse imaging pattern can be determined confidently using DECT.