Gregor Pache MD, Presenter: Nothing to Disclose

Bernhard Krauss PhD, Abstract Co-Author: Employee, Siemens AG, Forchheim, Germany

Ulrich Saueressig MD, Abstract Co-Author: Nothing to Disclose

Philipp Blanke, Abstract Co-Author: Nothing to Disclose

Mathias F. J. Langer MD, PhD, Abstract Co-Author: Nothing to Disclose

Tobias Baumann MD, Abstract Co-Author: Nothing to Disclose

To evaluate traumatized bone marrow with a Dual-Energy CT "virtual non-calcium" technique.

In this prospective, institutional review board approved study 21 patients with an acute knee trauma underwent Dual-Energy CT (Somatom Definiton, Siemens) and MRI scans. The application LiverVNC (Syngo Dual-Energy, Siemens) was used to virtually subtract calcium from the images. Presence of fractures was noted and presence of bone bruise was rated on a 4-point scale for 6 femoral and tibial regions, each by 2 radiologists. HU measurements were performed in the same regions. Consensus reading of independently read MRI scans served as the standard of reference. Image ratings and HU values were subjected to receiver-operator-characteristic (ROC) analysis.

After exclusion of 16 regions due to artifacts, MRI revealed 59 bone bruises in the remaining 236 regions (19 of 114 femoral, 40 of 122 tibial). Fractures were present in 8 patients. Visual rating revealed area-under-the-curve (AUC) values of 0.886 (0.897) in the femur and 0.974 (0.953) in the tibia for observer 1 and 2, respectively. For HU measurements the respective AUC values were 0.922 and 0.974. If scores of 1 and 2 (strong/mild bone bruise) were counted as positive, sensitivity and specificity were 86.4% (86.4%) and 94.4% (95.5%) for observer 1 and 2, respectively. The kappa statistic demonstrated good to excellent agreement (κ-value: 0.78/0.87 femoral/tibial).

Dual-Energy CT “virtual non-calcium” technique can subtract calcium from cancellous bone, allowing bone marrow assessment and potentially making posttraumatic bone bruises of the knee detectable with computed tomography.

Dual-Energy CT may be a potential tool in the diagnostic work up of traumatic knee lesions, however, with a not insignificant increase in radiation dose.

Pache, G, Krauss, B, Saueressig, U, Blanke, P, Langer, M, Baumann, T, Dual Energy "Virtual Noncalcium" Technique: Detecting Posttraumatic Marrow Lesions with Computed Tomography.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9000740.html