Chien-Kuo Wang MD, Presenter: Nothing to Disclose

Ruey-Mo Lin, Abstract Co-Author: Nothing to Disclose

To assess bone marrow edema within the vertebral compression fracture by use of a dual energy (DE) CT virtual noncalcium image compared with MR imaging as standard reference

From March to October 2011, consecutive patients with thoracic and lumbar compression fractures referred for MR and CT either to rule out fracture after an equivocal radiography result or to precisely assess the extent of a fracture. The exclusion criteria included age less than 18 years, pregnancy, or any contraindications to MR imaging. The MR examinations were performed with a 1.5-T imager with the fluid sensitive sequences. All CT examinations were performed on a DE CT scanner (Somatom Definition; Siemens). The system was equipped with two x-ray tubes (A and B) and two corresponding detectors oriented in the gantry with an angular offset of 90 degrees, allowing for simultaneous imaging at different energies. We performed a single acquisition CT scan of the collapsed vertebrae by using a DE protocol (collimation, 20 × 0.6 mm; pitch, 0.7; rotation time, 0.5 seconds) in a craniocaudal scan direction. Tube voltages were set at 140 kV (tube A) and 100 kV (tube B). Image analysis was based on a three material decomposition into bone mineral, yellow marrow, and red marrow. The method used the nominal absorption values of the three materials for the two x-ray spectra as input parameters. The circular region of interest (ROI) within the collapsed vertebra was determined by the color mapping virtual noncalcium image. The mean CT number of the ROI (10mm diameter) was calculated on the axial gray-scale virtual noncalcium image. The collapsed vertebrae were categorized into non-edematous and edematous compression fractures by the findings on MR images.

Fifty-four consecutive patients (13 men, 41 women) with 98 vertebral bodies were analyzed. The interval between MR imaging and DE CT was 0.9 days (range, 0-5 days). MR imaging revealed 62 non-edematous compression fractures and 36 edematous. By using DE CT virtual noncalcium technique and color mapping, the average CT number of non-edematous bodies was -158.26 and that of edematous bodies -120.34 with the P value of 0.0063.

DE CT virtual noncalcium images could provide the information of bone marrow edema in acute/aubacute vertebral compression fractures.

We can use DE CT to evaluate bone marrow of vertebral compression fracture.

Wang, C, Lin, R, Use of Dual-Energy CT in Detecting Bone Marrow Edema of Vertebral Compression Fractures.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12035228.html