Differentiation of Acute/Subacute versus Old Vertebral Fractures in Multislice Detector Computed Tomography: Is Magnetic Resonance Imaging Always Needed?

Abstract

To assess the ability of multislice detector computed tomography (MDCT) to differentiate old versus acute/subacute vertebral fractures (VF) and to identify characteristic MDCT imaging signs. 74 consecutive patients demonstrated 192 VF that were classified as either acute/subacute or old based on magnetic resonance imaging, MDCT, and clinical information as reference standard. Classification as acute/subacute versus old fractures based on MDCT alone was evaluated on a Likert scale by 2 independent radiologists. Morphologic MDCT features of fractures, such as trabecular compaction or fracture line, were recorded. Receiver operating characteristic analyses and Cohen's κ were used to assess the discriminatory power of the MDCT and interrater agreement, respectively. Out of all 192 VF, 148 fractures were acute/subacute and 44 were old according to the reference standard. Receiver operating characteristic analyses of sole MDCT assessment showed very good identification of acute/subacute VF, with areas under the curve of 0.854 and 0.861 for readers 1 and 2, respectively. When indeterminate findings were treated as acute/subacute fractures, sensitivity and specificity were 97.2% and 58.1% for reader 1 and 94.5% and 65.1% for reader 2. Interrater agreement regarding fracture age was good (weighted Cohen's κ= 0.607). Trabecular compression/callus distinct from the cortex (double compaction sign) was present in approximately half of acute/subacute VF and highly specific for acute/subacute VF (specificity= 93.2% and 88.6% for readers 1 and 2, respectively). The acuity of VF can be assessed by MDCT alone with high sensitivity and in case of a double compaction sign with high specificity.