The diagnostic value of dual-layer detector spectral CT calcium suppression technique in acute and chronic thoracolumbar compression fractures / 中华放射学杂志

ABSTRACT

Objective:To evaluate the diagnostic value of spectral CT calcium suppression (CaSupp) technique in acute and chronic thoracolumbar compression fractures.Methods:A total of 31 patients with thoracolumbar compression fractures were given spectral CT and MR scans from March to October 2020 in the Second Hospital of Shanxi Medical University. Acute and chronic vertebral fractures were diagnosed by doctor A and B based on CaSupp diagram, and the consistency between the two doctors was evaluated by Kappa test. CT values of fractured vertebra and adjacent normal vertebra were measured on conventional CT and CaSupp graphs respectively, and the CT value difference between fractured vertebra and adjacent vertebra was calculated. Independent sample t-test was used to compare the conventional CT value and CT value difference, CaSupp CT value and CT value difference between acute and chronic fractured vertebra. Using MRI as the gold standard, the ROC curves were drawn to evaluate the subjective diagnostic efficacy of physicians and the diagnostic efficacy of each quantitative parameter. DeLong test was used to compare the area under the curve (AUC) of each quantitative parameter in pairs. Results:The number of vertebral bodies in acute and chronic compression fractures diagnosed by MRI was 48 and 11 respectively. The Kappa value of subjective diagnosis of acute and chronic vertebral fractures by doctors A and B was 0.782, and the AUC, sensitivity, specificity were 0.882 and 0.857, 85.4% and 89.6%, 90.9% and 81.8%, respectively. The differences of conventional CT value, CaSupp CT value and CaSupp CT value difference between acute and chronic compression fractures were statistically significant (all P<0.05), and the AUC values of conventional CT value, CaSupp CT value, conventional CT value difference and CaSupp CT value difference were 0.824, 0.930, 0.706 and 0.934, respectively. Pair comparison showed that the AUC of the CaSupp CT value and CaSupp CT value difference was greater than that of conventional CT value difference, with statistically significant differences ( Z=2.014, P=0.044, Z=2.028, P=0.043), while there were no statistically significant differences between other AUC values (all P>0.05). Conclusion:The dual-layer detector spectral CT CaSupp technique has high value in differentiating acute and chronic thoracolumbar compression fractures, and the CaSupp CT value and CaSupp CT value difference are recommended for diagnosis.