Abstract: Objective To explore the differential diagnostic value of CT findings combined with some routine blood parameters in brucella spondylitis (BS) and pyogenic spondylitis (PS), and to provide a reference basis for clinicians to accurately distinguish between the two diseases and optimize diagnosis and treatment plans. Method The clinical and CT imaging data of BS and PS patients diagnosed by pathology and etiology in the Third People's Hospital of Kunming City from January 2022 to December 2024 were retrospectively collected, and the differences of CT signs and peripheral blood leukocyte count, neutrophil count, lymphocyte count, eosinophil count and basophil count between the two groups were compared. The indexes with statistical significance between groups were screened out, binary Logistic regression was performed on them, and receiver operating characteristic (ROC) curves were drawn by using the predictive probability values calculated by regression equations to evaluate the diagnostic efficacy of CT imaging signs combined with some routine blood parameters for BS and PS. Result In total, 50 patients were included in the BS group and 40 patients in the PS group. There were statistically significant differences between the two groups in terms of bony destruction of spinal appendages, bone destruction centered on the intervertebral disc, loss of vertebral height, lace-like vertebral sign, white blood cell count, neutrophil count, and lymphocyte count (all P<0.05). Binary logistic regression analysis revealed that the lace-like vertebra sign(OR=0.128,95%CI:0.042-0.387), vertebral height loss(OR=10.651,95%CI:2.845-39.869), and elevated peripheral blood neutrophil count(OR=3.211,95%CI:1.132-9.107) were independent predictive factors for the differential diagnosis of BS and PS. When CT imaging reveals the lace-like vertebral sign, with no vertebral height loss and no elevation of the peripheral blood neutrophil count, the diagnosis is suggestive of BS. Conversely, in the absence of the lace-like vertebral sign, accompanied by vertebral height loss and an elevated peripheral blood neutrophil count, the diagnosis is suggestive of PS. The area under the ROC curve (AUC) for differentiating BS from PS by combining lace-like vertebral sign, loss of vertebral height, and elevated neutrophil count was 0.833 (95%CI:0.749-0.916), with a sensitivity of 82.0% and a specificity of 70.0%. Conclusion Combined assessment of the lace-like vertebral sign, vertebral height loss and elevated peripheral blood neutrophil count yields high diagnostic value for the differentiation between BS and PS, and can provide an important reference basis for their accurate clinical differentiation.

Key words: Computed tomography, Blood routine examination, Brucella spondylitis, Pyogenic spondylitis, Differential diagnosis