Performance comparison of dual-layer detector CT parameters from different blood vessels in the detection of anemia.

Background: Anemia negatively affects an individual's overall prognosis and quality of life, and thus represents a significant health burden. Dual-layer computed tomography (DLCT) detector imaging enables substance differentiation. This study aimed to compare the performance of DLCT parameters for different blood vessels in detecting anemia.

Methods: DLCT parameter values [i.e., the computed tomography (CT) value, effective atomic number, and electron density] were retrospectively derived from the aortic arch, pulmonary artery, and portal vein of 240 patients. Differences in DLCT parameters between the anemia and normal groups were analyzed. Pearson correlation analysis and logistic regression models were employed to examine the relationships between the DLCT parameters and hemoglobin concentration. The diagnostic performance of DLCT parameters for anemia among different blood vessels was evaluated by receiver operating characteristic (ROC) analysis.

Results: The anemia group (n=101) had significantly lower hemoglobin concentration than the normal group (n=139) (107.96±13.95 138.40±12.64 g/L, P<0.001), as well as significantly lower CT and electron density values for the three vessels (all P<0.05). The CT value and effective atomic number of the portal vein were significantly lower than those of the aortic arch and pulmonary artery (all P<0.05). The correlation of the CT value of the portal vein to hemoglobin concentration was significantly lower than that of the aortic arch (r=0.435 0.583, P=0.029) and slightly lower than that of the pulmonary artery (r=0.435 0.527, P=0.192). Regarding the correlation between electron density and hemoglobin concentration, there were no significant differences among the three blood vessels (all P>0.05). When using the CT value to detect anemia, the aortic arch had an area under the curve (AUC) value of 0.79, which was significantly higher than that of the portal vein (AUC =0.68, P=0.008) and slightly higher than that of the pulmonary artery (AUC =0.73, P=0.126). In relation to electron density, the aortic arch had an AUC value of 0.81, which was slightly higher than that of both the portal vein (AUC =0.77, P=0.239) and the pulmonary artery (AUC =0.75, P=0.095). Among the six CT predictors, the CT value of the portal vein had the lowest AUC value (AUC =0.68), and the value was significantly lower than that of the aortic arch (P=0.008), that of the electron density of the aortic arch (P=0.002), and that of electron density of the portal vein (P=0.007). The multivariable logistic regression showed that the CT value of the aortic arch, electron density of the pulmonary artery, and electron density of the portal vein were independent predictors of anemia. The logistic regression model that integrated the above three CT indicators showed the best performance (AUC =0.85) in predicting anemia, outperforming any single CT predictor of an individual vessel (all P<0.05).

Conclusions: DLCT may assist in the detection of anemia. The DLCT parameters of the aortic arch demonstrated higher performance than those of the pulmonary artery and portal vein. Additionally, integrating different DLCT parameters (i.e., the CT value and electron density) of multiple vessels may improve diagnostic performance.