الملخص
Objective:To investigate the value of the virtual monoenergetic image (VMI) obtained by a new dual-layer detector spectral CT combined with metal artifact reduction algorithms(O-MAR) in reduction of different types of artifacts caused by 125I seeds implantation and in improvement of the post-operative CT image quality. Methods:This was a cross-sectional study. Thirty-five patients who underwent dual-layer detector spectral CT scanning of the chest and abdomen after 125I seeds implantation were retrospectively included at the First Affiliated Hospital of Zhengzhou University from March to September 2022. The spectral data were collected and reconstructed into conventional CT image (CI), VMI image (50-150 keV, 20 keV/level), CI+O-MAR image, and VMI+O-MAR image (50-150 keV, 20 keV/level). The artifacts′ removal effects and image quality improvement in each group were evaluated. Two slices with the strongest artifacts were selected for analysis for each patient, resulting in a total of 70 slices. Objective indicators including artifact index (AI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of soft tissue regions affected by artifacts were measured and calculated. Subjective indicators including the overcorrected artifacts and new artifacts, the different forms of artifacts, the diagnosis of artifacts, and the image quality were assessed. One-way analysis of variance was used for comparisons among multiple groups. Paired t test was used to compare the quantitative indicators between the combined O-MAR group and the non-O-MAR group. Kappa statistics was used to evaluate the consistency between observers. Results:In high/low-density artifacts (ROI H/L), the AI values in all groups showed decrease with increasing VMI keV. In artifact-affected tissue (ROI T), SNR of the CI/VMI (70-150 keV)+O-MAR group were significantly higher than those of the CI/VMI group ( P<0.05), CNR of the CI/VMI(50-150 keV)+O-MAR group were significantly higher than those of the CI/VMI group ( P<0.05). Both overcorrection and new artifacts mainly presented in VMI 50 keV and VMI 70 keV groups; Compared with VMI (50-70 keV) group, significantly less numbers of overcorrection and new artifacts were found in VMI (50-70 keV)+O-MAR group ( P<0.05); regarding the comparison of artifact types, with the VMI keV increasing, the number of a-type banded artifacts gradually decreased on images with high-density artifacts, reaching a minimum of 3 in the VMI 150 keV+O-MAR group; while the number of e-type artifacts with little or no artifacts increased, with the highest number of 23 in the VMI 150 keV+O-MAR group. The total number of high-density artifacts in each type decreased with increasing VMI keV. As VMI keV increased, the diagnostic and image quality scores of high-density artifacts in each group were significantly higher than those of low-density artifacts in the VMI+O-MAR group ( P<0.05). Conclusions:VMI combined with O-MAR can significantly improve the objective and subjective image quality of follow-up CT imaging after 125I seed implantation, enhancing lesion visibility and diagnostic confidence. Additionally, VMI+O-MAR showed more pronounced correction effect on high-density artifacts.
الملخص
Objective:To explore the clinical value of quantitative parameters on spectral CT in predicting the invasiveness of lung adenocarcinoma manifesting as ground-glass nodules (GGN).Methods:The clinical and imaging data of 129 patients with pathologically confirmed lung adenocarcinoma who were surgically resected in the First Affiliated Hospital of Zhengzhou University from March to October 2022 were retrospectively analyzed, including 45 males and 84 females, aged from 33 to 81. According to the pathological results, they were divided into the minimally invasive adenocarcinoma (MIA) group ( n=64) and the invasive adenocarcinoma (IAC) group ( n=65). All patients underwent enhanced spectral CT within two weeks before surgery. The iodine density map, Z-Effective (Z eff) map, and electron density (ED) map were reconstructed on the post-processing workstation, and the spectral parameters, including normalized iodine concentration (NIC), arterial enhancement fraction (AEF), Z eff, and ED were measured and calculated. Conventional CT features were analyzed, including maximum diameter, CT value, nodule types, margin, lobulation sign, spiculation sign, bubble sign, pleural retraction sign, abnormal vascular sign, and air bronchial sign. The clinical features, conventional CT characteristics and spectral CT parameters of two groups were compared using the independent sample t test, the Mann-Whitney U test, and the χ 2 test. Multivariate logistic regression analysis was used to evaluate the independent risk factors of lung adenocarcinoma invasiveness, and the model was constructed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of parameters and models in predicting the invasiveness of lung adenocarcinoma. Results:There were significant differences between the MIA group and IAC group in maximum diameter, CT value, nodule type, margin, spiculation sign, pleural retraction sign, air bronchial sign, venous phase NIC, AEF, venous phase Z eff, arterial phase ED, venous phase ED ( P<0.05). Multivariate logistic regression analysis showed that the maximum diameter (OR=1.183, 95%CI 1.062-1.318), CT value (OR=1.004, 95%CI 1.001-1.007), venous phase NIC (OR=1.185, 95%CI 1.083-1.298), AEF(OR=0.975, 95%CI 0.957-0.994), venous phase Z eff (OR=0.031, 95%CI 0.005-0.196) were independent influence factors for the invasiveness of lung adenocarcinoma. The conventional CT model was established with the maximum diameter and CT value, and the spectral CT model was established with venous phase NIC, AEF, and venous phase Z eff. The combined model was established with all the parameters above. Areas under the ROC curve of the conventional CT model, the spectral CT model, and the combined model for predicting the invasiveness of lung adenocarcinoma were 0.828, 0.854, and 0.902, respectively. Conclusion:The quantitative parameters of double-layer detector spectral CT can be used as an indicator to predict the invasiveness of lung adenocarcinoma manifesting as GGN, and AEF has the highest diagnostic efficacy. Spectral CT combined with conventional CT features can further improve the diagnostic efficiency.
الملخص
Objective:To evaluate the necessity, safety and efficacy of endovascular treatment for cerebral infarction caused by middle cerebral artery (MCA) stenosis with hypoperfusion in the blood supply area of the lenticulostriate artery.Methods:The clinical and surgical data of patients with MCA atherosclerotic disease who underwent endovascular treatment in the First Affiliated Hospital of Zhengzhou University from January 2014 to October 2021 were retrospectively analyzed. A total of 6 patients with cerebral infarction caused by MCA stenosis with hypoperfusion in the blood supply area of the lenticulostriate artery were selected. The preoperative and postoperative clinical imaging characteristics, perioperative complications and follow-up of these 6 patients were summarized and evaluated.Results:After the endovascular treatment, the imaging of the lenticulostriate artery in all the 6 patients was clearer than that before the operation, and the number of main trunks of the lenticulostriate artery shown by imaging in 2 patients was more than that before operation. The computer tomography perfusion of 6 patients after the endovascular treatment showed that perfusion in the supply area of the lenticulostriate artery was significantly improved compared with pre-operation. No stroke, transient ischemic attack (TIA) and death occurred during the perioperative period. The time of clinical follow-up was 360 (322, 495) days, and there were no stroke, TIA or death occurring in the corresponding artery. All the 6 patients underwent imaging follow-up, of which 3 patients underwent digital subtraction angiography and 3 underwent CT angiography. The lumen of the target vessels showed patency in all patients.Conclusions:With rigorous imaging evaluation, endovascular treatment may be safe and effective for cerebral infarction caused by MCA stenosis with hypoperfusion in the blood supply area of the lenticulostriate artery.