ABSTRACT
Objective To explore the biological activities and the MR imaging signal intensities (SIs) characteristics of differentiations of neural-like cells induced by superparamagnetic iron oxide (SPIO) and green fluorescent protein (GFP) double-labeled bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Methods GFP-BMSCs were labeled with different concentrations of SPIO in vitro (the concentration of the A, B, C and D group was 25, 50, 75 and 100 ug/ml, respectively;the E group without labels of SPIO served as the control group). The Prussian blue stainings were used to detect the labeling rates of SPIO. The iron contents of cells were measured by atomic absorption spectrometer. The CCK8 experiments were used to detect the cell proliferation rates. The cell cycles were detect by PCR. Each of the A-E groups had a test tube with 1 × 108 cells. All test tubes underwent T2* weighted imaging (T2*WI) and susceptibility weighted imaging (SWI) in a MR imaging scanner. The optimal group was defined by comparing the measurements of SIs between T2*WI and SWI. The optimal group and the E group together induced the differentiations of osteogenesis and neural-like cells. The stainings of alizarin red, osteocalcin and Nissl, NeuN, and NF-200 were performed at 72 hours. Real-time quantitative PCR was used to detect the expression levels of RNA in tub3, nestin, NSE, MAP-2 and Syt1. The positive staining rates and the expression levels of RNA were compared between the two groups. Finally, SWI was used to analyse the changes of SIs. One-way analysis of variance (ANOVA) was used to the multi-group comparison. Using least significant difference (LSD) test to analyse the comparisons between the multi-groups. Results The labeling rates of the A-D groups were 100%. The iron contents of cells in the A-E groups were (14.36 ± 7.61), (21.73±3.42), (30.54±8.73), (33.65±9.62), and (2.31±0.32) pg/cell, respectively. The iron contents of cells in the A-D groups were significantly higher than those in the E group ( F=3.852, P=0.003). There was no significant difference between the C and D groups (P=0.267). In all groups, the D group had the lowest OD value in the CCK-8 experiments (3.18 ± 0.46). In the A-E groups, the changes of SIs in SWI were significantly lower than those in T*2 WI. There was no significant difference in SIs of SWI between the C group (145.89±14.31) and the D group (127.37±12.21). Except the comparison between the group C and D, the comparisons between all the groups had significant differences (P0.05). The expression levels of tub3, nestin and NSE were significantly higher before than after induced differentiations (P<0.01). SIs of SWI had no significant difference between before and after induced differentiations in the C group (t=1.26, P=0.236). Conclusions SPIO and GFP double-labeled BMSCs can induce neural-like cells without influencing biologic activities. MR SIs are decreased by the increase of SPIO concentrations in cells. SWI was the most sensitive sequence. The SIs of SWI has no differnce between before and after induced differentiations.
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Objective To investigate the application of quantitative parameters associated with iodine concentration derived from iodine overlay image by dual-source dual-energy computed tomographic (CT) in differentiating benign and malignant thyroid nodules. Methods Seventy-eight patients (total 112 nodules, including 64 benign and 48 malignant nodules) with thyroid nodules who underwent plain scan (PS), arterial phase (AP) and venous phase (VP) enhanced scan by DSCT (80 kVp/ Sn140 kVp) were analyzed retrospectively. Iodine overlay images were obtained by the dual energy post-processing software. The mean iodine concentrations in the normal thyroid parenchyma (ICThy), the lesion (ICLes), and the carotid artery(ICCar) of PS, AP and VP were measured from iodine overlay images. The iodine concentration difference (ICD), the iodine concentration difference-to-normal parenchyma ratio (ICDNR) and the normalized iodine concentration ratio (NIC) were calculated. The two-sample t test was performed to compare quantitative parameters between the benign and malignant nodules. ROC curve with quantitative parameters of three phases was used to analyze the diagnostic efficiency of ICD, ICDNR, NIC and ICles. Results During PS, mean ICDNR, ICD and ICLes of malignant nodules were respectively 1.04 ± 0.95, (2.20 ± 1.82) mg/ml, (-0.04 ± 1.65) mg/ml, ICDNR, ICD and ICLes of benign nodules were respectively 0.04 ± 0.41, (0.35 ± 0.97) mg/ml, (2.19 ± 0.55) mg/ml. ICDNR and ICD of malignant nodules were higher than benign nodules (t'=6.63, 6.39, P<0.05), while ICles of malignant nodules were lower than benign nodules (t=10.13, P<0.05). During AP , mean ICDNR, ICD, ICLes of malignant nodules were 0.39 ± 0.29, (2.23 ± 1.77) mg/ml, (3.81 ± 1.50) mg/ml, and benign nodules were 0.49 ± 0.22, (2.97 ± 1.91) mg/ml, (3.17 ± 1.64) mg/ml, respectively. ICDNR, ICD of malignant nodules were lower than benign nodules (t'=2.08, t=2.12;P<0.05),while ICles of malignant nodules were higher than benign nodules (t=2.12, P< 0.05). During VP, mean NIC of the malignant and benign nodules were 0.45 ± 0.21, 0.58 ± 0.37, respectively. NIC of malignant nodules were lower than benign nodules (t'=2.35, P< 0.05). AUC of ICDNR during PS was 0.892, the sensitivity was 83.3% and the specificity were 90.5%. Conclusion Quantitative parameters associated with iodine concentration by dual-source dual-energy CT may increase the efficiency and accuracy in differentiating benign and malignant thyroid nodules.
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Objective To investigate the correlation between cerebral microbleed (CMB) and hemorrhage transformation (HT) after urokinase intra-arterial thrombolysis in patients with acute ischemic stroke.Methods The patients with acute cerebral infarction treated with intra-arterial urokinase were enrolled.They were divided into either an HT group or a non-HT goup according to whether they had HT or not.Conventional MRI sequences,susceptibility-weighted imaging (SWI),and CT scan were performed before procedure.CT or MRI was reexamined within 48 hours after procedure.The patients' demographic data,vascular risk factors,and the SWI sequences showed the numbers of CMB were documented in detail and they were compared and analyzed.Results A total of 62 patients were included,22 in HT group and 40 in non-HT group.Univariate analysis showed that the proportions of hypertension (81.8％ vs.57.5％ ; x2 =3.125,P =0.048),diabetes (63.6％ vs.40.0％ ; x2 =4.019,P =0.042),smoking (72.7％ vs.37.5％ ; x2 =4.971,P =0.030),and presence of CMB (x2 =5.297,P =0.018) of patients in the HT group were significantly higher than those in the non-HT group.Multivariate logistic regression analysis showed that hypertension (odds ratio [OR]1.51,95％ confidence interval [CI]1.102-2.954; P =0.028),diabetes (OR 1.48,95％ CI 1.09-2.825; P =0.039),and CMB (OR 1.867,95％ CI 1.103-3.158; P =0.020) were the independent risk factors for HT after urokinase intra-arterial thrombolysis in patients with acute ischemic stroke.Conclusions CMB was one of the independent risk factors for occurring HT after urokinase intra-arterial thrombolysis in patients with acute ischemic stroke.