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Objective:To explore high-resolution MRI (HR-MRI) characteristics in patients with ischemic stroke caused by vertebral artery dissection.Methods:A total of 47 patients with suspected vertebral artery dissection in the First People′s Hospital of Lianyungang, Kangda College, Nanjing Medical University from June 2015 to June 2020 were consecutively enrolled. All patients underwent routine MRI before HR-MRI, and three-dimensional arterial spin labeling (3D-ASL) was performed in those with negative MR. Patients with posterior circulation infarction on MRI and ischemic hypoperfusion on 3D-ASL were included in the ischemic stroke group, while patients with negative plain MRI and normal 3D-ASL were included in the normal group. The clinical characteristics and HR-MRI imaging characteristics between the two groups were compared using t-test or χ 2 test, while the correlations of quantitative data or ranked data were analyzed by Pearson or Spearman test. Results:There were 27 patients in the ischemic stroke group and 20 patients in the normal group, and there were no significant differences in clinical characteristics such as gender, age, site of onset, history of hypertension, hyperlipidemia, and history of diabetes between the two groups ( P>0.05). Basilar artery lateral deviation classification (χ2 =7.013, P=0.030), basilar lateral bend angle (140°±19° vs. 137°±15°, t=2.231, P<0.026), minimum bending angle of vertebral basilar artery (131°±27° vs. 90°±13°, t=42.630, P<0.001), the minimum bending angle of vertebrobasilar artery ≤ 90° distribution (3 cases vs. 21 cases, χ2=15.240, P<0.001) and effective lumen index (0.33±0.10 vs. 0.17±0.09, t=35.934, P<0.001) of normal group and ischemic stroke group showed statistically significant differences. Among them, the minimum bending angle of the vertebrobasilar artery was negatively correlated with posterior circulation ischemic hypoperfusion ( r=-0.621, P<0.001), and the effective lumen index was negatively correlated with posterior circulation ischemic stroke ( r =-0.713, P<0.001). However, the location of the dissection, the distribution of hematoma, the shape of the lumen and the enhancement type were not statistically significant between the normal group and ischemic stroke group ( P>0.05). Conclusion:HR-MRI shows that the lateral deviation of the basilar artery of grade 3, the minimum bending angle of the vertebrobasilar artery less than 90°, and small effective lumen index are related to posterior circulation stroke caused by vertebral artery dissection, which may help for the proper formulation of clinical treatment plan.
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Objective:To assess the diagnostic value of whole-lesion intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in differentiating benign and malignant thyroid nodules based on turbo spin echo (TSE) sequence.Methods:Totally 57 patients with thyroid nodules diagnosed by pathology were prospectively collected at the Affiliated Lianyungang Hospital of Xuzhou Medical University from March 2019 to December 2019. A total of 62 nodules were included for analysis, including 27 benign nodules and 35 malignant nodules. All patients underwent routine MRI scan and IVIM-DWI based on TSE sequence before surgery. The regions of interest were drawn along the edge of the lesion on multiple consecutive slices to cover the entire nodule, and the apparent diffusion coefficient (ADC), diffusivity (D), pseudo-diffusivity (D *) and quantitation of perfusion fraction (f) values were measured, and the mean value of the multilayer measurement was recorded for further analysis. The differences of the parameters between benign and malignant thyroid nodules were analyzed using independent samples ttest (normal distribution) and Mann-Whitney U test (non-normal distribution). The diagnostic efficacy of parameters with statistical significance was evaluated using the receiver operating characteristics (ROC) curve. Results:The ADC, D and D *values in the malignant nodules were lower than those in benign nodules, the differences were statistically significant ( t=3.821, P=0.001; t=2.034, P=0.046).There were no statistical differences of D * and f values ( t=-1.170, P=0.247; Z=-0.559, P=0.577).The optimal cut-off values of ADC and D were 1.90×10 -3mm 2/s and 1.10×10 -3mm 2/s, with both sensitivity of 81.5%, specificity of 73.5% and 61.8%, respectively. The area under ROC curve of ADC and D were 0.782 and 0.688, and the statistical difference was found ( Z=2.098, P=0.040). Conclusion:The whole-lesion IVIM parameters (ADC and D) based on the TSE sequence provide imaging features for preoperative differentiation of benign and malignant nodules of the thyroid gland.
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Objective To investigate the value of dynamic contrast-enhanced(DCE)-MRI and DWI for the early assessment of curative effects in NSCLC. Methods Forty patients from September 2012 to September 2014 with NSCLC proven by pathology were examined with DCE-MRI and DWI, at one week before the first chemotherapy and one month after treatment. DCE parameters (MER, slope, WR) and ADC values of the tumors were calculated on the workstation. According to the changes of the tumor-size after treatment, all patients were divided into two groups: good response group and poor response group. Pretreatment parameters were compared between the two groups with independent-samples t test, and parameter changes before and after treatment were compared with paired-samples t Test. ROC curve of tumor response characteristic was analyzed. Pearson correlation coefficient was used to study the correlation between post-treatment parameter changes and tumor size reduction. Results Pretreatment ADC, MER and slope value were (1.15 ± 0.09) × 10-3 mm2/s, 1.13 ± 0.28, (3.76 ± 1.27)% in the good response group(15 patients), and were (1.34±0.33)×10-3mm2/s, 0.78±0.16, (2.63±0.58)%in poor response group(25 patients), respectively. There was significant difference between tumors in two groups(t=2.329, 3.152, 4.556,P=0.027, 0.032, 0.009), the lower ADC value and the higher MER/slope value was observed in the good response group. The change rates of ADC after one month treatment in the two groups were (20.43±6.40)%, (2.98±1.65)%(t=3.485,P=0.009), and slope change were (-61.80±19.21)%, (-30.80±11.16)%(t=3.280, P=0.020). Both the rising rate of ADC and decreasing rate of slope value were significant higher in good response group than the poor response group. The ROC curve was used to analyze the change rate of ADC and slope after tumors treatment, the area under the ROC curve in ADC was largest(Az=0.790), the diagnosis efficiency was highest. We found significant positive correlation between ADC, MER, slope change rate and tumor maximum diameter reduction rate after chemotherapy(r=0.637, 0.396, 0.532,P<0.05). Conclusions DCE parameters and ADC values possess important clinical value to evaluate the early effect of chemotherapy in NSCLC. ADC value is more sensitive to early lung cancer response.