Background and Purpose— This study aims to investigate the association between the characteristics of atherosclerotic plaques of middle cerebral artery and recurrent ischemic stroke using magnetic resonance vessel wall imaging. Methods— One hundred and five patients with ischemic stroke attributed to middle cerebral artery plaque underwent high-resolution black-blood magnetic resonance vessel wall imaging. They were divided into group 1, with the first episode of acute stroke (imaging within 4 weeks of stroke, n=44); group 2, with recurrent acute stroke (n=29); and group 3, with chronic stroke (imaging after 3 months of stroke, n=32). Plaque characteristics including plaque area, plaque burden, contrast-enhancement ratio, eccentricity, and degree of stenosis were measured and compared across 3 groups. Association between plaque characteristics and recurrent strokes was investigated by multivariate analysis. Results— Plaque burden was significantly greater in recurrent stroke group than the other 2 groups (median: group 2, 82.7%, versus group 1, 76.3%, and group 3, 73.4%; P =0.001). Patients with acute stroke had higher enhancement ratio than patients with chronic stroke (median: group 1, 1.59, and group 2, 1.90, versus group 3, 1.33; P =0.014). Comparing to first-onset acute stroke patients, recurrent stroke patients were older, more likely with female sex and hypertension, and had higher plaque burden. After adjustment of clinical factors, plaque burden was the only independent imaging feature associated with recurrent stroke (odds ratio, 2.26, per 10% increase [95% CI, 1.03–4.96]; P =0.042). Conclusions— Higher plaque burden of middle cerebral artery identified on magnetic resonance vessel wall imaging is independently associated with recurrent ischemic stroke.

No abstract

No abstract

BackgroundThis study aims to explore the utility of whole-lesion apparent diffusion coefficient (ADC) histogram analysis for differentiating nasopharyngeal lymphoma (NPL) from nasopharyngeal carcinoma (NPC) following readout-segmented echo-planar diffusion-weighted imaging (RESOLVE sequence).MethodsThirty-eight patients with NPL and 62 patients with NPC, who received routine head-and-neck MRI and RESOLVE (b-value: 0 and 1,000 s/mm2) examinations, were retrospectively evaluated as derivation cohort (February 2015 to August 2018); another 23 patients were analyzed as validation cohort (September 2018 to December 2019). The RESOLVE data were obtained from the MAGNETOM Skyra 3T MR system (Siemens Healthcare, Erlangen, Germany). Fifteen parameters derived from the whole-lesion histogram analysis (ADCmean, variance, skewness, kurtosis, ADC1, ADC10, ADC20, ADC30, ADC40, ADC50, ADC60, ADC70, ADC80, ADC90, and ADC99) were calculated for each patient. Then, statistical analyses were performed between the two groups to determine the statistical significance of each histogram parameter. A receiver operating characteristic curve (ROC) analysis was conducted to assess the diagnostic performance of each histogram parameter for distinguishing NPL from NPC and further tested in the validation cohort; calibration of the selected parameter was tested with Hosmer–Lemeshow test.ResultsNPL exhibited significantly lower ADCmean, variance, ADC1, ADC10, ADC20, ADC30, ADC40, ADC50, ADC60, ADC70, ADC80, ADC90 and ADC99, when compared to NPC (all, P < 0.05), while no significant differences were found on skewness and kurtosis. Furthermore, ADC99 revealed the highest diagnostic efficiency, followed by ADC10 and ADC20. Optimal diagnostic performance (AUC = 0.790, sensitivity = 91.9%, and specificity = 63.2%) could be achieved when setting ADC99 = 1,485.0 × 10−6 mm2/s as the threshold value. The predictive performance was maintained in the validation cohort (AUC = 0.817, sensitivity = 94.6%, and specificity = 56.2%)ConclusionWhole-lesion ADC histograms based on RESOLVE are effective in differentiating NPC from NPL.

Background: The ability to distinguish between a normal thymus, thymic hyperplasia, and thymoma should aid in clinical management and decision making for patients with myasthenia gravis (MG). We sought to determine the accuracy of routine radiological examinations in predicting thymic pathology.Methods: We retrospectively analyzed the records of patients with MG who had undergone thymectomy from the Second Affiliated Hospital of Zhengzhou University. Each patient received at least one initial radiological diagnosis and one histological diagnosis, and the patients were classified into the all-patient, CT, contrast CT, and MRI groups. The sensitivity, accuracy and specificity of each group were calculated for different histological types.Results: This study included 114 patients. All sensitivity, specificity and accuracy values except for sensitivity to hyperplasia in each group for different histological types were satisfactory. MRI had higher sensitivity (68.4, 95% CI: 43.5–87.4%) to histological hyperplasia than did CT (14.3, 95% CI: 0.4–57.9%) and contrast CT (26.7, 95% CI: 7.8–55.1%). Contrast CT had higher specificity (97.9, 95% CI: 88.9–99.95%) for histological hyperplasia than did MRI (88.5, 95% CI: 69.9–97.6%).Discussion: For patients with MG, CT, contrast CT, and MRI examinations can effectively identify thymoma. Additionally, compared with CT or contrast CT, MRI may have a stronger ability to distinguish thymoma and detect hyperplasia.

No abstract

The electrochemical behaviour of Si(IV) ions on Fe electrode in the NaCl-NaF-KCl-SiO2 molten salt system (0.177 mol·L−1 SiO2) at 1,103 K was studied by using cyclic voltammetry, square wave voltammetry, chronoamperometry, and chronopotentiometry．Experiments conducted using the first two methods indicated that the reduction of Si(IV) occurred in two steps: Si(IV) → Si(II) → Si(0). Furthermore, the electrochemical reaction is a quasi-reversible process, which is controlled by both the ion diffusion and electron transport rates. The electrochemical crystallization of Si was found to be a transient, the three-dimensional nucleation process. The cyclic voltammetry curves indicate that the diffusion coefficient of Si(IV) is 1.16×10–5 cm2·s−1. The phases formed on the surface of the deposit were analysed by scanning electron microscopy and X-ray diffractometer. The results show that Fe and Si have formed intermetallic compounds Fe3Si, FeSi, and Fe5Si3.

a total of 80 consecutive patients who were prenatally diagnosed with morbidly adherent placenta were assigned into two groups: the balloon occlusion group (n=40) and the non-balloon occlusion group (n=40).The intraoperative estimated blood loss, blood transfusion, urine output, serum creatinine (Scr), blood urea nitrogen (BUN) and hysterectomy rate were recorded and compared between the two groups.Results: The estimated blood loss in the balloon occlusion group was signi cantly lower than that in the non-balloon occlusion group (811.75±299.93 ml vs 1529.75±808.01 ml, P<0.001). The median amount of packed RBCs transfused in the balloon occlusion group and non-balloon occlusion group was 0 U and 2 U, respectively (P=0.001). The women in the former group had a lower blood transfusion rate than those in the latter group (30% vs 57.5%, P=0.013). Hysterectomy occurred in none in the balloon occlusion group but in 6 patients in the non-balloon occlusion group (P=0.011). Conclusion:The middle abdominal aorta (Zone II) is not a forbidden zone for occlusion as long as the single occlusion time is limited to 15 mins. Balloon occlusion at the Zone II aorta can effectively reduce blood loss, transfusion requirements and hysterectomy rates in patients with morbidly adherent placenta.