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Objective:To evaluate the safety and efficacy of a dedicated neonatal-infant brain 0.35 T MRI system.Methods:A dual-center controlled clinical trial was conducted with single-arm objective performance criteria. From June to July 2020, sixty-six infants aged 0-12 (6.3±3.4) months were recruited from Children′s Hospital of Soochow University and the First People′s Hospital of Lianyungang prospectively. All infants underwent brain MRI with a dedicated neonatal-infant 0.35 T brain MRI system, using the dedicated two-channel transceiver head coil. MRI protocol included spin echo T 1WI, fast spin echo T 2WI, fluid attenuated inversion recovery, diffusion weighted imaging and 3D gradient echo sequence. MRI sequences were set with three orientations (axial, sagittal and coronal). Each case received at least two scanning planes and two scanning sequences. Five-point Likert scoring system was used to evaluate the image quality of acquired images, and the target value was set as at least 3 points per image. The temperature, heart rate and breathe of the infants were recorded before and after MRI; the acoustic noise of the MRI system was measured during the scanning process; and the adverse reactions were recorded if presented. Results:Five infants successfully completed their examination during non-sedated sleep in a single attempt, and 61 infants after sedation with chloral hydrate. Based on MRI-based five-point Likert scoring system, 41 cases achieved a score of 5, 21 cases with a score of 4 and 4 cases with a score of 3. Cases with score of 3 was due to movement of the infants during the scan, which resulted in motion related artifacts. The vital signs of all infants showed stable before and after imaging, with heart rate of (126.8±12.9) beats per minute, breathe of (38.2±6.8) times per minute. It was found that 47 cases showed no sign of temperature raise after brain MRI, 15 cases had less than 0.3 ℃ raise and 4 cases had 0.3 ℃ to 0.5 ℃ raise. The noise recorded during the scanning process was (57.5±1.8) dB(A). One case had mild diarrhea on the day of MR scan, and the symptoms disappeared on the second day without treatment; no adverse reactions were found for the rest subjects.Conclusion:Dedicated neonatal-infant 0.35 T brain MRI system allows data acquisition with high safety and excellent image quality, which has potentials in the clinical applications.
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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 Electrocardiographic (ECG) gated 4?dimensional CT angiography (4D?CTA) was performed to analyze the morphological characteristic differences between ruptured and unruptured intracranial aneurysms less than 5 mm to predict the rupture risk of small intracranial aneurysms. Methods A total of 118 patients with intracranial aneurysms less than 5 mm who underwent 4D?CTA examinations in our hospital from May 2014 to May 2017 were retrospectively analyzed. The whole study population was divided into ruptured group and unruptured group. Seventy?two patients were in the ruptured group and 46 patients were in the unruptured group. Original scanning data were reconstructed to produce 20 data sets of cardiac cycles with 5% time intervals. In addition, 20 groups of images and dynamic graphs were generated using three?dimensional software. We concluded the convex was point of impulse if small bubble or small pointed convex could be found in continuous three or more images at the same location. The morphological characteristics and clinical features of the two groups of aneurysms were firstly analyzed by univariate analysis, and then the meaningful indicators were analyzed by logistic regression, and the optimal diagnostic cutoff values were calculated using ROC curves. Results Univariate analysis showed that women, smoking history, location of aneurysm at the bifurcation, pulsation point, aspect ratio (AR) and size ratio (SR) were statistically significant different between the two groups of small aneurysms (P<0.05), but age, hypertension, type 2 diabetes, family history, history of multiple aneurysms, history of drinking, location, size, neck and tumor height had no significant differences between the two groups (P>0.05). Multivariate regression analysis showed that pulsation point (odds ratio=8.843, 95% confidence interval: 2.800—27.925) and large SR value (odds ratio=4.484, 95% confidence interval: 1.094—18.385) were independent risk factors for the aneurismal rupture. when the SR value was greater than 1.65, the area under the ROC curve was 0.832, the sensitivity to diagnose the risk of small aneurysm rupture was 76%, and the specificity is 70%. Conclusion The occurrence of pulsation point and SR value greater than 1.65 are independent predictors of the risk of intracranial aneurysm rupture less than 5 mm.
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Objective To explore the correlation between dual energy imaging indices,microvessel densi-ty(MVD),vascular endothelial growth factor(VEGF)and lung cancer lymph nodes metastasis and its practical sig-nificance by applying dual source CT(DSCT)dual energy imaging.Methods 62 cases of non-small cell lung can-cer(NSCLC)were underwent DSCT dual energy imaging and divided into groups with and without lymph node me-tastasis according to the results of pathology.The expressions of MVD and VEGF were detected as well.All the indi-ces were compared between the two groups. Results(1)The differences between the lung cancer lymph node groups in the iodine concentration,normalized iodine concentration(NIC),spectrum curve of arterial phase,MVD and VEGF were statistically significant(P<0.05).(2)The iodine concentration,NIC and spectrum curve of arte-rial phase were positively correlated with MVD and VEGF.Conclusion Iodine concentration,NIC,and spectrum curve of arterial phase of DSCT dual energy imaging can be regarded as part of the important indices for preopera-tive diagnosis of lymph node metastasis of NSCLC.
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Objective To investigate the value of dual source CT iodine concentration in the assessment of pathological grade of esophageal carcinoma. Methods Retrospective review was performed on 60 cases with pathologically?confirmed esophageal carcinoma. Among them, 17 tumors were well differentiated, 24 were moderately differentiated and 19 were poorly differentiated. The dual?energy plain scan and double phase enhanced scan of dual?source CT were performed on all 60 cases. Normalized iodine concentration (NIC) and the enhancement degree of the esophageal carcinoma in the arterial and venous phase were measured. The difference of NIC and enhancement degree among different grades of esophageal carcinoma were analyzed by analysis of variance. To evaluate the efficiency of NIC and enhancement degree in differentiating the well?moderately differentiated esophageal carcinoma from poorly differentiated esophageal carcinoma, ROC curve was plotted. Results The NIC values of the well differentiated, the moderately differentiated and the poorly differentiated esophageal carcinoma in the arterial phase were (1.54±0.34),(1.72±0.50)and(2.10±0.40)mg/ml, respectively;the NIC values in venous phase were(1.55± 0.52),(1.80±0.62)and(2.18±0.35)mg/ml,respectively, and the degrees of CT enhancement in venous phase were(25.65 ± 4.43),(27.55 ± 6.82)and(30.77 ± 6.38)HU, respectively. The differences between groups were statistically significant(P<0.05). The degrees of CT enhancement of well differentiated, moderately differentiated and poorly differentiated esophageal carcinoma in arterial phase were(14.40 ± 3.91),(14.26 ± 7.35)and(16.17 ± 6.89)HU, respectively, and there were no statistically significant differences(P=0.582). Areas under the ROC curves to differentiate well?moderately differentiated from poorly differentiated esophageal carcinoma for NIC in arterial phase, NIC in venous phase and the degree of CT enhancement in venous phase were 0.801, 0.817 and 0.730. Conclusion The iodine concentration measured on dual source CT has a certain value in evaluating the pathological grades of esophageal carcinoma.
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Objective To explore the way to evaluate hemodynamics of posterior circulation distal ischemia with PWI. Methods Thirty-two patients with vertebral basilar artery severe stenosis were reviewed and compared with thirty normal persons. Information and data of PWI and MRA were collected and analyzed. Following parameters were observed, index of vascular stenosis, collateral vessels, cerebral blood flow (rCBF), cerebral blood volume (rCBV), and mean transit time (rMTT). Results All the patients had at least one vertebral basilar artery with more than 70% stenosis. There were 17 cases with severe vertebral artery stenosis , 20 cases with severe basal artery stenosis , 8 cases with severe superior cerebellar artery stenosis , 17 cases with posterior cerebral artery stenosis , 22 cases with after the traffic artery open , 11 cases with soft meningeal arteries show and 12 cases with small artery show. The ratio of ROI with frontal white matter was lower than the rCBF and rCBV in the country group. MTT value was extended and P value of the parameters in both groups was less than 0.05, reflecting the statistical difference. Conclusions PWI combined with MRA can effectively evaluate the posterior circulation distal ischemia area and tissue perfusion , as well as the hemodynamic status of ischemia area.
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Objective To investigate the feasibility and value of diffusion-weighted imaging (DWI) in the prediction and early assessment of response to concurrent chemoradiotherapy (CCRT) for esophageal cancer.Methods A total of 40 patients with pathologically confirmed esophageal cancer who received CCRT were included in the study.Routine 3.0 T MRI and DWI were performed at different time points of treatment.The RECIST standard was adopted to evaluate short-term outcomes and divide the patients into remission group (complete remission and partial remission) and non-remission group (stable disease and progressive disease).Group t-test was used for between-group comparison.The receiver operating characteristic (ROC) curve was used to analyze the change rates of apparent diffusion coefficient (ADC) value at different time points of treatment.Results There were 30 patients in the remission group and 10 patients in the non-remission group.The remission group had a significantly higher increase in ADC value than the non-remission group by the end of the first week of treatment (P =0.000).The maximum diameters of tumors for the emission group and non-remission group at the end of the first week of treatment were not significantly different from those before treatment (66.10 mm vs.62.63 mm,P =0.407 ; 70.90 mm vs.68.30 m,P =0.552).The ADC value before treatment had a negative correlation with the reduction rate of the maximum diameter of tumor (r =-0.680,P =0.000).The area under the ROC curve was the largest at the end of the first week of treatment (Az =0.783).If using 15.5 ％ increase in ADC value by the end of the first week as the threshold value for evaluating tumor response,the sensitivity,specificity,positive predictive value,and negative predictive value were 86.7％,70.0％,89.7％,and 63.6％,respectively.Conclusions DWI can be used as a new imaging method for the prediction and early assessment of the response to CCRT for esophageal cancer.The change rate of ADC value by the end of the first week of treatment is sensitive in assessing treatment response,so ADC value can be monitored at this time point.