0.05) . Conclusion An acceptable image quality can be achieved for pediatric patients by reducing the mA value to 40 to 80mA used for conventional temporal bone, and the low dose CT scanning ought to be extended in the temporal bone decease for children.

Objective To determine the correlation between coronary artery calcium score (CACS) and carotid calcification, and their risk factors. Methods 162 cases underwent coronary and carotid pre-contrast CT scan with dual-source CT scanner within 2 weeks. The reconstructed parameters were the same. The calcifications of coronary and carotid arteriae were quantified by calculating the Agatston score. The main risk factors such as age, sex, hypertension, total cholesterol, low-density-lipoprotein cholesterol (LDL), high-density-lipoprotein cholesterol (HDL), diabetes, smoking and coronary heart disease history were recorded. The CACS and carotid calcium scores were comparatively analyzed using Spearman's correlative analysis. The relativity between the risk factors and CACS scores, carotid calcium scores. Results In 162 subjects, there was positive relativity between CACS and carotid cal-cium score(r=0.690, P<0.01). Logistic regression analysis showed that CACS were of relativity with age, diabetes, total cholesterol and LDL cholesterol,otherwise, carotid calcium scores only with age and diabetes. Conclusion There is significant correlation be-tween CACS and carotid calcium score, but their risk factors are not same.

Objective:To explore the value of fast susceptibility weighted imaging (SWI) generated by a deep learning model in assessment of acute ischemic stroke (AIS).Methods:From January 2019 to January 2021, 118 AIS patients [75 males and 43 females, aged 23-100 (66±14) years] who underwent MR examination and SWI sequence scanning within 24 h of symptom onset in the First Medical Center of PLA General Hospital were retrospectively analyzed. MATLAB ′s randperm function was used to divide 118 patients into a training set of 96 cases and a test set of 22 cases at a ratio of 8∶2. Fourty-seven AIS patients [38 males and 9 females, aged 16-75 (58±12) years] from one center of a multicenter study were selected to build the external validation set. SWI image and filtered phase image were combined into complex value image as full sampling reference image. Undersampled SWI images were obtained by retrospective undersampling of reference fully sampled images, and the undersampling multiple was five times which could save 80% of the scanning time, then the complex-valued convolutional neural network (ComplexNet) was used to develop reconstruct fast SWI. Interclass correlation coefficient (ICC) or Kappa tests were used to compare the consistency of image quality and the diagnostic consistency for the presence of susceptibility vessel sign (SVS), cerebral microbleeds and asymmetry of cerebral deep medullary veins (DMVs) in AIS patient on fully sampled SWI and fast SWI based on ComplexNet.Results:In test set, score of image quality was 4.5±0.6 for fully sampled SWI image and 4.6±0.7 for fast SWI based on ComplexNet, and coefficient was excellent (ICC=0.86, P<0.05). Full sampling SWI had good agreement with fast SWI based on ComplexNet in detecting SVS (Kappa=0.79, P<0.05), microbleeds (Kappa=0.86, P<0.05), and DMVs asymmetry (Kappa=0.82, P<0.05) in AIS patients. In the external validation set, score of image quality was 4.1±1.0 for fully sampled SWI image and 4.0±0.9 for fast SWI based on ComplexNet, and coefficient was excellent (ICC=0.97, P<0.05). Full sampling SWI had good agreement with fast SWI based on ComplexNet in detecting SVS (Kappa=0.74, P<0.05), microbleeds (Kappa=0.83, P<0.05), and DMVs asymmetry (Kappa=0.74, P<0.05) in AIS patients. Conclusions:Deep learning techniques can significantly accelerate the speed of SWI, and the consistency of image quality and detected AIS signs between fast SWI based on ComplexNet and fully sampled SWI is good. The fast SWI based on ComplexNet can be applied to the radiographic assessment of clinical AIS patients

Objective:To evaluate the clinical value of different shimming methods at 7.0 T MR in two-dimensional (2D) and three-dimensional (3D) T 2WI. Methods:Totally 23 healthy volunteers were prospectively recruited from the First Medical Center of PLA General Hospital from November, 2022 to May, 2023, including 12 volunteers who underwent 2D shimming mode and 14 volunteers who underwent 3D shimming mode. 2D shimming mode included patient-specific (PS) mode, direct signal control (DSC) mode, the standard circularly polarized (CP) mode, and volume-specific (VS) mode. 3D shimming mode included universal pulses (UP) mode and CP mode. The image quality for the subtentorial and supratentorial region was assessed by the subjective image quality score and signal-to-noise ratio. Comparisons of quantitative indices between multiple groups were performed using repeated-measures ANOVA or Friedman′s test; comparisons of quantitative indices between 2 groups were performed using paired-samples t test or Wilcoxon signed-rank test. Results:The image quality of subtentorial region and SNR was significant differences in 2D T 2WI with PS mode, DSC mode, CP mode and VS mode ( F=26.74, P<0.001; F=28.24, P<0.001), and the image quality score and SNR of PS mode, DSC mode, VS mode were better than CP mode ( P<0.05). In 2D T 2WI, there was no significant difference in image quality score and SNR of supratentorial region in PS mode, DSC mode, CP mode ( P>0.05). Besides, in 3D T 2WI, the image quality score for subtentorial and supratentorial region of UP mode were better than those of CP mode ( Z=-2.74, P=0.006; Z=-3.24, P=0.001); SNR of subtentorial region was significantly better in UP mode than those in CP mode ( t=3.49, P=0.004). But there was no significant difference in SNR of supratentorial region between the UP mode and CP mode in 3D T 2WI ( P>0.05). Conclusion:T 2WI with different shimming methods at 7.0 T MR can provide data support for the clinical application, which is helpful for the accurate diagnosis of patients with subtentorial lesions.

Objective:To investigate the relationship between the cerebral small vascular disease (CSVD) total burden and the imaging markers and the degree of unilateral middle cerebral artery (MCA) stenosis.Methods:The study was a cross-sectional study. Clinical and imaging data of patients with chronic unilateral MCA stenosis who underwent multimodal MRI from October 2015 to January 2019 in the First Medical Center of PLA General Hospital were retrospectively analyzed. A total of 261 patients were included, 187 males and 74 females. According to the degree of MCA stenosis, the patients were divided into 102 cases in severe stenosis-occlusion group (stenosis degree ≥70%) and 159 cases in mild-moderate stenosis group (stenosis degree <70%). CSVD imaging marker scores (including white matter hyperintensity, perivascular space, cerebral microbleed, and lacune of presumed vascular origin) were assessed according to the ?standards for reporting vascular changes on neuroimaging 1 in the 2 groups, and the CSVD total burden score was calculated. Mann-Whitney U test was used to compare the indicators between the two groups, and the CSVD total burden score and imaging marker scores were ultimately included in a multifactorial binary logistic regression to assess the association of CSVD imaging markers with severe stenosis-occlusion of the MCA after adjusting for vascular risk factors (age, gender, drinking, smoking, hypertension, hyperlipidemia, atrial fibrillation and coronary heart disease). Results:There were significant differences in the CSVD total burden, centrum semiovale perivascular space and lacune of presumed vascular origin score between the mild-to-moderate stenosis group and the severe stenosis-occlusion group (all P<0.05), and none of the differences in the remaining imaging marker scores were statistically significant (all P>0.05). Multivariate binary logistics regression analysis showed CSVD total burden score ( OR=1.300, 95% CI 1.047-1.613, P=0.017), centrum semiovale perivascular space score ( OR=2.099, 95% CI 1.540-2.860, P<0.001) and lacune of presumed vascular origin score ( OR=2.609, 95% CI 1.294-5.261, P=0.007) were independent associated with severe stenosis-occlusion of MCA. Conclusion:The higher CSVD total burden score, centrum semiovale perivascular space score and lacune of presumed vascular origin score are associated with severe stenosis-occlusion of MCA.

OBJECTIVE: To investigate the pre-treatment preventive maintenance and quality control procedure of MRI system and transcranial MRI-guided focused ultrasound (TcMRgFUS) treatment system by monitoring quality control of these two systems. METHODS: The general performance index and image quality control index of MRI system, as well as the quality assurance program of TcMRgFUS EXABLATE 4000 system were tested and recorded. RESULTS: The general performance index and image quality control index of MRI system met requirements. CONCLUSIONS Through system detection, the system performance could be monitored, ensuring the accuracy and safety of surgery.
Hyperthermia, Induced ; Magnetic Resonance Imaging ; Phantoms, Imaging ; Quality Control