Objective: To explore the neuromechanism of nicotine dependence, structural covariation networks (SCNs) based on voxel-based morphometry (VBM) were used to study the synergistic changes in gray matter volume in different cerebral cortices of nicotine dependent individuals. Methods: During the period from August 2016 to February 2018, a total of 118 long-term smokers and 57 non-smoking healthy controls (both 18-55 male volunteers) through online platforms and leaflets were recruited. The subjects were scanned with SIEMENS Skyro 3.0T magnetic resonance scanner and underwent routine MRI sequence (preliminary elimination of intracranial lesions) and 3D-T1 (3D-mprage) sequence structure. Two imaging experts used Matlab software platform to carry on segmentation by using SPM8, and to find out the differences between the two groups of brain regions, and differences in brain regions as region of interest (ROI) structure association network analysis. Results: The gray matter volume (GMV) of the right anterior central gyrus and the left inferior parietal lobe in the smoking group decreased(voxels size were 55 and 284, respectively), and no gray matter volume (GMV) area increased. The network structure of covariant analysis found that when the inferior parietal lobe as the seed points, the smoking group showed a rising trend in left parietal lobe and left temporal pole, bilateral middle temporal gyrus, left postcentral gyrus and right middle frontal gyrus gray matter volume, and a downtrend in the right side of the left medial frontal gyrus, superior parietal lobe, bilateral temporal gyrus, left cingulate gyrus and left cerebellum (central) compared with the control group. Conclusion: In long-term smokers, there is a volume change of gray matter in the brain structure. Abnormal changes in the structure covariant network of the inferior parietal lobe can lead to impaired brain function in nicotine dependent patients.目的： 应用基于体素形态学测量（VBM）的结构协变网络（SCNs）分析方法研究尼古丁依赖者不同脑区皮质之间灰质体积的协同改变。 方法： 本研究于2016年8月至2018年2月期间通过网络平台、宣传单等手段共招募118名长期吸烟者和57名不吸烟的健康对照（均为18~55岁男性志愿者）。采用西门子Skyro 3.0 T磁共振扫描仪进行常规MRI序列及3D-T1结构像（3D-mprage）序列扫描，并由两位影像学专家采用盲法在Matlab软件平台上的SPM8进行分割，并找出两组间的差异脑区，然后以差异脑区作为感兴趣区（ROI）进行结构协变网络分析。 结果： （1）吸烟组左侧顶下叶、右侧中央前回灰质体积（GMV）减少，体素大小分别为55和284，未发现灰质体积升高的区域。（2）结构协变网络分析发现：以左侧顶下叶为种子点，吸烟组相较于健康对照组表现出左侧顶下叶与左侧颞极中部、双侧颞下回、左侧中央后回及右侧额中回灰质体积相关趋势上升，而与左内侧额上回、右侧顶上叶、双侧颞下回、左侧扣带回（中部）及左侧小脑灰质体积相关趋势下降。 结论： 尼古丁依赖者存在大脑结构灰质体积的改变，且顶下叶相关的结构协变网络的异常可为尼古丁依赖者脑损伤机制的研究提供新的思路。.
Objective: To investigate the value of T2 map and synthetic T2WI generated by T2 mapping in evaluating the histological type, pathological classification and depth of myometrial invasion of endometrial carcinoma (EC). Methods: Seventy-three patients with pathologically proven EC diagnosed at the First Affiliated Hospital of Zhengzhou University from December 2019 to December 2021 and 42 healthy volunteers were enrolled in the study. All subjects underwent conventional MRI, diffusion weighted imaging (DWI) and T2 mapping sequence for the pelvic cavity to test the T2 values and the apparent diffusion coefficient (ADC) of the focus nidus of the patients and the normal endometrium of the volunteers. The T2 and ADC values of EC vs normal endometrium, and those of different histological types and pathological grades were compared. The receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic performance of T2 and ADC values in determining the pathological type and classification of EC. In addition, two radiologists used synthetic T2WI combined with T2 map and conventional T2WI combined with DWI, respectively, to evaluate the depth of myometrial invasion, and compared the imaging results with the results of pathological diagnosis to evaluate the diagnostic efficacy of the two methods in determining the depth of myometrial invasion. Results: The T2 and ADC values of endometrial carcinoma were 85.0 (80.8, 92.5) ms and 0.71 (0.64, 0.77) ×10(-3) mm(2)/s, respectively, which were significantly lower than those of normal endometrium [147.4 (123.4, 176.7) ms and 1.46 (1.26, 1.76)×10(-3) mm(2)/s, respectively; both P<0.05]. The T2 values of endometrioid carcinoma (EA) [84.1 (79.5, 88.7) ms] were significantly lower than those of non-EA [98.8 (92.1, 102.8) ms; P<0.05]. There was no significant difference in ADC values between EA and non-EA (P=0.075). The T2 values of G1, G2 and G3 groups in EA were 89.1 (84.4, 94.4) ms, 83.6 (80.9, 86.2) ms, and 76.5 (71.4, 80.3) ms, respectively. There were significant differences in the T2 values between G1 vs G2, G1 vs G3, and G2 vs G3 groups, respectively (all P<0.017). Significant difference was also found in the ADC values between the G1 and G3 groups (P<0.017). The area under the ROC curve (AUC) of T2 values in distinguishing EA from non-EA was 0.867. The AUC of T2 values, ADC values and their combination in predicting high-grade EA was 0.888, 0.730 and 0.895, respectively. The accuracy of synthetic T2WI+ T2 map and conventional T2WI+ DWI in the diagnosis of deep myometrial invasion was 78.1% and 79.5%, respectively, with no significant difference (P>0.05). Conclusions: T2 mapping has great potential in preoperative evaluation of EC. The quantitative T2 value can be used in the diagnosis, pathological classification and grading of EC. The combination of synthetic T2WI and T2 map may be helpful to determine the depth of myometrial invasion.目的： 探讨基于磁共振T2 mapping技术生成的合成T2WI和T2 map图像在鉴别子宫内膜癌组织类型、病理级别和肌层浸润深度中的应用价值。 方法： 对2019年12月至2021年12月在郑州大学第一附属医院经病理确诊为子宫内膜癌的患者73例、健康志愿者42例，分别行常规盆腔磁共振成像(MRI)、扩散加权成像(DWI)和T2 mapping序列检查，测定子宫内膜癌患者病灶和健康志愿者正常子宫内膜的T2值和表观扩散系数(ADC)。比较子宫内膜癌与正常子宫内膜、肿瘤不同组织类型、不同病理级别间T2值和ADC值的差异，采用受试者工作特征(receiver operating characteristic, ROC)曲线分析评估T2值和ADC值对子宫内膜癌病理类型和病理分级的诊断效能。由2名磁共振科医师分别应用合成T2WI与T2 map、常规T2WI与DWI融合图像评估肌层浸润深度，与病理诊断结果进行比较，评价其对肌层浸润深度的诊断效能。 结果： 子宫内膜癌的T2值和ADC值分别为85.0(80.8，92.5)ms和0.71(0.64，0.77)×10(－3) mm(2)/s，均低于正常子宫内膜[分别为147.4(123.4，176.7)ms和1.46(1.26，1.76)×10(－3) mm(2)/s，均P<0.001]。子宫内膜样癌的T2值[84.1(79.5，88.7)ms]低于非子宫内膜样癌[98.8(92.1，102.8)ms，P＝0.001]，但子宫内膜样癌与非子宫内膜样癌的ADC值差异无统计学意义(P＝0.075)。病理分级G1、G2和G3子宫内膜样癌的T2值分别为89.1(84.4，94.4)、83.6(80.9，86.2)和76.5(71.4，80.3)ms，G1与G2、G1与G3、G2与G3间差异均有统计学意义(均P<0.017)，但ADC值仅在G1与G3组间差异有统计学意义(P<0.017)。以T2值鉴别子宫内膜样癌与非子宫内膜样癌的ROC曲线下面积(AUC)为0.867；T2值、ADC值及T2值联合ADC值预测高级别(G3)子宫内膜样癌的AUC分别为0.888、0.730和0.895。合成T2WI与T2 map融合图像、常规T2WI与DWI融合图像诊断子宫内膜癌深肌层浸润的准确性分别为78.1%和79.5%，差异无统计学意义(P＝0.840)。 结论： T2 mapping技术在子宫内膜癌术前评估中具有较大应用价值，定量参数T2值可用于子宫内膜癌的诊断、病理分型与分级，合成T2WI联合T2 map有助于肌层浸润深度的判定。.
Objective: To investigate the alterations in effective connection of default mode network (DMN) in long-term male smokers and its correlation with clinical characteristics of smoking. Methods: A total of 131 subjects through WeChat platform and underwent resting-state functional magnetic resonance (rs-fMRI) examinations were recruited, including 76 long-term smokers [long-term smoking group, male, aged 20 to 55 (32.1±6.3) years] and 55 non-smokers [healthy controls, male, aged 20 to 55(32.3±7.4) years] from January 2014 to December 2018. Long-term smokers were defined as those who smoked at least 10 cigarettes per day for more than 2 years, and met the Diagnostic and Statistical Manual of Mental Disorders-Four Edition (DSM-Ⅳ) criteria for substance dependence. Four major nodes of DMN, including left inferior parietal lobule (LIPL), right inferior parietal lobule (RIPL), posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC) were chosen as for the region of interest. The effective connectivity (EC) alterations of DMN between smoking group and healthy controls were compared using dynamic causal modeling (DCM). The correlation between EC with significant difference among the two groups and Nicotine Dependence Scale (FTND) score, pack-year score and smoking duration were evaluated. Results: Compared to the healthy controls, the EC of LIPL to PCC and PCC to mPFC were decreased in the smoking group (EC = -0.091, -0.174, respectively, Bayesian-PP>0.95), and the EC of RIPL to PCC was increased (EC = 0.136, Bayesian-PP>0.95). Besides, EC of LIPL to PCC showed negative correlation with pack-year scores(r=-0.282,P=0.017). No significant linear correlations were observed between EC with significant group difference and FTND score or smoking duration (r=-0.103、-0.089,all P>0.05). Conclusion: Long-term smokers showed multiple abnormalities in IPL-PCC-mPFC circuits, and associated with the pack-year scores.目的： 探讨男性长期吸烟者默认网络有效连接的异常改变，及其与吸烟临床特征的相关性。 方法： 回顾性分析2014年1月至2018年12月通过微信等网络平台招募的131名受试者的静息态功能磁共振成像数据，其中长期吸烟者76名［长期吸烟组，男性，年龄20~55（32.1±6.3）岁］，对照者55名［对照组，男性，年龄22~55（32.3±7.4）岁］。长期吸烟者定义为每天吸烟不少于10支，烟龄2年以上且符合美国精神障碍诊断统计手册第4版（DSM-Ⅳ）关于物质依赖诊断标准的人群。选取默认网络中4个主要节点为感兴趣区，分别为左侧顶下小叶（LIPL），右侧顶下小叶（RIPL），后扣带回皮质（PCC），内侧前额叶皮质（mPFC）。基于动态因果模型分析吸烟组及对照组默认网络有效连接（EC）的改变。并分析有差异的EC与尼古丁依赖量表评分（FTND）、吸烟指数及烟龄的相关性。 结果： 与对照组相比，吸烟组LIPL至PCC、PCC至mPFC的EC减弱（EC分别为-0.091、-0.174，均贝叶斯后验概率>0.95），RIPL至PCC的EC增强（EC为0.136，贝叶斯后验概率>0.95）。此外，从LIPL到PCC的EC与吸烟指数呈负相关（r=-0.282，P=0.017）。差异有统计学意义的EC与FTND评分及烟龄在组间比较时未发现存在相关性（r=-0.103、-0.089，均P>0.05）。 结论： 长期吸烟者在IPL-PCC-mPFC神经回路中表现出异常的信息传递，并与吸烟指数相关。.
A superconducting magnet with a warm-bore size of 800 mm and a center magnetic field of 9.4 T for the whole-body magnetic resonance imaging (MRI) system was developed in IEECAS, China. To achieve a highly homogeneous magnetic field over the 400 mm diameter of spherical volume (DSV), both active shimming and passive shimming techniques were employed. This paper mainly focuses on the implementation of passive shimming for the 9.4 T MRI magnet system. After four iterations, we were able to achieve peak-to-peak and root mean square field homogeneities over the DSV at 3.05 and 0.94 ppm, respectively. In addition, this paper analyzes the electromagnetic forces and system errors of passive shimming for ultra-high fields, providing valuable insights into MRI magnet engineering.
Passive shimming is widely used in magnetic resonance imaging (MRI) systems due to its excellent efficacy and cost-effectiveness. However, conventional shim tray structures have difficulty in effectively adjusting magnetic field distributions under specific conditions. This limitation can lead to insufficient cancellation of harmonics and result in significant residual forces on the trays, impeding accurate placement of the trays. In this study, instead of using the conventional design of the shim tray slot, we propose a dedicated passive shimming tray tailored for 3T cryogen-free animal MRI superconducting magnets. Passive shimming experiments were conducted to evaluate the performance of this novel design, in which we were able to improve the peak-to-peak magnetic field homogeneity within the 180 mm diameter imaging region, reducing peak-to-peak (p–p) variation from 349.35 ppm to 19.08 ppm. Furthermore, the p–p homogeneity of the magnetic field measured at the imaging area with a diameter of spherical volume (DSV) of 160 mm reached 8.67 ppm. In addition, we strictly controlled the residual magnetic force of the shim tray to ensure its accurate placement. The experimental results indicate that the proposed structural optimization method and the residual magnetic force control strategy show potential in high-field MRI instruments requiring high homogeneity and handling of high residual magnetic force.
To investigate the abnormal changes of intrinsic neural time scale (INT) in male smoking addicts based on whole brain resting state functional magnetic resonance imaging (rs-fMRI).
This article focuses on the design and implementation of superconducting shim coils for the 9.4 T whole-body magnetic resonance imaging (MRI) superconducting magnet developed at the Institute of Electrical Engineering, Chinese Academy of Sciences. Through conducting a comparative analysis of the harmonic components of the magnetic field, we observed that the long solenoid structure of the ultrahigh field magnet often has a better homogeneity and smaller high-order harmonics compared with lower field split-design magnets. Thus, the third-order shim coils were able to be eliminated, leading to cost reduction and a simplified magnet structure. The implementation of this active shimming strategy resulted in significant improvements in field homogeneity in an efficient manner. Compared with the bare magnetic field over a 30 cm diameter spherical volume, the peak-to-peak and root-mean-square homogeneity of the shimmed field was 15.82 ppm and 4.11 ppm, which achieved 78.9% and 83.2% improvement, respectively. These enhancements will effectively facilitate subsequent passive shimming procedures. The research findings presented in this work provide valuable insights into the practical implementation of shimming methods for the ultrahigh field whole-body MRI superconducting magnet.
Objective: To investigate the diagnostic value of diffusion-weighted imaging (DWI) and apparent diffusion coefficient(ADC) values in the differentiation of sellar malignant germ cell tumors and raniopharyngioma. Methods: This retrospective study included 36 patients(14 cases of malignant germ cell tumor and 22 patients with raniopharyngioma) with histopathologically-confirmed sellar tumors from January 2013 to April 2017 in the First Affiliated Hospital of Zhengzhou University.All patients underwent conventional MRI and DWI before the treatment. ADC maps were reconstructed, and ADC values of the sellar lesions were calculated and compared between the groups. Diagnostic value of ADC was evaluated by receiver operating characteristic(ROC) curves. Results: The mean ADC values of malignant germ cell tumors were significantly lower than that in raniopharyngioma[(0.93±0.23)×10(-3) mm(2)/s vs (1.69±0.21)×10(-3) mm(2)/s, t=-10.19, P<0.01]. The area under the ROC curves of ADC values diagnosing malignant germ cell tumors and raniopharyngioma was 0.987. The optimal cutoff values of ADC for differential diagnosis of malignant germ cell tumors and raniopharyngioma was 1.52×10(-3) mm(2)/s, the sensitivity, specificity and accuracy was 81.2%, 100%, 88.9%, respectively. ADC value had a high consistency with pathological results (Kappa value was 0.887). Conclusion: Malignant germ cell tumors and raniopharyngioma have different ADC value, which can improve the diagnostic accuracy.目的： 探讨扩散加权成像(DWI)和表观扩散系数(ADC)在诊断及鉴别诊断鞍区恶性生殖细胞肿瘤与颅咽管瘤的价值。 方法： 回顾性分析郑州大学第一附属医院2013年1月至2017年4月经病理证实的治疗前行常规MRI平扫和DWI检查的36例鞍区病变患者的临床资料，其中恶性生殖细胞肿瘤14例，颅咽管瘤22例，测量比较两种病变的ADC均值。运用受试者工作特征(ROC)曲线评价ADC值的诊断价值。 结果： 恶性生殖细胞肿瘤平均ADC值为(0.93±0.23)×10(－3) mm(2)/s，颅咽管瘤平均ADC值为(1.69±0.21)×10(－3) mm(2)/s，前者明显低于后者(t＝－10.19，P<0.01)。ADC值诊断鞍区恶性生殖细胞肿瘤与颅咽管瘤的ROC曲线下面积为0.987，以ADC值1.52×10(－3) mm(2)/s为阈值时，与病理结果对照，判断恶性生殖细胞肿瘤与颅咽管瘤的敏感度为81.8%，特异度为100%，准确度为88.9%，与病理结果行一致性检验，Kappa值为0.887。 结论： 鞍区恶性生殖细胞肿瘤与颅咽管瘤具有不同扩散特征，ADC值对于两者之间的鉴别诊断具有重要参考价值，可提高诊断准确率。.
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