Objective:To investigate the effect of radiotherapy on sacral nerve morphology in patients with rectal cancer using the three-dimensional T2-weighted fast field echo (3D-T2WI-FFE) sequence combined with curved planar reformation, and to explore its clinical significance.Methods:From November 2019 to May 2022, 19 patients with rectal cancer were enrolled at the Department of Gastrointestinal Surgery of Peking University Shougang Hospital. The average number of radiotherapy sessions was 23.26±4.27, and the radiation dose was 16~54 Gy. At the same time, 26 healthy volunteers were collected. Pelvic scans were performed with a Philips Ingenia 1.5TX magnetic resonance machine, including T1WI axial scan and T2W-3D-FFE coronal scan. The original data obtained from the two sets of scans were used in the workstation to reconstruct the sacral nerve using curved planar reformation (CPR), and the score was graded according to the imaging quality of the sacral nerve. The scores of sacral nerve rating, sacral nerve signal intensity, piriform muscle signal intensity, and the contrast noise ratio (CNR) of the two groups were compared by the t-test.Results:After the original data of 3D-T2-FFE sequence were reconstructed by curved planar reformation, the sacral nerve exhibited a high signal strip structure, the surrounding musculoskeletal tissues had a low signal, and the sacral nerve and surrounding tissues were clearly contrasted. There were statistical differences between the two groups in the scores of the first, second, and third sacral nerves. There was no significant difference in nerve signal intensity between the two groups (χ2=1.978, P=0.051). There was a statistical difference in the signal intensity of the piriformis muscle between the two groups (χ2=6.77, P＜0.05). The CNR of the sacral nerve and adjacent piriformis muscle also differed significantly between the two groups (χ2=-3.78, P＜0.05).Conclusion:3D-T2-FFE sequence combined with curved planar reformation technology can directly and accurately display the sacral nerve, and can display the changes of sacral nerve morphology after radiotherapy, which provides a basis for further clinical planning and evaluation of therapeutic effects.

Objective To explore the comparative study of artificial reconstruction and artificial intelligence（AI） in coronary volume rendering（VR）. Methods The images of 102 patients [56 males and 46 females, with an average age of（60.28±10.37） years] who underwent coronary CT examination in our hospital from April 17 to April 22, 2021 were scanned by Toshiba 320 row Aquilion ONE CT machine for VR imaging artificial reconstruction（group A） and artificial intelligence reconstruction（group B）, respectively. The total score, analysis group score and non-analysis group score of the two groups were compared. Results 102 patients, including 56 males and 46 females, aged 37 to 84 years old, the average age was（60.28±10.37）, were compared with the scores of the two groups of artificial reconstruction and artificial intelligence reconstruction. The total score of the artificial group was（52.22±7.79）%, of which the score of the analysis group was（69.84±9.26）%, and the score of the non-analysis group was（19.41±14.57）%. The total score of the AI group was（88.42±5.98）%, including（92.16±5.79）% in the analysis group and（79.81±14.21）% in the non-analysis group. The results showed that the number and length of vessels in the AI group, including those in the analysis group and those in the non-analysis group, were better than those in the artificial reconstruction group. Conclusion The number and quality of branches detected by AI is higher than that of artificial reconstruction, and the operation time is shorter, which improves the work efficiency of the operation technician.

RATIONALE:Desmoid-type fibromatosis is a rare benign mesenchymal neoplasm. Only 8% of desmoid-type fibromatosis develops in the abdominal cavity. The mesentery is seldom affected and gastrointestinal stromal tumors need to be considered in the differential diagnosis, particularly when imaging examination shows a tumor containing gases in the abdominal cavity. Only a few cases of gas-containing mesenteric desmoid-type fibromatosis have been reported in the literature.PATIENT CONCERNS:A 69-year-old male patient presented with hematochezia and intermittent upper abdominal pain.DIAGNOSIS:Contrast-enhanced computed tomography revealed a 3.9 × 3.6 cm gas-containing mass infiltrating the third portion of the duodenum. The tumor was heterogeneous, with cysts and air bubbles. It showed heterogeneous weak-to-mild enhancement in the solid part. Postoperative pathological examination confirmed a final diagnosis of mesenteric desmoid-type fibromatosis.INTERVENTIONS:The patient underwent surgical resection of intra-abdominal lesion.OUTCOMES:No evidence of local recurrence was noted during the 6 months of follow-up.LESSONS:Accurate preoperative diagnosis is difficult for an intra-abdominal gas-containing mass on computed tomography scan. The appearance of spiculated infiltrative margin suggests the diagnosis of desmoid-type fibromatosis. Further investigation of imaging evidence and treatment methods is necessary.

目的 探讨选择性水激励脂肪抑制(PROSET)序列与三维T2加权快速梯度回波(3D-T2-FFE)序列在观察坐骨神经穿梨状肌变异中的差异及应用价值.方法 使用Philips Ingenia 1.5TXD磁共振仪对26例健康志愿者行盆腔扫描,包括T1WI轴位、PROSET序列及3D-T2-FFE序列冠状位扫描.将后两者扫描数据在工作站中应用曲面重组(CPR)技术对坐骨神经重建,并观察其与梨状肌的关系.由两名医师对两种序列的后处理图像独立阅片,参照潘铭紫对国人坐骨神经与梨状肌关系的分型,按坐骨神经与梨状肌关系显示满意、不满意进行主观评价,对两种序列显示满意的例数采用卡方检验.结果 26例志愿者均可在PROSET序列及3D-T2-FFE序列中完成双侧坐骨神经重建,共计坐骨神经52支.坐骨神经在PROSET序列中呈稍低信号,在3D-T2-FFE序列中呈高信号.两种序列均能发现坐骨神经穿梨状肌变异,共17支(32.7％),Ⅱ型变异16支(94.1％),Ⅳ型变异1支(5.9％).坐骨神经走行正常时,PROSET序列与3D-T2-FFE序列对神经与梨状肌关系显示满意,两者无明显差异(x2=2.120,P=0.145＞0.005);坐骨神经穿梨状肌变异时,两者存在差异(x2=10.462,P=0.001＜0.005),3D-T2-FFE 序列图像显示梨状肌内神经的满意例数高于PROSET序列图像.在两种序列中神经的信噪比无明显差异(t=1.851,P=0.069,P＞0.05).在神经上段,神经与骶骨的对比噪声比无明显差异(t=0.100,P=0.921,P＞0.05).在神经梨状肌段,神经与梨状肌的对比噪声比有明显差异(t=5.529,P=0.000,P＜0.05),3D-T2-FFE序列的CNR神经上段高于PROSET序列.结论 PROSET序列及3D-T2-FFE序列都有较高的软组织对比度,可以很好的显示坐骨神经走行.但坐骨神经穿梨状肌变异时,3D-T2-FFE序列图像显示梨状肌内神经的满意例数要高于PROSET序列图像.在观察坐骨神经与梨状肌关系时,宜采用3D-T2-FFE序列.

目的 应用磁共振扩散张量成像(DTI)定量分析健康成人胫神经及腓总神经各向异性分数(FA),为临床研究胫神经及腓总神经病变提供基线数据.方法 对63名健康成人行膝关节DTI,测量髌骨上缘水平胫神经及腓总神经的FA,并进行统计学分析.结果 健康成人髌骨上缘水平测量胫神经及腓总神经FA值分别为0.562±0.119,0.577±0.123.两神经FA值在不同年龄组、正常体重组与超重及肥胖组差异具有统计学意义(P均＜0.05).胫神经、腓总神经FA值与年龄、体重及体质指数(BMI)存在负相关性(P均＜0.05),与身高无明显相关性(P＞0.05).结论 3.0 TMR DTI可测量髌骨上缘水平胫神经、腓总神经FA值,年龄及BMI与胫及腓总神经FA值具有相关性.

Objective:To investigate the functional imaging parameters that effectively distinguish isocitrate dehydrogenase (IDH) gene mutation status in clinical practice with long echo time (TE) point-resolved spectroscopy (PRESS) MRS.Methods:Totally 25 patients with suspected diagnosis of low grade gliomas(LGGs; Grade II) were recruited prospectively and divided into IDH mutation group and IDH wild group according to pathological results in the study. All patients were scanned with long TE PRESS MRS. In addition, IDH mutational status was determined by post-operation Sanger sequencing. The t test or Mann-Whitney U test was used to analyze the differences of 2-hydroxyglutarate (2HG), Glutamate (Glu), Glutamine (Gln) and 2HG/Glu+Gln between the IDH mutation group and the IDH wild group, then ROC curve was plotted with statistically significant indexes to obtain the efficacy of predicting IDH mutation status. Results:Of the 25 patients, 19 had IDH mutant gliomas and 6 had IDH wild-type gliomas. 2HG, Glu, Gln and 2HG/Glu+Gln in IDH mutated group were 1.42 (1.09, 1.93)mmol/L, (1.74±1.31)mmol/L, (1.68±0.66)mmol/L, 0.55 (0.28, 0.77), respectively; while the corresponding values were 0.00 (0.00, 1.30)mmol/L, (3.28±1.02)mmol/L, (2.55±1.47)mmol/L, 0.00 (0.00, 0.26) in IDH gene wild type group, respectively. The differences of 2HG, Glu, and 2HG/Glu+Gln between the two groups were statistically significant ( P values were 0.030, 0.016, 0.004, respectively). The area under the ROC curve of 2HG/Glu+Gln was the largest (0.877), and the sensitivity was the highest (84.2%). Conclusion:The integration of 2HG with Glu and Gln can effectively realize the noninvasive assessment of IDH mutation status.

目的 探讨体素内不相干运动模型(intravoxel incoherent motion,IVIM)参数在预测胶质瘤术前分级中的价值,及其与Ki-67标记指数表达的相关性.材料与方法 回顾性分析63例经组织病理学证实为胶质瘤患者,男43例,女20例,年龄16～74(47±13)岁,分为低级别组(WHOⅡ级30例)和高级别(WHOⅢ级、Ⅳ级33例),经免疫组化获得胶质瘤的Ki-67标记指数.患者术前均行颅脑MRI常规扫描、IVIM-DWI检查,分别测量肿瘤最大层面实性区域和对侧正常白质区域的IVIM参数,获得ADC、假扩散系数(pseudo-diffusion coefficient,D*)、纯水扩散系数(pure water diffusion coefficient,D)、灌注分数(perfusion fraction,f)值,将肿瘤实质区测量值除以对侧正常脑实质测量数值,获得校正后参数,包括相对表观扩散系数(relative ADC,rADC)、相对假扩散系数(relative D*,rD*)、相对纯水扩散系数(relative D,rD)以及相对灌注分数(relative f,rf).利用秩和检验(Mann-Whitney U检验)比较高、低级别组间4个定量参数、Ki-67标记指数的差异.利用Spearman法分析4组定量参数与Ki-67标记指数之间的相关性.应用ROC曲线评估4组定量参数在脑胶质瘤分级中的诊断效能.结果 低级别胶质瘤组rADC值、rD值及rf值均高于高级别胶质瘤组(P值均<0.05),两组间rD*值无统计学差异(P=0.139),高级别胶质瘤组平均Ki-67标记指数明显高于低级别胶质瘤组,两组间差异有统计学意义(P<0.01).rADC、rD、rf值的ROC曲线下面积分别为0.912、0.911、0.714;阈值分别为1.280、1.295、1.171;敏感度分别为93.3％、90.0％、86.7％;特异度分别为75.8％、78.8％、48.5％.rADC、rD与Ki-67标记指数存在较强的负相关性,rD*与Ki-67标记指数存在低度相关性,rf与Ki-67标记指数不具有明显相关性.结论 IVIM可以无创地评估胶质瘤级别,其中rADC的诊断效能最高.Ki-67标记指数在高、低级别胶质瘤间存在显著差异,且与rADC、rD存在较强负相关,可以为临床诊断、治疗及预后判断提供帮助.

Objective: To analyze the relationship between tumors of the musculoskeletal system and adjacent nerves by reconstructing images of peripheral nerves, and explore its value in surgical treatment. Methods: From May 2016 to April 2019, a total of 27 patients were collected in Department of Imaging,Shougang Hospital, who were with skeletal muscle system tumors, including 15 primary soft tissue tumors, 9 primary bone tumors, 3 metastatic tumors, all of them were closely related to nerves. There were 17 males and 10 females, aged 13-67 years, with an average age of 34 years. Before the operation, CT volume scanning was performed, and curved planar reconstruction (CPR) was used to reconstruct the peripheral nerves. All patients were operated within 2 weeks after the examination. According to the image characteristics before the operation, the nerve invasion was judged. The sensitivity, characteristic, positive predictive value and negative predictive value of the tumor invasion (compression) nerve were calculated according to the intraoperative findings as the gold standard. Result: Of the 27 cases, 25 cases (25/27, 92.6%) could show the relationship between the tumors and the adjacent nerves at the same level, and 22 cases (22/25, 88.0%) had the same preoperative image judgments as the intraoperative findings. In the reconstructed images, the peripheral nerve was a continuous strip-like structure on the same level with the tumor. The invaded nerve became thicker and the edge was blurred. Enhanced scan showed enhancement. The sensitivity, specificity, positive predictive value and negative predictive value of neuroimaging reconstruction were 100.0%, 89.5%, 75.0% and 100.0% respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the nerve compression were 92.3%, 100.0%, 100.0% and 80.0% respectively. Conclusions: Neurological reconstructed images can help clinicians evaluate the relationship between lesions and adjacent nerves quickly and intuitively. They can guide the selection of surgical methods, reduce the risk of intraoperative nerve injury, and have high sensitivity and specificity for nerves invasion.

目的 探讨CT周围神经重建技术在显示坐骨神经穿梨状肌变异中的应用价值及其临床意义.方法 顺序选取2018年12月至2019年5月间无明确坐骨神经痛的、并在北京大学首钢医院医学影像科行盆腔CT检查的住院患者50例;男17例,女33例;平均年龄61.8(36～82)岁.对扫描所得的原始CT图像,分别进行常规盆腔重建和双侧坐骨神经重建,按照潘铭紫对国人坐骨神经与梨状肌的关系分型,判断有无坐骨神经穿梨状肌变异,并比较两种重建方法有无差异.结果 本组50例患者共计左右两侧梨状肌及坐骨神经100侧,均可完成常规重建及神经重建.常规图像通过梨状肌形态(肌肉间是否出现低密度条片影)判断有无坐骨神经变异,共发现坐骨神经变异27例(27％),其中能确定为Ⅱ型变异的10侧;神经重建图像通过显示坐骨神经形态(坐骨神经是否出现分离)判断,共发现坐骨神经变异32侧(32％),其中能确定为Ⅱ型变异的28侧,能确定为Ⅵ型变异的1侧.常规组与重建组显示异常变异数差异无统计学意义(χ2=0.601,P=0.438),但是在判断变异类型数方面,重建组明显高于常规组(χ2=18.767,P<0.001).结论 虽然CT周围神经重建技术和常规重建技术均可发现坐骨神经变异,但CT周围神经重建图像更易判断变异类型,并且在同一层面直接显示坐骨神经自身形态,可以直观、准确地反映坐骨神经有无变异及神经与周围组织关系,为进一步研究坐骨神经痛提供一种新的影像学方法.

BACKGROUND:Primary intracranial myxomas (PIMs) are extremely rare benign tumors that arise from the skull base. The aim of this study was to characterize the radiologic manifestation of PIMs in a series of 14 cases.METHODS:We reviewed the imaging and clinical data of 14 patients with pathologically proven PIMs. Assessed features of lesions include shape, margin, bony destruction, attenuation and/or signal intensity, and pattern of enhancement.RESULTS:Extremely high-density foci indicating calcification or bony debris within the tumors were observed in 5 cases on computed tomography images. On magnetic resonance images, the tumors demonstrated heterogeneous hypointensity on T1-weighted images (T1WI) and hyperintensity on T2-weighted images (T2WI). A honeycomb pattern on enhanced T1WIs was observed in 63.6% (7/11) of the cases.CONCLUSIONS:Radiologic findings of PIMs include calcified foci or bone debris on computed tomography, heterogeneous hypointensity on T1WI and predominantly hyperintensity on T2WI, and honeycomb appearance on enhanced T1WI.

Objective To estimate the application value of head-neck CT angiography (CTA) and whole brain CT perfusion (CTP) in patients with chronic cerebral ischemia by the correlation comparison study of head-neck CTA and brain CTP. Methods A total of 150 patients' CTA and CTP were analyzed for their correlations with the distribution of perfusion region, responsible blood vessels and perfusion abnormalities. Results The responsible vessels of 98.72% perfusion abnormal region were moderate vascular stenosis. With the aggravation of the degree of the stenosis of the responsible vessels, the proportion of abnormal region of perfusion was significantly increased. The degree of responsible vascular stenosis was moderately positively correlated with the staging of CTP in the pre-infarction stage. Conclusions Combined with the results of head-neck CTA and whole brain CTP, the degree of chronic ischemia in patients with chronic cerebral ischemia can be comprehensively evaluated, which is more conductive to the selection of clinical treatment.

ObjectiveTo explore the effect of Orthopedic Metal Artifact Reduction (O-MAR) technique in reducing dental metallic artifacts in head and neck CT examination.Methods65 patients with dental titanium prosthesis were conducted head and neck CT angiography scan. The patients were selected from Jan. to Dec. in 2014 of our hospital. The images were reconstructed by two different algorithms of O-MAR technique (group A) and traditional technique (group B). The regions of interest were placed in bilateral masseter muscles. Two groups’ standard deviation of the regions of interest was measured with paired t-test and image quality was subjectively scored. The image quality scores and demonstration of the oral cavity were conducted between two doctors, and analyzed with rank sum test andχ2test.Results The results of two doctors’ image quality scores are: ipsilateral masseter (z=-6.06,P<0.05); contralateral masseter (z=-4.79,P<0.05), the difference is statistically significant. Image quality score in group A is higher than that of group B (χ2=34.03,P<0.05), the difference is statistically significant; The standard deviation results are ipsilateral masseter (t=-9.34,P<0.05) and contralateral masseter (t=-4.06,P<0.05), the difference is statistically significant. There is no significant difference of bilateral masseter standard deviation in group A (t=1.48,P>0.05), while the difference of bilateral masseter standard deviation in group B (t=5.38,P<0.05) is statistically significant.Conclusion O-MAR technique is superior in decreasing the effect of high atomic number artifacts on image quality, and provides valuable information for clinical diagnosis.

Objective To investigate the differences in the resting state network between patients with cognitive impairment related leukoaraiosis and normal control. Methods A total of 40 patients with leukoaraiosis related cognitive impairment diagnosed by iconographic and clinical diagnosis and 30 normal controls were included in this study. The resting-state functional magnetic resonance imaging was scanned. All subjects of the two groups were matched in age, gender and level of education. The independent component analysis was used to deal with the data, and the two-samplet-test was used to compare the differences between the two groups. Results Compared with the normal control group, leukoaraiosis patients with cognitive impairment showed significantly decreased activation at bilateral precuneus, left inferior temporal gyrus, left fusiform gyrus and right anterior cingulate; increased activation at left paracentral lobule and right cuneus; signiifcantly increased activation at left superior temporal gyrus; and signiifcantly decreased activation at bilateral cuneus, middle occipital gyrus and left lingual gyrus. Conclusion There were many differences in resting-state functional brain network between patients with cognitive impairment related leukoaraiosis and normal control.

目的探讨老年人脑白质病变（WMLs）相关性跌倒患者的脑静息态fMRI（rs-fMRI）特征。方法前瞻性选取本院60岁以上的WMLs患者40例,均接受rs-fMRI检查,根据Tinetti平衡和步态量表划分为跌倒风险组（Tinetti＜25,n=11）及对照组（Tinetti≥25,n=29）。应用SPM 8软件进行图像处理,识别跌倒风险患者脑网络内及网络间的功能连接异常,并与简易精神状态检查量表（MMSE）、蒙特利尔认知评估量表（MoCA）评分进行相关性分析。结果跌倒风险组的MMSE（t=4.04,P＜0.01）及MoCA（t=3.88,P＜0.01）量表评分低于对照组。与对照组比较,跌倒风险组的记忆网络（MeN）脑功能连接减弱（t=2.87,P=0.01）;带状盖任务控制网络（CON）和腹侧注意网络（VAN）的功能连接减弱（t=2.59,P=0.01）;默认网络（DMN）和额顶任务控制网络（FPN）的功能连接增强（t=-2.13,P=0.04）,所有WMLs患者的MeN网络内功能连接与MoCA评分（r=0.39,P=0.01）呈正相关;DMN和FPN功能连接与MMSE（r=-0.40,P=0.01）及MoCA（r=-0.37,P=0.02）呈负相关。结论具有跌倒风险的WMLs患者存在脑网络内及网络间的功能连接异常,并与其认知功能改变存在一定的相关性。

Objective: To analyze the diffusion tensor imaging (DTI) and clinical characteristic of the aged who had white matter lesions with fall risks, quantify the fall risk index and provide a basis for fall precautions. Materials and Methods: People aged more than 60 years old with brain white matter lesions from Beijing Tiantan Hospital, Capital Medical University, were included in study, according to the Tinetti Balance and Gait Analysis, 15 patients were divided into experimental group (Tinetti<25) and 29 contrast group (Tinetti≥25). The significantly different white matter fiber tracts were identified by Tract Based Spatial Statistics (TBSS) and were also made correlation analysis with MoCA, MMSE, Tinetti Gait Analysis, Tinetti Balance Analysis and TUGT. Results: There was statistic significance in the score of MMSE (t=2.806, P=0.008) and MoCA (t=2.890, P=0.006) between two groups with white matter lesions. In subjects with risk of falls, the mean FA of whole brain was lower than that of contrast group (t=2.862, P=0.007), and was positively correlated with MMSE (r=0.533, P=0.041) and MoCA (r=0.642, P=0.010). Significantly abnormal FA clusters (representing loss of WM integrity) of patients with risk of falls were seen in the right fasciculus uncinatus, genu, body and splenium of corpus callosum, both anterior corona radiate, right superior corona radiate, right superior longitudinal fasciculus and left cingulate gyrus. The mean FA of corpus callosum-genu, right superior corona radiate, body of corpus callosum, splenium of corpus callosum, right superior longitudinal fasciculus and left cingulate gyrus were positively correlated with MoCA scores in those with risk of falls(P<0.05). The mean FA of right fasciculus uncinatus (r=0.562, P=0.029) was positively correlated with Tinetti Balance Analysis. The mean FA of right fasciculus uncinatus (r=0.572, P=0.026), body of corpus callosum (r=0.538, P=0.038), splenium of corpus callosum (r=0.580, P=0.023) and left cingulate gyrus (r=0.520, P=0.047) were positively correlated with Tinetti Gait Analysis. The mean FA of body of corpus callosum (r=–0.582, P=0.023) and left cingulate gyrus (r=–0.538, P=0.039) were negatively correlated with TUGT. Conclusion: In subjects with risk of falls, the mean FA of whole brain and some white matter fiber tracts decreased, these differences were correlated with cognition, balance and gait. Therefore, DTI can identify the structural changes in brain of those with risk of falls and quantify the fall risk index.

目的 分析毛细胞黏液样星形细胞瘤(PMA)的临床及影像学特征.方法 回顾性分析35例经手术、病理及免疫组化证实的PMA患者的临床特点及影像学表现.结果 PMA主要位于下丘脑-视交叉-3脑室区域(23/35,65.71％),其次为大脑半球(6/35,17.14％).CT扫描多为稍低密度(23/28,82.14％)和等密度(2/28,7.14％),因出血呈高密度3例(3/28,10.71％);合并少许点状、线状钙化9例.MR扫描边界清晰30例(30/31,96.78％);无瘤周水肿28例(28/31,90.32％),轻度水肿3例(3/31,9.68％).T1WI实性部分为不均匀稍低信号28例(28/31,90.32％).T2WI为高信号伴絮片状稍高信号26例(26/31,83.87％),均匀高信号1例(1/31,3.23％),不均匀等信号2例(2/31,6.45％),因出血为低信号2例(2/31,6.45％);瘤体内见点、线状等信号27例(27/31,87.09％).增强扫描,实性部分明显强化27例(27/30,90.00％),轻度点线状强化1例(1/30,3.33％),无强化2例(2/30,6.67％);实性部分包含无强化区28例(28/30,93.33％),柔脑膜强化5例(5/30,16.67％).结论 PMA影像学表现具有一定特征性,结合临床及CT、MRI特征,可提高术前诊断的准确性.