磁敏感加权成像黑质“燕尾征”在帕金森病中的诊断价值

目的:探讨3.0 T磁敏感加权成像(susceptibility weighted imaging,SWI)中"燕尾征"缺失在帕金森病(Parkinson's dis-ease,PD)的诊断价值并分析黑质小体-1 (nigrosome-1)可视化与PD患者临床资料的相关性.方法:收集2017年9月至2019年11月于重庆医科大学附属第一医院神经内科住院的50例PD患者及年龄、性别与之匹配的57例非PD患者.所有受试者均接受3.0 T头颅SWI检查.在获得的SWI图像上,由2名临床医师采用盲法独立对双侧"燕尾征"进行评估.一侧"燕尾征"缺失即判定为PD.计算"燕尾征"缺失诊断PD的灵敏度、特异度、预测值和准确度,并分析nigrosome-1可视化与PD患者临床资料的相关性.结果:以临床诊断作为金标准,45例PD患者判断正确,评估者之间的一致性很高(k=0.963,P=0.000)."燕尾征"缺失诊断PD的灵敏度为90.0％,特异度为91.2％,阳性预测值为90.0％,阴性预测值为91.2％,准确度为90.7％.44例PD患者临床症状不对称,其中32例患者nigrosome-1可视化不对称.PD患者nigrosome-1可视化偏侧和临床症状偏侧比较差异无统计学意义(x2=5.756,P=0.056).11例PD患者双侧nigrosome-1全部缺失,纳入全部缺失组,其余PD患者为非全部缺失组.全部缺失组和非全部缺失组患者的汉密尔顿抑郁量表评分差异有统计学意义(U=126.500,P=-0.038),而病程、帕金森病统一评定量表第Ⅲ部分、改良Hoehn-Yahr(H-Y)分级、简易智能状态量表和蒙特利尔认知评估量表评分差异均无统计学意义(P=0.768、0.140、0.839、0.054、0.067).结论:"燕尾征"缺失诊断PD的准确率较高,缺失程度可能与PD患者的抑郁程度有关,对PD的诊断有一定参考价值.     

肝移植术后认知与脑改变的多模态神经成像

肝性脑病是终末期肝硬化的重要并发症,导致病人出现一系列神经及认知功能改变。肝移植术后病人在肝功能恢复的同时其认知功能也可明显改善。MRI可以从脑代谢、结构及功能方面更进一步揭示肝硬化病人移植术后认知及脑改变情况。综述肝移植术后认知改变的研究现状以及最新的多模态MRI技术在术后脑改变中的应用,及其在揭示术后认知恢复及残存损害的神经机制中的价值。     

The capability of detecting small vessels beyond the conventional MRI sensitivity using iron‐based contrast agent enhanced susceptibility weighted imaging

Imaging brain microvasculature is important in cerebrovascular diseases. However, there is still a lack of non‐invasive, non‐radiation, and whole‐body imaging techniques to investigate them. The aim of this study is to develop an ultra‐small superparamagnetic iron oxide (USPIO) enhanced susceptibility weighted imaging (SWI) method for imaging micro‐vasculature in both animal (~10 μm in rat) and human brain. We hypothesized that the USPIO‐SWI technique could improve the detection sensitivity of the diameter of small subpixel vessels 10‐fold compared with conventional MRI methods. Computer simulations were first performed with a double‐cylinder digital model to investigate the theoretical basis for this hypothesis. The theoretical results were verified using in vitro phantom studies and in vivo rat MRI studies (n = 6) with corresponding ex vivo histological examinations. Additionally, in vivo human studies (n = 3) were carried out to demonstrate the translational power of the USPIO‐SWI method. By directly comparing the small vessel diameters of an in vivo rat using USPIO‐SWI with the small vessel diameters of the corresponding histological slide using laser scanning confocal microscopy, 13.3‐fold and 19.9‐fold increases in SWI apparent diameter were obtained with 5.6 mg Fe/kg and 16.8 mg Fe/kg ferumoxytol, respectively. The USPIO‐SWI method exhibited its excellent ability to detect small vessels down to about 10 μm diameter in rat brain. The in vivo human study unveiled hidden arterioles and venules and demonstrated its potential in clinical practice. Theoretical modeling simulations and in vitro phantom studies also confirmed a more than 10‐fold increase in the USPIO‐SWI apparent diameter compared with the actual small vessel diameter size. It is feasible to use SWI blooming effects induced by USPIO to detect small vessels (down to 10 μm in diameter for rat brain), well beyond the spatial resolution limit of conventional MRI methods. The USPIO‐SWI method demonstrates higher potential in cerebrovascular disease investigations.     

Circumferential Resection Margin as a Hospital Quality Assessment Tool for Rectal Cancer Surgery

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In vivo characterization of emerging white matter microstructure in the fetal brain in the third trimester

The third trimester of pregnancy is a period of rapid development of fiber bundles in the fetal white matter. Using a recently developed motion‐tracked slice‐to‐volume registration (MT‐SVR) method, we aimed to quantify tract‐specific developmental changes in apparent diffusion coefficient (ADC), fractional anisotropy (FA), and volume in third trimester healthy fetuses. To this end, we reconstructed diffusion tensor images from motion corrected fetal diffusion magnetic resonance imaging data. With an approved protocol, fetal MRI exams were performed on healthy pregnant women at 3 Tesla and included multiple (2–8) diffusion scans of the fetal head (1–2 b = 0 s/mm² images and 12 diffusion‐sensitized images at b = 500 s/mm²). Diffusion data from 32 fetuses (13 females) with median gestational age (GA) of 33 weeks 4 days were processed with MT‐SVR and deterministic tractography seeded by regions of interest corresponding to 12 major fiber tracts. Multivariable regression analysis was used to evaluate the association of GA with volume, FA, and ADC for each tract. For all tracts, the volume and FA increased, and the ADC decreased with GA. Associations reached statistical significance for: FA and ADC of the forceps major; volume and ADC for the forceps minor; FA, ADC, and volume for the cingulum; ADC, FA, and volume for the uncinate fasciculi; ADC of the inferior fronto‐occipital fasciculi, ADC of the inferior longitudinal fasciculi; and FA and ADC for the corticospinal tracts. These quantitative results demonstrate the complex pattern and rates of tract‐specific, GA‐related microstructural changes of the developing white matter in human fetal brain.     

Sham-Controlled Randomized Trials of Catheter-Based Renal Denervation in Patients With Hypertension

Background

There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.

Correlation between magnetic resonance imaging characteristics and BRAF alteration status in individuals with optic pathway/hypothalamic pilocytic astrocytomas

Background and purposeMost individuals with optic pathway/hypothalamic pilocytic astrocytoma (OPHPA) harbor either the BRAF V600E mutation or KIAA1549-BRAF fusion (K-B). This study aimed to investigate the imaging characteristics of OPHPA in relation to BRAF alteration status.Materials and methodsSeven cases of OPHPA harboring either the BRAF V600E mutation or K-B fusion were included in the study. Preoperative magnetic resonance imaging (MRI) was assessed for degree of T2 hyperintensity on T2-weighted images (T2WI) and the ratio of nonenhancing T2 or fluid-attenuated inversion recovery (FLAIR) hyperintense area to the contrast enhanced area (CE) on gadolinium-enhanced-T1 weighted images (T2/FLAIR-CE mismatch). The T2 signal intensity was normalized to cerebrospinal fluid (T2/CSF) for both the V600E and K-B group and compared. T2/FLAIR-CE mismatch was assessed by calculating the proportion of the tumor volume of nonenhancing high T2 signal intensity to the whole lesion (nonenhancing and enhancing components).ResultsFour and three cases of OPHPA harboring the BRAF V600E mutation and K-B, respectively, were analyzed. The T2/CSF value was higher in the K-B group than in the V600E group. Moreover, the V600E group had a larger T2/FLAIR-CE mismatch than the K-B group.ConclusionsThe BRAF alteration status in individuals with OPHPA was associated with preoperative MRI by focusing on T2 signal intensity and T2/FLAIR-CE mismatch. The BRAF V600E mutation was associated with a lower T2/CSF value and larger T2/FLAIR-CE mismatch, whereas K-B fusion was associated with a higher T2/CSF value and smaller T2/FLAIR-CE mismatch.     

卒中合并脑微出血的影像学研究

目的 探讨ICH和脑梗死患者合并脑微出血（cerebral microbleeds，CMBs）数量分级及部位分布差异。 方法 连续选取2017年8月-2018年12月在北京市大兴区人民医院神经内科病房住院且资料完整的 卒中患者，分为ICH和脑梗死两组。收集患者发病2周内头颅MRI磁敏感加权成像影像，统计ICH与脑梗 死患者中CMBs数量分级及部位分布特点。 结果 共入组患者234例，其中ICH组79例，脑梗死组155例。ICH组合并CMBs 65例（82.3%），其中 CMBs＞5个的患者41例（51.9%）；脑梗死组合并CMBs 73例（47.1%），其中CMBs＞5个的患者21例 （13.6%），两组差异有统计学意义（P＜0.001）。ICH组中，CMBs同时累及脑叶和深部脑组织的患者40例 （50.6%）；脑梗死组中，CMBs同时累及脑叶和深部脑组织的患者25例（16.1%），两组差异有统计学意 义（P＜0.001）。 结论 CMBs病灶＞5个多见于ICH患者；CMBs同时累及脑叶及深部脑组织多见于ICH患者。