利用自旋回波平面成像T2加权序列提高肝脏实性病变的检出率

目的 评价自旋回波平面成像（ＳＥ０ＥＰＩ）Ｔ２Ｗ序列对肝脏实性病变的检出能力。方法 ７４例病人（２０２个病灶）接近肝脏３种ＳＥ－ＥＰＴ Ｔ２Ｗ序列磁共振扫描,评价其图像信噪比（ＳＮＲ）肝脾对比噪声比（Ｌ０Ｓ ＣＮＲ）、病灶对噪声比（ＣＲＮ）及病人出率,并卫真实彻态进行快速成像（ｔｒｕｅ０ＩＳＰ、快速自旋回波（ＴＳＥ）及半傅立叶采集单次激发快速自旋回波（ＨＡＳ％ＴＥ）等屏气Ｔ２Ｗ序列相比较。结果 快     

腹部磁共振成像的临床应用──探讨和比较几种扫描脉冲序列

笔者通过分析１００例腹部ＭＲＩ图像，研究和比较３对扫描脉冲序列的应用；研究结果表明：（１）Ｔ＿１加权像脉冲序列，快速ＳＰＧＲ（屏气）扫描速度快、呼吸伪影少、流动伪影多；而ＳＥ序列扫描时间长、流动伪影少、呼吸伪影多些；两者脉冲序列图像中解剖分辨和病变显示率相似（Ｐ＞０．０５，无显著差异）。（２）Ｔ＿２加权像脉冲序列，ＦＳＥ序列扫描时间短、呼吸伪影和流动伪影多；而ＳＥ序列扫描时间长、呼吸伪影和流动伪影少些；ＦＳＥ和ＳＥ图像中病变显示率相似（Ｐ＞０．０５，无显著差异）；ＳＥ图像中解剖分辨好于ＦｓＥ（Ｐ＜０．０１．有极显著差异）。（３）Ｔ＿２加权像加脂肪抑制序列图像中呼吸伪影、化学位移伪彤少，解剖分辨和病变显示清晰度均好于Ｔ＿２加权像不加脂肪抑制序列（Ｐ＜０．０ｌ，有极显著差异）。     

国产低场强磁共振设备脂肪抑制技术的应用研究

目的寻找国产低场磁共振设备（ＡＳＭ０．１６Ｔ）脂肪抑制的成像参数，并了解其在临床上的应用效果。方法应用动物组织样本１０块及２０例健康志愿者的头颅和上腹部各进行２次独立的ＳＥ序列扫描，然后行对应区域的脂肪组织信号强度（Ｓ）测量，最后代入Ｔ１值计算公式：Ｓ′／Ｓ″＝（１－ｅＴＲ′／Ｔ１）／（１－ｅＴＲ″／Ｔ１），分别求得标本及志愿者的脂肪组织Ｔ１值为１１３±８毫秒和１３５±１１毫秒。我们以ＴＩ（反转时间）等于６９％Ｔ１作为中心零点时间行短ＴＩ反转恢复序列（ｓｈｏｒｔＴＩｉｎｖｅｒｓｉｏｎｒｅｃｏｖｅｒｙ，ＳＴＩＲ）扫描，同时行ＳＥ序列Ｔ１ＷＩ及Ｔ２ＷＩ。然后通过脂肪信号强度差异及线形灰度曲线进行检测脂肪抑制效果。结果ＳＥＴ１ＷＩ、Ｔ２ＷＩ和ＳＴＩＲ（ＴＩ９０毫秒时）志愿者的脂肪信号强度分别为：３４０８±１６５、２８９９±１８８和３０５±１０６，并且，ＳＴＩＲ（ＴＩ９０毫秒时）的脾／肝和脑灰／白质对比度噪声比较常规ＳＥ序列明显增高（除ＳＥＴ２ＷＩ脾／肝Ｐ＜０．０５外，余Ｐ＜０．０１）。结论ＳＴＩＲ（ＴＩ９０毫秒时）在检测中综合指标最优，从而认定０．１６Ｔ场强下的脂肪抑制零点时间为９０毫秒。     

烟雾病的磁共振成像诊断

目的：回顾分析８例烟雾病的磁共振成像表现，探讨磁共振成像对烟雾病的诊断价值。方法：８例烟雾病中男女各４例。年龄４～４９岁，平均２０．４岁。磁共振成像应用Ｓｉｅｍｅｎｓ１．０ＴＭＲ系统和头表面线圈。均有ＳＥ序列Ｔ１ＷＩ和Ｔ２ＷＩ，７例有三维时间飞跃法磁共振血管造影（３Ｄ－ＴＯＦＭＲＡ），１例有ＤＳＡ。结果：ＳＥ序列ＭＲＩ均见丘脑－基底节区（单侧２例，双侧６例）有扩张的烟雾血管，其中以Ｔ１ＷＩ显示更为清楚直观。７例３Ｄ－ＴＯＦＭＲＡ和１例ＤＳＡ均见ＩＣＡ上端、ＭＣＡ和ＡＣＡ近端闭塞以及丘脑－基底节区的烟雾血管。这些病理血管分布侧别与ＳＥ序列磁共振成像所见一致。结论：ＳＥ序列磁共振成像和３Ｄ－ＴＯＦＭＲＡ是诊断烟雾病的有效方法。Ｔ１ＷＩ显示丘脑－基底节区烟雾血管优于Ｔ２ＷＩ。３Ｄ－ＴＯＦＭＲＡ尚适用于烟雾病血管旁路术后随诊及其高危人群普查。     

门静脉高压病人部分脾栓塞术对门静脉及其分支压力的影响

目的　研究门脉高压,脾功能亢进病人部分脾栓塞（ＰＳＥ） 前后门脉压力改变,以期得到ＰＳＥ对门脉压力改变的影响。方法　采用脾动脉插管及经皮经肝门脉置管在ＰＳＥ前后分别测量门脉主干,脾静脉及肠系膜上静脉压力,通过自身对照ｔ 检验进行统计学研究。结果　ＰＳＥ前门脉主干（ＰＶ）压力为（５１ ．４±１３．７）ｃｍ Ｈ２Ｏ,脾静脉（ＳＶ）为（５５ ．５±２３ ．２）ｃｍ Ｈ２Ｏ,肠系膜上静脉（ＳＭＶ）为（５１．８±１７ ．２）ｃｍ Ｈ２Ｏ,ＰＳＥ后ＰＶ 为（４２．４ ±８．７）ｃｍ Ｈ２Ｏ,ＳＶ 为（４２．３±１１ ．８）ｃｍ Ｈ２Ｏ,ＳＭＶ 为（４３ ．４ ±１３．１）ｃｍＨ２Ｏ,通过自身对照“ｔ”检验,ＰＶ,ＳＶ 为Ｐ＜ ０ ．０５ ,ＳＭＶ 为Ｐ＜ ０ ．００１ 。结论　ＰＳＥ前后门脉主干及其分支压力改变经检验差别有统计学意义。ＰＳＥ术后短期内门脉及其分支压力可明显降低     

急性心肌梗塞的SPIO磁共振增强实验

目的：研究超顺磁性氧化铁（ＳＰＩＯ）ＭＲ造影剂对犬急性心肌梗塞的诊断作用。材料和方法：用直接冠状动脉结扎法建立８只犬急性心肌梗塞模型；采用ＥＣＧ门控ＳＥ序列分别获增强前、后（静注ＳＰＩＯ剂量为１０ｍｇＦｅ／ｋｇ）犬心脏Ｔ２ＷＩ像，计算梗塞区的信号对比度／噪声比（ＣＮＲ）。结果：ＳＰＩＯ静注后３０ｍｉｎ，正常灌注心肌信号中等度下降，而梗塞区仍保持相对高信号，梗塞区ＣＮＲ由平扫的１．１３±０．１５提高至１．７３±０．２４。ＳＰＩＯ强化后显示的高信号心梗区，与ＴＴＣ离体心脏切片染色证实的梗塞区吻合。结论：ＳＰＩＯ是一种有价值的、潜在的心脏磁化率效应造影剂。     

腹部磁共振成像的临床应用

笔者者通过分析１００例腹部ＭＲＩ图像，研究和比较３对扫描脉冲序列的应用，研究结果表明：（１）Ｔ１加权像冲序列，快速ＳＰＧＲ（屏气）扫描速度快、呼吸伪影少、流动伪影多；而ＳＥ序列扫描时间长，流动伪影少，呼吸伪影多些；两者脉冲序列图像中剖分辨和变显示率相似（Ｐ＞０．０５，无显著差异）。（２）Ｔ２加权像脉冲序列，ＦＳＥ序列扫描时间短、呼吸伪影和流动伪影和流动伪影多，而ＳＥ序列扫描时间长，呼吸伪影和流动伪     

蒺藜总皂甙对TNF-α及IL-1β诱导内皮细胞粘附的抑制作用

目的：观察蒺藜总皂甙（ｇｒｏｓｓｓａｐｏｎｉｎｓｆｒｏｍ ＴｒｉｂｕｌｕｓｔｅｒｒｅｓｔｒｉｓＬ,ＧＳＴＴ） 对肿瘤坏死因子－ α（ＴＮＦ－ α） 、白细胞介素－１β（ＩＬ－１β） 诱导的培养新生牛脑微血管内皮细胞（ＣＭＥＣ） 粘附大鼠血单核细胞（ＭＮＣ） 及中性粒细胞（ＰＭＮ） 的影响。方法：用ＴＮＦ－α和ＩＬ－１β分别诱导传代的ＣＭＥＣ,计粘附ＭＮＣ及ＰＭＮ的细胞数,并计算粘附率。结果：ＣＭＥＣ 经ＴＮＦ－ α处理４ｈ 后,ＣＭＥＣ与ＭＮＣ及ＰＭＮ的粘附率,分别增加到３１．３±０．５％ 和３２．１±０．５％ （对照组分别为１２ ．５±０ ．２％ 和１３ ．８±０ ．４ ％） ,经ＩＬ－１β处理２ｈ 后,则分别为４４．５ ±１．０ ％ 和４４．８ ±０．７ ％ （ 对照组分别为１２ ．９ ±０．６ ％ 和１４．７ ±０．６％ ）。在ＴＮＦ－ α（ＩＬ－ １β） 处理前,用ＧＳＴＴ与ＣＭＥＣ共孵育,预处理２ｈ,则ＧＳＴＴ可剂量依赖性地抑制ＴＮＦ－ α和ＩＬ－ １β的作用。结论：ＧＳＴＴ可抑制ＣＭＥＣ 与ＰＭＮ及ＭＮＣ的粘附。     

高压氧治疗重型颅脑损伤后临床、脑电地形图、血浆内皮素、经颅多普勒超声的研究

目的研究高压氧（ＨＢＯ）治疗重型颅脑损伤（ＳＥＩ）的疗效及机制。方法治疗组３５例,对照组２０例,观察ＨＢＯ前后脑电地形图（ＢＥＡＭ）血浆内皮素（ＥＴ）及经颅多普勒超声（ＴＣＤ）查大脑中动脉收缩期流速,平均流速及搏动指数（ＭＣＡ－Ｖｓ,Ｖｍ,ＰＩ）等７项参数。结果治疗组的临床（ＧＣＳ）,ＢＥＡＭ,预后（ＧＯＳ）均明显迅速改善,与对照组有显著性差异。治疗组在ＨＢＯ１疗程后的ＥＴ值从（９１．２４±１２．１８）ｎｇ／Ｌ降到（６８．８８±１４．３７）ｎｇ／Ｌ（Ｐ＜０．０１）,与对照组相应时相比较,ＥＴ降至（８３．１２±１２．２２）ｎｇ／Ｌ,也有显著性差异（Ｐ＜０．０５）。相应的ＴＣＤ的ＭＣＡ－Ｖｍ从（６４．２±４．８）ｃｍ／ｓ降至（５１．６±４．２）ｃｍ／ｓ（Ｐ＜０．０１）,ＭＣＡ－Ｖｓ,ＰＩ的下降同样有极显著性差异（Ｐ＜０．０１）。结论ＨＢＯ能迅速改善重型颅脑损伤者的意识状态、ＢＥＡＭ异常率及生存质量。研究表明与急性期血浆ＥＴ下降和ＭＣＡ血管痉挛缓解有关,表现在ＭＣＡ血流速度和血管阻力的改善,从而减轻脑缺血缺氧,降低颅压,这是ＨＢＯ改善预后的重要机制之一。     

快速自旋回波颈脊髓MR造影技术-2D,3D比较

目的：分析评价２Ｄ，３ＤＴＳＥ颈脊髓造影。方法：１６例健康志愿者分别选２Ｄ，３ＤＴＳＥ行ＭＲ颈脊髓造影，３３例颈椎病患者选３ＤＭＲ颈脊髓造影，比较２Ｄ，３Ｄ图像及参数选择注意事项。结果：１．ＭＲ颈脊髓造影能良好地显示Ｃ１—Ｃ８神经根，对２Ｄ，３Ｄ各１９２幅ＭＩＰ分析３Ｄ在各方位对神经根显示清晰度明显优于２Ｄ（Ｐ＜０．０５）；２．ＴＳＥ序列中ＥＴＬ及ＥＳ的选择直接影响图像质量及成像时间，我们选择ＴＲ／ＴＥ为６０００ｍｓ／５００ｍｓ回波间隔（ＥＳ）选择在２１～２４ｍｓ图像质量较满意；３．ＭＲ颈脊髓造影像有两个解剖标志可记数Ｃ１，Ｃ２神经根：①双侧椎动脉进入硬膜处下缘为记数Ｃ１神经根标记，②环椎侧块对硬膜压迹形成的双侧凹陷，紧邻其下方为记数Ｃ２神经根标记；４．ＭＲ颈脊髓造影可直接显示神经根受压移位，骤拢，上翘的细节及根袖囊肿。结论：ＭＲ颈脊髓造影是一种无创，有效的脊髓造影方法，３Ｄ成像更为满意，可为常规颈椎ＭＲＩ成像提供重要的影像补充资料。     

A monitoring,feedback, and triggering system for reproducible breath-hold MR imaging

A technique is described that provides improved reproducibility of breath-holding for MR image acquisition by monitoring the superior-inferior (S/I) position of the diaphragm. The method incorporates detection of the level of inspiration using an MR signal, rapid display to the patient of diaphragm position to enable breath-hold adjustment, and triggering of image data acquisition once appropriate position is attained. The response time of the system is short, approximately 10 ms. Studies in six volunteers using this method demonstrate a considerable decrease in the S/I range of diaphragm position over 10 consecutive periods of suspended respiration. The mean range is 1.3 mm with the system, while it is 8.3 mm without using it is expected that this method will be of assistance in many abdominal and cardiothoracic studies that use breath-hold techniques.     

DSA功能性参数的提取与利用

本文介绍了在临床实际中利用功能性参数，对冠状动脉ＤＳＡ心肌血流灌注成像、冠状动脉血流量测定、左心室功能测定、肺动脉高压程度的评价等项目研究结果。重点讨论了提取ＤＳＡ功能性参数的一般方法，认为功能性参数在现代影像诊断学中的作用是对疾病做出程度、定量、动态及功能诊断。     

RARE spiral T2-weighted imaging

Spiral imaging has a number of advantages for fast imaging, including an efficient use of gradient hardware. However, inhomogeneity-induced blurring is proportional to the data acquisition duration. In this paper, we combine spiral data acquisition with a RARE echo train. This allows a long data acquisition interval per excitation, while limiting the effects of inhomogeneity. Long spiral k-space trajectories are partitioned into smaller, annular ring trajectories. Each of these annular rings is acquired during echoes of a RARE echo train. The RARE refocusing RF pulses periodically refocus off-resonant spins while building a long data acquisition. We describe both T₂-weighted single excitation and interleaved RARE spiral sequences. A typical sequence acquires a complete data set in three excitations (32 cm FOV, 192 × 192 matrix). At a TR = 2000 ms, we can average two acquisitions in an easy breath-hold interval. A multifrequency reconstruction algorithm minimizes the effects of any off-resonant spins. Though this algorithm needs a field map, we demonstrate how signal averaging can provide the necessary phase data while increasing SNR. The field map creation causes no scan time penalty and essentially no loss in SNR efficiency. Multiple slice, 14-s breath-hold scans acquired on a conventional gradient system demonstrate the performance.     

Echo-Time-Encoded Burst Imaging (EBI): A Novel Technique for Spectroscopic Imaging

A new technique for rapid spectroscopic imaging is presented. The proposed experiment enables a complete mapping of the two-dimensional reciprocal space k_x, k_o, and thus the acquisition of a 1D spectroscopic image in a single scan. The properties of the pulse sequence, based on the use of a burst of low flip angle pulses, are analyzed in the framework of linear response theory, and it is shown that chemical shift information may be introduced into the spatially encoded echoes. First experimental results are presented demonstrating that 32 x 32 proton spectroscopic images may be acquired within less than 1 min with a conventional imaging system.     

Fast imaging of phosphocreatine in the normal human myocardium using a three-dimensional RARE pulse sequence at 4 Tesla

PURPOSE: To investigate the use of a three-dimensional rapid acquisition with relaxation enhancement (RARE) pulse sequence for direct acquisition of phosphocreatine (PCr) images of the human myocardium. MATERIALS AND METHODS: A short elliptical birdcage radiofrequency (RF) body coil was constructed to produce a uniform flip angle throughout the chest cavity. In vivo images using a spectrally-selective RARE sequence with a spatial resolution of 1.2 cm x 1.2 cm x 2.5 cm (4 cm(3)) were acquired in nine minutes and 40 seconds. RESULTS: Scans of phantoms demonstrated excellent spectral selectivity. The signal-to-noise ratio in the myocardium ranged from 12.6 in the anterior wall to 5.3 in the mid septum. CONCLUSION: This study demonstrates that PCr data can be acquired using a three-dimensional RARE sequence with greater spatial and temporal resolution than spectroscopic techniques.     

Current Status of Optical Imaging for Evaluating Lymph Nodes and Lymphatic System

Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.     

Simultaneous multislice (SMS) imaging techniques

Simultaneous multislice imaging (SMS) using parallel image reconstruction has rapidly advanced to become a major imaging technique. The primary benefit is an acceleration in data acquisition that is equal to the number of simultaneously excited slices. Unlike in‐plane parallel imaging this can have only a marginal intrinsic signal‐to‐noise ratio penalty, and the full acceleration is attainable at fixed echo time, as is required for many echo planar imaging applications. Furthermore, for some implementations SMS techniques can reduce radiofrequency (RF) power deposition. In this review the current state of the art of SMS imaging is presented. In the Introduction, a historical overview is given of the history of SMS excitation in MRI. The following section on RF pulses gives both the theoretical background and practical application. The section on encoding and reconstruction shows how the collapsed multislice images can be disentangled by means of the transmitter pulse phase, gradient pulses, and most importantly using multichannel receiver coils. The relationship between classic parallel imaging techniques and SMS reconstruction methods is explored. The subsequent section describes the practical implementation, including the acquisition of reference data, and slice cross‐talk. Published applications of SMS imaging are then reviewed, and the article concludes with an outlook and perspective of SMS imaging. Magn Reson Med 75:63–81, 2016. © 2015 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance.     

Dynamic bioluminescence imaging for quantitative tumour burden assessment using IV or IP administration of <Emphasis Type="SmallCaps">d</Emphasis>-luciferin: effect on intensity,time kinetics and repeatability of photon emission

Introduction In vivo bioluminescence imaging (BLI) is a promising technique for non-invasive tumour imaging. d-luciferin can be administrated intraperitonealy or intravenously. This will influence its availability and, therefore, the bioluminescent signal. The aim of this study is to compare the repeatability of BLI measurement after IV versus IP administration of d-luciferin and assess the correlation between photon emission and histological cell count both in vitro and in vivo. Materials and methods Fluc-positive R1M cells were subcutaneously inoculated in nu/nu mice. Dynamic BLI was performed after IV or IP administration of d-luciferin. Maximal photon emission (PE_max) was calculated. For repeatability assessment, every acquisition was repeated after 4 h and analysed using Bland–Altman method. A second group of animals was serially imaged, alternating IV and IP administration up to 21 days. When mice were killed, PE_max after IV administration was correlated with histological cell number. Results The coefficients of repeatability were 80.2% (IV) versus 95.0% (IP). Time-to-peak is shorter, and its variance lower for IV (p < 0.0001). PE_max was 5.6 times higher for IV. A trend was observed towards lower photon emission per cell in larger tumours. Conclusion IV administration offers better repeatability and better sensitivity when compared to IP. In larger tumours, multiple factors may contribute to underestimation of tumour burden. It might, therefore, be beneficial to test novel therapeutics on small tumours to enable an accurate evaluation of tumour burden. Marleen Keyaerts is a Ph. D. fellow of the Research Foundation—Flanders (Belgium; FWO).     

Temporal resolution improvement in dynamic imaging

In some dynamic imaging applications, only a fraction, 1/n, of the field of view (FOV) may show considerable change during the motion cycle. A method is presented that improves the temporal resolution for a dynamic region by a factor, n, while maintaining spatial resolution at a cost of √n in signal-to-noise ratio (SNR). Temporal resolution is improved, or alternatively, total imaging time is reduced by reducing the number of phase encodes acquired for each temporal frame by 1/n. To eliminate aliasing, a representation of the signal from the static outer portion of the FOV is constructed using all the raw data. The k-space data derived from this representation is subtracted from the original data sets, and the differences correspond to the dynamic portion of the FOV. Improved resolution results are presented in phantom studies, and in vivo phase contrast quantitative flow imaging.