小脑血管母细胞瘤的MRI诊断价值

目的:探讨高场MR对小脑血管母细胞瘤的诊断价值及SWI、DWI序列在其鉴别诊断中的价值。方法:回顾性分析经手术及病理证实的血管母细胞瘤患者18例20个病灶的MRI表现。结果:单发16例,多发2例共4个肿块;小脑半球14例,小脑扁桃体3例,小脑蚓部1例。可分为3型:囊伴结节型12例,实质型5例7个肿块,单纯囊型1例。囊伴结节型囊内壁光整,囊液呈长T1、长T2信号,FLAIR上呈低信号;结节实性成分呈等T2、等T1信号,FLAIR呈稍高、等信号,DWI呈等低信号,SWI多为等信号(11例);增强扫描后囊壁呈轻度强化或不强化,结节瘤体实质部分均明显强化。实质型5例,实质肿瘤呈稍长混杂T2、等T1信号,FLAIR呈等高信号,DWI呈等低信号,SWI呈等信号。1例单纯囊型病灶表现为出血信号。大部分病灶(11例)周围可见轻度水肿带。综上所述,DWI在三型中均表现为等信号或等低信号,SWI大多数为等信号,出血少见。结论:小脑血管母细胞瘤的MRI表现具有特征性,SWI及DWI序列在鉴别诊断中有重要意义。     

颅内神经节细胞胶质瘤的MRI表现

目的：探讨颅内神经节细胞胶质瘤的MRI表现。方法：回顾性分析19例经手术病理证实的颅内神经节细胞胶质瘤的临床、病理及MRI表现。结果：19例中1例表现为2个病灶,18例为单发病灶。囊实性8例和实性11例。囊实性肿瘤中囊性部分MRI平扫表现为长T1、长T2信号,增强扫描2例囊壁可见环形强化,6例囊壁无强化;实性部分MRI平扫表现为稍长T1、稍长T2异常信号影,增强扫描2例无明显强化,1例呈条纹状强化,2例呈明显不均匀强化,明显壁结节样强化3例。11例实性肿瘤中MRI平扫示1例病灶呈长T1、长T2信号改变,1例呈囊实性信号表现,此2例增强扫描示瘤内长T2信号区均有不同程度的强化;其余9例病灶表现为稍长T1、稍长T2信号,增强扫描无明显强化3例,片絮状浅淡强化4例,明显不均匀强化2例。结论：颅内神经节细胞胶质瘤的MRI表现无明显特异性,但是当MRI上表现为囊实性肿块、尤其是伴有壁结节样强化,或者实性肿块且强化及水肿均不明显,而且系以癫痫为主要症状的年轻患者时,应考虑到神经节细胞胶质瘤的可能。     

肝脏炎性肌纤维母细胞瘤组织学分型与CT、MRI对比分析(附19例报告)

目的 探讨肝脏炎性肌纤维母细胞瘤(HIMT)CT、MRI特征与病理改变的关系,提高对其的诊断准确率.资料与方法 经手术及病理证实的HIMT患者19例,其中男12例,女7例,年龄27～79岁,平均46.7岁.18例行CT平扫及增强扫描;1例仅行CT平扫,7例同时行CT、MRI平扫及增强扫描.结果 19例中15例为单发病灶,4例多发,共26个病灶,位于肝左叶4个,肝右叶22个.组织学分型包括黄色肉芽肿型15例:CT平扫低密度12例,等密度3例;14例增强扫描,动脉期1例明显强化,门静脉期轻度强化10例,平衡期轻度强化4例.4例行MRI检查,T1WI呈等信号1例,低信号3例,T2WI均为高信号.增强扫描4例动脉期均无强化,门静脉期或平衡期轻度强化.浆细胞肉芽肿型3例:CT平扫呈稍低密度2例,等密度1例.增强扫描动脉期均无强化,门静脉期或平衡期轻度强化;行MRI检查2例,增强扫描呈壁结节强化.硬化型1例:CT平扫为等、低混杂密度影,增强扫描动脉期无强化,门静脉期呈均匀强化,平衡期病灶密度减低.MRI平扫T1WI为等信号,T2WI为高信号,增强扫描动脉期无强化,门静脉期轻度强化,延迟期强化明显.26个病灶中4个有假包膜.结论 CT及MRI平扫及增强扫描能够反映HIMT组织学变化特点,但对不同类型病变的CT、MRI鉴别诊断仍比较困难.     

肝脏孤立性坏死结节的CT、MRI表现与病理对照研究

目的:探讨肝脏孤立性坏死结节(SNN)的CT、MRI表现及其分型诊断价值和病理基础.方法:分析经临床和病理证实的肝孤立性坏死结节29例(所有病例均行MR检查,其中15例行CT检查),探讨SNN的CT、MRI表现及其分型诊断价值和病理基础.结果:①单纯凝固性坏死型(14例),T1WI、T2WI上均呈低或低-等信号,增强扫描病灶内凝固性坏死无强化,周围包膜呈延迟强化.其中8例行CT检查,CT平扫呈低或等密度,增强扫描无强化,5例可见包膜呈延迟期环形强化.②伴液化性坏死型(5例),T1WI上呈低信号,较大病灶内可见更低信号;T2WI上病灶呈低-等信号,其内液化性坏死呈点片状更高信号;增强后病灶无强化,周围包膜呈轻-中度强化.CT检查3例,CT平扫呈低或等密度,增强扫描无强化,2例周围包膜呈延迟期环形强化.CT不能反映病灶内液化性坏死.③多结节融合型(10例),T1WI呈低信号,其内可见低-等信号分隔;T2WI病灶以等-稍高信号为主,其内可见等或略高信号分隔,其中6例合并液化性坏死还可见裂隙状高信号.增强扫描病灶无强化,其内分隔及周围包膜呈轻-中度强化.CT检查4例,其中3例为低或等密度融合结节,增强扫描内部分隔及周围包膜呈延迟期强化.CT不能显示内部液化性坏死和病灶全部分隔.结论:CT、MRI能较好反映肝脏孤立性坏死结节的分型及各型的病理特征,MRI在多结节融合型和伴液化坏死型的诊断价值明显优于CT.     

微囊型脑膜瘤的MRI表现及病理对照

目的 探讨微囊型脑膜瘤的MRI表现及病理对照,分析其影像特征.方法 回顾性分析病理证实的微囊型脑膜瘤10例的临床及MRI资料,10例均行MRI平扫,其中增强扫描7例.结果 10例肿瘤发生于大脑半球凸面者4例,大脑镰旁4例,上矢状窦旁2例.9例肿瘤周围水肿显著,1例水肿轻微.9例肿瘤MRI平扫表现为较均匀长T1、长T2信号,其中2例肿瘤与相邻硬脑膜宽基底部可见单个或多个结节状等、稍长T1及等、稍长T2信号.1例肿瘤MRI表现为不均匀长T1、长T2信号,内见环形影,环壁呈长T1、长T2信号,环内呈短T1、短T2信号.增强扫描6例肿瘤呈均匀显著强化,1例肿瘤不均匀强化.结论 微囊型脑膜瘤的MRI表现与病理显著相关.     

肝脏上皮样血管内皮瘤的CT和MRI表现

目的 总结肝脏上皮样血管内皮瘤(HEHE)的CT和MRI表现.方法 搜集经手术或穿刺活检后病理证实的HEHE 11例,所有的病例均行CT检查,其中5例行CT平扫及双期增强扫描(动脉期+门静脉期),其他6例行CT平扫及三期增强扫描(动脉期+门静脉期+延迟期).11例中有5例加做MRI平扫及动态增强扫描.回顾性分析病变的生长方式、分布特点、密度(信号)特点、强化方式及邻近组织情况.结果 11例均表现为肝内多发病灶,大部分病灶位于肝包膜下,根据生长方式分为三型:结节型(5例),匍匐生长型(1例)和混合型(5例).CT平扫,病灶均呈低密度,直径＞2 cm的病灶内见类圆形更低密度.MRI平扫:病灶呈T1WI低信号、T2WI高信号,直径＞2 cm的病灶信号不均匀(T1WI内见更低信号,T2WI内见更高信号).其他影像学征象包括“棒棒糖征”(6例)、包膜退缩征(6例).增强扫描:病灶直径＜1 cm的表现为轻度较均匀强化;病灶直径为1～2 cm主要表现为轻度较均匀强化;病灶直径＞2 cm的多为不均匀渐进性强化.结论 HEHE的CT和MRI表现具有一定的特征性,其强化方式与病灶的大小相关.     

肾脏孤立性纤维性肿瘤的MRI特征

目的:探讨肾脏孤立性纤维性肿瘤(SFT)的MRI特征。方法:回顾性分析12例经手术病理证实的肾脏SFT的MRI资料,均行MRI平扫及增强。结果:左肾7例,右肾5例,其中6例位于肾门压迫肾盂,4例位于肾被膜下突入肾周脂肪囊,2例位于肾实质内。平扫T1WI均呈低信号,反相位信号无减低;抑脂T2WI8例呈稍高信号伴线状、管状低信号,4例呈高低混杂信号,以低信号为主;DWI呈不均匀高信号或高低混杂信号。增强扫描:肾皮质期8例呈不均匀中度强化,4例轻度强化;髓质期强化程度均较皮质期升高,呈中度至明显强化,其中8例皮质期线状无强化区域呈中度强化;肾盂肾盏期所有病灶均持续强化,呈高信号,边界清晰。结论:SFT病理学基础决定其MRI表现具有一定特征,MR平扫信号及强化方式与SFT细胞的密集程度及排列方式、胶原纤维及供血血管多寡、有无玻璃样变或黏液变密切相关,MRI检查是诊断SFT的有效方法。     

多层螺旋CT及MRI对肝脏结核性肉芽肿的诊断价值

目的：探讨MSCT及MRI对肝脏结核性肉芽肿的诊断价值。方法：回顾性分析7例经手术或穿刺病理证实的肝脏结核性肉芽肿的影像表现。其中男5例,女2例,均行上腹部MSCT和MRI平扫及动态增强扫描,MRI扫描序列包括FSPGR T1WI、FRFSE T2WIF、SPGR T1WI动态增强和DWI（b=500 s/mm2）扫描。结果：7例中表现为肝实质内单发结节6例,多个粟粒结节聚集成簇状1例。5例CT平扫呈稍低密度,2例呈等密度,3例病灶内有点状或粉末状钙化。MRI平扫4例呈T1WI低信号、T2WI高信号,3例病灶T2WI上表现为中心低信号、周边高信号。DWI示病灶呈稍高信号,ADC值平均为（1.379±0.297）×10-3mm2/s,相对ADC为1.263±0.148。增强扫描示4例动脉期轻度不均匀强化,门静脉期及延迟期强化程度逐渐增加,其中3例病灶周围肝组织出现一过性晕状强化;3例动脉期未见明显强化,门静脉期及延迟期示病灶边缘轻度环状强化。结论：MSCT及MRI对肝脏结核性肉芽肿具有较高诊断价值,在一定程度上能反映病变所处的病理时期。     

肾脏原发原始神经外胚层肿瘤的影像学表现及病理分析

【摘要】目的：探讨肾脏原发原始神经外胚层肿瘤的病理及影像学特征,以提高诊断水平。方法：回顾性分析6例经手术病理证实的肾脏PNET的影像及临床资料。结果：6例肾脏PNET中,4例位于左肾,2例位于右肾;1例呈类圆形;2例呈椭圆形;1例呈葫芦形;2例呈不规则形;瘤体直径7.0~20.9cm。CT或MRI扫描6例均呈囊实性肿块,CT或MRI平扫6例呈混杂低密度或混杂高低不等信号。增强扫描皮髓质期6例均呈轻度强化,强化方式呈分隔状、条片状、絮状或不均质强化,实质期持续性强化或轻度延迟性强化;2例病灶边界较模糊,其余4例边界清晰。结论：肾脏原发PNET临床罕见,CT和MRI表现对本病的诊断具有一定的提示作用,但确诊仍需要依靠病理学检查。     

MRI诊断乳腺炎性病变的价值

目的 探讨乳腺炎性病变的MRI影像特点,提高乳腺炎性病变的诊断率.方法 回顾性分析经手术病理证实为乳腺炎性病变15例,术前均行常规MRI平扫和动态增强扫描.分析病灶MRI平扫及增强后形态学、血流动力学改变特点.结果 15例中,4例平扫病灶未见显示;10例表现为局灶或弥漫性不均匀信号,T1WI呈稍低信号,T2WI信号稍高;1例表现为多发结节,T1WI、T2WI均呈等信号;6例病灶伴脓腔形成,腺体结构紊乱、皮肤增厚、胸壁水肿、腋窝淋巴结增大.增强后3例表现为多发斑点状、结节状强化,5例表现为分隔、小环形强化,6例表现为多发结节状、斑片状、环形强化,1例表现为均匀结节状强化.其中7例急性乳腺炎与1例结核的早期强化率及峰值强化率高,时间-信号强度曲线表现为平台型;7例乳腺导管扩张症早期强化率较高,5例时间-信号强度曲线表现为流入型,余2例表现为平台型.结论 乳腺炎性病变MRI形态学及血流动力学具有一定的特征性,MRI增强扫描在乳腺炎性病变中具有较大的应用价值.     

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).     

Molecular imaging programs in the United States: results of a national survey

RATIONALE AND OBJECTIVES: We sought to identify and describe the characteristics of molecular imaging (MI) programs in the United States and to determine the factors considered critical for their future. MATERIALS AND METHODS: In a cross-sectional study, a validated survey was sent to members of the Society of Chairmen in Academic Radiology Departments (SCARD) in the United States, and 26 variables were studied. RESULTS: The response rate was 40.3%; 67.9% of the departments surveyed have an MI program. The main focus of 47.4% of departments is oncology. The number of radiologists working for the department was the only variable found to be significantly positively correlated with (1) number of researchers in the MI program, (2) number of MI modalities available, (3) total number of grants, and (4) having ongoing MI clinical trials. These four variables plus the number of federal grants and the space used by MI programs were independent of the geographical region, hospital size (number of beds), and department size (number of radiological examinations per year). All the MI programs received grants during 2005. Only 16.1% have no alliances with industry. Among all the departments, 82% identified staff training and recruitment as the keys for success; 78.57% considered oncology the most important future application of MI and cancer management the hospital service most affected by MI. CONCLUSION: MI programs are starting to be more widespread throughout the United States, and the trend is for more academic radiology departments to become engaged in MI activities; their development is independent of department characteristics. Radiology departments strongly agreed about the key components for success of MI initiatives and the areas that will be most affected by MI applications.