MR imaging of the head and neck

The purpose of this paper is to describe current imaging protocols for MR imaging of the head and neck region and to define results and clinical impact. Depending on the clinical question, different MRI protocols are presented for imaging of the head and neck. The appearance of different pathologic findings on imaging studies and how adapted imaging protocols help to improve differential diagnosis is discussed. In summary, MRI is the method of choice for imaging of the head and neck.     

多发性骨血管瘤 18F-FDG PET/CT显像一例

笔者报道了1例多发性骨血管瘤（IH）18F-氟脱氧葡萄糖（FDG）PET/CT显像的病例,从临床症状、实验室检查和影像学表现等方面进行鉴别诊断。不同部位的IH的影像学表现各异,而18F-FDG PET/CT能为临床鉴别肿瘤的良恶性提供参考。由于发生于扁平骨的IH非常少见,且其影像学表现缺乏特异性,笔者通过对该病例的18F-FDG PET/CT显像特点进行分析,以期提高影像科医师对该病的认识。     

树立多要素关联诊断新理念提升医学影像学在临床诊疗中的价值

人体正常运转是多种不同因素协同作用的结果,如今的医学影像学拥有更多样的成像方式与更多维的影像信息解析方法,其反映的人体病理生理信息更加全面。作为当代影像医师,应建立系统性影像诊断思维模式,针对不同病症,匹配多模式探测成像技术,建立多维度生理病理信息解析方法,形成多要素关联诊断理念,串联不同要素在病症发生发展中的作用,明确病症发生机制,丰富学科内涵,推动医学影像学诊疗能力跨越式提升。     

双模式分子影像探针研究进展

许多影像模式能应用于体内组织的解剖或功能成像.然而,每种影像模式都有自己的优缺点,目前还没有一种单纯模式能同时提供全部的解剖、功能以及分子信息.联合使用两种不同的影像模式,将大大提高影像诊断及治疗的能力.随着越来越多的双模式影像系统出现,人们对双模式探针的研究已经取得了很大的进展,这些双模式探针能充分发挥每种影像模式的优势,已经成为未来多模式影像的新工具,为临床诊断提供全面的信息.该文讨论了双模式影像探针的研究进展及其面临的挑战.     

电阻抗扫描成像物理模型仿真实验研究

目的在电阻抗扫描(electrical impedance scanning，EIS)乳腺成像的初期实验阶段，验证EIS成像的可行性，初步明确影响EIS成像的因素。方法基于EIS实验平台建立一个能有效模拟乳房组织分布的物理模型，并用电导率有差异的NaCl溶液、琼脂块模拟了3种不同情况下的电场分布。结果不同电导率分布引起的电场扰动会造成不同的成像结果。结论基于EIS原理的成像是可行的，初步明确了影响EIS成像的因素。     

Imaging of bone marrow disease in the spine

Bone marrow imaging has been greatly advanced with magnetic resonance (MR) imaging. Bone marrow contains fat and nonfat cells, which makes imaging with MR imaging the modality of choice, particularly within the spine. Any alteration within the marrow makeup is usually well seen with different MR imaging sequences. Conventional spin-echo sequences are helpful because of their great signal-to-noise ratio, and anatomic detail. Other, newer sequences--such as short T1 inversion recovery (STIR), diffusion weighted, fat suppression techniques; as well as in- and opposed-phase images--may also help to increase detection of or characterize certain diseases of the bone marrow within the spine. This article deals with the different imaging sequences available to radiologists when imaging the spinal bone marrow.     

颌面部肿瘤的影像学诊断进展

随着医学影像学技术的快速发展，颌面部肿瘤的检查方法不断增多。不同影像学检查技术对颌面部肿瘤的诊断具有各自的优缺点和互补点。本文对CT和MRI等影像诊断技术在颌面部肿瘤中应用现状和最新进展进行综述，以利于临床对影像学检查方法的选择和手术治疗计划的制订。     

A review of molecular imaging studies reaching the clinical stage

The practice of molecular imaging in the clinics is examined across various imaging modalities to assess the current status of clinical molecular imaging. The various physiologic and scientific bases of clinical molecular imaging are surveyed to assess the possibilities and opportunities for the deployment of the different imaging modalities in the near future. The requisites for successful candidate(s) of clinical molecular imaging are reviewed for future development.     

衍射增强成像与成像应用实验

目的:目前的常规X线医学成像是通过吸收衬度成像,但分辨率不够高,由于DEI采用相位衬度机制而不是依赖于物体的吸收,故适合弱吸收组织尤其是软组织成像。本实验旨在评价DEI在生物医学样品成像中的诊断价值。材料和方法:大鼠脏器样品切片,在BSRF的4W1A束线上进行DEI方法成像。首先扫描获得摇摆曲线,再选择摇摆曲线上不同位置进行成像,成像结果与常规吸收像进行对照,分辨率通过显微放大法获得。结果:图像能显示常规医学X成像方法无法显示的肝脏微细结构,分辨率达到微米。结论:DEI的优良分辨率和衬度将有望改进生物医学组织的影像诊断水平。     

神经黑色素敏感的MRI在帕金森病中的应用进展

帕金森病（PD）以含神经黑色素的儿茶酚胺类神经元进行性坏死为病理特征。神经黑色素敏感磁共振成像（NM-MRI）可以检测颅内神经黑色素的含量,从而对PD进行诊断、鉴别诊断、亚型评估及病情监测。目前PD NM-MRI的临床应用基于不同的成像技术及数据分析方法,包括不同的成像序列、成像维度、磁场强度及评估对象、评估指标、数据分析方法等。就NM-MRI的成像技术、PD的临床应用及其不同的数据分析方法予以综述。     

Diffusion-weighted magnetic resonance imaging of spinal bone marrow

Diffusion-weighted (DW) imaging is an alternative source of image contrast. DW imaging enables to measure the random motion of free water protons on a molecular basis by using different imaging sequences including steady-state free precession imaging, navigated spin-echo DW imaging, and single-shot echo planar imaging. Analysis of intravoxel incoherent motion of water protons is a promising tool that has shown to be of value in the differential diagnosis between benign and malignant spontaneous vertebral fractures. Acute benign osteoporotic fractures show hypo- or isointense signal on DW sequences that reflects persistent free water proton mobility. With increasing diffusion strength a substantial signal loss is found. Metastatic fractures show hyperintensity compared with normal surrounding bone marrow probably due to altered water proton mobility within neoplasm. The ability of the different methods for DW imaging to differentiate other bone marrow alterations needs to be investigated in further studies.     

The alphabet soup of perfusion CT and MR imaging: terminology revisited and clarified in five questions

The five questions answered in this article revolve around the different parameters resulting from perfusion imaging processing, and this clarifies the frequently confusing terminology used to describe these parameters. More specifically, the article discusses the different imaging techniques and main mathematical models behind perfusion imaging, reviews the perfusion attributes of brain tissue, and proposes a standardized parameter terminology to facilitate understanding and avoid common misinterpretations.     

Chemical-shift magnetic resonance imaging of two-line spectra by gradient reversal

A method of chemical-shift imaging is described using the invariance of chemical shifts to changes in magnetic field gradients used for frequency encoding of position in imaging. This enables separation of the effects on the observed signal of chemical shift from the effects of different positions along the imaging gradient when the signal is observed with different gradients. A simple implementation for a two-line spectrum is presented using signals observed with normal and reversed imaging gradients. This is used to create "fat" and "water" images of the thigh.     

Contrast-enhanced MR imaging of the spine: when, why and how? How to optimize contrast protocols in MR imaging of the spine

The optimal protocols and the role of contrast agents in spinal MR imaging are controversial. Although the diagnosis of many common spinal diseases can be reliably achieved by means of unenhanced images, contrast use is often necessary to improve lesion detection and differential diagnosis. The heterogeneity of the different spinal compartments and the wide variety of spinal pathology require tailored imaging strategies. Thus, the rules to achieve optimization of contrast protocols for MR imaging of the spine are frequently very different to those for brain imaging, and depend on the location and site of origin of the lesions in a specific spinal compartment, on the findings of unenhanced imaging, and on the concomitant use of fat-suppression techniques. Furthermore, in most cases, the small size of the examined structures requires a meticulous technique, and the administration of a contrast agent with high relaxivity, such as MultiHance, is advisable to enable the detection of tiny areas of contrast enhancement. The applications and clinical utility of post-contrast MR imaging are discussed with regard to different spinal diseases.     

Diffusion-weighted magnetic resonance imaging of the temporal bone

This paper summarizes the value of diffusion-weighted magnetic resonance imaging in the evaluation of temporal bone pathology. It highlights the use of different types of diffusion-weighted magnetic resonance imaging in the different types of cholesteatoma, prior to first stage surgery and prior to second look surgery. The value of diffusion-weighted magnetic resonance imaging in the evaluation of pathology of the apex of the petrous bone and the cerebellopontine angle is also discussed.     

Contrast agents and cardiac MR imaging of myocardial ischemia: from bench to bedside

This review paper presents, in the first part, the different classes of contrast media that are already used or are in development for cardiac magnetic resonance imaging. A classification of the different types of contrast media is proposed based on the distribution of the compounds in the body, their type of relaxivity and their potential affinity to particular molecules. In the second part, the different uses of the extracellular type of T1-enhancing contrast agent for myocardial imaging is covered from the detection of stable coronary artery disease to the detection and characterization of chronic infarction. A particular emphasis is placed on the clinical use of gadolinium-chelates, which are the universally used type of MRI contrast agent in the clinical routine. Both approaches, first-pass magnetic resonance imaging (FP-MRI) as well as delayed-enhanced magnetic resonance imaging (DE-MRI), are covered in the different situations of acute and chronic myocardial infarction.     

急性骨髓炎的影像学诊断研究进展

急性骨髓炎的影像学诊断技术包括X线平片、超声、CT、MRI及放射性核素显像.早期X线平片的诊断灵敏度低.超声能早期发现深部软组织及骨膜下脓肿,但图像质量取决于操作者的熟练程度.CT能早期观察到微小的骨质改变,但灵敏度较低.MRI可优于其他检查显示髓腔内的病变,但对于死骨、钙化的诊断不如CT灵敏.放射性核素显像剂的种类繁...     

核素乏氧显像在肿瘤放射治疗中的应用

核素乏氧显像是一种可以为肿瘤乏氧程度提供定性及定量信息的显像,方法简便、安全、无创伤性。常用的乏氧组织显像剂有硝基咪唑类和非硝基咪唑类,前者进入细胞后,被还原的有效基团(-NO₂)在乏氧细胞中不能再氧化而滞留于肿瘤细胞中,后者在乏氧组织中的滞留机制因显像剂的不同而不同。运用核素乏氧显像了解肿瘤组织的乏氧状态,对临床制定合理的放疗方案、评估放疗疗效有重要意义。     

Hybrid cardiac imaging with MR-CAT scan: a feasibility study

We demonstrate the feasibility of a new versatile hybrid imaging concept, the combined acquisition technique (CAT), for cardiac imaging. The cardiac CAT approach, which combines new methodology with existing technology, essentially integrates fast low-angle shot (FLASH) and echoplanar imaging (EPI) modules in a sequential fashion, whereby each acquisition module is employed with independently optimized imaging parameters. One important CAT sequence optimization feature is the ability to use different bandwidths for different acquisition modules. Twelve healthy subjects were imaged using three cardiac CAT acquisition strategies: a) CAT was used to reduce breath-hold duration times while maintaining constant spatial resolution; b) CAT was used to increase spatial resolution in a given breath-hold time; and c) single-heart beat CAT imaging was performed. The results obtained demonstrate the feasibility of cardiac imaging using the CAT approach and the potential of this technique to accelerate the imaging process with almost conserved image quality.     

Combined application of MR imaging and spectroscopy in neonates and children: installation and operation of a 2.35-T system in a clinical setting

Published pediatric magnetic resonance (MR) imaging results are usually obtained with medium-field-strength whole-body systems, while MR spectroscopy is done on a different high-field-strength/small-bore laboratory system. The authors investigated metabolism and structural development of the brain in over 100 neonates and children with combined MR imaging and spectroscopy at 2.35 T. With a 40-cm-bore magnet, MR imaging and spectroscopy data are obtained in the same session with use of the same system. The approach demands modified technical devices and elaborate patient handling. Concepts for sedation in different age groups and for patient monitoring, as well as protocols for the combined use of imaging and spectroscopy, have been worked out. The data prove high quality of imaging and spectroscopy at 2.35 T.