Magnetic resonance imaging of chest wall lesions

Magnetic resonance imaging (MRI) demonstrates surface anatomy, nerves, and soft tissue pathology. Selective placement of the cursor lines in MRI displays specific anatomy. The MR images can then be used as adjunct in teaching surface anatomy to medical students and to other health professionals. Because the normal surface anatomy could be imaged at UCLA's radiology department, it was decided to image soft tissue abnormalities with MR to assist in patient care. Patients imaged were scheduled for special procedures of the chest or staging lymphangiograms. Patients were placed into categories depending on known diagnosis or interesting clinical presentation. The diagnostic categories included Hodgkin's disease, melanoma, carcinomas (eg, lung or breast), lymphedema, sarcomas, dermatological disorders, and neurological disorders. All images were orchestrated by the radiologist. This article discusses both the teaching and clinical impact on patient care.     

Peripheral facial nerve communications and their clinical implications

The facial nerve (CN VII) nerve follows a torturous and complex path from its emergence at the pontomedullary junction to its various destinations. It exhibits a highly variable and complicated branching pattern and forms communications with several other cranial nerves. The facial nerve forms most of these neural intercommunications with branches of all three divisions of the trigeminal nerve (CN V), including branches of the auriculotemporal, buccal, mental, lingual, infraorbital, zygomatic, and ophthalmic nerves. Furthermore, CN VII also communicates with branches of the vestibulocochlear nerve (CN VIII), glossopharyngeal nerve (CN IX), and vagus nerve (CN X) as well as with branches of the cervical plexus such as the great auricular, greater, and lesser occipital, and transverse cervical nerves. This review intends to explore the many communications between the facial nerve and other nerves along its course from the brainstem to its peripheral branches on the human face. Such connections may have importance during clinical examination and surgical procedures of the facial nerve. Knowledge of the anatomy of these neural connections may be particularly important in facial reconstructive surgery, neck dissection, and various nerve transfer procedures as well as for understanding the pathophysiology of various cranial, skull base, and neck disorders.     

Magnetic resonance imaging of the brainstem and cranial nerves

Ten normal human volunteers and 44 patients with pathology of the brainstem or cranial nerves were scanned using a. 3 Tesla permanent MR imaging system. MR images were obtained of the cranial nerves and brainstem using various spin-echo pulse sequences and scanning planes. 4 mm thick sections with .75 mm pixels on a 256 display matrix were used whenever possible. The normal MR images were correlated with thin section cryodissection specimens of fresh human cadavers. Brainstem structures including major nuclei and tracts were then identified. The cranial nerves were followed through the subarachnoid cisterns and the base of the skull. Pathological involvement of the brainstem by tumors, infarcts, and demyelinating disease was well shown and correlated with clinical findings. Examples of optic glioma, fifth, eighth, and twelfth nerve schwannomas as well as other cranial nerve pathology were also demonstrated. Magnetic resonance produces excellent images of cranial nerves and brainstem with high contrast resolution. Unlike CT, there is no beam hardening artifact from bone. T1 weighted images maximize brainstem-CSF contrast and are useful for demonstrating the external anatomy of the brainstem and cranial nerves. The T2 weighted images show internal brainstem anatomy, CSF within neural foramina, and highlight many pathological conditions.     

人体十二对脑神经的解剖脸谱

目的探讨12对脑神经的解剖脸谱教学方法在学生学习12对脑神经时的作用。方法近3年来,我们在北京大学基础医学院的解剖教学中,绘制并应用了12对脑神经的解剖脸谱便于医学生学习记忆。结果脑神经解剖脸谱对于培养医学生的学习兴趣和医学生的讨论交流能力,增加记忆的牢固性,学习的积极主动性和知识的系统性等方面均有明显提高,医学生的应试成绩也有明显提升。结论脑神经解剖脸谱取得了理想的教学效果。     

FIESTA: An MR arthrography celebration of shoulder joint anatomy,variants, and their mimics

Magnetic resonance (MR) arthrography is currently the gold standard radiological investigation for shoulder joint instability. Not only does this investigation allow for identification of important disease processes, but the reduced slice thickness and increased in‐plane resolution allowed by the latest imaging sequences also gives excellent demonstration of shoulder joint internal anatomy. This article describes the technique of MR arthrography of the shoulder practiced at our institution, briefly outlining features of the FIESTA (fast imaging employing steady state acquisition) MR sequence employed, including its advantages and limitations. A pictorial review of shoulder MR arthrography performed with this technique is presented, concentrating on normal shoulder joint internal anatomy and anatomical variants that may mimic pathology. Clin. Anat., 2013. © 2012 Wiley Periodicals, Inc.     

Cerebrovascular MRI: a review of state‐of‐the‐art approaches,methods and techniques

Cerebrovascular imaging is of great interest in the understanding of neurological disease. MRI is a non‐invasive technology that can visualize and provide information on: (i) the structure of major blood vessels; (ii) the blood flow velocity in these vessels; and (iii) the microcirculation, including the assessment of brain perfusion. Although other medical imaging modalities can also interrogate the cerebrovascular system, MR provides a comprehensive assessment, as it can acquire many different structural and functional image contrasts whilst maintaining a high level of patient comfort and acceptance. The extent of examination is limited only by the practicalities of patient tolerance or clinical scheduling limitations. Currently, MRI methods can provide a range of metrics related to the cerebral vasculature, including: (i) major vessel anatomy via time‐of‐flight and contrast‐enhanced imaging; (ii) blood flow velocity via phase contrast imaging; (iii) major vessel anatomy and tissue perfusion via arterial spin labeling and dynamic bolus passage approaches; and (iv) venography via susceptibility‐based imaging. When designing an MRI protocol for patients with suspected cerebral vascular abnormalities, it is appropriate to have a complete understanding of when to use each of the available techniques in the ‘MR angiography toolkit’. In this review article, we: (i) overview the relevant anatomy, common pathologies and alternative imaging modalities; (ii) describe the physical principles and implementations of the above listed methods; (iii) provide guidance on the selection of acquisition parameters; and (iv) describe the existing and potential applications of MRI to the cerebral vasculature and diseases. The focus of this review is on obtaining an understanding through the application of advanced MRI methodology of both normal and abnormal blood flow in the cerebrovascular arteries, capillaries and veins. Copyright © 2015 John Wiley & Sons, Ltd.     

视神经磁共振成像方法研究

目的　探讨视神经磁共振 (MRI)成像最佳方法及正常视神经MRI征象 .方法　随机选择 4 0例进行头部检查 ,无眼部疾患或视力障碍患者作为正常视神经研究对象 .使用PhilipsACS -NT15 1.5T超导型磁共振成像仪及正交头线圈 .成像序列包括自旋回波T1加权成像 (SET1WI)及超快速自旋回波加或不加脂肪频谱饱和技术成像 (TSE±SPIRT2WI) .扫描方位包括与视神经平行轴位、斜矢状位及与视神经长轴垂直冠状位和标准冠状位 .结果　视神经眶内段、管内段及视束粗细均匀 .SET1WI显示视神经较周围的蛛网膜下腔信号强度稍高 ,T2WI显示视神经呈相对低信号 ,与脑髓质信号相等 ,周围包绕高信号脑脊液 .与视神经长轴平行的轴位及斜矢状位T1WI及T2WI均可显示视神经全貌 ,与视神经长轴垂直冠状位TSE +SPIRT2WI技术显示视神经信号均匀 .结论　MRI可以较好地显示视神经解剖 ,与视神经长轴垂直冠状位TSE +SPIRT2WI可以较好地显示信号特征 .     

MR microscopy and high resolution small animal MRI: applications in neuroscience research

The application of magnetic resonance (MR) imaging in the study of human disease using small animals has steadily evolved over the past two decades and strongly established the fields of "small animal MR imaging" and "MR microscopy." An increasing number of neuroscience related investigations now implement MR microscopy in their experiments. Research areas of growth pertaining to MR microscopy studies are focused on (1). phenotyping of genetically engineered mice models of human neurological diseases and (2). rodent brain atlases. MR microscopy can be performed in vitro on tissue specimens, ex vivo on brain slice preparations and in vivo (typically on rodents). Like most new imaging technologies, MR microscopy is technologically demanding and requires broad expertise. Uniform guidelines or "standards" of a given MR microscopy experiment are non-existent. The main focus therefore of this review will be on biological applications of MR microscopy and the experimental requirements. We also take a critical look at the biological information that small animal (rodent) MR imaging has provided in neuroscience research.     

Anatomical variations of the ulnar and median nerves in the upper limb

The aim of our study was the evaluation of the anatomy of ulnar and median nerves in the upper limb in order to ameliorate knowledge on the clinical anatomy of these nerves. In fact, further information on this topic may be useful owing to its possible clinical relevance when planning surgical anatomy and reconstructive surgery in tumor affected and injured patients. The relationships between ulnar and median nerve and neighbouring anatomical structures have been examined, together with the course and ramification of the ulnar and median nerves in six fresh cadavers. Moreover, we have performed a review of the literature. Four specific aspects were evaluated during dissection: 1) division modality of the ulnar nerve at the wrist; 2) anatomical details of the medial humeral epicondyle; 3) anatomical relationships between median nerve and retinaculum flexorum; 4) median-ulnar nerves anastomosis. Our results show that: the medial humeral epicondyle shows specific anatomical details in relation to the ulnar nerve; the relationships between the median nerve and the transverse carpal ligament may be characterized by one or two nerve trunks (two cases of bifid median nerve in our experience); median-ulnar nerve anastomosis may be also found at various levels. Comparing our results with those of the available literature we can conclude that anatomical variations of ulnar and median nerve in the upper limb are not an infrequent finding and their clinical, diagnostic and surgical relevance should be considered.     

The use of MR B+1 imaging for validation of FDTD electromagnetic simulations of human anatomies

In this study, MR B(+)(1) imaging is employed to experimentally verify the validity of FDTD simulations of electromagnetic field patterns in human anatomies. Measurements and FDTD simulations of the B(+)(1) field induced by a 3 T MR body coil in a human corpse were performed. It was found that MR B(+)(1) imaging is a sensitive method to measure the radiofrequency (RF) magnetic field inside a human anatomy with a precision of approximately 3.5%. A good correlation was found between the B(+)(1) measurements and FDTD simulations. The measured B(+)(1) pattern for a human pelvis consisted of a global, diagonal modulation pattern plus local B(+)(1) heterogeneties. It is believed that these local B(+)(1) field variations are the result of peaks in the induced electric currents, which could not be resolved by the FDTD simulations on a 5 mm(3) simulation grid. The findings from this study demonstrate that B(+)(1) imaging is a valuable experimental technique to gain more knowledge about the dielectric interaction of RF fields with the human anatomy.     

Development and use of iron oxide nanoparticles (Part 1): Synthesis of iron oxide nanoparticles for MRI

Contrast agents, such as iron oxide, enhance MR images by altering the relaxation times of tissues in which the agent is present. They can also be used to label targeted molecular imaging probes. Unfortunately, no molecular imaging probe is currently available on the clinical MRI market. A promising platform for MRI contrast agent development is nanotechnology, where superparamagnetic iron oxide nanoparticles (SPIONS) are tailored for MR contrast enhancement, and/or for molecular imaging. SPIONs can be produced using a range of methods and the choice of method will be influenced by the characteristics most important for a particular application. In addition, the ability to attach molecular markers to SPIONS heralds their application in molecular imaging.There are many reviews on SPION synthesis for MRI; however, these tend to be targeted to a chemistry audience. The development of MRI contrast agents attracts experienced researchers from many fields including some researchers with little knowledge of medical imaging or MRI. This situation presents medical radiation practitioners with opportunities for involvement, collaboration or leadership in research depending on their level of commitment and their ability to learn. Medical radiation practitioners already possess a large portion of the understanding, knowledge and skills necessary for involvement in MRI development and molecular imaging. Their expertise in imaging technology, patient care and radiation safety provides them with skills that are directly applicable to research on the development and application of SPIONs and MRI.In this paper we argue that MRI SPIONs, currently limited to major research centres, will have widespread clinical use in the future. We believe that knowledge about this growing area of research provides an opportunity for medical radiation practitioners to enhance their specialised expertise to ensure best practice in a truly multi-disciplinary environment. This review outlines how and why SPIONs can be synthesised and examines their characteristics and limitations in the context of MR imaging.     

Is the cranial accessory nerve really a portion of the accessory nerve? Anatomy of the cranial nerves in the jugular foramen

The accessory nerve is traditionally described as having both spinal and cranial roots, with the spinal root originating from the upper cervical segments of the spinal cord and the cranial root originating from the dorsolateral surface of the medulla oblongata. The spinal rootlets and cranial rootlets converge either before entering the jugular foramen or within it. In a recent report, this conventional view has been challenged by finding no cranial contribution to the accessory nerve. The present study was undertaken to re-examine the accessory and vagus nerves within the cranium and jugular foramen, with particular emphasis on the components of the accessory nerve. These nerves were traced from their rootlets attaching to the spinal cord and the medulla and then through the jugular foramen. The jugular foramen was exposed by removing the dural covering and surrounding bone. A surgical dissecting microscope was used to trace the roots of the glossopharyngeal nerve (CN IX), vagus nerve (CN X) and accessory nerve (CN XI) before they entered the jugular foramen and during their travel through it. The present study demonstrates that the accessory nerve exists in two forms within the cranial cavity. In the majority of cases (11 of 12), CN XI originated from the spinal cord with no distinct contribution from the medulla. However, in one of 12 cases, a small but distinct connection was seen between the vagus and the spinal accessory nerves within the jugular foramen.     

The thin sectional anatomy of the sellar region with MRI correlation

The purpose of this study was to explore the anatomical complexity and adjacent relationships of the sellar region in thin continuous sections so as to provide intimate morphological data for imaging diagnosis and surgical operations of the diseases in this region. After CT and MR examination verifying no brain lesions, one normal cadaver head was selected for this study from four Chinese adult male cadavers. After being embedded and frozen, the head was sliced into serial sections at 0.1 mm intervals in the transverse plane with SKC 500 computerized freezing milling machine. Then the serial transverse sections were photographed by a high-resolution digital camera and saved in the computer. Subsequently, the anatomic structures of the sellar region on the thin transverse sections were investigated and correlated with the MR images of the specimen as well as in vivo MR images, which were obtained from 20 normal Chinese male adult volunteers by a 3.0 T GE MR scanner. The base lines of the sectioning and the MR scan were all parallel to the AC-PC line. A total of 320 transverse sections and 10–12 transverse MR images related with the sellar region were obtained, respectively. We investigated the sectional anatomy of the sellar region and divided it into three parts: supra hypophysial area, hypophysial area and infra hypophysial area. The cavernous sinus was a venous passage full of blood and it could be divided into four interspaces according to its position relation with the internal carotid artery. The third, fourth, sixth cranial nerves and trigeminal branches ophthalmic nerve, maxillary nerve displayed from the anterior to the posterior in the lateral wall of cavernous sinus in transverse planes. Comparing continuous thin sections with MR images offers a better understanding of the complex anatomical structures and provides practical submillimeter anatomical data for imaging diagnosis and clinical treatment in this region.     

Three-dimensional display of cortical anatomy and vasculature: Magnetic resonance angiography versus multimodality integration

We present two methods for acquiring and viewing integrated three-dimensional (3D) images of cerebral vasculature and cortical anatomy. The aim of each technique is to provide the neurosurgeon or radiologist with a 3D image containing information which cannot ordinarily be obtained from a single imaging modality. The first approach employs recent developments in MR which is now capable of imaging flowing blood as well as static tissue. Here, true 3D data are acquired and displayed using volume or surface rendering techniques. The second approach is based on the integration of x-ray projection angiograms and tomographic image data, allowing a composite image of anatomy and vasculature to be viewed in 3D. This is accomplished by superimposing an angiographic stereo-pair onto volume rendered images of either CT or MR data created with matched viewing geometries. The two approaches are outlined and compared. Results are presented for each technique and potential clinical applications discussed.     

Imaging the hepatic lymphatics: experimental studies in swine.

Magnetic resonance (MR) imaging augmented with 3-D MR reconstruction provides an excellent display of the soft tissues and surface anatomy of the human body. The excellent anatomical detail of MR images makes this radiographic modality an ideal tool to teach anatomy to all health-care professionals. Previous studies of the lung and liver in swine revealed that the hepatic lymphatics communicated with the visceral pleural lymphatics via the so-called pulmonary ligament, which appears as a sheet of visceral pleura containing lymphatics and small blood vessels in the swine model. A review of the surgical operative reports at the UCLA School of Medicine revealed that the hepatic lymphatics are not connected or even ligated during hepatic resections and transplantations. Therefore, the authors hypothesized that the unattached lymphatics may be a cause of postoperative complications and that interruption of these important lymphatic pathways may specifically result in immediate ascites and right pleural effusions. Cannulation of the hepatic lymphatics is proposed as a method to reduce postoperative complications. The purpose of this research is to demonstrate the visual and radiographic display of the hepatic lymphatics in a swine model and to provide a means to teach anatomical-pathological correlation.     

Integrated megavoltage portal imaging with a 1.5 T MRI linac

In this note, the feasibility of complementing our hybrid 1.5 T MRI linac (MRL) with a megavoltage (MV) portal imager is investigated. A standard aSi MV detector panel is added to the system and both qualitative and quantitative performances are determined. Simultaneous MR imaging and transmission imaging can be performed without mutual interference. The MV image quality is compromised by beam transmission and longer isocentre distance; still, the field edges and bony anatomy can be detected at very low dose levels of 0.4 cGy. MV imaging integrated with the MRL provides an independent and well-established position verification tool, a field edge check and a calibration for alignment of the coordinate systems of the MRI and the accelerator. The portal imager can also be a valuable means for benchmarking MRI-guided position verification protocols on a patient-specific basis in the introductory phase.     

The pre-styloid compartment of the parapharyngeal space: a three-dimensional digitized model based on the Chinese Visible Human

To build a digitized visible model of the parapharyngeal space of the Chinese Visible Human and to provide a sectional anatomic basis for radiological and clinical diagnosis of the parapharyngeal space, sectional anatomy data of the parapharyngeal space were selected from the Chinese Visible Human male and female to compare with MR imaging findings in the axial planes. From these data the parapharyngeal space and surrounding structures were segmented. They were then reconstructed in three dimensions on PC. In the axial planes of the sectional anatomy and MR imaging, the shape, content and relations of the parapharyngeal space were clearly displayed and the dominant plane for showing the parapharyngeal space was elicited. The three-dimensional reconstructed images displayed perfectly the anatomic relationships of the parapharyngeal space, parotid, muscles, mandible and vessels. All reconstructed structures can be displayed singly, in groups or as a whole; any diameter or angle of the reconstructed structures can be easily measured. The Chinese Visible Human male and female data set can provide complete and accurate data. The digitized model of the parapharyngeal space and its surroundings offers unique insights into the complex anatomy of the area, providing morphologic data for imaging diagnosis and surgery of the parapharyngeal space.Grant sponsor: National Science Fund of China (NSFC)Grant number: 30270698, 60373112     

蝶鞍区薄层横断面解剖与MRI对照研究

目的 研究蝶鞍区的薄层断层解剖与对应的MRI图像,探讨该区域结构在薄层断层解剖上的变化规律.为影像学诊断及临床开展该区手术提供详细的形态学资料.方法取2例成人头部标本,用1.5T MRI以眦耳线为基线进行扫描获取薄层MRI图像,经冷冻包埋后采用铣削精度为0.001mm的SKC500型数控机床由下往上铣削层厚为0.1mm的薄层标本,其中蝶鞍区层厚为0.05mm.从标本中选取典型断面,与相应的MRI图像相对照,观察蝶鞍区的重要解剖结构. 结果 共获得MRI图像T1加权40幅和41幅,T2加权40幅和41幅,薄层断层图像304张和310张.在薄层断层标本上进行连续追踪,并与相应的MRI图像对照,总结其规律.在垂体层面能清楚地显示海绵窦内结构及其相互关系:1.颈内动脉弯曲走行于海绵窦内,且与海绵窦之间形成几个间隙;2.第Ⅲ、Ⅳ、Ⅵ脑神经以及三叉神经的眼神经支、上颌神经支在海绵窦外侧壁由前向后依次排列.在视交叉层面能够清楚地看到垂体柄穿过鞍膈与垂体相连.结论冷冻数控铣削技术获得的超薄断面与MRI图像对照能精确显示蝶鞍区的微细解剖结构,为该区病变的断层影像诊断和临床治疗提供实用的亚毫米断层解剖学依据.     

A history of the enumeration of the cranial nerves by European and British anatomists from the time of Galen to 1895, with comments on nomenclature

The enumerations of the modern 12 pairs of cranial nerves by a number of anatomists are reviewed in a continuous historical perspective using original texts and modern translations. The history of the numeration of the nerves is traced from Galen's classification into seven pairs (second century A.D.), through to Willis' nine pairs (1664) and Soemmerring's 12 pairs (1778). Authors describing individual structures (e.g., trochlear and olfactory nerves) for the first time are particularly noted. The contributions made by medieval anatomists such as Achillini, Berengario da Carpi, and Massa are emphasized, as also are the political and religious constraints placed upon the practical activities of anatomists up until the 16th century. It is shown that although the classification of the nerves into 12 pairs was accepted after 1778 by European authors, British texts continued to classify them as nine pairs until the end of the 19th century. © 1992 Wiley-Liss, Inc.     

Quality assessment in magnetic resonance images

Assessing quality of medical images is critical because the subsequent course of actions depend on it. Extensive use of clinical magnetic resonance (MR) imaging warrants a study in image indices used for MR images. The quality of MR images assumes particular significance in the determination of their reliability for diagnostics, response to therapies, synchronization across different imaging cycles, optimization of interventional imaging, and image restoration. In this paper, we review various techniques developed for the assessment of MR image quality. The reported quality indices can be broadly classified as subjective/objective, automatic/semi-automatic, region-of-interest/non-region-of-interest-based, full-reference/no-reference and HVS incorporated/non-HVS incorporated. The trade-of across the various indices lies in the computational complexity, assumptions, repeatability, and resemblance to human perception. Because images are eventually viewed by the human eye, it is found that it is important to incorporate aspects of human visual response, sensitivity, and characteristics in computing quality indices. Additionally, no-reference metrics are the most relevant due to the lack of availability of a golden standard against which images could be compared. Techniques that are objective and automatic are preferred for their repeatability and to eliminate avoidable errors due to factors like stress, which arise in human intervention.