Recent progress of radiology in rheumatoid arthritis: a role of magnetic resonance imaging

Since MR imaging directly visualizes all articular components with excellent contrast resolution, it allows the joint to be viewed as a whole organ. An increasing aggressive therapeutic strategy has attracted growing attention to the potentials of MR imaging in the diagnosis, prognostication, and outcome measure of RA. The introduction of MR imaging into the diagnostic criteria for early RA contributes to more accurate diagnosis in patients suspected of having RA and thus allow an earlier decision to start proper medication. Quantification of inflammatory synovitis by MR imaging can assess treatment outcome in fewer subjects than with traditional measures. We believe MR imaging can be cost-effectively incorporated in the treatment trial.     

MR imaging of the bladder

MR imaging is a useful modality for evaluating diseases of the bladder. MR imaging can detect and stage bladder cancer by determining the presence and depth of muscle invasion.Direct multiplanar imaging and superb soft-tissue contrast make MR imaging an ideal modality for evaluating less common neoplastic diseases of the bladder, such as urachal carcinoma, and tumors that develop within bladder diverticula. Dynamic breath-held fast T2-weighted imaging can evaluate for cystocele and other components of pelvic floor relaxation.     

The interventional MR imaging suite: magnet designs and equipment requirements

Soon after the introduction of MR imaging as an imaging tool, researchers began to investigate its capabilities to guide interventional minimally invasive procedures, such as biopsies. These early efforts have encouraged vendors and numerous research groups worldwide to identify clinical problems in the field of image-guided intervention, for which MR imaging is beneficial as an imaging modality, and to develop and refine soft-ware and hardware components to meet the specific requirements of interventional MR imaging. Over nearly 20 years, continuous advances in magnet and system design have accelerated the progress of MR-guided intervention.     

Role of MR imaging in sports medicine research. Basic science and clinical research studies

The advent and advancement of MR imaging have provided an entire new dimension for medical imaging. MR imaging has been especially useful because of its capacity to image nonmineralized tissues with a very high degree of resolution. Although modalities such as ultrasound and scintigraphy have proven useful for specific purposes, it is MR imaging that has the most utility and capabilities, especially in the area of sports-induced injuries. The technology associated with MR imaging has expanded greatly, and it continues to evolve at a rapid pace. The result has been an ever-increasing diagnostic capability that has become more economic with time. As described previously, MR imaging is gaining importance in the area of comparative medicine for animal athletes as well. It is also interesting to note that MR imaging now has a greater potential for monitoring physiological and biochemical changes as well as anatomic ones. Some newer MR units actually include physiologic data acquisition components. Consequently, new bioassays and nondestructive tissue tests can be performed to further understand the molecular biology and ongoing cellular processes in any given condition. Coupled with MR spectroscopy, the enhanced MR techniques should continue to contribute to the overall information that will be integrated into the training and rehabilitation of patients with sports-induced inflammation and injuries. The authors support and encourage ongoing efforts in the area of MR imaging research, both basic science and clinical studies.     

Characterization and molecular detection of atherothrombosis by magnetic resonance--potential tools for individual risk assessment and diagnostics

This review focuses on recent non-invasive or minimally invasive magnetic resonance (MR) approaches to study atherothrombosis. The potential benefits of combining diverse metabolic information obtained by the variety of MR techniques from tissues in vivo and ex vivo and from body fluids in vitro are also briefly discussed. A well established methodology is available for lipoprotein subclass quantification from plasma by 1H MR spectroscopy providing information for assessing the long-term risk of atherosclerosis. Multi-contrast MR imaging in vivo relying on endogenous contrast allows partial characterization of components in atherothrombotic plaques. The use of exogenous contrast agents in MR angiography enhances blood-tissue contrast and provides functional information on plaque metabolism, improving plaque characterization and assessment of plaque vulnerability by MR imaging. Recent applications of molecular targeted MR imaging have revealed novel opportunities for specific early detection of atherothrombotic processes, such as angiogenesis and accumulation of macrophages. Currently, MR imaging and spectroscopy can produce such metabolic in vivo and in vitro information that in combination could facilitate the screening, identification and follow-up of cardiovascularly vulnerable patients in research settings. The recent developments imply that in the near future MR techniques will be part of clinical protocols for individual diagnostics in atherothrombosis.     

Imaging of the lower cranial nerves

Knowledge of the nuclear origins and the normal course of the cranial nerves, and their functional components, is important in any evaluation of cranial neuropathy. MR imaging allows detailed evaluation of cranial nerve anatomy and pathology. Newer MR sequences allow more sensitive methods of detecting pathology and determining the cause of cranial neuropathy. The correlation of clinical findings with MR images will allow for more definitive evaluation.     

Diffusion and perfusion MR imaging of the prostate

Conventional anatomic MR imaging has evolved to a superior modality in the evaluation of prostate carcinoma and is now a widely established technique in the detection and staging of this disease, aiding in clinical decision making on treatment and therapy evaluation. Recent improvements in functional MR techniques, such as diffusion-weighted MR imaging and dynamic contrast-enhanced MR imaging, have greatly increased the impact of MR imaging in prostate cancer. The combination of T2-weighted imaging, diffusion-weighted MR imaging, and dynamic contrast-enhanced MR imaging may overcome the limitations of conventional T2-weighted MR imaging of the prostate and may be able accurately to detect, localize, stage, and grade prostate carcinoma and guide biopsies.     

胰腺实性假乳头状瘤CT和MRI诊断

目的探讨胰腺实性假乳头状瘤(SPT)的CT和MRI表现。方法回顾性分析9例病理证实的胰腺SPT的CT和MRI表现。结果肿瘤囊实性比例相当4例,实性和囊性为主各4例和1例。CT平扫囊性呈低密度,实性呈等低密度。钙化2例。MRI上实性结构T1WI低信号,T2WI高信号。动脉期实质部分不同程度强化,门脉期及延时期持续强化。病灶包膜完整,延迟强化。结论胰腺SPT影像学表现有一定的特征。当胰腺出现包膜清晰的囊实性肿瘤,实质部分呈不同程度强化时,结合病人的临床资料,应考虑胰腺SPT的诊断。     

New acquisition techniques: fields of application

Conventional MR imaging of the liver has a central role in the assessment of liver diseases. Diffusion-weighted MR imaging, MR elastography, and time-resolved dynamic contrast-enhanced MR imaging improve the anatomical information provided by conventional MR imaging and add quantitative functional information in diffuse and focal liver diseases. Particularly, accurate detection and characterization of liver fibrosis are feasible with quantitative MR elastography, detection of liver tumors is increased with diffusion-weighted MR imaging and time-resolved dynamic contrast-enhanced MR imaging, characterization of tumors can be improved with quantitative diffusion-weighted MR imaging and MR elastography. These methods also have the potential to provide adequate biomarkers for assessing the response to treatment. Currently, the main limitations of quantitative MR imaging are related to reproducibility, standardization, and/or limited clinical data. It is important to improve and standardize the quantitative MR methods and validate their role in large multicenter trials.     

MR imaging and MR spectroscopic imaging of prostate cancer

The primary indication for prostate MR and MR spectroscopic imaging is evaluating men with newly diagnosed prostate cancer who are deciding whether to undergo surgery or radiotherapy. Other applications of MR and MR spectroscopic imaging in prostate cancer are not defined fully. Areas of research include volumetric localization of prostate cancer, in vivo MR spectroscopic imaging at high field strength, in vitro MR spectroscopic imaging at very high field strength, novel spectroscopic markers of malignancy,and interventional MR guidance of biopsy and therapy. MR spectroscopic imaging remains a relatively novel technique, and successful implementation is demanding. Nonetheless, only MR and MR spectroscopic imaging allow structural and metabolic evaluation of prostate cancer location, aggressiveness, and stage, and MR imaging provides clinically and therapeutically relevant information on prostatic and periprostatic anatomy.     

成人髓母细胞瘤的CT、MR 影像诊断

目的 研究成人髓母细胞瘤的ＣＴ、ＭＲ影工与儿童髓母细胞瘤的影像表现进行对照。方法 回顾性分析了经手术、病理证实的成人髓母细胞瘤工例。并与１３５例１８岁以下锐利２髓母细胞瘤进行了对照。结果 ４１例中,１５例（３６．６％）发生在小脑半球,位于四 室者１９例（４６．３％）,位于小脑蚓部７例（１７．１％）。 肿瘤量大径大于５ｃｍ,３１例肿瘤大小为３～５ｃｍ之间,９例肿瘤小于３ｃｍ。１７例表现为圆形或椭圆形     

Functional magnetic resonance imaging of the liver: parametric assessments beyond morphology

There is growing interest in exploring and using functional imaging techniques to provide additional information on structural alterations in the liver, which often occur late in the disease process. This article presents a summary of the different functional MR imaging techniques currently in use, focusing on dynamic contrast-enhanced MR imaging, diffusion-weighted MR imaging, MR spectroscopy, in- and oppose-phase MR imaging, and T2*-weighted imaging. For each technique, the biologic underpinning for the technique is explained, the clinical applications surveyed, and the challenges for their application enumerated. Developing and less frequently used techniques such as MR elastography, blood oxygenation level dependent imaging, dynamic susceptibility contrast-enhanced MR imaging, and diffusion-tensor imaging are reviewed. The challenges widespread adoption of functional MR imaging and the translation of such techniques to high field strengths are also discussed.     

Breast MR imaging in assessing extent of disease

Breast MR imaging is valuable in assessment of extent of disease in the ipsilateral and contralateral breast in women who have breast cancer. In the ipsilateral breast, MR imaging depicts otherwise unsuspected sites of cancer in 16% (range, 6%-34%). In the contralateral breast, MR imaging depicts otherwise unsuspected sites of cancer in 6% (range, 3%-24%). MR imaging is most likely to depict additional sites of cancer in women with invasive lobular cancer and a family history of breast cancer. MR imaging can also assist in evaluating involvement of skin, pectoral muscle, and chest wall. Disadvantages of breast MR imaging include cost and additional procedures (follow-up and biopsy); furthermore, no data as yet show that breast MR imaging in the extend of disease evaluation improves disease-free or overall survival. If breast MR imaging is used in evaluating extent of disease, it is necessary to have the capability to perform biopsy of lesions detected by MR imaging only.     

MR imaging and spectroscopy of brain development

MR imaging provides an invaluable tool for the study of brain development in vivo. Current MR imaging techniques allow noninvasive methodologies, without ionizing radiation, that provide a diversity of information on structure, metabolism, and function of the developing brain. This article focuses on the application of conventional and advanced MR imaging techniques, including quantitative morphometric MR imaging, diffusion-weighted, functional MR, and MR spectroscopic imaging to the study of early human brain development.     

Cancer staging with breast MR imaging

Breast MR imaging is a useful tool for staging breast cancer patients, and staging is more accurate with MR imaging than with conventional imaging techniques. MR imaging is the preferred imaging test for the accurate staging of breast cancer before surgery and for assessment of patients with positive axillary adenopathy and negative mammogram and physical examination. There are many important questions regarding the role of MR imaging in breast cancer staging that must be addressed by future research and involvement of MR imaging of the breast in clinical trials.     

Hepatocellular nodules in liver cirrhosis: contrast-enhanced MR

Nowadays, the diagnosis of hepatocellular carcinoma (HCC) is increasingly demanded to imaging techniques. Anyway, imaging cirrhotic patients still remains a challenging issue, since pre-neoplastic hepatocellular lesions, as dysplastic nodules (DNs), may frequently mimic small neoplasms. Differently from other imaging modalities, magnetic resonance (MR) can give an accurate evaluation of both intracellular and vascular changes occurring during the carcinogenetic pathway from dysplasia to full malignancy. Both DNs and HCC may in fact show a large variety of signal intensities, strictly reflecting nodules’ characteristics, such as lesion architecture, grading, stromal components, as well as intracellular contents. In these last years, the introduction of dedicated contrast media has increased MR diagnostic efficacy, permitting to explore both vascular as well as the pathological changes occurring in the biliary and reticuloendothelial systems during the carcinogenetic process. MR performed with tissue specific contrast agents (hepatobiliary and reticulo-endothelial) may thus give an insight on this “gray area”, in whom significant histological changes are already present without an evident nodule arterial supply. This peculiar MR prerogative permits to give predictive information about the evolution trend in a cirrhotic parenchyma and to identify patients at high risk for developing carcinoma who would benefit from well-timed treatments.     

颅底脊索瘤的CT、MR影像诊断

目的 探讨ＣＴ、ＭＲ对颅底脊索瘤的诊断价值。方法 回顾性分析７１例病理证实的颅底脊索瘤的ＣＴ、ＭＲ影像表现及特点。结果 ７１例脊索瘤中,发生在斜坡３９例、鞍区１８例、颅中凹１２例和颈静脉孔区２例。３７例肿瘤内可见小囊变、坏死灶。２１例经ＭＲ检查者见肿瘤内有小出血灶。６３例可见邻的骨结构破坏。５０例经ＣＴ检查的病例中,４１中人有斑块样高密度钙化影。２７例可见非均匀性轻度增强,肿瘤边缘清楚。３９例肿瘤     

心血管磁共振成像临床应用和新进展

近年来由于MRI的进展,现已成为医学成像技术的主要组成部分,心血管MRI已广泛、有效地应用于心脏、大血管、内脏和外周血管成像及诊治工作.本文简要叙述心血管MRI临床应用概况,如对胸主动脉疾患、缺血性心脏病、心肌病、心脏肿瘤、先心病、心包疾患和心脏瓣膜病的诊断评价等.重点讨论一些新进展,如MR心肌灌注成像和心肌存活的评价;MR冠脉造影和斑块成像;深静脉血栓和肺栓塞的MR诊断以及MR血管造影对腹主-髂股-下肢动脉狭窄性病变的诊断及效果分析.     

高分辨率磁共振扫描在颅内动脉狭窄中的应用

目的：探索高分辨率磁共振扫描技术在颅内动脉狭窄处管壁成像中的应用价值。方法采用3.0T 磁共振扫描仪,应用3D-TOF,TIRM,T2WI,T1WI(平扫+增强)序列对37例颅内动脉造影证实的颅内动脉狭窄患者进行扫描。结果3例患者因躁动及幽闭恐惧等原因无法完成扫描,其余34例患者正常完成扫描,可以有效的显示颅内动脉狭窄的程度及原因。结论应用3.0T 磁共振高分辨率扫描技术,可以明确显示颅内动脉狭窄的程度及原因,提供更有意义的诊断信息。     

Extracranial carotid MR imaging at 3T

Some controversy exists over the accuracy and optimal parameters for carotid CE MR angiography at 1.5T. Spatial resolution remains more important than does temporal resolution to address the key question of vessel stenosis, based upon a review of the available literature that compares CE MR angiography with DSA. Specifically, CE MR angiograms with 0.9- to 1.2-mm resolution in all three planes before interpolation have a high reported sensitivity and specificity compared with DSA. To achieve this type of spatial resolution, cover the entire course of the carotid arteries from the aortic arch through the skull base, and achieve an absence of venous signal usually requires an elliptic-centric phase encoding CE MR angiogram that lasts for 50 to 60 seconds without the use of parallel imaging techniques. This near-millimeter resolution requires an accurate timing of the gadolinium bolus arrival to maximize intra-arterial SNR and to minimize venous contamination. Parallel imaging techniques can decrease the imaging time, but at a cost of some SNR. Initial experience with eight-channel or higher neurovascular coils at 3T indicates an increase in SNR/CNR compared with 1.5T. This should allow more consistent submillimeter-resolution carotid CE MR angiography with adequate SNR to maintain good IQ in a wide variety of clinical patients. Although a definite, prospective comparison of various CE MR angiography techniques,including a 20- to 30-second scan with 1.2- to 1.4-mm(3) voxel resolution and 50- to 60-second scan with 0.9- to 1.1-mm(3) voxel resolution at 1.5T, as well as 0.5- to 0.6-mm(3) voxel resolution with scan time of 50 to 60 seconds at 3T versus rotational DSA does not exist, the expectation is that the higher resolution and increased SNR that has resulted from 3T carotid CE MR angiography will have high sensitivity and specificity in detecting severe carotid stenosis. The most exciting application of 3T for carotid artery imaging may not be the higher resolution CE MR angiogram, however. Early work has demonstrated the potential of 3T, combined with sensitive surface coils, to depict carotid plaque with sufficient SNR to identify important plaque components consistently in most patients. This could help move MR imaging of the carotid arteries away from a strict evaluation of luminal narrowing to a focused evaluation of plaque morphology. Much work needs to be done. Although there is a growing body of literature to support the contention that plaque morphology is a predictor of subsequent thrombo-embolic disease, the natural history of these various plaque components in a large number of patients needs to be elucidated. If plaque characterization proves to be an independent risk factor that predicts stroke, more aggressive clinical treatment option strategies may be devised for patients who are at the highest risk. Currently, plaque characterization at 3T requires a different set of coils compared with the global assessment of the entire course of the carotid arteries. Future generations of 16- to 32-channel carotid coils should be able to combine the best features of current 4- to 8-channel surface carotid coils and neurovascular coils. These will enable a comprehensive evaluation of the entire course of the carotid artery and detailed carotid bifurcation plaque characterization at 3T within a clinically acceptable 1-hour time frame. This comprehensive carotid artery evaluation with 3T MR imaging would be far superior to that which is possible with US or CT.