前列腺MRI的新技术进展

随着前列腺MRI的发展,多项新技术在前列腺癌诊断中得到应用,如定量磁共振技术、扩散相关技术、混合多维磁共振成像、时间依赖性扩散磁共振成像等,在提高前列腺癌诊断准确性的同时,还能提高观察者间的一致性。本文对近年前列腺MRI的新技术进行综述。     

“磁共振成像序列设计理论与实践应用”学习班通知

第十届磁共振成像序列设计理论与实践应用学习班将于2011年10月20～23日在北京大学第三医院举办。北京大学是国内最早进行磁共振成像研究的单位,在过去的30年中为全球培养了众多优秀的磁共振成像技术研发和应用专家。本学习班是由北京大学医学部和工学院联合举办,由北京大学第三医院承办的国家级继续教育项目。学习班以多学科交叉授课的形式,由MRI序列设计物理师、临床MRI序列设计技术专家以及临床疾病影像诊断专家共同授课,以MRI序列设计为切入点,配合各系统疾病MRI诊断的具体序列设计应用,并为学员提供MRI扫描仪生产现场实习,以系统地介绍     

《磁共振成像临床应用入门》已出版

《磁共振成像临床应用入门》由靳二虎教授主编,蒋涛、张辉教授担任副主编,马大庆教授主审由人民卫生出版社出版。该书集全国20位磁共振专家之智慧,耗时两年编写而成。全书共97万字,1392幅插图,介绍了磁共振成像的原理和相关概念、MRI检查技术、各种加权图像的特征、MRI在各系统疾病诊断中的应用、MRI伪影以及安全性问题。     

低场磁共振弥散成像诊断脑梗死16例

磁共振弥散成像(DWI)可以检测到脑缺血区极小的水分子弥散变化,从而发现超早期的脑梗死病灶。由于硬件条件所限,目前DWI多在高场磁共振才能实现。2003年3～11月,我们应用Signa Profile Ⅱ0．2T永磁型磁共振(GE公司)在低场磁共振上实现了弥散成像技术,并对脑梗死16例同时应用传统的MRI成像序列与DWI成像序列扫描,提示早期诊断脑梗死DWI比MRI更具优势,现报告如下。     

移植肾的磁共振检查

近年来磁共振技术的迅速发展,使得评估移植肾功能成为可能.本文旨在介绍常规磁共振成像(MRI),磁共振血管成像(MRA),磁共振泌尿系统成像(MRU),MR灌注加权成像(PWI),MR弥散加权成像(DWI)和血氧水平依赖成像(BOLD)在移植肾检查中的应用和意义.     

MRI检查在周围神经病变中的应用

周围神经病变是指各种损伤因素造成外周神经损伤引起相应支配区感觉及运动功能障碍。对于如何精确判断周围神经损伤的部位及程度,是临床亟待解决的难题。磁共振成像技术因其较高的组织分辨率、无辐射、可重复操作等优势,其在临床各个领域都有较普遍的应用。随着神经磁共振成像(magnetic resonance neurography, MRN)技术的不断成熟及完善,MRI在周围神经损伤中的应用越来越广泛。本文主要探讨周围神经病变的因素以及MRI各种成像技术在周围神经病变中的应用。     

肝外胆管癌MRI诊断新进展

肝外胆管癌一直是影像诊断的难点,随着MRI新成像序列的发展,MRI在肝外胆管癌的诊断中显露出越来越大的作用。着重就肝外胆管癌的MRI表现、磁共振扫描技术、磁共振胆胰管成像和动态增强MRI在肝外胆管癌诊断中的作用进行综述。     

全身磁共振扩散加权成像在肿瘤中的应用

磁共振成像具有良好的组织对比和空间分辨力,可以显示形态学的各种细微改变,因此其在肿瘤成像上有着很好的应用前景。以前MRI主要局限于某一器官或组织,随着快速成像序列的发展,如回波平面成像和并行采集技术的使用,磁共振扫描的应用范围越来越广泛。     

磁共振成像新技术在腮腺肿瘤中的应用进展

腮腺肿瘤的病理类型复杂,不同的病理类型手术方式不同,因此,准确的术前诊断对肿瘤手术方案的制定具有重要意义.随着MRI新技术的迅速发展,如扩散成像、动脉自旋标记磁共振成像、三维高分辨磁共振成像及影像组学等,在腮腺肿瘤鉴别诊断、预测疾病的发展、制定治疗计划和评估预后方面产生了革新.本文综述了 MRI新技术在腮腺肿瘤中的应用...     

腰骶部脊神经MRI成像技术的应用进展

MRI具有良好的组织对比分辨力,能清晰的显示腰骶部脊神经根及其周围的软组织,成为评估脊神经根病变的理想手段。随着MRI技术的发展,越来越多的新的成像技术应用于临床,包括磁共振神经成像术、选择性水激励脂肪抑制技术、平衡式稳态自由进动序列、扩散张量成像等对神经根病变的诊断、术前评估等方面起着越来越重要的作用。本文综述了MRI成像技术在腰骶部脊神经根中的应用进展。     

ViewRay磁共振引导放疗系统的研究进展

ViewRay磁共振引导放疗系统不但解决了成像剂量的问题,还能根据MRI进行精准摆位、在线自适应放疗以及门控照射。该系统的发展为精准放疗提供了一种新的技术手段。本文介绍ViewRay系统的主要结构,并综述质量控制体系、剂量学比较、呼吸运动管理、在线自适应放疗以及初步治疗效果。     

The value of magnetic resonance tomography (MRI) with reference to economic aspects of radiotherapy planning of vertebral metastases. A cost benefit analysis

Is magnetic resonance imaging (MRI) based target volume definition for treatment planning of vertebral metastasis effective under economic considerations. From 1994 to 1999, a total of 137 patients with bone metastases affecting the vertebral column underwent MRI of the cervical, thoracic, or lumbar spine for the treatment planning of palliative radiation therapy. The following radiation treatment consisted in a irradiation of the affected vertebral region up to a total dose of 30-40 Gy. The cost calculation for radiotherapy and magnetic resonance tomography was done using the common tariff model (EBM) of the German Health Insurances. In 73% of patients (101 patients), magnetic resonance imaging resulted in marked corrections of the irradiation fields which would have resulted in the necessity of treatment for recurrence in the case of treatment planning without MRI. Consequently, the higher cost of MRI of 345.00 DEM (176,40 EUR) lead to a saving of 497.00 DEM (254,11 EUR) compared to a recurrence treatment of 10 fractions and of 1,428.00 DEM (730,12 EUR) compared to 20 fractions. The transport expenses for the second treatment could be saved as well. Even under economic considerations MRI is effective.     

Carotid blowout syndrome with oronasal hemorrhage: magnetic resonance imaging findings

Carotid blowout syndrome (CBS) is a rare but well-known complication of aggressive radiotherapy management of head and neck cancer. Reports on magnetic resonance imaging (MRI) findings of CBS are limited in the relevant literature, probably because of the angiography priority of this complication. We describe MRI findings in a patient with nasopharyngeal carcinoma complicated with CBS.     

Pilomatrix carcinoma: role played by MR imaging

Summary We report the magnetic resonance imaging (MRI) of a pilomatrix carcinoma. We found a soft tissue tumor of the back entering the spinal canal and compressing the spinal cord and we monitored a good response to radiotherapy and chemotherapy. We have concluded that MRI played an important role in determination of the volume, extension and management of this rare malignant tumor.     

Magnetic resonance imaging (MRI) anatomy of the prostate and application of MRI in radiotherapy planning

Radiotherapy planning for prostate carcinoma has traditionally been performed on computed tomography (CT)-images, on which both the high dose areas (prostate with or without seminal vesicles) as well as the low dose areas (surrounding structures, such as the rectum and bladder) are anatomically delineated. However, magnetic resonance imaging (MRI) provides much more information than CT; it can superbly demonstrate the internal prostatic anatomy, prostatic margins and the extent of prostatic tumours. Hence, MRI becomes a powerful tool to improve the accuracy of planning delineations in radiotherapy for prostate carcinoma and is rapidly gaining popularity in the radiotherapy community. The present paper reviews some important anatomical landmarks and acquisition protocols relevant to radiotherapy planning and explains the rationale and importance of close collaboration between radiotherapists and radiologists in optimizing radiotherapy for patients with prostate carcinoma.     

MRI after preoperative radiotherapy for rectal cancer; correlation with histopathology and the role of volumetry

The objective is to assess if tumor size after radiotherapy in patients with rectal cancer can be assessed by a second magnetic resonance imaging (MRI), after radiotherapy prior to surgery and to correlate changes observed on MRI with findings at histopathology at surgery. Twenty-five patients with MRI before and after radiotherapy were included. Variables studied were changes in tumor size, T-staging and distance to the circumferential resection margin (CRM). RVs was measured as tumor volume at surgery (Vs) divided by tumor volume at the initial MRI (Vi) in percent. RVm was defined as the tumor volume at the second MRI (Vm) divided by Vi in percent. The ypT-stage was the same or more favorable than the initial MRI T-stage in 24 of 25 patients. The second MRI was not more accurately predictive than the initial MRI for ypT-staging or distance to CRM (p > 0.05). Vm correlated significantly to Vs, as did RVs to RVm, although the former was always smaller than the latter. Vm and RVm correlated well with ypT-stage (p < 0.001). Volumetry seems to correlate with ypT-stage after preoperative radiotherapy for resectable rectal cancer. The value of a second MRI after radiotherapy for assessment of distance to CRM and ypT-staging is, however, not apparent.     

Role of fusion in radiotherapy treatment planning

The fusion of functional imaging to traditional imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), is currently being investigated in radiotherapy treatment planning. Most studies that have been reported are in patients with lung, brain, or head and neck neoplasms. There is a potential role for either positron emission tomography (PET) or single photon emission computed tomography (SPECT) to delineate biologically active or tumor-bearing areas that otherwise would not be detected by CT or MRI. Furthermore, target volumes may be modified by using functional imaging, which can have a significant impact in the modern era of three-dimensional radiotherapy. SPECT may also be able to identify "nonfunctional" surrounding tissue and may influence radiotherapy beam arrangement.     

Resonancia magnética en la planificación de la braquiterapia intracavitaria para el tratamiento del cáncer de cérvix localmente avanzado

Cervical cancer is the third most common gynecological cancer. Its treatment depends on tumor staging at the time of diagnosis, and a combination of chemotherapy and radiotherapy is the treatment of choice in locally advanced cervical cancers. The combined use of external beam radiotherapy and brachytherapy increases survival in these patients. Brachytherapy enables a larger dose of radiation to be delivered to the tumor with less toxicity for neighboring tissues with less toxicity for neighboring tissues compared to the use of external beam radiotherapy alone. For years, brachytherapy was planned exclusively using computed tomography (CT). The recent incorporation of magnetic resonance imaging (MRI) provides essential information about the tumor and neighboring structures making possible to better define the target volumes. Nevertheless, MRI has limitations, some of which can be compensated for by fusing CT and MRI. Fusing the images from the two techniques ensures optimal planning by combining the advantages of each technique.     

Nasopharyngeal carcinoma: the impact of CT-scan and of MRI on staging, radiotherapy treatment planning, and outcome of the disease

The present study is a critical review of the role of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis and therapy of nasopharyngeal cancer. It is estimated that following CT-scan/MRI, T,N staging of the disease changes in about half of cases, which results in important adjustments of the radiotherapy treatment planning, both in terms of radiation field dimensions and of dose specifications. The development of novel technology with CT-scan-simulated 3-D conformal or intensity-modulated radiotherapy (IMRT) planning is gradually becoming the standard therapy for nasopharyngeal carcinoma (NPC). CT-scan/MRI is also of value in detecting massive parapharyngeal involvement, low-neck lymphadenopathy or fixation of nodes onto adjacent structures, which are important features indicating the necessity to integrate chemotherapy or surgical neck dissection in the overall treatment policy. CT-positron emission tomography (PET) scan is recently under evaluation for the identification of the most active tumor regions, which will allow a biological radiotherapy planning (RTP) using IMRT techniques.     

MRI诊断放射治疗前后宫颈癌的临床价值

目的:探讨MRI在子宫颈癌(UCC)及其放射治疗后的诊断价值.材料和方法:24例经病理学证实为UCC在治疗前根据MRI表现做出临床分期,并与手术及外科探查术结果相对照;其中12例UCC在放疗后行MRI复查.结果:UCC MRI T2WI呈均匀或不均匀高信号软组织肿块,T1WI呈等或低信号,增强扫描呈不均匀增强;对术前MRI UCC 分期的准确率为91.7%(22/24);放疗后肿瘤组织纤维化,T2WI表现为低信号.结论:MRI平扫 T2WI为UCC检查的首选序列;MRI在检测UCC肿瘤大小、宫旁浸润及转移等方面有优越性,有助于临床分期及监测UCC对放疗的反应.