胰腺癌磁共振功能成像的最新进展

胰腺癌发病隐匿,进展迅速,死亡率高,预后差。手术虽是主要治疗手段,但术后5年生存率小于5％l^[1]。另外,近85％的患者都是在晚期才得到诊断,丧失了手术机会,而传统的放化疗手段也不能明显改善患者的预后,且疗效不确切。副作用多121。由于极高的软组织对比度、多参数成像及无放射性,MR对于胰腺癌的筛查、诊断、分期及疗效评价起着不可或缺的作用。近年来,随着3．0TMR在临床上的应用推广,其对胰腺癌形态学的评价效果不仅可以与64排CT相媲美,另外在小胰腺癌的筛查诊断和转移灶的发现上甚至要优于64排CT^[1]”,而且MR功能成像可以评价CT所不能提供的肿瘤细胞恶性生物学特征及其微环境的生物信息,为进一步研究胰腺癌的诊断及其疗效评价提供了有效的成像方法,从而有助于提高胰腺癌患者的治疗效果和生存率。肿瘤的MR功能成像通常包括弥散加权成像（Diffusion weighted imaging,DWI）、灌注加权成像（Perfusion weighted imaging,PWI）和磁共振波谱分析（Magnetic resonance spectroscopy,MRS）。DWI是基于水分子布朗运动的不同对组织病理特征进行评价,主要通过显示肿瘤细胞密集程度及间质内纤维含量所导致的水分子受限程度来反映肿瘤组织的病理生物活性状态：PWI是一种无创性研究肿瘤组织的微血管分布及血流灌注情况的一类MR检查技术,反映肿瘤细胞微环境血液动力学方面的信息;MRS是一种无创性研究活体器官组织代谢、生化变化及化合物定量分析的方法,主要反映肿瘤组织内癌细胞及其赖以生存的周围微环境所发生的生物代谢变化。本文就近年来MRDWI、PWI及。^1H-MRS在胰腺癌中的应用作一综述。     

State-of-the-art computed tomographic and magnetic resonance imaging of the gastrointestinal system

Among the major innovations in radiology of the gastrointestinal (GI) system are the replacement of classic invasive diagnostic methods with noninvasive ones and the improvement in lesion characterization and staging of pancreatobiliary malignancies. Developments in imaging technology have led to many improvements in the field of diagnostic GI radiology. With its fast and thin-section scanning abilities, multidetector-row CT (MDCT) strengthens the place of CT as the most efficient tool to diagnose, characterize, and preoperatively stage pancreatic neoplasms. MR cholangiopancreatography has widely replaced endoscopic retrograde cholangiopancreatography in the diagnosis and staging of pancreatobiliary malignancies. MR imaging, using phased-array or endorectal coils, demonstrates local tumor invasion accurately in rectal cancers and thus allows an improved surgical planning. Virtual colonoscopy with MDCTs is an efficient screening method for colon cancer, and MDCT enterography is becoming the standard imaging technique for many small bowel disorders. The continuing developments in CT and MR technology will most probably further improve the accuracy of these and other imaging applications in the near future.     

磁共振成像对胰腺癌与肿块型胰腺炎的诊断中的应用

目的探讨磁共振成像(MRI)对胰腺癌、肿块型胰腺炎的诊断价值。方法回顾性分析经病理证实的胰腺癌32例、肿块型胰腺炎30例患者、胰腺正常受检者30例的MRI资料,所有受检者均行常规MRI系列、DWI扫描及动态增强扫描,比较三组患者MRI影像学表现、DWI值及时间信号强度曲线(TIC)。结果 1胰腺癌T1WI病灶多呈低信号,部分病灶为等信号或混杂信号,T2WI多呈稍高信号;肿块型胰腺炎T1WI上多呈等、低信号,T2WI多呈不均匀稍高信号或等信号;2DWI序列胰腺癌组28例呈高信号,肿块型胰腺炎均呈稍高信号;胰腺癌ADC值显著高于肿块型胰腺炎,低于正常胰腺,差异有统计学意义(P0.05),肿块型胰腺炎ADC值显著低于正常胰腺,差异有统计学意义(P0.05);3胰腺癌组TIC曲线以缓升平台型为主,占84.36%,肿块型胰腺炎以缓升缓降型为主,占73.33%,正常胰腺组以速升速降型为主,占100%,三组TIC曲线比较差异有统计学意义(P0.05)。结论 MRI DWI序列及动态增强扫描对胰腺癌与肿块型胰腺炎的鉴别诊断具有显著价值。     

Endometrial cancer: magnetic resonance imaging

Carcinoma of the endometrium is the most common invasive gynecologic malignancy of the female genital tract. Clinically, patients with endometrial carcinoma present with abnormal uterine bleeding. The role of magnetic resonance imaging (MRI) in endometrial carcinoma is disease staging and treatment planning. MRI has been shown to be the most valuable imaging mod-ality in this task, compared with endovaginal ultrasound and computed tomography, because of its intrinsic contrast resolution and multiplanar capability. MRI protocol includes axial T1-weighted images; axial, sagittal, and coronal T2-weighted images; and dynamic gadolinium-enhanced T1-weighted imaging. MR examination is usually performed in the supine position with a phased array multicoil using a four-coil configuration. Endometrial carcinoma is isointense with the normal endometrium and myometrium on noncontrast T1-weighted images and has a variable appearance on T2-weighted images demonstrating heterogeneous signal intensity. The appearance of noninvasive endometrial carcinoma on MRI is characterized by a normal or thickened endometrium, with an intact junctional zone and a sharp tumor-myometrium interface. Invasive endometrial carcinoma is characterized disruption or irregularity of the junctional zone by intermediate signal intensity mass on T2-weighted images. Invasion of the cervical stroma is diagnosed when the low signal intensity cervical stroma is disrupted by the higher signal intensity endometrial carcinoma. MRI in endometrial carcinoma performs better than other imaging modalities in disease staging and treatment planning. Further, the accuracy and the cost of MRI are equivalent to those of surgical staging.     

Evaluation of cancer therapy using diffusion magnetic resonance imaging

Assessment of the effectiveness of cancer therapy traditionally relies on comparison of tumor images acquired before and after therapeutic intervention by inspection of gross anatomical images to evaluate changes in tumor size. The potential for imaging to provide additional insights related to the therapeutic impact would be enhanced if a specific parameter or combination of parameters could be identified that reflect tissue changes at the cellular or physiological level. This information could also provide a more sensitive and earlier indicator of treatment response in an individual animal or patient. Diffusion magnetic resonance imaging can detect relatively small changes in tissue structure at the cellular level and thus provides an opportunity to quantitatively and serially follow therapeutic-induced changes in solid tumors. This article provides an overview of the use of diffusion magnetic resonance imaging as a surrogate marker for quantitating treatment responsiveness in both preclinical and clinical studies.     

前列腺癌磁共振分子影像学研究进展

前列腺癌严重影响男性健康。MR分子影像学结合了MRI和分子影像学优势,为前列腺癌的早期诊断和靶向治疗提供了新的方法,具有良好的应用前景。本文将就前列腺癌的MR分子影像学研究进展进行综述。     

三阴乳腺癌磁共振成像研究

三阴性乳腺癌(TNBC)具有特殊的生物学和临床病理学特征。由于侵袭性强,缺乏有效的靶向治疗和内分泌治疗,预后差。目前磁共振成像是诊断乳腺癌最准确的影像学检查方法,可协助诊断和预后评估。三阴性乳腺癌典型MRI表现为单一病灶,呈肿块型,形态不规则,边缘光滑,在T2WI上病变中心呈高信号。进一步的工作是研究磁共振成像的临床应用,动态增强磁共振成像(DCE-MRI)、DWI、MR波谱(MRS)等。     

Whole-body magnetic resonance imaging

Whole-body magnetic resonance imaging is a fast and accurate modality for the detection of disease throughout the entire body. Technical improvements including the availability of different high image quality MR sequences, the remote movement of the imaging table, and the use of specialized surface coils have rendered whole-body screening with MRI a feasible method. In this article we describe underlying techniques and report on first clinical experiences of whole-body magnetic resonance imaging as a staging and screening method. Furthermore, advantages and limitations compared with whole-body imaging based on computed tomography are discussed.     

Breast magnetic resonance imaging

Breast MRI is becoming an important tool for the improved management of breast cancer. The technical attributes of high contrast, high-resolution breast MRI acquisitions are summarized. The fundamentals of image interpretation are outlined, including lesion enhancement, morphological features, and extent categories. The indications for breast MRI include compromised mammography, staging of disease within the breast and adjacent structures, difficult histology, and other special diagnostic situations. Patients with compromised mammography include previous surgery, radiographically dense breasts, and silicone augmentation. The improved determination of disease extent aids in the management of breast conservation treatment. Certain lesions, particularly lobular carcinoma and ductal carcinoma in situ, can be better managed with the information available with breast MRI. Other potential indications are also discussed, including patients presenting with positive axillary nodes and no known primary, women with a high risk of malignancy, and recently postoperative breasts with positive margins. The need for MRI stereotaxis is reviewed, with indications and potential solutions. The potential future roles for MRI-directed interstitial hyperthermia are outlined.     

全身磁共振成像在前列腺癌中的研究现状

国内前列腺癌发病率逐年上升,初诊前列腺癌患者中转移性前列腺癌占较大比例,确定转移负荷对于前列腺癌患者治疗方式的选择及预测预后至关重要.全身磁共振成像(whole-body magnetic resonance imaging,WB-MRI)可对前列腺癌转移负荷进行精准评估和疗效评价.相比于正电子发射计算机断层显像(po...     

Three-dimensional magnetic resonance imaging

Three-dimensional surface reconstruction images of the heart and great vessels can be produced from contiguous sequences of ECG-triggered MR scans in patients with congenital heart disease. The methods allow separation of the epi- and endocardial surfaces and definition of the enclosed blood volumes on a slice-by-slice basis. Surface reconstruction images have value in communicating the results of MR examinations to clinicians in cases where cardiac morphology is unusually complex; in depicting intracardiac defects, size, and location; and in aiding the study of pulmonary venous drainage. This method can be practical in studying cardiac morphologic abnormalities and especially in planning cardiac surgery.     

Intravascular magnetic resonance imaging

The purpose of this article is to review the current state of the art with respect to intravascular magnetic resonance imaging, including intravascular coils, their implementation for plaque identification and characterization, and strategies for future approaches to coronary imaging and other cardiovascular applications.     

Fetal magnetic resonance imaging

Ultrafast magnetic resonance imaging (MRI) sequences have changed the use of MRI to evaluate fetal abnormalities. Currently, the best application is the evaluation of suspected brain abnormalities found on ultrasound. MRI differentiates the various types of fetal ventriculomegaly. Superior posterior fossa visualization allows differentiation of Dandy-Walker malformation from a large cisterna magna. Anomalies of the corpus callosum can be seen. MRI also is valuable in the evaluation of fetal giant neck masses for planning delivery of the baby and surgery for life-threatening airway obstruction. In the chest, MRI differentiates masses such as diaphragmatic hernia, cystic adenomatoid malformation, and sequestration, and it aids in planning fetal surgery because MRI directly visualizes the position of the lung, liver, and bowel.     

Intraoperative magnetic resonance imaging

Intraoperative magnetic resonance imaging (MRI) allows neurosurgeons to perform surgery interactively using magnetic resonance (MR) guidance. Low-field and high-field strength MRI has been developed and implemented for multiple neurosurgical procedures, including brain biopsies, craniotomies for resection of mass lesions, cyst drainages, laminectomies, thermal ablations, functional neurosurgery, and a variety of miscellaneous cases. Both technologies have the advantage over frameless neuronavigational systems of being able to perform near real-time imaging, which allows the surgeon to compensate for intraoperative brain shift. Intraoperative functional techniques such as MR spectroscopy, functional MRI, MR angiography and venography, and diffusion-weighted imaging, which have become routine at some high-field MR units, can significantly influence surgical decision making. The potential complications associated with intraoperative MR-guided neurosurgery are similar in incidence to those seen in the conventional neurosurgical operating room. However, the immediate recognition of such intraoperative complications with MRI should lead to improved outcomes and decreased medical costs. Untoward events associated with performing surgery in an MR environment are uncommon. Intraoperative MR-guided neurosurgery represents a natural progression from framed and frameless stereotactic techniques. Intraoperative MRI is still in its infancy, and the full capabilities of this technology have yet to be determined or implemented.     

Coronary magnetic resonance imaging

This article highlights the technical challenges and general imaging strategies for coronary MRI. This is followed by a review of the clinical results for the assessment of anomalous CAD, coronary artery aneurysms, native vessel integrity, and coronary artery bypass graft disease using the more commonly applied MRI methods. It concludes with a brief discussion of the advantages/disadvantages and clinical results comparing coronary MRI with multidetector CT (MDCT) coronary angiography.