磁共振扩散加权成像在眼眶病变中的应用

眼眶大部分病变在常规MRI图像上容易诊断,但如淋巴瘤与炎性假瘤等鉴别诊断困难。磁共振扩散加权成像(DWI)是一种较成熟的技术,已运用到全身各个系统。本文主要是对该技术在眼眶疾病中国内外应用情况进行综述评价。     

磁共振扩散加权成像在诊断肝脏占位性病变中的应用进展

随着磁共振扩散加权成像（DWI）的表面扩散系数（ADC）值的变化规律及扩散成像的量化分析、背景抑制磁共振弥散加权成像（DWIBS）等技术开发应用,肝占位性病变的准确诊断与鉴别诊断已成为可能。     

原发性脑淋巴瘤的MRI功能成像和延迟强化特点

目的:探讨原发性脑淋巴瘤的MRI延迟强化方式及弥散加卡义成像、氢质了磁共振波谱、灌注加权成像的特点.方法:同顾性分析23例原发性颅内淋巴瘤的MRI延迟强化以及弥敞加权特点,同时对其中12例磁共振波谱成像和9例灌注加权成像表现进行仔细分析.结果:多发16例,单发7例,共检出50个病灶,T1.WI呈等或稍低信号,T2WI呈等或稍高信号,23例DWI呈高或稍高信号.延迟强化显示15个强化灶范围增大、8个新增强化灶、9个不均匀强化灶趋十均匀、6个强化灶内低信号范围缩小.行磁共振波谱成像的12例中增强后首次扫描即出现强化的病灶表现为Cho升高、NAA下降、出现高Lip峰,其中5个病灶出现Lac峰,另外4个新增延迟强化病灶的MRS表现为NAA轻微下降、Cho稍升高、Iip峰矮小、未见Lac峰.9例灌注加权成像显示脑淋巴瘤呈低灌注趋势.结论:综合分析常规MRI表现及其延迟强化方式、弥散加权成像、磁共振波谱成像及灌注加权成像的特点,能够做出脑淋巴瘤的定性诊断.延迟强化或许可以更充分反映病灶的数量和范围.     

磁共振新技术评价脑肿瘤伽玛刀治疗效果的研究进展

早期定量评估脑肿瘤的伽玛刀治疗效果对临床治疗方案的制定具有重要意义。扩散加权成像（DWI）、灌注加权成像（PWI）、磁共振波谱（MRS）等MRI新技术能够从分子、功能、代谢角度早期了解脑肿瘤伽玛刀治疗后的病情进展,并为预后提供重要信息。就脑肿瘤的伽玛刀治疗概况及MRI新技术在评价脑肿瘤伽玛刀治疗效果中的应用予以综述。     

磁共振弥散加权成像对急性皮层下脑梗塞的评价

目的 研究磁共振弥散加权成像（DWI）诊断急性皮层下脑梗塞的准确性以及对急性与非急性皮层下脑梗塞的鉴别诊断。材料与方法 对32例临床诊断为急性皮层下脑梗塞的患者和20例对照者在不同时间内进行常规MRI检查和弥散加权MRI检查,并用盲法进行对照观察。对所有病例的病变部位均按神经解剖进行准确定位并与患者的症状、体征相联系。结果 DWI诊断急性皮层下脑梗塞的敏感性、特异性及准确性分别为97％、95％和96％。32例中有3例常规MRI检查未发现急性梗塞性。另20例常规MRI检查均显示为多发梗塞,而DWI只显示单个急性病灶,且患者的症状、体征与DWI上显示的病灶相符。结论 DWI对诊断急性皮层下脑梗塞有很高的准确性,能发现常规T2WI不能发现的早期脑梗塞,并能鉴别急性与非急性梗塞。     

MRI评价肝癌热消融疗效的研究进展

【摘要】肝癌热消融治疗（TAT）在临床上应用较为广泛,MRI在其疗效评价方面有重要作用,尤其是随着功能磁共振成像技术如扩散加权成像（DWI）、灌注成像（PWI）及磁共振波谱成像（MRS）的发展,以及一些特异性对比剂的使用,使得MRI在肝癌热消融疗效评价方面的优势更加明显。大量研究显示,MRI有助于TAT治疗后对消融灶与周边组织的鉴别,能更早期发现肿瘤残余或复发。本文就MRI在肝癌热消融术疗效评价方面的研究进展进行叙述。     

磁敏感加权成像在脑淋巴瘤与胶质母细胞瘤鉴别诊断的价值

目的：探讨脑淋巴瘤与胶质母细胞（GMB）的磁敏感加权成像（SWI）影像学特征以及肿瘤内磁敏感信号强度（ITSS）对其鉴别诊断的价值。方法回顾性分析经手术或活检病理证实的13例脑原发性淋巴瘤和19例胶质母细胞瘤的常规MRI及SWI影像学表现,测量肿瘤内磁敏感信号强度（ITSS）,对比分析两者的影像学表现特点。结果13例淋巴瘤ITSS评分为0～1级,ITSS评分0级8例,1级5例。19例胶质母细胞瘤ITSS评级均为3级,胶质母细胞瘤ITSS级别明显高于淋巴瘤,两者ITSS级别有明显统计学差异（ P ＜0．001）。结论定量测量肿瘤内ITSS有助于脑淋巴瘤与胶质母细胞瘤的鉴别诊断,可以作为常规MR检查的补充手段。     

高血压脑病发病机制及相关MRI表现

高血压脑病（hypertensive encephalopathy ,HE）是内科较为常见的急症,常发生在重症高血压患者,其发病机制目前较为公认的主要有血管痉挛学说和脑血管自动调节功能崩溃学说。M RI在高血压脑病诊断、鉴别诊断、疗效观察及预后评定中有重要帮助,以下主要通过 M RI不同成像技术方法,包括常规平扫、弥散加权成像、磁共振血管成像（MRA）、磁共振波谱成像（MRS）、磁共振增强扫描、磁共振灌注成像（PWI）及磁敏感成像（SWI）,综合起来阐述该病各有何种表现,就其相关临床发病机制予以综述。     

胰腺外分泌功能的MRI研究进展

胰腺外分泌功能检查对胰腺生理功能研究及胰腺外分泌功能不全相关性疾病的诊断及疗效评估有十分重要的意义。近年来,多种MRI技术用于检测胰腺外分泌功能,如胰泌素刺激增强MR胆胰管水成像（s-MRCP）可进行功能诊断及分级,基于扩散加权的磁共振成像（DW-MRI）能够对主胰管内胰液的流速进行半定量检测,基于空间选择反转恢复脉冲的电影胆胰管水成像（CINE-MRCP）可直接观察胰管内胰液流动。综述常用胰腺外分泌功能MRI检查技术及应用进展。     

MR DWI对急性脑梗死的诊断优势

目的 评价磁共振弥散加权成像（MRDWI）对急性期脑梗死（发病后6h内）的诊断价值。方法对卒中样起病且发病时间在2h．24h以内、临床高度怀疑脑梗死的18例患者进行DWI和常规MRI扫描。分析比较了早期MR DWI和常规MRI所见。结果MR DWI提示中风的18例患者最终l临床均诊断为急性期脑梗死，常规MRI仅为5例。DWI诊断急性期脑梗死的敏感性为100％，特异性为100％，而常规MRI诊断急性期脑梗死的敏感性和特异性分别为27．8％和100％。结论DWI对急性期脑梗死的诊断高度准确，其敏感高度明显高于常规MRI。     

Physiologic and pathologic calcifications and ossifications in the face and neck

The aim was to give a systematic presentation of physiologic and pathologic calcifications and ossifications in the face and neck with a special emphasis on clinical relevance. In a sometimes subacute setting one should recognize specific calcifications which often lead to important diagnoses such as fungal sinusitis or sclerosing labyrinthitis. In a more chronic situation intraocular calcifications in small children are pathognomonic for retinoblastoma. Juxtatumoral sclerosis of the laryngeal cartilage in laryngopharyngeal carcinoma is usually caused by tumor infiltration of the cartilage resulting in a higher tumor stage and, this way, has a major impact on the therapeutical strategy. Calcified lymph nodes are mainly unspecific but can be the result of tuberculosis or metastases of thyroid cancer. Cross-sectional imaging methods, most of all computed tomography, are ideally suited to reveal head and neck calcifications and ossifications, especially those which are clinically relevant.     

Head and neck infection and inflammation

This article discusses the imaging manifestations of infectious and inflammatory conditions of the head and neck. Special attention is paid to the sites, routes of spread, and complications of neck infections. Because the clinical signs and symptoms and the complications of these conditions are often determined by the precise anatomic site involved, anatomic considerations are stressed. Familiarity with the fascial layers, spaces of the neck, and the contents of each space is helpful for this discussion. The fascial layers of the neck are important barriers to infection, and once infection is established, the fascial layers play a part in directing its spread.     

Staging and surgical management of pancreatic and biliary cancer and inflammation

Management of benign and malignant diseases of the pancreas, liver, and biliary tract has made remarkable progress in the last two decades. Advances in minimally invasive surgery, interventional radiology, and diagnostic and therapeutic endoscopy have changed the treatment of common diseases such as cholelithiasis and more serious diseases such as pancreatic adenocarcinoma. Advances in biliary tract and pancreatic surgery have paralleled the advances in ultrasonographic imaging, CT, and MR imaging. This article outlines the surgeon's perspective on radiologic imaging and preoperative staging of benign and malignant biliary and pancreatic disease.     

The thyroid and parathyroid glands. CT and MR imaging and correlation with pathology and clinical findings

Thyroid imaging approach is based on the preliminary clinical evaluation. Lesions that are smaller than 2 cm should be assessed with US, which is capable of discriminating masses as small as 2 mm and distinguishing solid from cystic nodules. US-guided FNAB provides tissue for cytologic examination of thyroid nodules. CT and MR imaging are indicated for larger tumors (greater than 3 cm diameter) that extend outside the gland to adjoining structures, including the mediastinum, and retropharyngeal region. Metastatic lymph nodes in the neck and invasion of the aerodigestive tract are also in the realm of CT and MR imaging. Thyroid nodules are categorized on scintigraphy as hot or cold nodules. Hot nodules are rarely malignant, whereas cold nodules have an incidence of 10% to 20% of malignancy. Calcifications (amorphous, globular, nodular, and linear) occur in adenomas and carcinomas and have no differential diagnostic features except for psammomatous calcifications, which are a pathognomonic finding in papillary carcinomas and a small percentage of medullary carcinomas. Papillary carcinoma is the most common malignant tumor (80%) followed by follicular (20% to 25%); medullary (5%); undifferentiated; anaplastic carcinomas (< 5%); lymphoma (5%); and metastases. Lymph node metastases are common in papillary carcinoma, 50% at presentation, and less common in follicular carcinomas. The metastatic nodes in papillary carcinoma may enhance markedly (hypervascular); show increased signal intensity on T1-weighted images (increased thyroglobulin content or hemorrhage); and reveal punctate calcifications. Localized invasion of the larynx, trachea, and esophagus occurs predominantly in papillary and follicular carcinomas; the incidence is less than 5%. Ectopic thyroid tissue may be encountered in the tongue (foramen cecum); along the midline between posterior tongue and isthmus of thyroid gland; lateral neck; mediastinum; and oral cavity. Goiter and malignant tumors, notably papillary carcinoma, may develop in ectopic thyroid tissue. Carcinomas may also arise in thyroglossal duct cysts, which develop from duct remnants between the foramen cecum and thyroid isthmus. Infectious disease of the thyroid gland is not common and the CT and MR imaging findings are similar as described under neck infection. Other types of inflammatory disorders including Hashimoto's thyroiditis, granulomatous thyroiditis, and Riedel's struma display no specific imaging features. Imaging studies may, however, be indicated to confirm a suspected clinical diagnosis and assess compromise of the airway (Riedel's struma). HPT is a clinical diagnosis in which hypercalcemia is the most important finding. Parathyroid hyperplasia, adenoma, and carcinoma represent underlying lesions. To relieve the patient's symptoms surgical extirpation is indicated. The surgical success rate without imaging is 95%. The indications for imaging studies vary but it is generally agreed that reoperation after a previous failed surgical attempt and suspicion of an ectopic parathyroid adenoma should be investigated by imaging. These consist of US, nuclear medicine studies, CT and MR imaging. US and technetium sestamibi scanning have the highest accuracy rate for localizing an adenomatous gland at and near the thyroid gland. Ectopic adenomas, particularly if they are located in the mediastinum, are preferrably investigated with CT and MR imaging with gadolinium and fat suppression. Carcinomas and parathyroid cysts are optimally evaluated by CT and MR imaging. On MR imaging adenomas are low in signal intensity on T1-weighted images, high in signal intensity on T2-weighted images, and enhance post introduction of gadolinium.     

细胞自噬与肿瘤发生发展

自噬是真核生物中一种高度保守的胞内降解途径.其主要通过溶酶体或液泡进行饥饿状态下的营养动员,清除受损蛋白质、细胞器和胞内病原体.自噬主要包括巨自噬、分子伴侣介导自噬(CMA)和微自噬.自噬已被证实与多种人类疾病相关,其在肿瘤发生发展中具有重要意义.近年研究中,对于自噬和肿瘤关系有了进一步的认识,该文就自噬分子机制、调控...