骨骼肌运动损伤的MRI研究进展

骨骼肌是人体维持姿势、产生能量、提供力量的重要结构,体育运动需要借助骨骼肌完成,因此运动损伤不容忽视。MR因具有较高的软组织分辨力和空间分辨力而具有独特的诊断优势。本文就MR技术在骨骼肌运动损伤方面的应用进展进行综述。     

三阴性乳腺癌MRI征象与临床病理特征的研究现状

三阴性乳腺癌指雌激素受体、孕激素受体和人表皮生长因子受体2均表达阴性的乳腺癌。该型乳腺癌具有特殊的生物学行为和临床病理特征,侵袭性强,缺乏有效的内分泌治疗和靶向治疗,是乳腺癌分子亚型中预后最差的一种。MRI是目前诊断乳腺癌最有价值的检查方法之一。MRI表现为肿块型单一病灶．形状不规则．边缘光滑,呈环形强化,T2WI上病变中心呈高信号,表现为Ⅲ型时间一信号强度曲线以及较高的ADC值,对诊断三阴性乳腺癌有一定的参考价值。     

兔脑缺血区扩散、灌注成像及细胞内钙的对照研究

目的　本实验预通过制作兔大脑中动脉持久性闭塞 (MCAo)模型 ,采用MR扩散和灌注加权成像 (DWI和PWI)确认半暗带 ,并与病理脑片水平不同缺血区域的细胞内钙离子浓度的变化进行对照研究 ,试图了解脑缺血早期半暗带MR特征及其与细胞内钙超载的关系。方法　 2 8只新西兰兔按MCAo后 0 5～ 3 6h间不同时间分为 7组 ,在既定时间行DWI及PWI,最后 1次MR检查完后立即处死动物 ,并迅速取脑 ,制作病理脑片及钙离子荧光探剂标记。将制备好的脑片置于激光共聚焦显微镜下观察兴趣区荧光强度。将缺血侧尾壳核区 (Ⅰ区 )、额顶叶皮质区 (Ⅱ区 )的MR各项参数及钙离子荧光强度进行配对t检验及方差分析。结果　MR结果显示MCAo后 ,缺血侧Ⅰ区、Ⅱ区脑血流量(CBF)、脑血容量 (CBV)较对侧有明显的降低 ,MCAo后 0 5～ 6h ,Ⅰ区的相对表观扩散系数 (rADC)明显低于Ⅱ区 (t=2 6 3 3 ,P <0 0 0 1)。 12h后差异无显著性意义 (F =1 60 ,P >0 0 5)。细胞内钙荧光检测结果显示MCAo后 0 5h ,Ⅰ区的荧光强度 (FI)即较对侧增强 3 18± 0 14倍 (t =5 2 7,P <0 0 5) ,而Ⅱ区与对侧相应区域在缺血后 1 5h以内FI差异无显著性意义 (F =3 2 1,P >0 0 5) ,3h后缺血侧Ⅱ区FI较对侧相应区域升高 (F =10 3 8,P <0 0 1)。Ⅰ区缺血 3h以内rA     

兔肢体VX2软组织肿瘤MR扩散加权成像

目的:建立兔肢体软组织肿瘤模型,探讨MR扩散加权成像在软组织肿瘤诊断中应用的可行性及适用于软组织肿瘤成像的合适的b值。方法:25只新西兰大白兔(月龄2～3个月,体重1.5～2.0kg,雌雄不限),将肿瘤瘤株种植在左前上肢内侧。在种植瘤株后2～3周使用1.5T磁共振仪行常规MRI及DWI检查,b值取200、400、600、800和1000s/mm2。在MRI检查后3～4周分批处死荷瘤兔,取出肿瘤组织,观察肿瘤的大体形态及病理学表现。结果:肿瘤成瘤率96%(24/25)。种瘤后14、21和28天,肿瘤直径分别约为2.0、4.0和5.5cm。肿瘤直径比较小(14天)时,质地硬,肿瘤坏死、瘤周水肿很少见。在常规T1WI上肿瘤实质多呈等信号,瘤内出血少见;T2WI上肿瘤实质为不均匀高信号,肿瘤中央和瘤周可见信号更高的坏死、水肿区;增强后肿瘤实质明显强化,肿瘤边缘强化更显著。DWI图像上,当b值较小时(200s/mm2)受T2透过效应影响明显,b值比较大时(1000s/mm2)图像信噪比下降明显,b值为600和800s/mm2时,图像质量比较好;b值为200、400、600、800和1000s/mm2时肿瘤的ADC值分别为(1.56±0.11)、(1.32±0.12)、(1.25±0.10)、(1.19±0.08)和(1.14±0.07)mm2/s;b值为600和800s/mm2时,肿瘤实质的ADC值明显小于坏死区及周围肌肉组织,差异有显著性意义(P<0.005)。结论:DWI可以用于兔肢体VX2软组织肿瘤的观察,b值为600和800s/mm2时可以获得比较好的DWI图像。肿瘤组织、肌肉组织及坏死组织的ADC值明显不同,DWI在软组织肿瘤的诊断和预后评估等方面具有广阔的应用前景。     

犬严重烧伤早期脑水肿MRI与病理观察的对比分析

目的　探讨严重烧伤早期脑水肿MRI表现与病理改变的相关性。方法　 2 6只犬随机分为对照组 (6只 )和致伤组 (伤后 6、12、18和 2 4h ,各组分别为 5只 ) ,采用体表烧伤法将致伤组犬制成 5 0 %总烧伤面积 (TBSA)Ⅲ度创面 ,并于伤后 6h静脉输注 5 %葡萄糖液 ,以建立严重烧伤脑水肿模型。应用MRI与病理 (巨检、光学显微镜、电子显微镜 )对比分析法对各致伤组犬进行了动态观察。结果　MRI形态改变显示的最早时间为伤后 12h ,以弥漫性脑肿胀为其表现特征。与对照组比较 ,当T1WI信号强度比值 (SIR)下降达 10 39%(t=2 2 6 1,P <0 0 5 )前 ,MRI难以发现 ;伤后 2 4hT2 WISIR增高 8 2 9%(t=3 6 95 ,P <0 0 5 ) ,脑灰、白质分界模糊 ,以致部分消失。病理学观察烧伤 6h以后毛细血管内皮细胞及血管周围星形胶质细胞终足肿胀 ;神经细胞出现空泡状现象 ;毛细血管内皮细胞、神经细胞及轴突呈不同程度的缺血性改变。随着观察时间的延长 ,这种改变逐渐明显 ,以伤后 2 4h表现最为显著。结论　严重烧伤早期脑水肿模型兼有血管源性和细胞毒性脑水肿的MRI及病理组织学特征。     

原发性输卵管癌的MRI表现特征

目的 探讨原发性输卵管癌(PFTC)的MRI表现特征.方法 选取经手术病理证实的23例PFTC患者,对其MRI表现特征,包括大小、形态、信号特点和强化方式进行回顾性分析.结果 23例患者均为单侧型,左侧10例,右侧13例,其中呈管状(香肠)型8例,肿瘤在输卵管内生长,肿瘤大小范围为管状型0.75 cm×1.69 cm～...     

原发性肾脏淋巴瘤的MRI特征

目的:探讨原发性肾脏淋巴瘤(PRL)的MRI特征.方法:回顾性分析9例经手术病理证实的PRL的MRI检查资料,均行MRI平扫及增强.结果:9例共16个病灶,位于左肾6例8个,右肾2例2个,1例双肾受累6个病灶.病灶呈结节状或类圆形4例,不规则或地图状4例,新月形1例.瘤体直径0.6～7.8cm.MRI表现:肾内结节/肿块型4例,肾周型2例,肾盂型2例,弥漫浸润型1例,其中7例肾脏保持正常形态,所有病灶均无包膜.均呈等或稍长T1、等或稍长T2信号,T1WI反相位信号均无减低,DWI高信号,6例信号均匀,3例信号不均匀,其内见小片坏死呈长T1长T2信号.增强皮质期病变均呈轻度强化,髓质期8例轻度持续强化,1例明显强化,分泌期均呈低信号.结论:PRL的MRI表现具有较典型的特征,MRI检查是诊断PRL的有效方法.     

特发性腹膜后纤维化的MRI诊断

目的：探讨特发性腹膜后纤维化（IRPF）的MRI表现。方法：回顾性分析8例经穿刺活检病理证实的IRPF患者的MRI图像资料。所有患者均行腹部MRI常规扫描,其中5例同时行增强扫描,4例行DWI检查,5例行MRU检查。结果：IRPF呈类圆形或不规则形软组织信号,包绕腹膜后大血管及输尿管等腹膜后器官,早期病变呈稍长T1、稍长T2信号,动态增强扫描动脉期示病灶明显强化,DWI上呈稍高信号;中晚期病变T2WI信号逐渐减低,呈等信号或低信号,动态增强扫描动脉期及静脉期无明显强化,延迟期呈轻度不均匀强化,DWI上呈不均匀稍低信号。当病变包绕输尿管时,MRU检查可见一侧或双侧输尿管变细,病变段以上输尿管积水及肾盂积水。结论：MRI多序列检查有助于IRPF的诊断及鉴别诊断,有较大的临床应用价值。     

兔早期动脉粥样硬化斑块的MRI表现与组织病理学对照研究

目的通过与组织病理学对照研究，探讨MRI在早期动脉粥样硬化斑块中的诊断价值。方法用高脂饮食方法建立20只新西兰大白兔的早期动脉粥样硬化模型，分别于不同时期（9、18周）对实验兔进行以右肾动脉水平为中心的腹主动脉段MR扫描，数字法随机将所有实验兔编号，按单数、双数将实验兔分为2组，每组10只，在不同时期扫描结束后处死1组实验兔取其相应段血管进行HE染色，与MR图像进行组织病理学对照。扫描序列为常规的SE T1WI及快速自旋回波质子加权成像（FSE—PDWI）脂肪抑制序列，并使用钆喷替酸葡甲胺（GD—DTPA）增强扫描。观察不同序列上的早期斑块在不同时期的影像学表现并与组织病理学对照，评价MRI在早期动脉粥样斑块中的诊断价值，并分析斑块的组织学成分及生理病理学的动态发展变化。结果所有实验兔在高脂饮食后9周，血管内膜即可见明显的局部斑块形成，且具有弱强化性质，SE T1WI序列显示早期病变最佳，18周斑块厚度及范围进一步扩大，斑块及血管壁均可强化，组织病理学显示早期病变主要发生于血管内膜，9周主要以泡沫细胞为主，18周在泡沫细胞周围有大量的基质纤维成分及小的毛细血管存在。结论常规的MR扫描技术能对早期动脉粥样斑块的发生发展进行动态观察，并能从组织学水平对其进行评价。     

后循环缺血的功能MRI研究

后循环缺血(PCI)也称椎基底动脉系统缺血,虽然其发病率远低于前循环缺血(ACI),但其致死率显著高于ACI,严重威胁人类健康,故越来越受到国内外研究者的关注。早期诊断和治疗是改善PCI预后的关键。各种功能MRI技术不仅能够获得后循环结构的形态学和解剖学信息,而且能够无创性观察活体脑组织血流、代谢及功能情况,对PCI的早期诊断和疗效评估等具有重要价值。对各种功能MRI技术在PCI中的研究应用进行综述。     

MR appearance of skeletal neoplasms following cryotherapy

Cryotherapy is an increasingly popular mode of therapy adjunctive to surgical curettage in the treatment of certain skeletal neoplasms, such as giant cell tumors or chondrosarcomas. The magnetic resonance (MR) findings following cryotherapy have not been previously reported. We reviewed the MR findings in seven patients with skeletal neoplasms following curettage and cryotherapy. In six cases we found a zone of varying thickness extending beyond the surgical margins, corresponding to an area of cryoinjury to medullary bone. This zone displayed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, consistent with the presence of marrow edema. This zone of edema almost certainly reflects underlying thermal osteonecrosis. This zone may vary in size and intensity over time as the area of cryoinjury evolves or resolves. MR is currently the imaging procedure of choice for follow-up of most musculoskeletal neoplasms. Knowledge of the MR findings following cryotherapy should help prevent confusion during the interpretation of follow-up MR examinations.     

Infiltrating angiolipoma of skeletal muscle: MR findings

Infiltrating angiolipoma of skeletal muscle is a rare benign tumor that has a tendency to recur unless completely excised. Although CT and angiography have been used to determine its extent, they will not allow a definite diagnosis. We present magnetic resonance findings and assert that an accurate preoperative diagnosis can be made based on those findings.     

Prediction of muscle viability after electrical burn necrosis.

In this preliminary study, Tc-99m MIBI, a muscle perfusion agent, was used to assess the viability of tissues in two patients with extensive high-tension electrical burns. This proved to be an easy and definitive diagnostic procedure and a practical solution to determining the level of amputation before surgery.     

Steroid receptors in two types of rabbit skeletal muscle

Radiolabeled synthetic steroid hormones and a charcoal adsorption assay were used to identify cytosolic androgen, glucocorticoid, and estrogen receptors in skeletal muscle from rabbits. The presence of the receptors was verified by saturation analysis showing low-capacity, high-affinity binding for the steroid-receptor complexes, specific for each class of steroids. The concentration of androgen and estrogen receptors were of the same magnitude, whereas the corresponding value for the glucocorticoid receptor was about tenfold higher. Comparisons of fast-twitch (the gastrocnemius/plantaris complex) and slow-twitch (soleus) muscles revealed that the latter contained higher concentrations (expressed per g of tissue wet weight) of glucocorticoid and estrogen receptors, but not of androgen receptor. Expressed per mg of soluble protein, the slow-twitch muscle contained higher concentrations of all three receptors, but when related to the concentrations of all three receptors, but when related to the concentration of DNA, only the concentration of estrogen receptor was higher in the slow-twitch muscle. Different response of the two fiber types to direct action of steroid hormones can hence be expected. The fast-twitch muscle contained a higher concentration of soluble protein, whereas the slow-twitch muscle contained higher concentration of DNA, resulting in lower protein/DNA ratio, i.e., smaller "cell units," in the latter muscle.     

Cardiac and skeletal muscle effects of electrical weapons

Conducted Electrical Weapons (CEWs) are being used as the preferred non-lethal force option for police and special forces worldwide. This new technology challenges an exposed opponent similarly to the way they would be challenged by physical exercise combined with emotional stress. While adrenergic and metabolic effects have been meta-analyzed and reviewed, there has been no systematic review of the effects of CEWs on skeletal and cardiac muscle. A systematic and careful search of the MedLine database was performed to find publications describing pathophysiological cardiac and skeletal muscle effects of CEWs. For skeletal muscle effects, we analyzed all publications providing changes in creatine kinase, myoglobin and potassium. For cardiac effects, we analyzed reported troponin changes and arrhythmias related to short dart-to-heart-distances. Conducted electrical weapons satisfy all relevant electrical safety standards and there are, to date, no proven electrocution incidents caused by CEWs. A potential cardiovascular risk has been recognized by some of the experimental animal data. The effects on the heart appear to be limited to instances when there is a short dart-to-heart-distance. The effect on the skeletal muscle system appears to be negligible. A responsible use of a CEW on a healthy adult, within the guidelines proposed by the manufacturer, does not imply a significant health risk for that healthy adult.     

高压电烧伤致白内障一例报道

高压电烧伤诱发白内障属少见并发症，本院曾救治一例。现报道如下。     

Hemangiomas of skeletal muscle: MR findings in five patients

Skeletal muscle hemangiomas are uncommon tumors of young adults. More than 90% are misdiagnosed preoperatively. Plain-film examinations, bone scans, CT studies, and angiography may not always be specific for this tumor. Seven MR examinations were performed in five young adult patients with pathologically proved skeletal muscle hemangiomas. All five hemangiomas showed high signal intensity on both T1- and T2-weighted images. The signal intensity in these tumors was less than that of subcutaneous fat on relatively T1-weighted images and greater than that of fat on relatively T2-weighted images. Four tumors had a serpiginous pattern. Four patients had focal muscle atrophy. Three patients had all three findings (high signal intensity on both T1- and T2-weighted images, serpiginous pattern, and associated focal muscle atrophy) while the other two patients had at least two of the three findings. These three patients did not undergo angiography or needle biopsies before surgery because the MR findings were highly suggestive of hemangioma. Our experience with this small series of patients suggests that skeletal muscle hemangiomas have a consistent appearance on MR. MR may be able to contribute significantly to the preoperative diagnosis of this tumor and may also supply valuable information about the extent of the lesion.     

Structural and metabolic characteristics of human skeletal muscle following 30 days of simulated microgravity

Percutaneous needle biopsy samples were obtained from the vastus lateralis and soleus muscles before and after 30 d of 6 degree head-down bedrest to determine the influence of this model of simulated microgravity on human skeletal muscle. Fiber atrophy was evident in both muscles with both fast-twitch and slow-twitch fiber cross-sectional areas decreasing. Predominant atrophy of slow-twitch fibers was not evident. The soleus had a greater proportion of slow-twitch fibers than the vastus lateralis before bedrest. Neither muscle showed a change in fiber type percentage with bedrest. Phosphofructokinase and lactate dehydrogenase activities in the soleus and vastus lateralis muscles were similar before and after bedrest. The activities of beta-hydroxyacyl-CoA dehydrogenase and citrate synthase, however, were reduced during bedrest with these responses being somewhat greater in the soleus. While the ultrastructure of most of the fibers of the soleus and vastus lateralis appeared normal after bedrest, evidence of remodeling was present in both muscles. The proliferation of core/targetoid lesions, honeycomb networks, regenerating satellite cells, necrotic foci and myofibrillar disorganization after bedrest indicates that force development is an important factor in determining the organization of the fine structure of muscle. The results indicate that short-duration exposure to simulated microgravity decreases fiber size and the capacity for aerobic energy supply of human skeletal muscle. Moreover, disorganization of the contractile machinery occurs. Thus, it appears that bedrest alters the "normal" load-time constraints imposed on skeletal muscle sufficiently to change its inherent structural and metabolic characteristics.