European Radiology科学论著摘要（2011年11月、12月杂志）

摘要目的根据2008年影响因子的高低,选取影响因子高的前70本影像学杂志．再分别从非影像学杂志的35个生物医学类别中分别选取影响因子高的前2本杂志,将选取的影像学杂志与非影像学杂志的摘要格式进行比较。方法搜索MEDLINE数据库中影响因子高的影像学与非影像学杂志已出版的文章。     

Radiology科学论著摘要（2011年11月、12月杂志）

摘要目的评估超快速模式与标准模式动态对比增强MR成像的药代动力学分析方法对乳腺癌诊断的准确性。材料与方法本研究通过机构伦理委员会审核且符合HIPAA规定。89名高危妇女（年龄28～83岁）填写了知情同意书,共发现92个可疑病变,其乳腺钼靶检查为阴性,而MR检查为阳性。     

超急性期脑梗死半影区弥散-灌注磁共振成像实验研究

目的　应用弥散加权 灌注 (DWI PI)磁共振成像技术对改良线栓栓塞大脑中动脉制作的大鼠超急性脑梗死模型进行实验研究 ,并与病理结果对照。明确联合应用PWI PI对超急性脑梗死半影区诊断价值。材料与方法　 5 0只SD大鼠 ,随机分成 5组 ,A组 (10只 )作假手术对照 ;其余按栓塞时间 30min、1、3、6h均分成B、C、D、E4组。A组于 30min、1、3、6h的时间点 ,B、C、D、E于各自栓塞时间点行弥散加权成像 (DWI)和灌注成像 (PI)扫描 ;工作站后处理获得表观弥散系数 (ADC)、脑血容量或血流量 (CBV或CBF)、平均通过时间 (MTT)形态图 ,计算ADC、CBV、CBF、MTT相对值 (与对侧相应部位比值 )。将成像结果与四氮唑红 (TTC)染色和病理观察对比。结果　 (1)A组DWI、PI成像无异常信号 ,病理观察无变化。 (2 )B、C、D、E组PI显示栓塞侧大脑中动脉供血区灌注缺损范围无变化 ,基底节区最重 ,皮质区较轻 ;DWI显示高信号 ;ADC比值降低 (6 5 .2 % ) ,D组达到最低 (32 .2 % ) ,E组基本不变(2 9.9% ) ;ADC形态图显示病灶范围逐渐扩大 ,最终 (E组 )与PI异常信号区基本一致。 (3)超急性脑梗死的DWI高信号范围与TTC染色所见的异常染色 (白色 )范围比较无显著性差异 (t检验 ,P >0 .1)。 (4 )在超急性脑梗死中存在PI DWI不重叠区 (缺血半     

Diffusion and Perfusion Characteristics of MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-Like Episode) in Thirteen Patients

Objective

We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies.

Materials and Methods

We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed.

Results

Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 ± 40.9% in the MELAS and 64 ± 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively.

Conclusion

The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage.     

3.0T MR多模态功能成像在胶质瘤术后复发与放射性坏死鉴别诊断中的价值

目的 探讨联合扩散加权成像(DWI)、灌注加权成像(PWI)和磁共振波谱(MRS)在胶质瘤术后复发与放射性坏死鉴别诊断中的价值.方法 34例胶质瘤术后复发和20例放射性坏死患者采用Siemens Verio 3.0 T磁共振扫描仪行常规MRI、DWI、PWI或MRS检查.分别测量DWI的表观扩散系数(ADC)值和rADC值、PWI的血流动力学参数和MRS的代谢物参数,利用两样本t检验和受试者工作特征曲线(ROC)分析各参数,并联合筛检DWI、PWI和MRS各自的最佳参数.结果 rADC值、rCBV和Cho/NAA分别是DWI、PWI和MRS的最佳诊断参数,对两种疾病鉴别诊断均有统计学意义(P＜0.05).以Youden指数最大值作为诊断临界点,rADC值诊断胶质瘤术后复发的敏感度和特异度分别为86.7％和72.9％.rCBV诊断胶质瘤术后复发的敏感度和特异度分别为76.5％和94.7％.Cho/NAA诊断胶质瘤术后复发的敏感度和特异度分别为77.8％和100％.联合rADC值、rCBV和Cho/NAA诊断胶质瘤术后复发的敏感度和特异度分别为94.7％和100％.结论 DWI、PWI和MRS在胶质瘤术后复发与放射性坏死鉴别诊断中有重要价值,联合最佳参数有助于两者的鉴别诊断.     

Acute stroke: Imaging and intervention

“Stroke” is defined as sudden-onset nonconvulsive neurologic deficit of a cerebrovascular origin. Each year, in the United States, 350,000 people experience a first stroke, and another 100,000 have a recurrent attack. A total of 400,000 to 500,000 new strokes occur annually, and there are 3 million stroke survivors. Stroke is the #3 cause of death and the #1 cause of disability (1992 Heart and Stroke Facts. Dallas: American Heart Association, 1991;1–48). This article will review recent advances in echoplanar diffusion-weighted magnetic resonance imaging and intravenous thrombolytic therapy of acute stroke.     

幕上脑内肿瘤磁共振灌注成像的初步研究

目的 探讨磁共振灌注成像(PWI)在幕上脑内肿瘤中的诊断价值。资料与方法 56例幕上脑内肿瘤,行双倍剂量PWI后,计算病灶的相对局部脑血流容积(rrCBV)。结果 Ⅲ、Ⅳ级星形细胞瘤和Ⅱ级少突胶质瘤为高灌注,而Ⅱ级星形细胞瘤和淋巴瘤为低灌注,低、高灌注肿瘤的rrCBV间差异显著,而高灌注肿瘤之间和低灌注肿瘤之间无差异。肺癌和乳腺癌脑转移瘤的rrCBV高于消化道癌肿脑转移瘤。结论 PWI在幕上脑内肿瘤的鉴别诊断、星形细胞瘤的分级和寻找转移瘤原发灶方面具有一定的价值。     

磁共振DWI和PWI在超急性脑梗死诊治中的应用

目的评价磁共振弥散加权成像（DWI）和灌注加权成像（PWI）在超急性脑梗死诊断及指导临床早期溶栓治疗中的应用价值。方法 56例发病在6 h以内且临床提示处于超急性期脑梗死患者均行急诊MRI检查,扫描序列包括T1WI、T2WI、FLAIR、DWI及PWI,部分病例行MRA检查。结果 56例患者T1WI均未见异常信号,35例患者T2WI、FLAIR发现有轻微异常信号影。56例DWI和PWI均发现异常,但在DWI上显示的高信号急性脑梗死区域与在PWI上显示的脑灌注延长区域不匹配,PWI显示的病灶范围更大。图像后处理显示平均通过时间（MTT）、达峰时间（TTP）均有不同程度的延长,脑血流量（CBF）出现不同程度的减少。结论急诊MRI,特别是DWI和PWI序列对超急性脑梗死患者可以作出准确的诊断,可以安全、迅速、有效地指导临床进行早期溶栓治疗。     

MR imaging in hyperacute ischemic stroke

Brain and vascular imaging are required components of the emergency assessment of patients with suspected stroke. Either CT or MRI may be used as the initial imaging test. MRI is more sensitive to the presence of acute and chronic ischemic lesions, and chronic microbleeds, but CT remains the most practical and used initial brain imaging test. Although, a non-enhanced CT or T2* MRI sequence showing no haemorrhage is sufficient for deciding intravenous treatment eligibility within the first 4.5 h after stroke onset, a non-invasive intracranial vascular study is strongly recommended during the initial imaging evaluation of the acute stroke patient, particularly if mechanical thrombectomy is contemplated. Advanced imaging with multimodal MRI may facilitate accurate ischemic stroke diagnosis and characterization, and should be considered as an alternative to CT, especially for the selection of patients for acute reperfusion therapy in extended time windows, and in patients in which time of stroke onset is unknown. However, MRI should only be considered in the acute stroke workflow if centres are able to achieve speed and triaging efficiency similar to that which is currently available with CT-based imaging.     

Perfusion CT and angio CT in the assessment of acute stroke

In order to evaluate the clinical utility of non-enhanced CT with perfusion and angio CT in the assessment of acute ischaemic stroke, 42 patients with symptoms of acute stroke were examined within the first 6 h from onset of symptoms with non-enhanced CT (NECT), perfusion CT (PCT) and CT angiography (CTA). Maps of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were analysed visually, and after drawing regions of interest (ROIs) in the territory of anterior, middle and posterior cerebral arteries, maximum-intensity projection and volume-rendering images of the cervical and cerebral vessels were created. All patients underwent a control CT or MR examination 24–48 h after the initial examination. Twenty-nine patients developed an area of infarction at control examinations. Significant perfusion abnormalities were found in 27 cases, whilst in two patients the perfusion studies were considered to be normal. All the cases with perfusion abnormalities showed arterial stenoses or occlusions on angio CT. Small infarctions at levels other than the ones selected for perfusion CT, and arteriosclerotic changes, were observed in the two cases with no perfusion abnormalities. In conclusion, combining non-enhanced CT with PCT and CTA is a simple and a very valuable tool in the initial assessment of acute stroke.     

Magnetic resonance diffusion-perfusion mismatch in acute ischemic stroke: An update

The concept of magnetic resonance perfusion-diffusion mismatch(PDM) provides a practical and approximate measure of the tissue at risk and has been increasingly applied for the evaluation of hyperacute and acute stroke in animals and patients.Recent studies demonstrated that PDM does not optimally define the ischemic penumbra;because early abnormality on diffusion-weighted imaging overestimates the infarct core by including part of the penumbra,and the abnormality on perfusion weighted imaging overestimates the penumbra by including regions of benign oligemia.To overcome these limitations,many efforts have been made to optimize conventional PDM.Various alternatives beyond the PDM concept are under investigation in order to better define the penumbra.The PDM theory has been applied in ischemic stroke for at least three purposes:to be used as a practical selection tool for stroke treatment;to test the hypothesis that patients with PDM pattern will benefit from treatment,while those without mismatch pattern will not;to be a surrogate measure for stroke outcome.The main patterns of PDM and its relation with clinical outcomes were also briefly reviewed.The conclusion was that patients with PDM documented more reperfusion,reduced infarct growth and better clinical outcomes compared to patients without PDM,but it was not yet clear that thrombolytic therapy is beneficial when patients were selected on PDM.Studies based on a larger cohort are currently under investigation to further validate the PDM hypothesis.     

Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques

In recent years, advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic problems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical decision support systems (CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually increased. Hence, the purpose of the current review article is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be introduced into intelligent systems to significantly improve their diagnostic specificity and clinical application.