磁共振弥散成像在急性脑梗死的诊断应用

目的 探讨磁共振弥散成像(DWI)对急性脑梗死诊断价值。方法对54例脑梗死患者的常规MRI、液体衰减翻转恢复(FLAIR)及DWI图像进行比较研究分析。结果超急性、急性和亚急性脑梗死在DWI上均表现为高信号，在超急性脑梗死弥散加权像可显示T2加权像不能显示的病灶，在T2WI及HLAIR加权像可显示的病变中，弥散加权像可更清楚更全面地显示病灶。结论DWI对诊断急性脑梗死十分敏感，能对早期脑缺血做出明确诊断，结合T2WI及HAIR可鉴别新旧梗死灶。     

DWI诊断急性脑梗死36例分析

目的：探讨弥散加权成像（DWI）技术在急性脑梗死中的临床应用价值。方法：收集36例急性脑梗死患者，均行常规T1WI、T2WI、及FLAIR、DWI扫描。结果：（1）DWI对病灶的显示范围、对比度均优于常规T1WI、T2WI及T2FLAIR。（2）DWI的b值越高，弥散效果越好，显示病灶越清晰。结论：DWI技术对急性脑梗死病变敏感性最高，可准确、可靠地诊断急性脑梗死。     

DWI序列在急性脑梗塞中的应用

目的:分析磁共振弥散加权成像(DWI)在急性脑梗塞临床诊断中的应用。方法:对从2014年8月至2015年8月在我院就诊的64例急性脑梗塞患者的临床资料进行回顾性分析,经过CT平扫、常规MR序列、DWI序列检查对比分析。结果:(1)64例患者脑梗塞患者中,有8例患者为超急性期脑梗塞,56例为急性期脑梗塞患者。64例脑梗塞患者总共检测出85个病灶,其中75个为新发病灶。(2)急性期脑梗塞患者DWI检出率为100.0%,显著的高于FLAIR检出率(89.26%)(x~2=2.341,P0.05)、SE/TSE T1WI检出率(80.36%)(x~2=3.128,P0.05)、SE/TSE T2WI检出率(78.57%)(x~2=3.517,P0.05);超急性期脑梗塞患者DWI检出率为100.0%,显著的高于FLAIR检出率(0.00%)(P0.05)、SE/TSE T1WI检出率(0.00%)(P0.05)、SE/TSE T2WI检出率(0.00%)(P0.05)。结论:DWI序列在急性脑梗塞临床诊断中具有着很高的应用价值,尤其是对超急性期脑梗塞患者的临床诊断更具有优势,能够为患者提供更为科学、直接的影像资料,为临床溶栓治疗提供科学的指导意义。     

磁共振弥散加权成像诊断急性脑梗死的价值

目的评价磁共振弥散加权成像(DWI)和表观扩散系数(ADC)图在急性脑梗死诊断中的应用价值。方法回顾性分析41例急性脑梗死患者的MRI检查资料,其中超急性期(<6 h)4例,急性期(6~72 h)37例,均行磁共振常规T1WI、T2WI、Dark-fluid及DWI检查。结果 DWI显示病灶、病灶边界以及范围均优于常规T1WI、T2WI、Dark-fluid像;41例在DWI像上均表现为异常高信号,ADC图上表现为低信号。结论 DWI结合ADC图对诊断急性脑梗死具有很高的准确性和敏感性,能发现常规T1WI、T2WI、Dark-fluid像上不能发现的超急性期脑梗死,DWI与T2WI、ADC图结合能判断不同时期脑梗死。     

MRA结合DWI在急性脑梗死中的诊疗价值

目的:探讨磁共振血管成像(MRA)结合磁共振弥散加权成像(DWI)在急性脑梗死中的诊疗价值。方法:回顾性分析经影像学和临床联合诊断为急性脑梗死32例患者的完整MR资料(包括T1WI、T2WI、FLAIR、DWI、MRA),首次分析患者T1WI、T2WI、FLAIR图像,得出初步诊断结论,最终分析完整MR资料,得出最终诊断结论,对比两次分析方法对病变的检出率。结果:首次分析对急性脑梗死患者病灶检出率为43.75%,其中8例FLAIR序列局部血管为高信号;最终分析完整MR资料对急性脑梗死患者病灶检出率100.00%,DWI显示病灶解剖定位均与MRA上血管异常解剖定位有较好的一致性。最终分析对病变检出率明显大于首次分析检出率,P0.05,有统计学意义。结论:通过MRA结合DWI检查,对急性脑梗死初期的诊断更为确切和及时,能尽早的确认病灶位置,血管情况,值得在临床上广泛使用。     

超急性期脑梗塞的影像学诊断分析

目的:分析超急性期脑梗塞影像学特点。材料与方法:回顾性分析138例超急性期脑梗塞,56例行头颅CT平扫;82例行头颅MRI,其中59例为MRI平扫(T1WI、T2WI、FLAIR序列、矢状位T1WI)+弥散加权像(diffusion-weighted imaging,DWI),23例为MRI平扫+DWI+灌注成像((perfusion-weighted imaging,PWI);比较不同检查检出情况。结果:头颅CT阳性检出率为10.71%,常规MRI平扫阳性检出率为13.41%,无显著差异;DWI、PWI阳性检出率皆为100%,且异常信号定位与临床症状体征皆一致;DWI、PWI检查的23例中,16例PWI异常信号区域明显大于DWI,7例PWI与DWI大小类似;CT平扫与DWI+PWI检查阳性检出率比较,具有显著性差异。结论:在超急性期脑梗塞的影像学诊断方面,CT的优势在于排除脑出血,以及扫描快捷、易于实施;在阳性检出率方面,CT平扫与常规脑MRI平扫皆无优势;MRI弥散加权像、灌注成像具有强大诊断敏感性,能发现其它检查不能发现的阳性征象,其中灌注成像意义更重要。     

磁共振弥散加权成像在超急性、急性期脑梗塞诊断中的价值

目的探讨磁共振弥散加权成像(DWI)在超急性、急性期脑梗死诊断中的价值。方法对30例发病2～72h内临床考虑脑梗塞患者行MR常规T1WI、T2WI及DWI序列检查。结果 30例脑梗塞患者T1WI、T2WI共检出病灶110个,其中51个超急性、急性期梗塞病灶在DWI上显示呈高信号,ADC上呈低信号,梗塞部分均对应相应临床症状,阳性率为100%,51个病灶中T1WI及T2WI显示40个,阳性率为78%。结论 DWI技术在超急性、急性脑梗死的早期诊断以及判断分期方面,较常规MRI优越,为临床溶栓治疗提供最佳治疗方案。     

磁共振弥散加权成像诊断急性脑梗死30例分析

目的评价磁共振弥散加权成像(DWI)技术在诊断急性脑梗死中的临床应用价值。方法回顾性分析30例急性脑梗死患者的MRI检查资料,其中超急性期10例,急性期12例,亚急性期8例。均行常规TSE T1加权像(WI)、TSET2WI、FLAIR T2WI及SE-EPI DWI扫描,其中6例行3D时间飞行磁共振血管造影术(TOF MRA)。结果 30例DWI均清晰显示相应神经体征分布区的梗死灶,DWI对病灶的显示范围、对比度均明显优于TSE T1WI、TSE T2WI、FLAIR T2WI序列。6例行TOF MRA检查,其中2例大脑中动脉M2段完全闭塞,2例大脑前动脉主干闭塞,1例大脑后动脉闭塞,1例大脑中动脉远侧分支减少。结论 DWI在急性脑梗死的诊断中具有重要作用,结合常规TSE T1WI、TSE T2WI、FLAIR T2WI的信号变化,对判断患者脑缺血的时间有很大帮助。     

低场磁共振弥散成像在脑梗塞诊断中的应用

目的探讨低场磁共振弥散成像(DWI)序列对脑梗塞的诊断及分期的作用。方法应用(0.35T)磁共振T1WI、T2WI、FLAIR和DWI序列对77例脑梗塞病人进行扫描,分析各序列显示的结果及信号强度特点。结果3例超急性期脑缺血病例中,DWI显示为高信号,而T1WI、T2WI、FLAIR信号均无变化,65例急性期脑梗塞,在DWI、T2WI、FLAIR上以高信号为主,在T1WI表现为略低或低信号,9例急性腔隙性脑梗塞在DWI等信号,在T2WI、FLAIR呈高信号。结论DWI对脑缺血病变高度敏感,并能区分不同时期的脑梗塞,有助于临床治疗措施。     

DWI、ADC图在急性脑梗塞中的诊断价值

目的:探讨磁共振弥散加权成像(DWI)及表观弥散系数图(ADC mapping)在急性脑梗塞中的诊断价值。材料与方法:应用单次激发平面回波三向同性弥散加权MRI和常规MRI对28例急性脑梗塞患者进行检查,其中超急性期3例,急性期25例,测定病灶平均表观弥散系数(ADC)值、相对表观弥散系数(rADC)及病灶中心—边缘ADC值。结果:超急性期3例均在DWI及ADC图上显示出缺血灶,但其在CT及T2WI上表现正常。超急性、急性期脑梗塞在DWI上表现为高信号,其ADC值明显低于对侧相应区域,平均ADC值为(0.596±0.112)×10-3mm2/s,而对侧部位的平均ADC值为(0.880±0.148)×10-3mm2/s(P<0.01),28例超急性、急性期病灶ADC值均出现梯度征。结论:三向同性DWI及ADC图对急性脑梗塞,尤其是超急性脑梗塞较常规MRI及CT具有更高的敏感性,能快速、准确地诊断超急性、急性脑梗塞,并能反映缺血半暗带等相应的病理生理变化。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.