磁共振磁化传递对比技术在脑内微小转移瘤中的应用

目的探讨磁共振磁化传递对比(MTC)技术对脑内微小转移瘤的应用价值。方法对37例患有脑转移瘤的病人行常规扫描后再行T_1-FLAIR和SE序列的T_1WI加MTC技术增强扫描,分别统计增强后T_1-FLAIR和T_1WI+MTC序列显示转移瘤的数目、大小、位置等,并比较2种序列图像的病灶-背景的对比度/噪声(C/Ns)值。结果 37例患者中,共计135个病灶,T_1WI+MTC显示133个病灶,显示率为98.5%,T_1-FLAIR序列显示129病灶,显示率为95.6%。T_1WI+MTC序列图像病灶-背景的C/Ns值为28.95±6.43,T_1-FLAIR序列图像病灶-背景的C/Ns值为14.45±7.64,T_1WI+MTC序列的C/Ns值高于T_1-FLAIR序列的C/Ns值(t=7.06,P0.01)。结论在显示脑内微小转移瘤方面,增强T_1WI+MTC序列比T_1-FLAIR序列更为敏感,MTC技术对评估脑内转移瘤具有重要的临床意义。     

对比增强磁敏感加权成像对肺癌脑转移瘤检出的研究

目的:探索对比增强磁敏感加权成像(CE-SWI)在肺癌脑转移瘤检出中的价值.方法:肺癌脑转移病例50例,分析增强T1WI(CE-T1WI)、SWI与CE-SWI对脑转移瘤的检出个数,采用χ2检验分析三种序列之间的差异,评估CE-SWI在肺癌脑转移瘤检出的敏感性.结果:CE-T1WI、SWI与CE-SWI共检出病灶142...     

MRI在肺癌脑转移瘤诊断和放疗疗效判定中的价值

目的 探讨增强MRI和弥散加权(DWI)在肺癌脑转移瘤诊断和放疗疗效判定中的价值.方法 回顾性分析经病理确诊为肺癌并经临床诊断为脑转移瘤的27例患者,所有病例均行MRI检查,包括T1WI、T2WI、T1WI增强及DWI扫描.结果 与其他序列相比T1WI增强检出率最高.转移瘤实质部分,瘤周水肿区和对侧正常脑实质区三者间ADC值差异显著.转移瘤放疗前后:瘤灶实质区ADC值差异显著,瘤周水肿区ADC值差异无统计学意义.结论 增强T1WI是发现脑转移的最佳序列,DWI和ADC值有助于脑转移瘤的定性诊断和放疗前后疗效评估.     

鼠肝MR成像技术参数探讨

探寻大白鼠肝脏MR成像序列及参数。材料和方法:采用GE0.5T Veetra MR成像仪匹配的SE序列,选择不同大小的像素及TR、TE进行MR成像,然后根据图像的解剖结构图像的均一性,伪影信噪比(SNR),对比噪声比(CNR),和对癌灶的显示,判断图像的优劣,分析不同的成像参数对图像的影响。结果:像素为0.491mm(成像孔径11cm,成像矩阵224×128)时,T_1加权图像的SNR,CNR及优质率分别为17.851±1.774,14.333±3.152,及77.78％(7/9),T_2加权图像的SNR,CNR及优质率分别为8.851±2.518,7.435±1.096及77.78％(7/9);像素为0.351mm(成像孔径9cm,成像矩阵256×160)时,T_1加权图像的SNR,CNR及优质率分别为9.207±1.644,8.203±0.657,及20％(1/5),T_2加权图像SNR,CNR及优质率分别为5.961±1.326,4.463±0.590及20％(1/5)。前者明显后者(P<0.05)。TR 2000ms图像的清晰度和对癌灶显示能力较TR 1500,2500ms为好;TE 30ms,80ms较60ms,120ms好。结论:T_1加权像(TR 480ms,TE 21ms),T_2加权像(TR 2000ms,TE 30/80ms)像素0.491mm是GE0.5T Vectra鼠肝MR成像较为理想的成像参数。     

常规SE 序列和高分辨MRI 动态增强诊断胸膜局灶性病变的比较

目的比较常规SE序列与高分辨MR(HR-MR)动态增强扫描显示胸膜局灶性病变的价值。方法对30例胸膜局灶性病变做了常规SE平扫和HR-MR T1WI动态增强扫描;进行了图像对比噪声比(CNR)值的测量,分析比较常规SE序列和动态增强的图像质量、病灶检出情况和病灶与周围胸壁深层结构的显示情况。结果30例胸膜局灶性病变总的CNR值在动态增强早期、增强后期和延迟期均高于T2WI(P均<0.05或<0.01),但具体到不同病种,则不同扫描序列CNR值各不相同。含胶原纤维成分的良性肿瘤T2WI的CNR值均高于动态增强(P均<0.01);胸膜恶性肿瘤动态增强的CNR值则均高于T2WI(P<0.05或<0.01);炎性病变动态增强的CNR值亦高于T2WI(P<0.05或<0.01)。MR动态增强的清晰度、图像质量等评分均高于T2WI(P均<0.01);而T2WI的伪影最多,多于动态增强(P<0.01)。HR-MRI T1WI动态增强扫描可检出所有胸膜局灶性病灶且有助于明确病灶的内部结构及其血流灌注情况,且在显示肿瘤浸润胸壁的深层结构的准确性较常规SE序列要高。结论动态增强HR-MRI扫描可提高胸膜恶性病变和炎症病变的对比噪声比值,能改善图像质量,有助于明确病灶的浸润范围,对胸膜局灶性病变有一定的诊断价值。     

脑转移瘤伽玛刀后复发和放射性脑坏死的磁共振灌注成像鉴别诊断

目的:探讨磁共振灌注成像(PWI)对脑转移瘤伽玛刀后复发和放射性脑坏死鉴别诊断价值。方法:21例经伽玛刀治疗的脑转移瘤患者和6例病史明确的放射性脑坏死,均行PWI。结果:前21例经手术证实,18例为脑转移瘤,3例放射性脑坏死,PWI定性诊断正确。18例脑转移瘤的rCBV值均升高,肿瘤最大rCBV比率为6.04±2.86,健侧为3.16±0.93(P<0.01);肿瘤MTT比率为1.49±0.58。9例放射性脑坏死rCBV值均降低,病灶最大rCBV比率为2.02±1.36,健侧为4.30±1.22(P<0.05);病灶MTT比率为1.08±0.14。结论:PWI对脑转移瘤伽玛刀后复发和放射性脑坏死鉴别有重要价值。     

扩散加权成像用于中央型肺癌与肺不张鉴别的初步研究

目的探讨扩散成像用于鉴别中央型肺癌与阻塞性肺不张的可行性及与常规的T1WI,T2WI,STIR序列和增强CT间鉴别能力进行比较。方法对33例中央型肺癌合并阻塞性肺不张的病例进行前瞻性研究。全部病例均经病理证实诊断。采用GE1.5T超导磁共振机检查。扫描序列包括:SE-TIWI、FRFSE-T2WI、STIR、扩散加权成像(DWI),b=0,500s/mm2,4个NEX,分次屏气扫描。CT检查采用GE64排CT,常规增强扫描,扫描时间为注药后28~30s。结果扩散加权图像基本上能满足诊断需要,33例中32例可用于研究。DWI图像对肺癌、肺不张的鉴别能力优于T1WI及增强CT(P<0.05);DWI、T2WI及STIR三种序列间鉴别能力无显著性差异(P>0.05);7个T2WI无法鉴别的病例在DWI能够鉴别,联合T2WI与DWI鉴别能力明显高于单独运用T2WI。DWI图像的信号强度比明显高于T2W和STIR;DWI图像的对比噪声比高于T2WI,与STIR图像无明显差别。扩散图像上肺癌的信号强度高于肺不张(P<0.001);肺癌的ADC值低于肺不张(P<0.001),肺癌和肺不张的ADC值分别为(1.48±0.56)×10-3s/mm2、(2.91±0.66)×10-3s/mm2。结论扩散成像可用于鉴别中央型肺癌与肺不张,并且是T2WI的有效补充。     

肝脏恶性肿瘤扩散加权成像与T2加权成像对比研究

目的比较肝脏扩散加权成像(DWI)和T2WI反映肝脏恶性肿瘤扩散特征、病理特征及肿瘤范围的价值.方法回顾性研究肝脏恶性肿瘤44例48灶(肝细胞癌30例30灶,肝转移瘤10例14灶,胆管细胞癌4例4灶),比较DWI与T2WI图像液体(脑脊液,胆囊胆汁)和肝脏恶性肿瘤的信号,肿瘤/肝脏信号强度比(SIR),对比噪声比(CNR)以及肿瘤范围,测量肿瘤表观扩散系数(ADC)值.结果在b=600 s/mm2的图像中,所有病例的脑脊液均显示为低信号.肝脏恶性肿瘤多表现为高信号,其信号分布特征与T2WI不同;肿瘤的信号强度和瘤/肝SIR,DWI与T2WI不相关;DWI信号强度与ADC值呈负相关.DWI的病灶对比噪声比高于T2WI,二者差异有显著性.DWI显示病灶范围与T2WI差异无显著性.结论b=600 s/mm2的肝脏DWI图像受T2穿透效应影响较小,能够较好地反映肝脏恶性肿瘤的扩散特征.DWI肿瘤对比噪声比更高,有助于病灶边界的确定.DWI反映的肝脏恶性肿瘤的扩散特征,可作为其影像学特征之一.     

基于深度学习重建技术的头部增强T1WI序列在垂体神经内分泌肿瘤病变成像中的应用

目的 对比分析基于深度学习重建（deep learning reconstruction, DL Recon）技术的头部T1WI增强序列与常规T1WI增强序列对垂体神经内分泌肿瘤病变的成像质量。材料与方法 前瞻性纳入行头部MRI增强扫描的50例垂体神经内分泌肿瘤患者,均在注射对比剂后行定制的T1WI（试验组）及常规T1WI（对照组）轴位扫描,其中试验组出两组图像,经DL Recon处理的图像记作A组,未经DL处理的原始图像记作B组,对照组记作C组,对比分析各组图像在灰质、白质和病灶区域的信噪比（signal to noise ratio, SNR）及对比噪声比（contrast to noise ratio, CNR）,并由两位诊断医师分析图像总体质量和诊断置信度。结果 试验组T1WI扫描时间（42 s）比传统T1WI扫描时间短（76 s）。A组的SNR灰质、SNR白质和SNR病灶显著高于B组和C组（P<0.001）;A组的CNR灰质/白质以及CNR病灶/白质均高于B组和C组（P<0.001）;A组的图像总体质量评分（5 vs. 3和4）显著高于B组和C组（P<0.0...     

增强FLAIR在脑转移瘤诊断中的价值

目的:分析增强后液体衰减反转恢复(fluid-attenuated inversion recovery,FLAIR)序列对脑转移瘤的诊断价值。方法:25例脑转移瘤患者行增强前后T1WI及FLAIR序列成像,图像由2名有经验的放射科医师评估。结果:3例增强后FLAIR序列脑实质病灶数目显示较增强T1WI多,11例脑膜转移者中,7例病灶强化程度优于增强后T1序列。结论:增强FLAIR序列是增强后T1序列的有效补充,尤其是对位于皮层表面和脑膜病灶更敏感。     

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.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.