合成MRI联合弥散加权成像评估胶质瘤级别及肿瘤细胞增殖活性

目的 观察合成MRI联合弥散加权成像（DWI）鉴别高、低级别胶质瘤及评估肿瘤细胞增殖活性的价值。方法 回顾性分析69例经病理学证实的胶质瘤患者资料，包括低级别胶质瘤（LGG）27例、高级别胶质瘤（HGG）42例，术前均接受颅脑MRI、合成MRI和DWI。检测肿瘤实质T1值、T2值、质子密度（PD）和表观弥散系数（ADC），比较LGG与HGG间各参数差异。采用受试者工作特征（ROC）曲线评价各参数单独及联合鉴别LGG与HGG的效能，分析各参数与Ki-67标记指数（Ki-67 LI）的相关性。结果 LGG T1值及PD低于HGG （P均<0.001），而ADC高于HGG （P<0.001），二者T2值差异无统计学意义（P=0.328）。单一参数中，以ADC鉴别LGG与HGG的曲线下面积（AUC）为0.901，高于T1值（AUC=0.862）和PD （AUC=0.848）（P均>0.05）；T1值＋PD＋ADC的AUC （0.988）高于任一单一参数（P均<0.05），其敏感度和特异度分别为92.86%和100%。肿瘤ADC与其Ki-67 LI呈中等负相关（r=-0.617，P<0.001），T1值和PD与Ki-67 LI呈中等正相关（r=0.441、0.437，P均<0.001），T2值与Ki-67 LI无明显相关性（r=-0.044，P=0.719）。结论 合成MRI联合DWI可无创评估胶质瘤级别及细胞增殖活性。     

扩散峰度成像模型与传统扩散加权成像单指数模型鉴别乳腺肿块良恶性的对比分析

目的 对比分析扩散峰度成像（DKI）模型与传统DWI单指数模型对乳腺良恶性肿块的鉴别诊断价值。方法 对78例乳腺肿块患者于术前行MR检查,包括常规平扫、传统DWI、DKI及动态对比增强（DCE）扫描。通过传统DWI单指数模型获得病灶的ADC值,通过DKI模型获得病灶的平均扩散峰度（MK）及平均扩散系数（MD）值。采用独立样本t检验比较乳腺良恶性肿块间ADC、MK、MD值的差异。以ROC曲线评价ADC、MK和MD值对乳腺恶性肿块的诊断效能。并采用χ²检验比较MK、MD、MK联合MD值的曲线下面积（AUC）与ADC值的AUC间的差异。结果 78例共87个病灶,其中良性病灶29个,恶性病灶58个。恶性病灶的ADC和MD值明显低于良性病灶（P均<0.001）,MK值明显高于良性病灶（P<0.001）。良性及恶性病灶的MD值均高于其ADC值（P均<0.001）。以ADC值诊断乳腺恶性肿块的敏感度、特异度、准确率分别为86.21%、89.66%、87.36%;MK值的敏感度、特异度、准确率分别为84.48%、96.55%、88.51%;MD值的敏感度、特异度、准确率分别为82.76%、93.10%、89.66%。MK值的AUC及MK联合MD值的AUC均为0.94（P<0.05）,且均高于ADC值的AUC（χ²=5.90,P=0.02）,而MD与ADC值的AUC差异无统计学意义（χ²=0.15,P=0.70）。结论 相对于传统DWI单指数模型,DKI模型更有利于乳腺肿块良恶性的鉴别。     

弥散峰度成像预测皮质脊髓束周围高级别胶质瘤患者肌力下降

目的 观察弥散峰度成像（DKI）预测皮质脊髓束（CST）周围高级别胶质瘤（HGG）患者肌力下降的价值。方法 纳入21例HGG累及CST走行区及其周围患者,比较患侧及健侧CST DKI定量参数的差异;根据手术前肢体肌力改变情况将患者分为正常组（n=14）及肌力下降组（n=7）,比较组间Karnofsky功能状态（KPS）评分及CST DKI定量参数的差异。绘制受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价CST相对定量参数预测患者肌力下降的效能。结果 与健侧比较,患侧纤维束数量、体积、各向异性分数（FA）、平均峰度（MK）、轴向峰度（AK）和径向峰度（RK）均显著降低（P均<0.05）,而平均弥散系数（MD）及径向弥散系数（RD）均显著增高（P均<0.05）。肌力下降组KPS评分、相对FA（rFA）、相对MK（rMK）、相对AK（rAK）及相对RK（rRK）均明显低于正常组（P均<0.05）,而相对MD（rMD）、相对轴向弥散系数（rAD）及相对RD（rRD）均明显高于正常组（P均<0.05）。各相对CST定量参数预测HGG患者肌力下降的效能均较高（AUC均高于0.850）。结论 肌力下降HGG患者肿瘤周围CST的DKI定量参数改变显著;术前DKI可用于预测患者肌力下降,并间接判断CST损伤。     

同时多层分段读出平面回波弥散加权成像

目的 评价同时多层（SMS）分段读出平面回波（RS-EP）弥散加权成像（DWI）用于乳腺的可行性及全肿瘤直方纹理分析参数鉴别乳腺良、恶性肿瘤的价值。方法 纳入185例经病理证实的女性乳腺肿瘤患者,均为单发病灶,根据肿瘤性质分为良性组（n=58）及恶性组（n=127）;采集SMS RS-EP DWI图像,提取全肿瘤直方图参数及纹理参数,采用组内相关系数（ICC）评价观察者内及观察者间的可重复性,并对比组间各参数差异。绘制受试者工作特征（ROC）曲线,计算曲线下面积（AUC）评价定量参数鉴别乳腺良、恶性肿瘤的效能。结果 观察者内及观察者间ADC_Kurtosis、观察者间ADC_Entropy一致性中等（ICC均 ≤ 0.75）,其余参数均一致性较好或极好（ICC均>0.75）。除ADC_SD和ADC_Kurtosis外,其他参数组间差异均有统计学意义（P均<0.05）。直方图参数中,ADC_Median鉴别乳腺良、恶性肿瘤的AUC最高（0.879）;纹理参数中,ADC_Entropy的AUC值最高（0.764）;二者联合诊断的AUC为0.911,敏感度和特异度分别为90.55%和81.03%。结论 SMS RS-EP DWI可用于乳腺检查;联合全肿瘤直方纹理分析有助于鉴别乳腺良、恶性肿瘤。     

基于MRI影像组学预测肝泡型包虫病边缘微血管侵犯

目的 评估基于MR T2WI影像组学模型预测肝泡型包虫病（HAE）病灶边缘微血管侵犯的价值。方法 回顾性分析89例经术后病理证实的HAE患者,其中32例病灶边缘存在微血管侵犯、57例无侵犯。提取病灶MR T2WI影像组学特征,以方差阈值法和单变量选择法筛选最优特征,以随机森林（RF）、极限梯度增强树（XGBoost）和逻辑回归（LR）三种分类器构建预测HAE病灶边缘微血管侵犯的机器学习（ML）模型。按8：2比例将患者分为训练集（n=70）和测试集（n=19）,验证模型的预测效能;绘制受试者工作特征（ROC）曲线,计算其曲线下面积（AUC）。结果 共提取1 409个影像组学特征,经特征降维选出7个最优影像组学特征,并以之构建模型。ROC曲线显示,XGBoost模型在训练集及测试集中的AUC分别为0.96和0.89。结论 基于MR T2WI影像组学XGBoost模型可有效预测HAE病灶边缘微血管侵犯。     

扩散峰度成像在胶质瘤分级和预测细胞增殖中的诊断效能

目的 探讨MR扩散峰度成像（DKI）在胶质瘤分级的价值,及其与Ki-67标记指数的相关性。方法 收集经手术病理证实的脑胶质瘤患者32例,根据病理结果分为高级别胶质瘤组（HGG组,n=18）和低级别胶质瘤组（LGG组,n=14）,术前行常规MR、DWI及DKI扫描,测定肿瘤实质区的平均扩散峰度（MK）、轴向扩散峰度（Ka）、径向扩散峰度（Kr）、平均扩散系数（MD）、部分各向异性（FA）和ADC值,比较高低级别胶质瘤各参数值的差异和诊断效能、肿瘤区各参数与Ki-67标记指数的相关性。结果 高低级别胶质瘤各参数值差异均有统计学意义（P均<0.01）。HGG组的MK、Ka、Kr、FA值高于LGG组,而MD、ADC值低于LGG组。MK在鉴别高低级别胶质瘤的ROC曲线下面积最大（0.82,P<0.01）,特异度最高（90.40%）;ADC值敏感度最高（80.20%）。MK、Ka、Kr、MD和ADC值与Ki-67标记指数均有相关性,MK值与Ki-67标记指数相关性最大（r_s=0.61,P<0.01）。结论 DKI参数对鉴别高低级别胶质瘤有一定的价值,其诊断效能总体高于传统扩散参数。DKI参数值对预测肿瘤细胞增殖有潜在价值。     

拉伸指数弥散加权成像模型直方图分析预测单发肝细胞癌微血管侵犯

目的 评估拉伸指数模型弥散加权成像（DWI）直方图分析术前预测单发肝细胞癌（HCC）微血管侵犯（MVI）的价值。方法 回顾性分析43例经病理确诊单发HCC患者的腹部MRI,根据病理结果分为MVI（+）组（n=22）和MVI（-）组（n=21）。采用拉伸指数模型分析DWI,获得表观弥散系数（ADC）、分布弥散系数（DDC）和水分子各向异质性（α）直方图参数,比较组间临床资料及直方图参数差异;应用受试者工作特征（ROC）曲线分析差异有统计学意义的参数预测MVI的效能,并以多因素Logistic回归分析MVI的独立预测因素。结果 组间肿瘤直径、ADC第5百分位数（5th）、DDC第5、25、50百分位数（5th、25th、50th）及平均值差异均有统计学意义（P均<0.05）,其余直方图参数差异均无统计学意义（P均>0.05）。DDC 5th预测MVI的曲线下面积（AUC）最大,为0.86,高于DDC（25th、50th）及平均值、ADC 5th、肿瘤直径（Z=1.96~2.91,P均<0.05）,其余参数两两比较差异均无统计学意义（Z=0.12~1.91,P均>0.05）。DDC 5th是MVI的独立预测因素（P=0.005）。结论 拉伸指数DWI模型直方图分析有助于术前预测单发HCC的MVI,以DDC 5th诊断效能最佳。     

胸腺瘤的MRI表现

目的 分析胸腺瘤的MRI表现。方法 收集经病理证实并有完整影像学资料的29例胸腺瘤患者,分析平扫、DWI及增强扫描MRI表现,并根据病理结果分为低危组（n=18）和高危组（n=11）,分析其影像学表现的差异。结果 肿瘤均为单发,28例病灶位于前纵隔,1例位于左锁骨上窝;21例肿瘤形态不规则,21例与邻近结构分界清楚。24例病灶T2WI呈高/稍高信号;20例T1WI呈低—中等信号;9例病变内有囊变坏死,7例可见分隔,1例可见液平;全部病灶DWI呈均匀或混杂信号。9例病灶增强扫描轻度强化,11例中度强化,9例明显强化。低危组与高危组ADC值差异无统计学意义（P=0.42）。结论 胸腺瘤常规MRI及DWI表现有一定特征性,有助于术前诊断胸腺瘤。     

常规超声联合超声造影鉴别诊断甲状腺恶性与炎性病灶

目的 观察常规超声联合超声造影（CEUS）鉴别诊断甲状腺恶性与炎性病灶的价值。方法 纳入78例甲状腺疾病患者,根据病理结果将其分为恶性组（n=61）及炎性组（n=17）;对比2组病灶常规超声及CEUS特点,并将组间差异有统计学意义的因素纳入回归分析,观察常规超声联合CEUS鉴别诊断甲状腺恶性与炎性病灶的价值。结果 恶性组与炎性组病灶最大径、钙化情况、纵横比、造影剂到达时间、病灶增强模式及程度差异均有统计学意义（P均<0.05）。回归分析结果显示,病灶最大径<10 mm（OR=130.319,P<0.001）、慢进型增强（OR=6.177,P=0.013）、微钙化（OR=10.886,P=0.001）及向心性增强（OR=12.922,P<0.001）为甲状腺恶性病灶的预测因子,其曲线下面积分别为0.828[95%CI（0.740,0.916）]、0.703[95%CI（0.575,0.832）]、0.638[95%CI（0.501,0.775）]及0.630[95%CI（0.491,0.768）]。结论 常规超声联合CEUS有助于鉴别诊断甲状腺恶性与炎性病灶;病灶伴微钙化、慢进型增强及向心性增强为恶性病灶的预测因子。     

超声弹性成像诊断乳腺癌的价值

目的 探讨超声弹性成像（UE）对乳腺癌的鉴别诊断价值。方法 参考弹性成像改良评分法,对105个乳腺病灶的UE检查结果进行规范评分,然后按乳腺病灶长径大小分为2组,Ⅰ组（肿块长径≤2 cm,n=64）和Ⅱ组（肿块长径>2 cm,n=41）,比较UE对乳腺病灶的鉴别诊断效能及Ⅰ组与Ⅱ组的差异。结果 ①UE诊断乳腺癌的敏感度、特异度、准确率、阳性预测值、阴性预测值分别为82.98%（39/47）,74.14%（43/58）,78.10%（82/105）,72.22%（39/54）,84.31%（43/51）。②Ⅰ组（d≤2 cm）的阴性预测值为94.12%（32/34）,明显高于Ⅱ组,两组差异有统计学意义（P<0.05）。结论 UE对诊断乳腺癌有较好的价值,尤其是对于长径≤2 cm的乳腺癌阴性预测值相对较高,有助于乳腺癌的早期筛查。     

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.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.