基于增强CT影像组学模型预测胰十二指肠切除术后胰瘘

目的 评估基于术前腹部增强CT影像组学模型预测胰十二指肠切除术（PD）术后胰瘘（POPF）的价值。方法 回顾性分析252例接受PD患者的术前腹部增强CT资料,按7：3比例将其分为训练集（n=177）和验证集（n=75）。于训练集增强静脉期CT图像中勾画胰腺实质作为感兴趣容积（VOI）,提取其影像组学特征,并筛选最优特征建立影像组学模型;绘制模型预测PD术后POPF的受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价模型预测效能;以验证集数据进行验证。结果 共选出14个最优影像组学特征用于构建影像组学模型。影像组学模型在训练集和验证集的AUC分别为0.82[95%CI（0.76,0.88）]和0.82[95%CI（0.72,0.91）]。结论 基于术前增强CT影像组学模型能有效预测PD术后POPF。     

基于T2WI影像组学标签预测乳腺癌人表皮生长因子受体2表达状态

目的 探讨基于MR T2WI的影像组学标签在术前预测乳腺癌人表皮生长因子受体2（HER2）表达状态的价值。方法 回顾性收集209例乳腺癌患者的T2WI,将患者随机分为训练组（n=145）和验证组（n=64）。手动勾画病灶ROI,并于Matlab 2013a平台中提取组学特征。通过组间相关系数及最小绝对收缩和选择算子逻辑回归模型筛选组学特征并构建组学标签。比较HER2表达阳性与阴性亚组患者的影像组学得分差异,采用ROC曲线评价训练组中影像组学标签预测HER2的效能,并以获得的预测阈值用于验证组中进行验证。结果 最终获得由13个组学特征构成的影像组学标签。在训练组及验证组中,HER2阳性亚组与阴性亚组患者间组学得分差异均有统计学意义（P均<0.05）。基于T2WI的影像组学标签在训练组及验证组中的AUC分别为0.798、0.707。结论 基于T2WI构建的影像组学标签对术前预测乳腺癌HER2表达状态具有一定价值。     

MRI影像组学预测结直肠癌患者KRAS基因突变

目的 构建MR T2WI影像组学模型,评价其预测结直肠癌患者Kirsten大鼠肉瘤（KRAS）病毒癌基因亚型的价值。方法 将99例经病理证实的结直肠癌患者分为训练组（n=68）及验证组（n=31）,根据KRAS基因检测结果进一步将其分为突变亚组及野生亚组,训练组2亚组分别含36、32例,验证组2亚组分别含16、15例,比较亚组间实验室检查结果及肿瘤大小的差异;提取并筛选训练组MR T2WI影像组学特征,构建影像组学模型、临床模型及影像组学-临床联合模型。绘制受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价各模型预测结直肠癌患者KRAS基因亚型的效能;以DeLong检验比较各模型间效能差异。通过校正曲线分析3种模型的校正性能,以Hosmer-Lemeshow检验评价校准曲线的校准度;以决策曲线分析（DCA）评价3种模型临床应用价值。结果 训练组和验证组内亚组间实验室检查结果及肿瘤大小差异均无统计学意义（P均>0.05）。共提取3个组学特征用于构建预测模型。影像组学模型与临床模型、影像组学-临床联合模型预测2组KRAS基因亚型的AUC差异均无统计学意义（P均>0.05）;影像组学-临床联合模型预测训练组KRAS基因亚型的AUC显著高于临床模型（P<0.05）,但在验证组差异均无统计学意义（P>0.05）。校准曲线及Hosmer-Lemeshow检验显示3种模型预测值和观察值的一致性良好（P均>0.05）。影像组学模型和影像组学-临床联合模型在2组中的DCA曲线净收益值均高于临床模型。结论 MR T2WI影像组学纹理特征预测结直肠癌患者KRAS基因突变亚型具有一定潜力。     

瘤内及瘤周表观弥散系数影像组学特征预测髓母细胞瘤患儿预后

目的 观察瘤内及瘤周表观弥散系数（ADC）影像组学特征预测髓母细胞瘤（MB）患儿预后的价值。方法 回顾性分析74例MB患儿资料,根据术后2年随访结果将其分为进展组（n=29）及无进展组（n=45）,并按6：4比例分为训练集（n=44）或验证集（n=30）。基于ADC图提取并筛选瘤内及瘤周影像组学特征,分别建立瘤内、瘤周及瘤内+瘤周影像组学模型,并以之结合临床及常规影像学特征建立联合模型;比较各模型预测MB患儿预后的效能。结果 训练集中,临床-常规影像-瘤周影像组学模型、临床-常规影像-瘤内+瘤周影像组学模型曲线下面积（AUC）均大于单一瘤周影像组学模型（P均<0.05）;验证集中,临床-常规影像学-瘤内+瘤周影像组学模型的AUC最大,但与其他模型差异均无统计学意义（P均>0.05）。结论 瘤内及瘤周ADC影像组学特征可用于预测MB患儿预后;联合临床及常规影像学特征或有助于提高预测效能。     

高分辨率CT鉴别诊断良、恶性实性孤立性肺结节

目的 观察实性孤立性肺结节（SPN）高分辨率CT（HRCT）表现。方法 回顾性分析235例HRCT检出的实性SPN患者,其中54例良性（良性组）,181例恶性（恶性组）。比较组间HRCT表现差异,包括分叶征、毛刺征、空洞征、空泡征、钙化、远端穿行血管、胸膜牵拉征、贴近胸膜及牵拉性肺气肿;评估差异有统计学意义的征象鉴别良、恶性SPN的效能,分析良、恶性SPN的影响因素。结果 组间毛刺征、胸膜牵拉征、钙化征象差异均无统计学意义（P均>0.05）,其余征象差异均有统计学意义（P均<0.05）。血管集束征鉴别良、恶性SPN的效能最高,敏感度达92.30%。回归分析显示血管集束征是恶性SPN的危险征象,牵拉性肺气肿为其保护因素（P均<0.05）。结论 良、恶性SPN的HRCT表现存在差异,对鉴别诊断具有一定价值。     

基于增强CT放射组学预测肝细胞肝癌病理分级

目的 观察增强CT放射组学术前预测肝细胞肝癌（HCC）病理分级的可行性及价值。方法 回顾分析429例经手术病理证实的HCC患者，分为训练组（n=329）和测试组（n=100），记录其临床特征；提取动脉期（AP）及静脉期（VP）CT图像的放射组学特征，应用最小绝对值收敛和选择算子（LASSO）回归分析法对其进行降维，筛选最有价值的组学特征后，构建基于AP、VP、AP+VP图像特征的组学模型，计算2组放射学评分并进行二分类判别。根据病理结果定义高级别和低级别HCC，采用10倍交叉验证训练选择最优组学预测模型，筛选对预测HCC病理分级有意义的临床特征后，构建临床模型以及联合组学特征和临床特征的联合模型。绘制3种模型预测训练组和测试组HCC病理分级的ROC曲线，评估其诊断能力。结果 联合组学模型最优，其判别训练组及测试组高级别和低级别HCC的放射学评分的差异均有统计学意义（Z=8.58、3.24，P均<0.05）。测试组中，联合模型预测HCC病理分级的AUC值（0.70）与组学模型（0.69）和临床模型（0.63）差异均无统计学意义（P均>0.05）。结论 基于增强CT图像的放射组学特征可用于术前预测HCC病理分级。     

增强CT模型及影像组学模型预测肾透明细胞癌WHO/ISUP分级

目的 比较增强CT模型与影像组学模型预测肾透明细胞癌（ccRCC）WHO/ISUP分级的效能。方法 回顾性分析131例经病理确诊ccRCC患者,按照3 ∶ 2比例分层抽样分为训练集（n=78）和验证集（n=53）。根据2016版肾癌WHO/ISUP病理分级标准,以Ⅰ~Ⅱ级为低级别、Ⅲ~Ⅳ级为高级别ccRCC。训练集55例低级别、23例高级别ccRCC;验证集37例低级别、16例高级别ccRCC。以训练集构建增强CT模型及影像组学模型预测ccRCC级别,于验证集加以验证,比较其诊断效能。结果 增强CT模型在训练集及验证集预测高、低级别ccRCC的曲线下面积（AUC）分别为0.89及0.76,敏感度分别0.83及0.56,特异度分别为0.84及0.87;影像组学模型的AUC分别为0.98及0.85,敏感度分别0.96及0.91,特异度分别为0.75及0.84。训练集中影像组学模型的AUC大于增强CT模型（Z＝2.05,P<0.05）,验证集中二者AUC差异无统计学意义（Z＝0.95,P=0.34）。决策曲线分析结果显示高风险概率阈值为0.08~1.00时,影像组学模型净获益高于增强CT模型。结论 影像组学模型预测ccRCC WHO/ISUP分级的效能优于增强CT模型。     

基于MR-T2WI影像组学模型预测宫颈鳞癌临床分期

目的 观察基于MR-T2WI影像组学模型预测宫颈鳞癌临床分期的价值。方法 对159例经术后或活检病理证实的宫颈鳞癌患者采集盆部MRI,根据国际妇产科联盟（FIGO）分期系统及病理结果分为早期组（ⅠB~ⅡA期,n=73）和晚期组（ⅡB~Ⅳ期,n=86）。按照7 ：3比例将患者随机分为训练集（n=113）和验证集（n=46）。训练集包括52例早期、61例晚期宫颈鳞癌,验证集含21例早期及25例晚期宫颈鳞癌。提取轴位T2WI中病灶的影像组学特征,以最大相关最小冗余和最小绝对收缩选择算子回归分析方法筛选最优影像组学特征,构建预测早、晚期宫颈鳞癌的影像组学模型。分析影像组学模型的拟合优度,采用受试者工作特征（ROC）曲线评估模型的预测效能,以决策曲线分析（DCA）评估模型的临床应用价值。结果 共提取396个影像组学特征,最终筛选11个最优影像组学特征,并以之构建预测早、晚期宫颈鳞癌的影像组学模型。影像组学模型在训练集和验证集中的拟合优度均佳（χ²=2.68、8.87,P均>0.05）;其在训练集及验证集中的曲线下面积（AUC）均为0.80。DCA显示,阈值取0.10~1.00时,影像组学模型的净收益较大。结论 基于MR-T2WI的影像组学模型对预测宫颈鳞癌临床分期具有较高价值。     

多参数MRI影像组学与深度学习模型鉴别良、恶性黏液样软组织肿瘤

目的 观察基于多参数MRI构建的影像组学与深度学习(DL)模型鉴别良、恶性黏液样软组织肿瘤(MSTT)的价值。方法 回顾性纳入141例经病理证实的MSTT患者,以7 ∶ 3比例随机将其分为训练集(n=98,包括51例恶性及47例良性MSTT)及测试集(n=43,包括22例恶性及21例良性MSTT)。分别于训练集T1WI和脂肪抑制(FS)-T2WI中提取并遴选影像组学特征及DL特征,并以之构建鉴别良、恶性MSTT的影像组学模型及DL模型。绘制受试者工作特征(ROC)曲线、校准曲线及决策曲线,对比评估2个模型的区分度、校准度及净收益。结果 于训练集提取并筛选得到9个最佳影像组学特征用于构建鉴别良、恶性MSTT的影像组学模型,包括2个一阶特征、1个形态特征、3个灰度共生矩阵特征、1个灰度相关矩阵特征和2个灰度大小区域矩阵特征;以其中7个最佳DL特征构建DL模型。所获影像组学模型和DL模型鉴别测试集良、恶性MSTT的ROC曲线下面积分别为0.758及0.911,后者高于前者(P=0.017);2个模型均具有良好校准度;相比影像组学模型,DL模型在测试集的总体净收益更高。结论 基于MRI构建的DL模型鉴别良、恶性MSTT的效能较影像组学模型更好且净收益更高。     

基于CT影像组学术前预测胃癌淋巴血管侵犯

目的 探讨基于CT影像组学术前预测胃癌淋巴血管侵犯的价值。方法 回顾性收集经手术病理证实的181例胃癌患者,将其随机分为训练集（n=120）和验证集（n=61）。首先基于增强CT静脉期图像分割肿瘤区域并提取影像组学特征;然后利用训练集筛选与淋巴血管侵犯相关特征,构建影像组学标签;最后基于验证集验证模型,采用ROC曲线及校准曲线评估模型的预测效能及拟合度。结果 最终提取7个与胃癌淋巴管血管侵犯最相关的影像组学特征构建影像组学标签,其在训练集的ROC曲线AUC为0.742[P=0.001,95%CI（0.652,0.831）],验证集AUC为0.727[P=0.002,95%CI（0.593,0.853）]。基于训练集所得最优阈值为0.422,模型在训练集中的准确率、敏感度和特异度分别为0.708、0.586、0.806,将此阈值用于验证集,其准确率、敏感度和特异度为0.689、0.519、0.824。校准曲线显示影像组学标签在训练集及验证集均具有较好的拟合度（P均>0.05）。结论 CT影像组学可作为预测胃癌术前淋巴血管侵犯提供的全新的无创影像学方法。     

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.