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。     

11C-蛋氨酸PET/CT影像组学模型评估胶质母细胞瘤异柠檬酸脱氢酶1状态

目的 观察¹¹C-蛋氨酸(MET)PET/CT影像组学模型评估胶质母细胞瘤异柠檬酸脱氢酶1(IDH1)状态的价值。方法 回顾性分析157例接受¹¹C-MET PET/CT检查的胶质母细胞瘤患者资料,包括68例IDH1突变及89例野生型;按8 ∶ 2比例将其分为训练集(n=125)与验证集(n=32)。基于PET/CT图像勾画病灶ROI并提取、筛选影像组学特征,分别建立逻辑回归(LR)、支持向量机(SVM)及决策树(DT)影像组学模型;同时基于患者年龄及影像组学特征绘制列线图;对比观察影像组学模型及临床-影像组学列线图评估IDH1状态的效能。结果 DT影像组学模型评估训练集胶质母细胞瘤IDH1状态的曲线下面积(AUC)为0.910,大于LR(0.697)及SVM(0.698)模型(P均＜0.05)。验证集中,DT模型评估胶质母细胞瘤IDH1状态的AUC为0.805,大于LR模型(0.740)及临床-影像组学列线图(0.704)(P均＜0.05)。结论 基于DT的¹¹C-MET PET/CT影像组学模型有助于评估胶质母细胞瘤IDH1状态。     

联合临床、MR T2WI及表观弥散系数图影像组学特征列线图预测初发前列腺癌骨转移

目的 评估基于临床、MR T2WI及表观弥散系数(ADC)图影像组学特征构建的联合模型列线图预测初发前列腺癌骨转移的价值。方法 回顾性分析110例接受前列腺MR检查且经病理证实的初发前列腺癌患者,根据⁹⁹Tc^m亚甲基二磷酸盐(⁹⁹Tc^m-MDP)全身骨显像分为骨转移组(n=50)和无骨转移组(n=60)。基于T2WI及ADC图各提取851个、共1 702个影像组学特征,筛选最佳特征,计算影像组学评分并建立影像组学模型。应用单因素和多因素logistic回归分析筛选初发前列腺癌骨转移的临床相关独立危险因素,建立临床模型,并构建临床独立危险因素联合影像组学评分联合模型,绘制列线图将之可视化。以受试者工作特征(ROC)曲线评估各模型预测初发前列腺癌骨转移的效能,以决策曲线分析(DCA)评价联合模型的价值。结果 最终选出11个最佳影像组学特征,以之建立的影像组学模型预测初发前列腺癌骨转移的曲线下面积(AUC)为0.82。总前列腺特异性抗原、碱性磷酸酶和N分期是初发前列腺癌骨转移的临床独立危险因素(P均＜0.05),以之构建的临床模型的AUC为0.93。联合模型的AUC(0.96)高于临床模型(Z=－2.066,P=0.039)和影像组学模型(Z=－3.451,P＜0.001)。联合模型在阈值概率0~0.98时的临床净获益大于临床模型。结论 基于临床联合T2WI及ADC图影像组学特征的列线图可有效预测初发前列腺癌骨转移。     

超声弹性成像技术预测自发性早产:Meta分析

目的 应用Meta分析评价超声弹性成像技术对自发性早产的预测价值。方法 检索PubMed、Cochrane Library、中国知网及万方医学网自1990年1月1日-2020年1月1日收录的超声弹性成像预测早产相关文献，按照纳入及排除标准进行筛选，并评价其质量。采用Meta-disc 1.4软件进行Meta分析。结果 最终纳入9篇文献、共1 755名受试者，超声弹性成像预测早产的合并敏感度、合并特异度、合并阳性似然比、合并阴性似然比、合并诊断比值比及其95%CI分别为0.66[95%CI（0.60，0.71）]、0.78[95%CI（0.75，0.80）]、4.55（[95%CI（1.94，10.67）]、0.36[95%CI（0.21，0.61）]及15.30[95%CI（5.85，39.99）]，综合受试者工作特征曲线下面积（AUC）=0.878 6，Q^*=0.809 1。结论 超声弹性成像技术对预测自发性早产有一定价值。     

18F-FDG PET/CT评价胃肠间质瘤恶变潜能:Meta分析

目的 采用Meta分析评价¹⁸F-FDG PET/CT评价胃肠间质瘤（GIST）恶变潜能的价值。方法 检索PubMed、EMBASE、Cochrane图书馆、中国知网和中国生物医学数据库中有关¹⁸F-FDG PET/CT评价GIST恶变的中英文文献,检索时间截止2017年12月。由2名研究者进行数据提取和质量评价后,采用Meta-Disc软件进行统计分析。结果 共纳入6项研究、157例患者。Meta分析结果显示,合并敏感度、合并特异度、合并阳性似然比、合并阴性似然比及合并诊断比值比分别为[95%CI（0.76,0.92）]、0.79[95%CI（0.68,0.87）]、3.35[95%CI（1.81,6.20）]、0.22[95%CI（0.13,0.37）],汇总ROC（SROC）曲线下面积为0.9057（P<0.05）。Deek''s漏斗图提示存在发表偏倚的可能性较小。亚组分析和Meta回归分析结果显示诊断试验的准确率基本不受设备型号和SUV_max临界值的影响。结论 ¹⁸F-FDG PET-CT评价胃肠间质瘤恶变潜能具有较高诊断效能。     

基于CT影像组学模型预测肺原位腺癌及微浸润腺癌与浸润性腺癌

目的 探讨基于CT影像组学预测肺腺癌中的原位癌（AIS）和微浸润腺癌（MIA）以及浸润性腺癌（IAC）的价值。方法 回顾性分析542例经手术病理确诊且病理亚型明确的肺腺癌患者，将AIS及MIA归为第1组，IAC为第2组。比较2组患者性别和年龄差异。采用特征提取软件提取病灶三维纹理特征参数，分析组间差异明显的影像组学特征，筛选最佳影像组学特征构建预测模型。按2：1比例将数据分为训练集和验证集，采用6种机器学习算法对5倍交叉验证数据集进行分类，选择最佳分类器；以之分析5倍交叉验证数据集、训练集和验证集，获得模型预测肺腺癌病理分型的ROC曲线及相应AUC、特异度、敏感度及准确率。结果 第1组235例，第2组307例，组间性别和年龄差异均无统计学意义（χ²=0.56、t=-0.19，P=0.63、0.98）。共提取病灶1 766个三维纹理特征参数，其中988个影像组学特征存在明显组间差异，最终以10个最佳影像组学特征构建预测模型。以Perceptron分类器为最佳分类器。模型预测验证集病理分型的AUC为0.95，准确率、特异度、敏感度分别为0.88、0.87、0.84。结论 基于CT影像组学模型能有效预测肺腺癌中的AIS及MIA与IAC。     

术前CT影像组学联合CT及病理特征预测局部进展期食管鳞癌术后早期复发

目的 观察术前CT影像组学联合病理及CT特征预测局部进展期食管鳞癌(LAESCC)早期复发(ER)的价值。方法 回顾性分析334例LAESCC,按7 ∶ 3比例将患者分为训练集(n=234)或验证集(n=100),对其进行随访,记录术后有无ER(即术后12个月内肿瘤复发)。采用单因素及多因素logistic回归比较训练集有、无ER患者临床、CT表现及术前病理资料,筛选ER独立危险因素,构建CT-术前病理模型。基于训练集静脉期CT图像提取及筛选LAESCC影像组学特征并建立影像组学模型,以之联合独立危险因素建立联合模型。绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估各模型诊断效能。结果 334例中,168例ER、166例无ER;训练集有、无ER均为117例、验证集51例ER、49例无ER。CT显示LAESCC长度、cT分期、cN分期及术前病理分化程度均为ER独立危险因素(P均＜0.05);CT-术前病理模型在训练集和验证集的AUC分别为0.759和0.783。共选出10个最佳影像组学特征,以之建立的影像组学模型在训练集和验证集的AUC分别为0.770和0.730,联合模型在训练集和验证集的AUC分别为0.838和0.826。联合模型在训练集的AUC高于术前CT-病理模型及影像组学模型(P均＜0.01)。结论 CT影像组学联合CT及术前病理特征能有效预测LAESCC术后ER。     

基于CT增强图像纹理特征预测可切除胃癌患者预后

目的 探讨基于术前CT增强图像纹理特征预测可切除胃癌患者预后的价值。方法 回顾性分析197例经手术病理确诊胃癌患者，随机分为训练组（n=147）和验证组（n=50）。于术前CT增强门静脉期图像中提取90个病灶三维定量特征，采用组间相关系数（ICC）从中选择可重复性好者，以LASSO COX回归模型进行降维并筛选出与患者总生存时间（OS）相关特征，建立影像标签，对2组患者进行分类，根据标签分数的中位数值分为高危组和低危组，观察组间OS差异，分析临床、病理特征及影像纹理特征标签与患者预后的关系。构建融合纹理特征标签和临床病理特征的诺莫图，评价其预测胃癌患者预后的效能；绘制决策曲线，评价其临床价值。结果 经筛选获得2个与患者OS相关的CT纹理特征并以之建立影像标签。训练组（χ²=9.25）和验证组（χ²=8.49）中，高危组和低危组患者OS差异均有统计学意义（P均<0.01）。影像标签及TNM分期为胃癌的独立危险因素。影像标签预测训练组和验证组患者3年OS的AUC分别为0.72（P=0.02）和0.67（P=0.07），融合影像标签和TNM分期的诺莫图模型预测3年OS的AUC分别为0.78和0.81（P均<0.01）。阈值为0.13~0.59时，诺莫图模型的净获益高于单独影像标签。结论 基于CT增强图像纹理特征建立的影像标签可用于胃癌患者术后危险分层；联合病理特征构建的纹理诺模图模型有助于预测患者预后。     

基于增强CT影像组学模型鉴别肾透明细胞癌与非透明细胞癌

目的 建立基于增强CT的影像组学模型,评估其鉴别肾透明细胞癌（ccRCC）与非透明细胞癌（non-ccRCC）的应用价值。方法 将147例ccRCC及32例non-ccRCC患者随机分为训练集125例和测试集54例。将所有患者的增强CT资料导入ITK-SNAP软件,手动勾画ROI,获得16个特征,分别建立基于特征的随机森林（RF）模型和逻辑回归（LR）模型,采用ROC曲线观察模型对ccRCC的诊断效能。结果 训练集RF模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度0.83;LR模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度为0.83。测试集RF模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度为0.89;LR模型诊断ccRCC的AUC为0.88（P<0.05）,特异度为0.90,敏感度为0.77。结论 基于增强CT影像组学模型可用于鉴别ccRCC与non-ccRCC;RF模型诊断价值较LR模型更高。     

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。     

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.