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。     

联合含瘤周肿瘤全体积CT影像组学特征及临床相关独立预测因子列线图预测肺腺癌淋巴血管侵犯

目的 观察基于含瘤周的肿瘤全体积(GPTV) CT影像组学特征及临床相关独立预测因子构建的联合模型列线图预测肺腺癌淋巴血管侵犯(LVI)的价值。方法 回顾性分析142例经病理证实的肺腺癌患者,以7 ∶ 3比例将其随机分为训练集(n=100,40例LVI阳性、60例LVI阴性)和验证集(n=42,17例LVI阳性、25例LVI阴性)。以单因素分析及多因素logistic回归分析筛选肺腺癌LVI的临床相关独立预测因子,以之构建临床模型。分别基于肿瘤全体积(GTV)及含瘤周3 mm、6 mm、9 mm的GPTV (GPTV₃、GPTV₆和GPTV₉)的增强动脉期CT图提取并筛选最佳影像组学特征,构建影像组学模型,即GTV、GPTV₃、GPTV₆和GPTV₉模型并筛选最佳者;基于后者的影像组学评分和临床相关独立预测因子构建联合模型,绘制列线图进行可视化。以受试者工作特征(ROC)曲线评估各模型预测肺腺癌LVI的效能,以决策曲线分析(DCA)评价联合模型列线图的价值。结果 性别、吸烟和毛刺征均为肺腺癌LVI的临床相关独立预测因子(P均＜0.05)。分别基于GTV、GPTV₃、GPTV₆及GPTV₉筛选出7、16、10及8个最佳影像组学特征,用于构建GTV、GPTV₃、GPTV₆及GPTV₉模型。GPTV₃模型预测训练集、验证集肺腺癌LVI的曲线下面积(AUC)分别为0.82、0.77,均高于GTV (0.79、0.72,Z=3.74、2.62,P均＜0.01)、GPTV₆(0.80、0.72,Z=2.40、2.06,P均＜0.05)及GPTV₉(0.77,0.72,Z=3.03、2.59,P均＜0.01),为最佳影像组学模型。联合模型列线图(0.86、0.73,Z=2.66、2.31,P均＜0.05)及GPTV₃模型(0.82、0.77,Z=2.23、2.54,P均＜0.05)于训练集和验证集的AUC均高于临床模型(0.73、0.61),而联合模型列线图与GPTV₃模型的AUC差异均无统计学意义(Z=1.57、0.88,P均＞0.05)。阈值取0.20~0.50时,联合模型列线图与GPTV₃模型的净获益相当,且均大于临床模型。结论 基于GPTV₃影像组学特征及临床相关独立预测因子的列线图可有效预测肺腺癌LVI。     

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。     

基于临床、超声特征及影像组学构建机器学习模型预测慢性肾脏病患者肾功能损伤程度

目的 观察基于临床、超声特征及影像组学构建机器学习(ML)模型预测慢性肾脏病(CKD)患者肾功能损伤程度的价值。方法 回顾性分析199例CKD患者资料,以9 ∶ 1比例将其分为训练集(n=179)及验证集(n=20),根据估算肾小球滤过率(eGFR)划分轻中度或重度肾功能损伤。采用多因素logistic回归分析训练集临床及超声特征,筛选CKD患者肾功能损伤程度的独立预测因素,分别基于支持向量机(SVM)、极致梯度提升(XGBoost)及逻辑回归(LR)算法构建临床-超声模型、影像组学模型及联合模型;绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估各模型预测CKD患者肾功能损伤程度的效能。结果 肾脏长径为CKD患者肾功能损伤的独立预测因素(P＜0.05)。以不同算法所获模型中,以SVM算法所获临床-超声模型、影像组学模型及联合模型预测肾功能损伤的效能最高;训练集中,以SVM算法所获临床-超声模型的敏感度、特异度、准确率及AUC分别为81.93%,62.50%,71.51%及0.722,影像组学模型分别为89.16%,70.83%,79.33%及0.800,联合模型分别为84.34%,80.21%,82.12%及0.822;验证集中,以SVM算法所获临床-超声模型的敏感度、特异度、准确率及AUC分别为75.00%、66.67%、70.00%及0.708,影像组学模型分别为75.00%、58.33%、65.00%及0.667,联合模型分别为87.50%、75.00%、80.00%及0.812。结论 基于超声特征联合影像组学构建的ML模型可有效预测CKD患者肾功能损伤程度;利用SVM算法获得的联合模型具有最佳效能。     

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。     

多时相CT影像组学模型预测胸腺瘤风险分类

目的 观察多时相CT影像组学模型预测胸腺瘤风险分类的价值。方法 纳入86例经病理确诊的单发胸腺瘤患者,包括32例高风险及54例低风险胸腺瘤,按照7∶3比例将其分为训练集(n=59)和验证集(n=27);采用单因素及多因素logistic回归分析训练集临床及CT特征,筛选胸腺瘤风险分类的独立预测因素,构建临床-CT模型。分别基于平扫、动脉期(AP)、静脉期(VP)、平扫+AP、平扫+VP、AP+VP及平扫+AP+VP提取并筛选最优影像组学特征,计算影像组学评分(Rad-score);采用受试者工作特征(ROC)曲线选取最佳影像组学模型,以之联合临床-CT特征构建联合模型。绘制ROC曲线,计算曲线下面积(AUC),评估各模型预测胸腺瘤风险分类的效能。结果 周围脂肪浸润是胸腺瘤风险分类的独立预测因素(OR=0.029,P=0.004)。ROC曲线显示,模型_AP+VP为最佳影像组学模型,其与联合模型预测训练集胸腺瘤风险分类的AUC分别为0.860及0.877,均高于临床-CT模型的0.736(Z=1.925、-2.464,P均＜0.05),预测验证集的AUC分别为0.835及0.847,亦高于临床-CT模型的0.641(Z=1.840、-2.137,P均＜0.05);模型_AP+VP与联合模型在训练集和验证集的AUC差异均无统计学意义(Z=-1.180、0.291,P均＞0.05)。结论 多时相CT影像组学模型可有效预测胸腺瘤风险分类。     

CT影像组学预测结直肠癌肝转移术后患者1年内无进展生存期

目的 评价CT影像组学模型预测结直肠癌肝转移(CRLM)患者术后1年无进展生存期(PFS)的价值。方法 回顾性分析147例CRLM术前末次CT资料,将其分为训练集(n=100)及验证集(n=47),依据临床预后分为预后良好(PFS≥12个月)及预后不佳(PFS＜12个月)。手动分割CT所示肝转移灶,提取及选择特征后,基于训练集数据构建影像组学模型,以多因素logistic回归构建临床模型及联合模型。绘制受试者工作特征曲线,计算曲线下面积(AUC),评价并比较各模型预测CRLM患者术后PFS的效能。结果 共选出7个特征用于构建影像组学模型。临床模型中,原发灶N分期、有无基因突变及有无术后化疗是预测CRLM患者术后PFS的独立因素;联合模型中的独立因素还包括影像组学评分。影像组学模型、联合模型预测训练集CRLM患者术后PFS的AUC均大于临床模型(0.89、0.93及0.67,P均＜0.05);其在验证集的AUC依次为0.77、0.78及0.56,前二者的效能优于临床模型(P＜0.05)。结论 影像组学模型及联合模型预测CRLM患者1年内PFS的效能均较好。     

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。     

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T2WI影像组学模型产前预测胎盘植入性病变

目的 评估基于MR T2WI影像组学模型产前预测胎盘植入性病变（PAS）的价值。方法 回顾性分析241例孕妇及胎儿MRI,其中116例PAS、125例无PAS。按7：3比例将其分为训练集（n=168）和验证集（n=73）,于训练集提取并筛选半傅立叶采集单次激发快速自旋回波（HASTE）及真实稳态进动快速成像（TrueFISP）序列图像的影像组学特征,构建预测PAS的影像组学模型,并以回归分析方法构建临床模型、影像组学模型及临床-影像组学模型。采用校准曲线和受试者工作特征（ROC）曲线分析模型的效能,以决策曲线分析（DCA）评估其临床实用性。结果 对各序列图像分别提取1 130个影像组学特征,经LASSO回归等处理后,各筛选出9个影像组学特征,用于构建预测PAS的HASTE及TrueFISP影像组学模型。ROC曲线显示,临床模型、HASTE影像组学模型及TrueFISP影像组学模型在验证集中诊断PAS的曲线下面积（AUC）分别为0.882、0.968和0.930（P均>0.05）;HASTE联合TrueFISP影像组学模型的AUC为0.990,高于临床（Z=-2.36,P=0.02）、HASTE影像组学（Z=-2.48,P=0.02）及TrueFISP影像组学模型（Z=-2.43,P=0.02）;临床-HASTE-TrueFISP影像组学模型的AUC为0.995,与HASTE联合TrueFISP影像组学模型差异无统计学意义（Z=-0.85,P=0.40）,高于HASTE或TrueFISP影像组学模型（Z=-2.64、-2.47,P均<0.05）。临床模型之外,各模型在验证集数据中的校准度均较好;阈值取0~0.6时,其在验证集的临床净获益均大于临床模型。结论 基于产前HASTE及TrueFISP序列图像的联合影像组学模型有助于准确预测PAS。     

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.