CVR

CVR
  • 文章类型: Journal Article
    本研究调查了食管癌(EC)患者放疗(RT)期间心脏体积减小(CVR)的因素。这项回顾性研究包括在国立医院组织四国癌症中心(松山,日本)。心脏描绘基于初始和非脐带增强(保留脊髓方法)计划的计算机断层扫描图像。分析了CVR与其他相关参数的关系。2016年1月至2022年1月共调查了58例EC患者。单变量和多元回归分析显示,RT期间的CVR与下腔静脉(IVC)体积和体重指数(BMI)损失的变化率之间存在统计学上的显着关联。在CVR>10%的多变量分析中,只有IVC体积的变化表现出显著的相关性.相反,在RT期间的CVR显示与心脏剂量-体积参数没有关联,实验室数据,或血压和脉搏率的变化。在CVR>10%的12例中,冠状动脉左前降支区(LADR)的中位运动为1.35cm(范围,0.0-2.7厘米)。总之,RT期间的CVR与IVC体积变化密切相关,表明脱水是主要原因,而不是辐射引起的心脏损伤.由于CVR>10%引起的LADR移动可能导致LADR辐射过量。
    The present study investigated the factors contributing to cardiac volume reduction (CVR) during radiotherapy (RT) in patients with esophageal carcinoma (EC). This retrospective study included patients with EC treated at National Hospital Organization Shikoku Cancer Center (Matsuyama, Japan). Cardiac delineation was based on initial and off-cord boost (spinal cord-sparing approach) planning computed tomography images. The relationship between CVR and other relevant parameters was analyzed. A total of 58 patients with EC were investigated between January 2016 and January 2022. Univariate and multiple regression analyses revealed a statistically significant association between CVR during RT and the change ratio of the inferior vena cava (IVC) volume and body mass index (BMI) loss. In multivariate analysis of CVR of >10%, only the change in IVC volume exhibited a significant association. Conversely, CVR during RT displayed no association with heart dose-volume parameters, laboratory data, or changes in blood pressure and pulse rate. Among the 12 cases with CVR of >10%, the median movement of the left anterior descending coronary artery region (LADR) was 1.35 cm (range, 0.0-2.7 cm). In conclusion, CVR during RT was most strongly associated with changes in IVC volume, suggesting dehydration as the primary cause, rather than radiation-induced heart damage. LADR movement due to a CVR of >10% may lead to LADR radiation overdose.
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  • 文章类型: Journal Article
    BOLDfMRI信号已与血管舒张刺激结合使用,作为脑血管反应性(CVR)的标志物:由血管舒张刺激的单位变化引起的脑血流量(CBF)的相对变化。使用数值模拟,我们证明,血管舒张引起的相对BOLD信号变化的变异性受到含脱氧血红蛋白的脑血容量(CBV)变异性的强烈影响,因为这种变异性的来源可能比CVR更突出。它可能,因此,作为脱氧CBV(CBVdHb)而不是CVR的代表,更适合描述由同位代谢血管舒张引起的相对BOLD信号变化。考虑到这一点,实现了一种新的方法来绘制CBVdHb的标记,称为BOLD-CBV,基于通过估计来自充满静脉血的体素的血管内静脉BOLD信号来对逐体素BOLD信号变化进行归一化。血管内静脉BOLD信号变异,在反复屏气期间记录,从27名健康志愿者的上矢状窦提取,并用作整个大脑的回归因子,生成BOLD-CBV图。在同一个队列中,我们通过比较组水平的BOLDfMRI对视觉运动学习任务的反应,在包含和不包含BOLD-CBV的逐体素血管协变量和每mmHg潮气末二氧化碳变化的BOLD信号变化(BOLD-CVR)的情况下,证明了BOLD-CBV在刺激诱发BOLDfMRI正常化中的潜在用途.与根据潮气末二氧化碳记录估计的BOLD-CVR相比,BOLD-CBV的经验测量在运动任务引起的BOLD反应中占主体之间的变异性更大。新方法可以通过包括血管特征的测量来潜在地提高组fMRI研究的能力,并且具有不需要对潮气末二氧化碳进行实验测量的强大实践优势。与传统的估计BOLD-CVR的方法不同。与BOLD-CVR相比,它也更接近地代表了脑血管系统的特定生理特征,即血量。
    BOLD fMRI signal has been used in conjunction with vasodilatory stimulation as a marker of cerebrovascular reactivity (CVR): the relative change in cerebral blood flow (CBF) arising from a unit change in the vasodilatory stimulus. Using numerical simulations, we demonstrate that the variability in the relative BOLD signal change induced by vasodilation is strongly influenced by the variability in deoxyhemoglobin-containing cerebral blood volume (CBV), as this source of variability is likely to be more prominent than that of CVR. It may, therefore, be more appropriate to describe the relative BOLD signal change induced by an isometabolic vasodilation as a proxy of deoxygenated CBV (CBVdHb) rather than CVR. With this in mind, a new method was implemented to map a marker of CBVdHb, termed BOLD-CBV, based on the normalization of voxel-wise BOLD signal variation by an estimate of the intravascular venous BOLD signal from voxels filled with venous blood. The intravascular venous BOLD signal variation, recorded during repeated breath-holding, was extracted from the superior sagittal sinus in a cohort of 27 healthy volunteers and used as a regressor across the whole brain, yielding maps of BOLD-CBV. In the same cohort, we demonstrated the potential use of BOLD-CBV for the normalization of stimulus-evoked BOLD fMRI by comparing group-level BOLD fMRI responses to a visuomotor learning task with and without the inclusion of voxel-wise vascular covariates of BOLD-CBV and the BOLD signal change per mmHg variation in end-tidal carbon dioxide (BOLD-CVR). The empirical measure of BOLD-CBV accounted for more between-subject variability in the motor task-induced BOLD responses than BOLD-CVR estimated from end-tidal carbon dioxide recordings. The new method can potentially increase the power of group fMRI studies by including a measure of vascular characteristics and has the strong practical advantage of not requiring experimental measurement of end-tidal carbon dioxide, unlike traditional methods to estimate BOLD-CVR. It also more closely represents a specific physiological characteristic of brain vasculature than BOLD-CVR, namely blood volume.
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  • 文章类型: Journal Article
    背景:先天性肺畸形(CLM)很容易在妊娠早期发现,具有可变的自然史。诊断后建议监测病变大小和纵隔移位(MS)。这项研究的目的是提出一种风险分层的临床算法,用于CLM的产前监测。
    方法:经过伦理批准,我们对2015年1月至2022年6月在我们胎儿中心评估的所有CLM胎儿进行了回顾性分析.患者人口统计学,成像特性,收集胎儿干预措施。根据先天性肺畸形体积比(CVR)和MS的存在对病变进行分层。分析中采用了描述性统计和接收器工作特性曲线。
    结果:我们分析了111例患者,平均胎龄为23.4周,中位数CVR为0.5(四分位数间距,0.3-1.2),在初步评估中,111例患者中有76例(68%)出现MS。在低风险患者(CVR≤1.1)中,在最终评估中,96%的风险仍然很低。在生长期中,没有患者从低风险过渡到高风险。CVR>1.1的患者常出现持续性MS(P<0.001)。仅在CVR>1.1(P<0.001,P=0.002)和MS(P=0.144,P=0.214)的患者中发生积液(5/111,5%)和胎儿介入(4/111,4%)。关于接收机工作特性曲线分析,初始CVR>1.1对水肿和胎儿介入治疗有100%的敏感性和阴性预测值.
    结论:初始CVR≤1.1的CLMs发生水肿和胎儿干预的风险较低。我们提出了一种基于CVR的生长期CLM监测风险分层算法。虽然我们的经验表明CLM和MS患者的风险更高,目前对MS的主观评估不能充分预测。合并MS分级系统可以进一步完善CLM管理中的风险分层。
    Congenital lung malformations (CLMs) are readily identified early in pregnancy with a variable natural history. Monitoring for lesion size and mediastinal shift (MS) is recommended following diagnosis. The purpose of this study is to propose a risk-stratified clinical algorithm for prenatal monitoring of CLM.
    After ethical approval, all fetuses with CLMs evaluated at our fetal center from January 2015 to June 2022 were retrospectively reviewed. Patient demographics, imaging characteristics, and fetal interventions were collected. Lesions were stratified by congenital lung malformation volume ratio (CVR) and the presence of MS. Descriptive statistics and receiver operating characteristic curves were employed in the analysis.
    We analyzed 111 patients with a mean of 23.4 wk gestational age, a median CVR of 0.5 (interquartile range, 0.3-1.2), and MS in 76 of 111(68%) patients on initial evaluation. Among low-risk patients (CVR ≤1.1), 96% remained low-risk on final evaluation. No patients transitioned from low to high risk during the growth period. Patients with CVR >1.1 often had persistent MS (P < 0.001). Hydrops (5/111, 5%) and fetal intervention (4/111, 4%) only occurred in patients with CVR >1.1 (P < 0.001, P = 0.002) and MS (P = 0.144, P = 0.214). On receiver operating characteristic curve analysis, initial CVR >1.1 had 100% sensitivity and negative predictive value for hydrops and fetal intervention.
    CLMs with initial CVR ≤1.1 are low risk for hydrops and fetal intervention. We propose a risk-stratified algorithm for the monitoring of CLM during the growth period based on CVR. While our experience suggests that patients with CLM and MS are at higher risk, the current subjective assessment of MS is not adequately predictive. Incorporating an MS grading system may further refine risk stratification in the management of CLM.
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  • 文章类型: Review
    先天性肺气道畸形(CPAMs)是罕见的偶发性病变,常与胎儿预后不良相关。3型CPAM的特征在于小的高回声囊肿(<5mm)。积水通常是次要发展的,在这种情况下,胎儿存活率约为5%。
    我们介绍了一例大型3型CPAM并发胎儿积水的病例。病变在19孕周(GW)时检测到,并在29GW时通过胎儿MRI证实。在22GW时,作为3型CPAM的可能治疗方案,我们给予一个疗程的母体类固醇治疗.两次放置腹膜-羊膜分流术以减少胎儿腹水,结果不满意。同样,羊水过多通过两次羊膜减少缓解,但不久之后就重新开发了.一名女婴在33GW时自发分娩,并在生命的前三个月接受了两阶段部分肺叶切除术。去饱和需要在阶段之间具有挑战性的侵入性振荡通气。她的结果出乎意料地积极,她可能期望有良好的生活质量。她现在快一岁了,具有接近正常的生长和发展里程碑。
    3型CPAM并发胎儿水肿与高围产期死亡率相关。虽然开放式胎儿手术在某些专科中心仍然是可行的选择,产前干预通常是无效的。该婴儿的生存可归因于产前管理和产后早期手术干预。在这种情况下缺乏通气指南对新生儿重症监护医师来说是一个重大挑战。多学科的警惕和与频繁的专家随访的合作是母亲和孩子成功的关键。
    UNASSIGNED: Congenital pulmonary airway malformations (CPAMs) are rare sporadic lesions frequently associated with poor fetal prognosis. Type 3 CPAMs are characterized by small hyperechogenic cysts (<5 mm). Hydrops often develops secondarily, and the fetal survival rate is approximately 5% in this setting.
    UNASSIGNED: We present a case of a large type 3 CPAM complicated by fetal hydrops. The lesion was detected at 19 gestational weeks (GW) and confirmed by fetal MRI at 29 GW. At 22 GW, a course of maternal steroids was given as a possible treatment of type 3 CPAM. Peritoneal-amniotic shunt was placed twice to reduce fetal ascites, with unsatisfactory results. Similarly, polyhydramnios was relieved by two amnioreductions, but redeveloped soon after. A baby girl was delivered spontaneously at 33 GW and received a two-stage partial lobectomy in the first three months of life. Desaturations necessitated challenging invasive oscillatory ventilation between stages. Her outcome is unexpectedly positive and she may expect a good quality of life. She now approaches one year of age, with near-to-normal growth and developmental milestones.
    UNASSIGNED: Type 3 CPAMs complicated by fetal hydrops are associated with high perinatal mortality. While open fetal surgery remains a viable option in select specialist centers, antenatal interventions are typically ineffective. The survival of this infant can be attributed to prenatal management and early postnatal surgical intervention. The lack of guidelines for ventilation in this setting was a significant challenge for neonatal intensivists. Multidisciplinary vigilance and collaboration with frequent specialist follow ups were the key to success for both mother and child.
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  • 文章类型: Journal Article
    背景:多项研究表明,先天性肺气道畸形体积比(CVR)是产前诊断的肺部病变的新生儿结局的有用预测指标。然而,由于操作者的依赖性,对于哪些CVR值具有最佳的预测价值仍然缺乏共识,在整个妊娠期间肺部病变大小的固有变化,以及母体类固醇的广泛使用。
    目的:本研究旨在确定肺畸形胎儿的连续CVR测量与新生儿结局之间的关系。
    方法:回顾性队列研究于2010年1月至2021年12月在两个主要胎儿中心进行了产前诊断为肺畸形的胎儿。产前变量,包括前瞻性测量的CVR测量(初始,最大值,andfinal),进行了分析。结果与三个结果指标相关,即在生命30天之前进行手术切除,出生时需要补充氧气,出生时气管插管.使用接收器工作特征分析进行统计分析,Welch两个样本t检验,和多因素logistic回归(p<0.05)。
    结果:有123个胎儿有孤立的肺部病变。8人(6.5%)有积水。妊娠22.9±3.9周时,平均初始CVR为0.67±0.61cm2。妊娠27.0±4.0周时,平均最大CVR为1.08±0.94cm2。妊娠33.2±4.1周时,平均最终CVR为0.58±0.60cm2。分娩时的平均胎龄为38.3±2.6周,15例(12.2%)因有症状的疾病行新生儿肺切除术。在多元回归中,所有3项CVR测量结果均显示与新生儿肺切除术有显著相关性(p<0.001).根据初始CVR≥0.8cm2,最大CVR≥1.5cm2和最终CVR≥1.3cm2,确定最佳CVR截止值,曲线下的相关面积分别为0.89、0.97和0.93。最终的CVR在预测出生后早期的外科肺切除术方面具有最高的特异性。
    结论:在整个妊娠期间测量肺畸形胎儿的CVR对于产前咨询和分娩后规划护理过渡具有临床价值。最终CVR超过1.3cm2的胎儿可能需要新生儿手术,因此应在具有新生儿重症监护和儿科外科专业知识的三级护理中心分娩。
    Several studies have shown that the congenital pulmonary airway malformation volume ratio is a useful prognosticator of neonatal outcome in prenatally diagnosed lung lesions. However, there remains a lack of consensus on which congenital pulmonary airway malformation volume ratio values have the best predictive value because of operator dependence, inherent changes in lung lesion size throughout gestation, and the widespread use of maternal steroids.
    This study sought to determine the association between serial congenital pulmonary airway malformation volume ratio measurements and neonatal outcomes among fetuses with lung malformations.
    This was a retrospective cohort study of fetuses with a prenatally diagnosed lung malformation managed at 2 major fetal centers from January 2010 to December 2021. Prenatal variables, including prospectively measured congenital pulmonary airway malformation volume ratio measurements (initial, maximum, and final), were analyzed. The results were correlated with 3 outcome measures, namely surgical resection before 30 days of life, a need for supplemental O2 at birth, and endotracheal intubation at birth. Statistical analyses were performed using receiver operating characteristic curve analyses, Welch 2 sample t tests, and multivariable logistic regressions (P<.05).
    There were 123 fetuses with isolated lung lesions identified. Eight (6.5%) had hydrops. The mean initial congenital pulmonary airway malformation volume ratio was 0.67±0.61 cm2 at 22.9±3.9 weeks\' gestation. The mean maximum congenital pulmonary airway malformation volume ratio was 1.08 ± 0.94 cm2 at 27.0 ± 4.0 weeks\' gestation. The mean final congenital pulmonary airway malformation volume ratio was 0.58±0.60 cm2 at 33.2±4.1 weeks\' gestation. At a mean gestational age at delivery of 38.3±2.6 weeks, 15 (12.2%) underwent neonatal lung resection for symptomatic disease. In a multivariable regression, all 3 congenital pulmonary airway malformation volume ratio measurements showed a significant correlation with neonatal lung resection (P<.001). Optimal congenital pulmonary airway malformation volume ratio cutoffs were established based on an initial congenital pulmonary airway malformation volume ratio of ≥0.8 cm2, maximum congenital pulmonary airway malformation volume ratio of ≥1.5 cm2, and a final congenital pulmonary airway malformation volume ratio of ≥1.3 cm2 with associated areas under the curve of 0.89, 0.97, and 0.93, respectively. The final congenital pulmonary airway malformation volume ratio had the highest specificity for predicting surgical lung resection in the early postnatal period.
    Measuring congenital pulmonary airway malformation volume ratios throughout pregnancy in fetuses with pulmonary malformations has clinical value for prenatal counseling and planning care transition after delivery. Fetuses with a final congenital pulmonary airway malformation volume ratio of more than 1.3 cm2 are likely to require neonatal surgery and therefore should be delivered at tertiary care centers with a neonatal intensive care unit and pediatric surgical expertise.
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  • 文章类型: Journal Article
    背景:小脑横裂(CCD)是指小脑半球对侧幕上疾病的灌注和代谢下降。对脑血管反应性(CVR)中CCD的先前研究仅限于最终CVR估计(CVRend)。我们最近使用动态CVR分析证明了非持续CVR最大值(CVRmax)的存在,为血液动力学刺激提供CVR的完全动态表征。
    目的:从动态血氧水平依赖性(BOLD)MRI研究CVRmax中的CCD,通过与传统CVRend估计的比较。
    方法:回顾性。
    方法:共有23例患者(中位年龄:51岁,10名女性)患有单侧慢性狭窄闭塞性脑血管病,没有CCD状态的先验知识。
    A3-T,T1加权磁化准备的快速梯度回波(MPRAGE)和乙酰唑胺增强的BOLD成像使用梯度回波回波平面成像(EPI)序列进行。
    结果:使用自定义去噪管道生成BOLD-CVR时间信号。使用相对于第一分钟基线的BOLD响应的最后一分钟建立CVRend。根据健康与患病大脑半球的分类,计算双侧大脑和小脑半球的CVRmax和CVRend。三个独立的观察者评估了CCD存在的所有数据。
    方法:比较半球CVR的皮尔逊相关性,用于比较CCD患病率的两比例Z检验,和Wilcoxon符号秩检验比较中位数CVR。有统计学意义的水平设为P≤0.05。
    结果:在CVRend和CVRmax图中观察到与CCD相关的变化,所有CCD+病例可通过检查任一张地图来识别。与CVRmax(r=0.676)相比,使用CVRend(r=0.728)时,CCD患者的大脑和对侧小脑半球CVR相关性更强。CVRmax(r=0.739)的健康大脑半球与对侧小脑半球之间的CVR相关性强于CVRend(r=0.705)。
    结论:在CVR检查中可以观察到与CCD相关的改变。传统的CVRend可能会低估CVR,并可能夸大CCD。
    方法:4.
    第三阶段。
    Crossed cerebellar diaschisis (CCD) refers to depressions in perfusion and metabolism within the cerebellar hemisphere contralateral to supratentorial disease. Prior investigation into CCD in cerebrovascular reactivity (CVR) has been limited to terminal CVR estimations (CVRend ). We recently have demonstrated the presence of unsustained CVR maxima (CVRmax ) using dynamic CVR analysis, offering a fully dynamic characterization of CVR to hemodynamic stimuli.
    To investigate CCD in CVRmax from dynamic blood oxygen level-dependent (BOLD) MRI, by comparison with conventional CVRend estimation.
    Retrospective.
    A total of 23 patients (median age: 51 years, 10 females) with unilateral chronic steno-occlusive cerebrovascular disease, without prior knowledge of CCD status.
    A 3-T, T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) and acetazolamide-augmented BOLD imaging performed with a gradient-echo echo-planar imaging (EPI) sequence.
    A custom denoising pipeline was used to generate BOLD-CVR time signals. CVRend was established using the last minute of the BOLD response relative to the first-minute baseline. Following classification of healthy versus diseased cerebral hemispheres, CVRmax and CVRend were calculated for bilateral cerebral and cerebellar hemispheres. Three independent observers evaluated all data for the presence of CCD.
    Pearson correlations for comparing CVR across hemispheres, two-proportion Z-tests for comparing CCD prevalence, and Wilcoxon signed-rank tests for comparing median CVR. The level of statistical significance was set at P ≤ 0.05.
    CCD-related changes were observed on both CVRend and CVRmax maps, with all CCD+ cases identifiable by inspection of either map. Diseased cerebral and contralateral cerebellar hemispheric CVR correlations in CCD+ patients were stronger when using CVRend (r = 0.728) as compared to CVRmax (r = 0.676). CVR correlations between healthy cerebral hemispheres and contralateral cerebellar hemispheres were stronger for CVRmax (r = 0.739) than for CVRend (r = 0.705).
    CCD-related alterations could be observed in CVR examinations. Conventional CVRend may underestimate CVR and could exaggerate CCD.
    4.
    Stage 3.
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  • 文章类型: Journal Article
    目的:这项研究的目的是评估CPAM-体积比(CVR)是否可以预测产前期间有胎儿肺部肿块的胎儿的产后管理(随访以解决和手术治疗)。
    方法:分析了在我们中心就诊的产前诊断为CPAM(先天性肺气道畸形)和BPS(支气管肺隔离症)的44例患者。产科病史和结果,核型结果,CVR,额外的超声检查结果,记录了群众的特征。计算所有病例的CVR。在研究中,我们试图确定CVR阈值,并没有使用文献中经典使用的阈值。
    结果:分析20例胎儿BPS和24例CPAM。排除5名患者后,46%的患者被诊断为BPS,54%被诊断为CPAM。在这项研究中,CVR的截止值<0,53,它以85%的敏感性和88%的特异性预测产后手术不需要.当我们为在头10天内需要紧急手术的患者取>0.76的截止值时,它以90%的敏感性和89%的特异性预测手术的需要.此外,确定所有纵隔移位患者均接受手术治疗.
    结论:我们认为,在所有CPAM和BPS病例中,应评估CVR值和纵隔移位的存在,以预测手术。在纵隔移位且CVR值高于0.76的情况下,可以对家属进行适当的预后咨询。
    OBJECTIVE: The purpose of this study is to evaluate whether CPAM-volume ratio (CVR) can predict postnatal management (follow up for resolution and surgical treatment) in fetuses with fetal lung masses in the prenatal period.
    METHODS: 44 patients who presented at our center with prenatally diagnosed CPAM (Congenital Pulmonary Airway Malformation) and BPS (Bronchopulmonary Sequestration) were analyzed. Obstetric history and outcomes, karyotype results, CVR, additional sonographic findings, characteristics of masses were recorded. CVR was calculated for all cases. İn the study we sought to identify a CVR threshold and did not use the thresholds classically used in the literature.
    RESULTS: 20 fetal BPS and 24 CPAM cases were analyzed. After excluding 5 patients, 46% of the patients were diagnosed with BPS and 54% with CPAM. İn this study the cut off < 0,53 for CVR is taken, it predicts the no need for postnatal surgery with a sensitivity of 85% and a specificity of 88%. When we take the > 0,76 cut-off value for patients who will require emergency surgery within the first 10 days, it predicts the need for surgery with 90% sensitivity and 89% specificity. In addition, it was determined that all patients with mediastinal shift were operated.
    CONCLUSIONS: We believe that the CVR value and the presence of mediastinal shift should be evaluated in all cases of CPAM and BPS for prediction of the surgery. Proper counseling about the prognosis could be given to the family in cases with mediastinal shift and CVR value above 0,76.
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  • 文章类型: Journal Article
    随着移动互联网技术的发展,公司需要完成消费者定位的整个过程,广告内容生成,和广告显示在很短的时间窗口。因此,计算广告,例如社交媒体平台上的原生广告,以其自动化和个性化的特点成为网络广告的主流。然而,计算广告在使用人工智能技术生成内容时面临一些问题。首先,图像应该对消费者有足够大的影响,并且易于调整以节省计算能力;第二,计算广告系统的迭代依赖于消费者行为或广告有效性,企业需要学习广告设计与消费者行为之间的关系。在上述两个问题下,本文选取视距作为主要变量,和图像可以通过裁剪来调整,以节省计算能力。本文将形象设计和广告效果指标纳入解释层次理论框架,在这种情况下,可以快速确定有效性指标。根据以前的研究,我们用点击率(CTR)表示销售漏斗的早期阶段和较高的解释水平,用CVR(转化率)表示销售漏斗的后期阶段和较低的解释水平。因此,视觉上遥远的图像带来遥远的心理距离或更高的解释水平,可以获得更高的CTR;视觉上接近的图像带来近的心理距离或较低的解释水平,这可以带来更高的CVR。这些发现表明,企业可以通过了解消费者的心理状态来提高广告系统的效率并获得更多的收入。
    With the development of mobile Internet technology, firms need to complete the entire process of consumer targeting, ad content generation, and ad display in a very short time window. Therefore, computational advertising, such as native ads on social media platforms, has become the mainstream of online advertising with its automation and personalization features. However, computational advertising faces some problems when using artificial intelligence technology to generate content. First, the images should have a significant enough impact on consumers and be easy to adjust to save computational power at the same time; second, the iteration of the computational advertising system relies on consumer behaviors or advertising effectiveness, and firms need to learn the relationship between ad design and consumer behaviors. Under the above two problems, this paper selects visual distance as the main variable, and images can be adjusted by cropping to save computational power. This paper incorporates image design and ad effectiveness metrics into the construal level theory framework, under which the effectiveness metrics can be quickly determined. Following previous studies, we use click-through rate (CTR) to represent the early stage of the sales funnel and a higher construal level and CVR (conversion rate) to represent the later stage of the sales funnel and a lower construal level. Therefore, visually distant images bring distant psychological distance or higher construal level, which can get higher CTR; visually proximate images bring near psychological distance or lower construal level, which can bring higher CVR. These findings suggest that firms can improve the efficiency of their advertising systems and gain more revenue by understanding consumer psychological states.
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  • 文章类型: Journal Article
    脑血液到达和组织传输时间是组织灌注效率的敏感度量,并且可以提供有关侧支血流状态的有临床意义的信息。我们利用动脉血氧水平依赖性(BOLD)信号对比建立精确降低,然后增加,使用呼吸复氧来量化动脉血到达整个大脑的动脉血红蛋白饱和度挑战。我们将这种方法称为步骤血红蛋白再氧合对比刺激(SHOCS)。地毯图分析产生了信号开始(血液到达)的测量,全球运输时间(gTT)和相对总血量的计算。对于皮质灰色和深层白质,12名健康受试者的平均发病时间为1.1±0.4和1.9±0.6,分别。平均全脑gTT为4.5±0.9s。与白质相比,灰质的SHOCS反应高1.7倍;与组织特异性血液体积分数的已知差异一致。SHOCS也应用于单侧颈动脉闭塞的患者,显示同侧信号发作时间延长,未受影响的半球灌注正常。我们预计SHOCS将进一步告知上游狭窄闭塞性血管疾病患者侧支血流的程度,包括那些已知表现为血管舒张储备能力降低或血管窃血的患者。
    Cerebral blood arrival and tissue transit times are sensitive measures of the efficiency of tissue perfusion and can provide clinically meaningful information on collateral blood flow status. We exploit the arterial blood oxygen level dependent (BOLD) signal contrast established by precisely decreasing, and then increasing, arterial hemoglobin saturation using respiratory re-oxygenation challenges to quantify arterial blood arrival times throughout the brain. We term this approach the Step Hemoglobin re-Oxygenation Contrast Stimulus (SHOCS). Carpet plot analysis yielded measures of signal onset (blood arrival), global transit time (gTT) and calculations of relative total blood volume. Onset times averaged across 12 healthy subjects were 1.1 ± 0.4 and 1.9 ± 0.6 for cortical gray and deep white matter, respectively. The average whole brain gTT was 4.5 ± 0.9 s. The SHOCS response was 1.7 fold higher in grey versus white matter; in line with known differences in tissue-specific blood volume fraction. SHOCS was also applied in a patient with unilateral carotid artery occlusion revealing ipsilateral prolonged signal onset with normal perfusion in the unaffected hemisphere. We anticipate that SHOCS will further inform on the extent of collateral blood flow in patients with upstream steno-occlusive vascular disease, including those already known to manifest reductions in vasodilatory reserve capacity or vascular steal.
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  • 文章类型: Journal Article
    采用Meta分析评价CVR临界值1.6对先天性肺畸形(CLM)胎儿积液的诊断价值。
    对PubMed的系统搜索,Embase,WebofScience,CNKI,VIP,而万方在2021年7月30日前发表的一项诊断胎儿积液的先天性肺气道畸形容积比(CVR)截断值为1.6。根据纳入和排除标准,获得了符合要求的文献。共检索到75篇,并纳入12篇文章进行进一步分析。根据诊断准确性研究质量评估工具(QUADAS-2)标准评估这些研究的质量。Q检验和异质性I2用于评估由于非阈值效应引起的异质性,和Stata15.0进行统计学分析,以评估CVR临界值1.6对CLM引起的胎儿积水的诊断价值。
    共纳入12项研究。QUADAS-2表明偏倚风险相对较低,临床适用性较高。使用随机效应模型对纳入的研究进行统计分析。荟萃分析表明,合并敏感性,特异性,通过CVR诊断胎儿水肿的诊断率和综合接受者工作特征(SROC)为0.86(95%CI,0.72-0.93;I2=59.84),0.90(95%CI,0.88-0.93;I2=31.94),58(95%CI,22-149;I2=100%),0.93(95%CI,0.91-0.95)。
    CVR临界值1.6诊断CLM引起的胎儿水肿的敏感性和特异性较高,没有观察到发表偏倚,CVR临界值1.6对CLM诱发胎儿水肿的早期诊断预测有意义。
    Meta-analysis was used to evaluate the diagnostic value of a CVR cut-off value of 1.6 for fetal hydrops due to congenital lung malformation (CLM).
    A systematic search of PubMed, Embase, Web of Science, CNKI, VIP, and Wanfang published before 7/30/2021 for the value of a congenital pulmonary airway malformation volume ratio (CVR) cut-off value of 1.6 for the diagnosis of fetal hydrops. According to the inclusion and exclusion criteria, the literature that met the requirements were obtained. A total of 75 articles were retrieved, and 12 articles were included for further analysis. The quality of these studies was evaluated according to the Quality Assessment for Studies of Diagnostic Accuracy tool (QUADAS-2) criteria. The Q test and heterogeneity I2 were used to evaluate the heterogeneity due to non-threshold effects, and Stata 15.0 was used for statistical analysis to evaluate the diagnostic value of the CVR cutoff value of 1.6 for fetal hydrops due to CLM.
    A total of 12 studies were included. The QUADAS-2 indicated that the risk of bias was relatively low, and the clinical applicability was relatively high. Statistical analysis was performed on included studies using a random effect model. Meta-analysis showed that the pooled sensitivity, specificity, diagnostic ratio and summary receiver operating characteristic (SROC) for the diagnosis of fetal hydrops by CVR were 0.86 (95% CI, 0.72-0.93; I2 = 59.84), 0.90 (95% CI, 0.88-0.93; I2 = 31.94), 58 (95% CI, 22-149; I2 = 100%), 0.93 (95% CI, 0.91-0.95).
    The sensitivity and specificity of CVR cut-off value 1.6 for the diagnosis of CLM-induced fetal hydrops were high, no publication bias was observed, and the CVR cut-off value 1.6 is meaningful for the early diagnosis prediction of CLM-induced fetal hydrops.
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