多层螺旋CT灌注成像对肝硬化的诊断价值

肝脏CT灌注成像是一种新兴功能成像技术,通过同层动态扫描获得多种灌注参数,对肝动脉和门静脉血流变化进行定量分析,进而反映肝硬化形成过程中的血流动力学改变。目前用于肝硬化诊断的传统CT扫描技术以反映解剖学形态为主,CT灌注成像技术在肝肿瘤中的研究较多,而对肝硬化发生过程中的血流变化研究较少,对肝硬化灌注参数的分析较零散。因此,本文对多层螺旋CT灌注成像技术在肝硬化血液动力学变化方面的研究作一综述。     

CT 灌注成像能提高急性后循环卒中的诊断准确率

CT 灌注成像(computed tomography perfusion, CTP)在前循环急性缺血性卒中的检测中具有很高的诊断价值,但对疑似后循环卒中的诊断价值尚不确定,而且全脑容积灌注成像尚未得到广泛使用。因此,德国明斯特大学医院临床放射科的Sporns 等进行了一项回顾性研究,在非增强 CT 扫描( non-contrast CT, NCCT)和 CT 血管造影源图像(CT angiography source images, CTA-SI)的基础上进行全脑容积灌注成像,探讨其在疑似后循环急性缺血性卒中患者中检测梗死灶的额外价值。     

动态CT灌注成像在缺血半暗带评价中的应用

由于卒中的治疗受到时间窗的限制,血流灌注情况和半暗带的及时评价对治疗方案的确定至关重要。动态CT灌注成像因其快速、准确等优点在卒中影像学评价中越来越多得到重视。随着多排CT和商业软件的开发,动态CT灌注成像技术日趋成熟。文章就动态CT灌注成像在缺血半暗带评价中的应用进行了综述。     

CT灌注和CT血管成像在缺血性卒中早期诊断中的作用

目的探讨CT灌注和CT血管成像对缺血性卒中患者早期诊断缺血半暗带和缺血部位的作用。方法回顾20例缺血性卒中患者,于发病24h之内均行CT灌注检查,8例行CT血管成像,获取梗死侧与正常侧脑血流量(CBF)、脑血容量(CBV)和平均通过时间(MTT)参数图和脑血管影像,将上述结果进行统计学分析。结果本组急性脑梗死16例,4例TIA患者,经CT灌注检查梗死侧缺血中心区的CBV、CBF为(2.1±0.6)ml/100g、(22.8±26.2)ml.100g-1.min-1,较正常侧明显减少,MTT为(7.6±3.2)s,与正常对照区相比差异有显著性(P<0.01)。15例可见缺血半暗带存在,CT血管成像8例,与CT灌注判断的梗塞血管基本相符。结论CT灌注成像能快速、准确反映缺血半暗带的部位、范围,结合CT血管成像,可以准确判断栓塞血管部位,对早期诊断缺血性卒中和抓住动脉溶栓时机有较好的指导作用。     

交叉性小脑神经机能联系不能的发病机制及影像学检查技术的研究进展

交叉性小脑神经机能联系不能(CCD)是指幕上脑组织病变导致对侧小脑半球血流及代谢减低的现象。CCD的发病机制主要与血流动力学改变、迟发性神经元死亡、卒中后全脑炎、神经传导通路的中断或抑制等方面有关。随着影像学技术的逐渐完善,关于CCD的影像学检查技术也不断更新,主要体现在单光子发射计算机断层/PET成像、CT灌注成像、磁共振灌注成像、磁共振功能成像四个方面。     

颞浅动脉-大脑中动脉搭桥术在缺血性脑血管病中的应用

目的探讨颞浅动脉-大脑中动脉搭桥手术在缺血性脑血管病中的治疗应用及CT脑灌注成像对术前、术后脑血流量及手术效果的评价。方法选择2012年2月至2013年6月在山西医科大学第一医院神经外科进行颞浅动脉-大脑中动脉搭桥术的18例患者,脑血管造影或CT脑血管成像提示单侧血管闭塞或严重狭窄;术前行脑CT灌注成像,通过评估感兴趣区内相关指标,明确是否存在血流动力学改变。对脑血流动力学结果和临床表现进行综合评价,按照严格的纳入、排除标准选取患者进行颞浅动脉-大脑中动脉搭桥手术。术后复查脑血管造影或CT血管成像以及CT灌注成像,通过测量术后相关指标,与术前进行比较,评估手术患者的血管吻合口状况及血流动力学情况。应用美国国立卫生研究院卒中量表(NIHSS)对患者进行随访,评估患者手术前、后神经功能状况。所有收集的数据使用SPSS 13.0统计软件进行分析。结果 18例搭桥手术均顺利完成,术后CT灌注成像显示患侧脑血流量明显较术前升高(t=-6.443,P0.05),平均通过时间明显减少(t=6.270,P0.05),峰值时间也减少(t=3.574,P0.05)。术后12周随访NIHSS评分较术前下降(t=3.310,P0.05),神经功能症状有明显缓解。结论颞浅动脉-大脑中动脉搭桥术通过增加手术侧的脑血流量,可以在短期内缓解缺血区域的脑血流量,对于存在血流动力学改变的血管闭塞性疾病患者的神经功能症状有改善。CT灌注成像在颞浅动脉-大脑中动脉搭桥术术前评估及术后评价方面有一定的指导意义。     

急性缺血性卒中的影像学新进展

缺血性卒中是一种致死和致残率很高的常见病,近年来随着螺旋CT扫描技术和MR平面回波技术的发展,CT灌注成像和MR灌注、弥散加权成像技术可超早期显示脑缺血时的血流灌注情况,为超早期诊断提供了可靠的影像学信息。     

CT灌注联合能谱成像评价老年射频消融肺癌术后近期疗效的价值

目的探讨CT灌注联合能谱成像对老年射频消融肺癌术后患者近期疗效的。方法 60例经病理证实的老年肺癌患者,均行射频消融术治疗,并于术前及术后行CT灌注联合能谱成像检查,比较手术前后CT灌注参数值及能谱CT参数值变化,并对比治疗后缓解、复发者CT灌注参数值及能谱CT参数值。结果治疗后CT灌注参数血流量(BF)、血容量(BV)、表面通透性(PS)均低于治疗前(P<0.05);能谱CT参数碘含量均低于治疗前(P<0.05);缓解组CT灌注参数BF、BV、PS均低于复发组(P<0.05);缓解组能谱CT参数碘含量、水含量、CT值均低于复发组(P<0.05)。结论 CT灌注联合能谱成像能够客观反映老年肺癌射频消融术治疗前后病灶的灌注程度及血功特点,进而为平均射频消融术的早期疗效提供有利依据。     

急性缺血性卒中的影像学新进展

缺血性卒中是一种致死和致残率很高的常见病，近年来随着螺旋CT扫描技术和MR平面回波技术的发展，CT灌注成像和MR灌注、弥散加权成像技术可超早期显示脑缺血时的血流灌注情况，为超早期诊断提供了可靠的影像学信息。     

急性脑缺血的CT灌注成像

急性脑缺血后,局部脑组织发生一系列与血流动力学改变密切相关的病理生理学改变.CT灌注成像技术,特别是多层螺旋CT灌注成像是近几年发展起来的新型功能成像技术,不仅能在急性期对缺血病灶进行定位,而且能定量评估脑梗死前期以低灌注为特征的脑血流动力学异常并区分脑梗死与半暗带,为临床干预性治疗提供决策参考.     

Técnicas de imagen híbridas en cardiopatía isquémica

Hybrid imaging for ischemic heart disease refers to the fusion of information from a single or usually from multiple cardiovascular imaging modalities enabling synergistic assessment of the presence, the extent, and the severity of coronary atherosclerotic disease along with the hemodynamic significance of lesions and/or with evaluation of the myocardial function. A combination of coronary computed tomography angiography with myocardial perfusion imaging, such as single-photon emission computed tomography and positron emission tomography, has been adopted in several centers and implemented in international coronary artery disease management guidelines. Interest has increased in novel hybrid methods including coronary computed tomography angiography-derived fractional flow reserve and computed tomography perfusion and these techniques hold promise for the imminent diagnostic and management approaches of patients with coronary artery disease. In this review, we discuss the currently available hybrid noninvasive imaging modalities used in clinical practice, research approaches, and exciting potential future technological developments.     

Sublingual administration of captopril versus nitroglycerin in patients with severe congestive heart failure

Angiotensin-converting enzyme inhibition has proven to be a successful approach for the long-term treatment of patients with congestive heart failure. This investigation compared the acute hemodynamic changes after sublingual administration of the angiotensin-converting enzyme inhibitor captopril with those after nitroglycerin. A total of 24 patients with severe left heart failure (New York Heart Association classes III and IV) were given 25 mg captopril and 0.8 mg nitroglycerin sublingually in this randomized, cross-over study. Hemodynamic monitoring revealed a clear improvement in pre- and afterload parameters for both drugs (P less than 0.01 and P less than 0.001), while captopril induced a higher increase in cardiac index (+49.2% vs. +25%), stroke volume index (+53.5% vs. +25.7%), and stroke work index (+55% vs. +28%) than nitroglycerin (P less than 0.001). Although not statistically significant, the onset of change for most hemodynamic parameters was measured earlier after nitroglycerin (after 12-19 vs. 16-22 minutes). Captopril revealed later peak effects (after 47-84 vs. 25-55 minutes, P less than 0.001) and a longer sustained improvement in hemodynamic values (return to baseline values after 117-162 vs. 68-120 minutes, P less than 0.001). No side effects occurred after either captopril or nitroglycerin in this study. Thus, these results indicate there is an early improvement in hemodynamic parameters after the sublingual administration of both drugs in patients with severe congestive heart failure, and that captopril induces a more pronounced and prolonged improvement than nitroglycerin.     

Multimodality imaging in coronary artery disease – “The more the better?”

Multimodality imaging in coronary artery disease (CAD) comprises a combination of information from more than one imaging technique. These combinations, performed in a side-by-side or fusion mode, include computed tomography (CT) and single photon emission computed tomography (SPECT), positron emission tomography (PET) and CT, and PET with magnetic resonance imaging (MRI). Data thus obtained lead to either a summative or synergistic gain of information. For instance, morphology (coronary plaques/stenosis) can be depicted by coronary CT angiography, whereas functional aspects of CAD such as myocardial perfusion abnormalities or myocardial metabolism can be evaluated by the complementary technique in order to separate a hemodynamic significant coronary stenosis from a hemodynamic non-significant stenosis. Distinguishing these two entities has an important impact on patient management. Beyond the diagnostic yield, some of these combinations in multimodality imaging also have prognostic implications. In this article, we will describe different multimodality imaging approaches (CT/SPECT, PET/CT and PET/MRI) for evaluation of CAD in patients with suspected or known CAD and put them into the context of current knowledge.     

Neuroimaging in acute ischaemic stroke: insights into unanswered questions of pathophysiology

Wardlaw JM (Western General Hospital, Edinburgh, UK). Neuroimaging in acute ischaemic stroke: insights into unanswered questions of pathophysiology (Review). J Intern Med 2010; 267: 172–190. Abstract. The treatment of acute ischaemic stroke is based on the principle that there is ischaemic but still potentially salvageable tissue that could be rescued if blood flow could be restored quickly. It is assumed that salvage might only be possible in the first few hours, and that infarct expansion is a direct result of failed recanalization of the main artery. This concept arose from experimental work in the 1970s, supported more recently by studies using imaging to identify penumbral tissue. However, although magnetic resonance diffusion and perfusion imaging is a way of imaging penumbral tissue and has been around for over a decade, it is not an easy technique to apply in practice and its use has produced conflicting results. Computed tomography perfusion, and any other tissue perfusion imaging technique, is likely to encounter the same difficulties. Indeed many factors, other than the presence of a diffusion‐perfusion mismatch acutely, may determine or influence ultimate tissue fate even days after the stroke, and in turn, clinical outcome. Many of these potential influences are beginning to emerge from studies using different forms of imaging at later times after stroke. This review will explore the information now emerging from imaging studies in large artery ischaemic stroke to summarize knowledge to date and indicate unresolved issues for the future.     

FUNCTIONAL NEUROIMAGING IN ACUTE STROKE

To the present day, the first and most widespread diagnostic approach in the assessment of acute stroke remains CT scan. Its sensitivity is very high (nearly 100%) in detecting intracerebral hemorrhage in the acute period, but its capability of revealing ischemic injury in the very first hours from symptom onset is relatively poor. Since the efficacy of thrombolytic treatment in acute stroke has been suggested by the ECASS and NINDS rt-PA trials, functional neuroimaging able to distinguish potentially salvageable tissue from irreversibly injured areas has acquired primary importance. The possibility to correctly identify the tissue of the ischemic penumbra within the first hours from symptom onset is essential for correct patient selection for thrombolitic treatment. Different imaging strategies are available for the definition of perfusion deficits within the acute time window; among these are positron emission tomography (PET), single photon emission computed tomography (SPECT), Xenon CT (XeCT), dynamic CT perfusion imaging (CTP), diffusion weighted magnetic resonance imaging (DW-MRI), and perfusion weighted magnetic resonance imaging (PW-MRI). Though each technique has its advantages and limitations to present day functional MRI remains the most widespread imaging technique in the assessment of acute stroke being more accessible than both SPECT and PET, and capable of giving information on both perfusion and tissue functional status in a single imaging session.

In this paper we discuss the role of functional neuroimaging in acute stroke.     

Functional neuroimaging in acute stroke

To the present day, the first and most widespread diagnostic approach in the assessment of acute stroke remains CT scan. Its sensitivity is very high (nearly 100%) in detecting intracerebral hemorrhage in the acute period, but its capability of revealing ischemic injury in the very first hours from symptom onset is relatively poor. Since the efficacy of thrombolytic treatment in acute stroke has been suggested by the ECASS and NINDS rt-PA trials, functional neuroimaging able to distinguish potentially salvageable tissue from irreversibly injured areas has acquired primary importance. The possibility to correctly identify the tissue of the ischemic penumbra within the first hours from symptom onset is essential for correct patient selection for thrombolitic treatment. Different imaging strategies are available for the definition of perfusion deficits within the acute time window; among these are positron emission tomography (PET), single photon emission computed tomography (SPECT), Xenon CT (XeCT), dynamic CT perfusion imaging (CTP), diffusion weighted magnetic resonance imaging (DW-MRI), and perfusion weighted magnetic resonance imaging (PW-MRI). Though each technique has its advantages and limitations to present day functional MRI remains the most widespread imaging technique in the assessment of acute stroke being more accessible than both SPECT and PET, and capable of giving information on both perfusion and tissue functional status in a single imaging session. In this paper we discuss the role of functional neuroimaging in acute stroke.     

Quantification of angiogenesis by CT perfusion imaging in liver tumor of rabbit

BACKGROUND:Tumor angiogenesis is essential for primary and metastatic tumor growth.Computed tomography perfusion(CTP)is a new imaging method,made possible by the recent development of fast CT scanners and improved data analysis techniques,which allows measurement of the physiologic and hemodynamic properties of tissue vasculature.This study aimed to evaluate CTP in the quantification of angiogenesis and to assess the relationship between tissue perfusion parameters and microvascular density(MVD)and vascular...     

Influence of canrenoate potassium (aldactone pro injections) on hemodynamics and myocardial ischemia in experimental myocardial infarct]

The effects of the positive-inotropic drug Canrenoat-Kalium (CRK) on the extent and severity of myocardial ischemic injury and on hemodynamic parameters were studied in 17 dogs following coronary occlusion. Acute myocardial infarction causes depression of left-ventricular function. There eas a significant decrease in dp/dtmax, stroke volume and cardiac output; average values for mean arterial pressure were reduced, but not significantly. There was a significant increase in left-ventricular enddiastolic pressure. Heart rate was unchanged. In the healing phase of myocardial infarction a significant elevation of left-ventricular enddiastolic pressure and a significant decrease of arterial pressure persisted, but the other parameters had returned toward normal. Intravenous administration of CRK (20 mg/kg) one hour after coronary occlusion causes a significant increase in left-ventricular dp/dtmax, cardiac output and stroke volume, but no significant change in arterial pressure, heart rate and left-ventricular enddiastolic pressure. Four days after myocardial infarction administration of CRK causes also a significant incrrease in left-ventricular dp/dtmax and -n 4 out of 5 animals an increase in stroke volume. Heart rate, arterial pressure and left-ventricular enddiastolic pressure are unchanged. There is a continuous deterioration of all hemodynamic parameters in the control group 1 hour and 96 hours after experimental myocardial infarction. This spontaneous deterioration has to be taken into consideration estimating the effect of CRK in experimental conditions. 120 epicardial electrocardiographic recordings were used to assess the extent and severity of myocardial ischemic injury. The average ST-segment elevation and the number of sites with abnormal ST-segments were significantly reduced 20 min after CRK administration. The study suggests a beneficial therapeutic role for CRK treatment of left-ventricular failure in the acute and healing phase after myocardial infarction.     

Hyperacute imaging of ischemic stroke: Role in therapeutic management

Ischemic stroke remains a significant cause of morbidity and mortality. Current therapeutic options for acute ischemic stroke include intravenous thrombolysis and endovascular approaches for recanalization of proximal arterial occlusion. The rapid identification of underlying stroke etiology or mechanism may facilitate selection criteria for emergent therapy. Hyperacute imaging plays an integral role in the delineation of stroke pathophysiology and the formulation of rational stroke therapy. Hyperacute imaging of ischemic stroke may demonstrate proximal vascular occlusion, compensatory collateral circulation, residual or collateral tissue perfusion, and the differentiation of ischemic core from penumbral regions. Characterization of the ischemic field, including core and penumbra, with various mismatch models on multimodal computed tomography or MRI may refine current therapeutic strategies for cerebral ischemia. The diagnostic and therapeutic role of hyperacute imaging has emerged as a pivotal component in the evaluation and management of ischemic stroke.     

急性卒中患者的缺血半暗带评价

卒中的发病率、致残率和死亡率均很高.缺血半暗带评价对于指导临床治疗和评估预后具有非常重要的意义.目前,可采用MRI、CT、正电子发射体层摄影和单光子发射计算机体层摄影等影像学技术评价缺血半暗带.