多层螺旋CT灌注成像在缺血性脑卒中的临床应用

多层螺旋CT灌注成像(CT perfusion,CTP)因其成本较低、精确性高、操作容易等优点,在判断脑血流、脑代谢方面为临床提供了新的途径,已逐渐成为缺血性脑卒中的重要诊断方法,对目前指导治疗和观察疗效具有非常重要的意义.现就CTP检查方法和各项指标意义进行阐述,探讨CTP在缺血性脑卒中的临床应用,同时与其他灌注成像方法作比较,提出脑卒中"一站式"CT检查方案.     

多层螺旋CT在伴皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病诊断中的应用价值

伴皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosomal dominant aneriopathy with subcortical infarcts and leukoencephalopathy,CADASIL)是人类19p13上的Notch 3基因突变所致的常染色体显性遗传的、非动脉硬化或淀粉样变性的缺血性脑小动脉病[1-2].国内外影像学多限于MRI检查[2-4].,我们应用多层螺旋CT平扫(NCCT)、CT血管成像(CTA)及CT灌注成像(CTP)检查CADASIL一家系,以初步探讨多层螺旋CT对该病的应用价值.     

多层螺旋CT三维图像重建和脑灌注成像在急性颅脑损伤动态变化中应用

目的 探讨超薄多层螺旋CT、颅骨三维图像重建和脑灌注成像在急性颅脑外伤动态变化中的临床应用价值.方法 收集2009年12月至2011年10月我院收治的245例急性颅脑外伤(TBI)检查资料,均于伤后3-6h行常规多层螺旋CT(MSCT),超薄多层螺旋CT以及颅骨三维图像重建和脑CT灌注成像(CTP)检查,全部病例于伤后2-7d动态复查MSCT和超薄MSCT,将数据进行回顾性分析,采用卡方检验评价.结果 超薄MSCT在脑挫裂伤、脑内血肿诊断中优于常规MSCT;CTP除弥漫性轴索损伤无统计学意义外,其余明显优于常规MSCT;CTP在脑挫裂伤、硬膜下血肿和脑内血肿优于超薄MSCT差异具有统计学意义(P＜0.05).颅骨三维图像重建在对颅骨骨折的检查优势明显.结论 联合应用超薄MSCT、颅骨三维图像重建和CTP对于急性颅脑外伤早期和微小损伤的诊断优于常规MSCT,可以降低误诊率,并为早期治疗和预后判断提供可靠的依据.     

超薄多层螺旋CT与脑灌注成像在颅脑损伤早期诊断中的对比研究

目的探讨超薄多层螺旋CT和脑灌注成像在急性颅脑外伤(TBI)早期诊断中的临床应用价值。方法收集2010年12月~2012年10月我院收治的200例急性颅脑外伤患者检查资料,均于伤后6 h内行超薄多层螺旋CT(MSCT)和CT脑灌注成像(CTP)检查,全部病例于伤后2~3 d动态复查MSCT明确诊断,将数据进行回顾性分析,采用卡方检验评价。结果在MSCT与CTP这两种检测方法中,CTP在脑挫裂伤、硬膜下血肿和脑内血肿的诊断中优于超薄MSCT(P0.05),并且病灶周围低灌注区域大于超薄MSCT。结论 CTP对于急性颅脑外伤早期和微小损伤的诊断优于超薄MSCT,同时可以反映脑组织的灌注情况,具有可靠的临床价值。     

多层CT脑灌注成像在早期脑梗塞中的应用

脑梗塞是最常见的脑血管病,且致残率很高,早期诊断及时治疗可明显避免或降低并发症的发生。多层CT脑灌注成像是利用多层CT高时间分辨率及快速扫描特点,充分显示脑血管硬化程度及血流灌注情况,作出早期脑缺血诊断。本文综述了该方法的原理、多层CT特点及技术方法和早期脑梗塞的CT灌注表现。     

64层螺旋CT脑灌注联合CT血管造影对颈内动脉狭窄或闭塞的诊断价值

目的探讨64层螺旋CT脑灌注联合CT血管造影对颈内动脉狭窄或闭塞的诊断价值。方法选取因颈内动脉狭窄或闭塞在我院进行治疗的80例患者,对其进行64层螺旋CT脑灌注、CT血管造影扫描。观察64层螺旋CT脑灌注的平均通过时间、对比脑血流量、脑血容量、对比剂峰值时间,观察血管造影后患者的劲内动脉狭窄程度。结果短暂性脑缺血发作、急性脑梗死患者患侧的对比剂峰值时间均明显长于健侧的对比剂峰值时间,差异有统计学意义(P<0.05)。结论采用64层螺旋CT脑灌注联合CT血管造影,能同时诊断颈内动脉狭窄或闭塞的脑部血流灌注及颈动脉狭窄的程度。     

多层螺旋CT脑灌注成像与平扫CT值差值的测量对诊断急性脑梗死的价值

目的探讨多层螺旋CT(MSCT)脑灌注成像与测量CT值的差值(△Hu)在急性脑梗死早期诊断中的价值。方法对34例临床拟诊为急性脑梗死的患者行头部CT平扫和脑CT灌注成像。评价脑CT灌注成像的达峰时间(TTP),脑血流量(CBF),脑血容量(CBV),测量两侧对称部位CT值的差值(△Hu)。全部病例3⁷ d内复查头部CT及临床随访。另选取34例无脑部疾病、神经系统功能正常的为对照组。结果 34例病例中,头部CT平扫肉眼观察发现可疑病灶15例,测量对称部位CT值差值发现可疑病灶21例;脑CTP显示:32例脑CTP灌注异常,2例脑CTP灌注正常,脑CTP显示患者感兴趣区内脑血流量(rCBF)、脑血容量(rCBV)、对比剂达峰时间(rTTP)明显改变,病灶侧与对照侧、病灶中心区与周边区比较,差异有显著意义(P<0.01)。头部CT平扫肉眼观察发现病灶的敏感度44.11%,脑CTP发现病灶的敏感度94.11%。结论脑CTP检查能够早期诊断急性脑梗死,定量分析可区分中心梗死区与缺血半暗带区,有助于临床医生判断梗死病灶的存在和早期选择治疗方案。     

多层螺旋CT脑血管成像技术的临床应用

目的分析多层螺旋CT脑血管造影成像技术及临床应用价值。方法选取我院2012-12-2013-12收治的55例疑患有脑血管病变或脑肿瘤的患者为研究对象,对所有患者进行多层螺旋CT脑血管造影成像检查。结果所有检查病例均能通过多层螺旋CT脑血管造影成像清楚地显示1~4级脑血管结构,多层螺旋CT扫描能在短时间内准确的完成各项数据的采集工作。结论多层螺旋CT脑血管造影成像能够比较准确显示脑血管的状况,从而为临床医师诊断及治疗提供更多有价值的参考数据,具有重要的临床应用价值。     

CT灌注成像联合CT血管造影在颈内动脉系统短暂性脑缺血发作中的应用研究

目的探讨CT灌注成像联合CT血管造影在颈内动脉系统短暂性脑缺血发作中的应用价值。方法颈内动脉系统短暂性脑缺血发作患者63例,于症状发作后7d内采用东芝320排螺旋CT行头部CT灌注成像以及CT血管造影,观察并比较感兴趣区以及镜像区CT灌注成像各参数,以及两种影像学检查的符合情况。结果比较感兴趣区与镜像区CT灌注成像各参数发现,感兴趣区与镜像区脑血容量无显著性差异(P0.05);感兴趣的脑血流量显著低于镜像区(P0.05);感兴趣区的造影剂通过时间显著短于镜像区(P0.05)。CT血管造影发现责任血管狭窄54例,其中灌注异常患者43例,CT血管造影未发现责任血管狭窄9例,灌注异常3例,CT灌注异常在有责任血管狭窄的阳性率显著高于无责任血管狭窄(P0.05)。结论 CT灌注成像可反映颈内动脉系统短暂性脑缺血发作的脑灌注状态,CT血管造影可用于检测责任血管的病变情况,CT灌注成像联合CT血管造影可为颈内动脉系统短暂性脑缺血发作的病因以及为诊断提供影像学依据。     

脑CT灌注成像技术在中枢神经系统疾病中应用进展

CT灌注成像(computed tomography perfusion imaging,CTPI)是一种功能成像的方法。1991年,Miles等[1]学者首先提出CTPI的概念,利用CT扫描和计算机图像处理系统,既能显示形态学变化,又能反应功能改变。随着多层螺旋CT的应用与数学模型的不断改进,CTPI不断发展和完善,在脑及全身多种组织和器官疾病的研究和临床诊断中都已经用到该项技术。本文就当前CTPI在中枢神经系统疾病诊断中的应用和研究进展综述如下。     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.     

Effects of NMD A- and AMPA-Receptor Antagonists on Different Forms of Epileptiform Activity in Rat Temporal Cortex Slices

Summary: Lowering extracellular magnesium induces different patterns of epileptiform activity in rat hippocampus and entorhinal cortex. Short recurrent epileptiform discharges in the hippocampus are stable over time, whereas seizurelike events (SLEs) in the entorhinal cortex, the subiculum, and the neighboring neocortex develop into late recurrent discharges which are not blocked by clinically employed antiepileptic drugs. We tested the sensitivity of the different epileptiform discharge patterns to. /V-methyl-D-aspartate (NMDA)- and non-NMDA-receptor antagonists. As NMDA-receptor antagonist we used dextrorphan, ket-amine, and 2-aminophosphonovalerate (2APV); as α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-receptor antagonist we employed the quinoxaline derivative glutamate 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The findings show that the different patterns of epileptiform activity, including the late recurrent discharges, are sensitive to all NMDA-receptor antagonists. However, when dextrorphan was employed to suppress seizure-like events, later recurrent discharges did not develop during the remaining time course of the experiment. CNQX reversibly suppressed recurrent discharges in the hippocampus and SLEs in the entorhinal cortex. However, late recurrent discharges become insensitive to CNQX, even at a high concentration of 60 μM m. This finding suggests a prominent role for NMDA receptors in the generation of late recurrent discharges.