Classification of spatiotemporal hemodynamics from brain perfusion MR images using expectation-maximization estimation with finite mixture of multivariate gaussian distributions.

The ability to cluster different perfusion compartments in the brain is critical for analyzing brain perfusion. This study presents a method based on a mixture of multivariate Gaussians (MoMG) and the expectation-maximization (EM) algorithm to dissect various perfusion compartments from dynamic susceptibility contrast (DSC) MR images so that each compartment comprises pixels of similar signal-time curves. This EM-based method provides an objective way to 1) delineate an area to serve as the in-plane arterial input function (AIF) of the feeding artery for adjacent tissues to better quantify the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT); 2) demarcate regions with abnormal perfusion derangement to facilitate diagnosis; and 3) obtain parametric maps with supplementary information, such as temporal scenarios and recirculation of contrast agent. Results from normal subjects show that perfusion cascade manifests (in order of appearance) the arteries, gray matter (GM), white matter (WM), veins and sinuses, and choroid plexus mixed with cerebrospinal fluid (CSF). The averaged rCBV, rCBF, and MTT ratios between GM and WM are in good agreement with those in the literature. Results from a patient with cerebral arteriovenous malformation (CAVM) showed distinct spatiotemporal characteristics between perfusion patterns, which allowed differentiation between pathological and nonpathological areas.     

依达拉奉防治缺血性脑损伤研究的新进展

近年来,依达拉奉脑保护作用的研究取得了很大进展,尤以对缺血性脑卒中和新生儿缺血缺氧性脑病的防治研究最为深入,而联合治疗策略也得到了广泛的重视.本文就近5年这些热点研究的新进展进行综述.     

静滴1,6-二磷酸果糖局部疼痛对急性心肌梗死患者心肌耗氧量的影响

目的评估急性心肌梗死（AMI）患者静滴1,6-二磷酸果糖（FDP）时局部轻度、中度、重度疼痛对心肌耗氧量的影响。方法用长海痛尺评估120例AMI患者静滴FDP过程中疼痛程度,并对患者进行心电监护,对静滴FDP的患者在输液前、后的心率、血压、心肌耗氧量进行比较。结果输液后心肌耗氧量均高于输液前。结论AMI患者静滴FDP时局部疼痛的发生率高。轻度、中度、重度时均能引起心肌耗氧量的增加。     

大脑中动脉钙化的CT与经颅多普勒超声对照研究

目的探讨大脑中动脉（middle cerebral artery,MCA）水平段（M1）钙化的量化指标与血流动力学的关系。资料与方法搜集经头颅CT确诊M1段钙化且行经颅多普勒超声（transcranial Doppler,TCD）检查者41例,按有无钙化分为钙化组和无钙化组。分析MCA钙化组血流动力学参数与钙化量化指标是否有相关性;检验钙化组与无钙化组血流动力学参数及狭窄发生率的差异。结果MCA搏动指数（pulsatility index,PI）与钙化体积以及积分值呈线性相关;钙化组与无钙化组PI差异有统计学意义（P〈0.05）,但狭窄发生率差异无统计学意义（P〉0.05）。结论MCA钙化程度与TCD反映血管弹性的PI相关,但与反映狭窄程度的血流速度无相关性。     

心肌梗死后死亡率的性别差异前瞻性研究

目的:比较心肌梗死(MI)患者的特征、处置与病死率在性别方面的差异。方法:收集1998～2004年在贵阳医学院附属医院住院的首次MI患者856例男性和587例女性资料并随访至2005年6月,分析比较MI患者的临床特征、处置与病死率在性别方面的差异。结果:在随访期有351例(41.00%)男性和283例(48.21%)女性死亡。单因素分析显示女性有较高的病死率(风险率1.44,95%CI为1.24～1.67,P<0.01),但经过年龄、吸烟、伴存疾病、心血管病病史、糖尿病、高血压和情感抑郁等多因素调整后无差异(风险率1.01,95%CI为0.87～1.19,P>0.05)。MI后1个月内女性有较高的病死率(风险率1.53,95%CI为1.19～1.96,P<0.01),但经过上述多因素调整后无差异(风险率1.03,95%CI为0.78～1.36,P>0.05)。分析用药的情况发现女性使用他汀类药物比例高(调整后OR=1.47,95%CI为1.09～1.96,P<0.01),而β受体阻滞剂较少(调整后OR=0.77,95%CI为0.59～1.00,P<0.05)。其他2级预防药物及溶栓药物无差异。结论:男、女性在MI预后差别的主要原因在于患者的年龄、处置和多因素的影响,如果女性患者能得到相同的处置,则生存率将与男性相同。     

脑梗死后早发性癫(癎)发作临床特点分析

目的:探讨脑梗死(CI)后早发性癫癎发作(EES)的临床特点。方法:对2643例确诊为CI患者的临床资料进行回顾性研究。结果:CI后EES的发生率为4.58%,女性高于男性(P<0.05);婴幼儿及未成年人高于成年人(P<0.01)和老年人(P<0.01);累及皮质的发生率高于未累及皮质的(P<0.01);EES作为CI首发症状者占49.59%,24h内出现者占76.03%,1周内出现者占94.21%,仅有5.79%在第2周出现;局灶性发作占65.29%,全面性发作占34.71%;给予AEDs治疗发作均可控制,伴有EES的患者病死率高于不伴有者(P<0.05)。结论:CI后EES较为常见,女性多于男性,未成年人的发生率高于成年人及老年人,与梗死部位有关,以局灶性发作为主,抗癫癎治疗有效,临床预后较差。     

单光子发射计算机断层扫描在颅脑创伤后的临床研究

目的 探索单光子发射计算机断层扫描（SPECF）在脑外伤评估及预后方面的价值的依据。方法 28例中、重度颅脑损伤患者分别于伤后3天、10天及3～4周接受SPECF、CT检查及临床评定。3个月后所有患者行脑外伤综合征的临床测试，对首检SPECF显像阳性者复查SPECF，分析首检SPECF显像阳性者与损伤程度的关系，动态观察SPECF显像与预后的关系。结果 SPECF显像阳性与脑损伤程度有关，首检SPECF显像阳性提示预后良好，复查SPECF显像阳性提示多出现脑外伤综合征。对幕上损伤患者表现的小脑症状、体征可以做出合理的解释。结论 在中至重度颅脑损伤后SPECF显像与CT扫描比较更敏感，脑SPECF具有无创性、功能性及灵敏性高等特点，是脑外伤后功能评估、预后判断及临床研究的可靠方法。     

Saccular Aneurysm of the Azygos Anterior Cerebral Artery: Three Case Reports

The azygos anterior cerebral artery, a rare anomaly in the circle of Willis in which only a single vessel supplies the medial aspects of both anterior cerebral hemispheres, is closely associated with saccular aneurysms. We present three cases of azygos anterior cerebral artery aneurysms among the 781 cerebral aneurysms surgically treated at our institution in an 11-year period. These three cases all involved elderly women who presented with subarachnoid hemorrhage. Conventional cerebral angiography and CT angiography revealed small saccular aneurysms at the distal ends of the azygos anterior cerebral arteries. These aneurysms were clipped successfully using a bifrontal interhemispheric approach. Hence, the pathogenesis of these particular aneurysms relating to hemodynamic change, associated anomalies, and surgical pitfalls is discussed with review of literature.