BACKGROUND & AIMS: :We present an unusual case of an aneurysm of the distal posterior inferior cerebellar artery (PICA). The aneurysm was associated with a unilateral PICA that supplied both cerebellar hemispheres and arose from an anastomotic vessel to the contralateral circulation, a branch of the contralateral PICA. Such an aneurysm has not been reported previously. The associated of vascular anomalies with aneurysms of the PICA is discussed.

背景与目标： : 我们介绍了一个不寻常的小脑后下动脉 (PICA) 动脉瘤病例。动脉瘤与单侧PICA有关，该PICA提供了两个小脑半球，并从吻合血管出现到对侧PICA的分支对侧循环。这种动脉瘤以前没有报道过。讨论了血管异常与PICA动脉瘤的相关性。

BACKGROUND & AIMS: Malignant gliomas continue to be a significant source of mortality in young and middle aged adults. The introduction of new treatment strategies and multidisciplinary approaches has improved the outcome of patients with these tumors only slightly. Because retinoic acid has growth inhibitory activity against glioma and neuroblastoma cells in cultures, we assessed the efficacy of all-trans-retinoic acid in the treatment of recurrent cerebral gliomas. Thirty-six patients with recurrent cerebral gliomas were entered in the study and treated with 120 or 150 mg/ m2/day of all-trans-retinoic acid as a single agent. The drug was given for 3 weeks followed with one week of rest. Two blocks of 4 weeks constituted one course of treatment. One (3%) of 34 evaluable patients had a minor response and 14 (41%) had stable disease. In the rest of the patients (56%), tumors continued to progress despite treatment. The median time to progression of all evaluable patients was 8 weeks, and for the responders was 17 weeks. The higher dose level (150 mg/m2) was associated with high incidence of headache, which responded to dose reduction. The lower dose level was very well tolerated, with mild, mainly dermatological toxicity. All-trans-retinoic acid as a single agent has no significant activity against recurrent cerebral gliomas.

背景与目标： 恶性神经胶质瘤仍然是中青年成年人死亡的重要来源。新的治疗策略和多学科方法的引入仅略微改善了这些肿瘤患者的预后。由于视黄酸对培养物中的神经胶质瘤和神经母细胞瘤细胞具有生长抑制活性，因此我们评估了全反式视黄酸在治疗复发性脑胶质瘤中的功效。36例复发性脑胶质瘤患者进入研究，并以120或150 mg/ m2/天的全反式维甲酸作为单一药物进行治疗。给药3周，然后休息一周。两个为期4周的块构成一个疗程。34名可评估患者中有1名 (3% 名) 反应轻微，14名 (41% 名) 疾病稳定。在其余患者 (56%) 中，尽管进行了治疗，但肿瘤仍在继续发展。所有可评估患者的中位进展时间为8周，应答者为17周。较高的剂量水平 (150 mg/m2) 与头痛的高发生率相关，头痛对剂量减少有反应。较低的剂量水平耐受性良好，具有轻度 (主要是皮肤病学毒性)。全反式维甲酸作为单一药物对复发性脑胶质瘤没有显着活性。

BACKGROUND & AIMS: :Near infrared spectroscopy (NIRS) was used to investigate the effect of behavioural states on changes of oxygenated (O2Hb), deoxygenated haemoglobin (HHb) and total haemoglobin (tHb), during endotracheal suctioning. In an open prospective design, NIRS measurements have been done during 20 suctioning episodes in 13 preterm neonates. Heart rate, arterial oxygen saturation, and carbon dioxide tension were monitored continuously. Behavioural state (BS) observations were made and documented as well. The statistical analysis showed that in patients who were active, with crying periods during suctioning (behavioural states 4-5), changes of oxygenated (p < 0.005) and deoxygenated haemoglobin (p < 0.05), as well as of arterial oxygen saturation (p < 0.05) and heart rate (p < 0.05) were significantly greater than in patients who were quiet with predominant behavioural state 1, 2 and 3. These results underline the influence of behavioural states on the physiological answers to endotracheal suctioning. NIRS proved to be a valuable tool to evaluate possible harmful effects of different suctioning techniques.

背景与目标： : 近红外光谱 (NIRS) 用于研究行为状态对气管内抽吸过程中含氧 (O2Hb)，脱氧血红蛋白 (HHb) 和总血红蛋白 (tHb) 变化的影响。在开放的前瞻性设计中，已在13例早产新生儿的20次吸痰发作中进行了NIRS测量。连续监测心率，动脉血氧饱和度和二氧化碳张力。还进行了行为状态 (BS) 观察并记录在案。统计分析显示，在活动的患者中，在吸痰过程中有哭闹期 (行为状态4-5)，氧合 (p < 0.005) 和脱氧血红蛋白 (p < 0.05) 的变化，动脉血氧饱和度 (p < 0.05) 和心率 (p < 0.05) 均显着高于以主要行为状态1、2和3安静的患者。这些结果强调了行为状态对气管内抽吸的生理答案的影响。事实证明，NIRS是评估不同抽吸技术可能产生的有害影响的宝贵工具。

BACKGROUND & AIMS: Our aim was to determine the effects of 12 h of hypoxaemia on cerebral blood flow (CBF) and cerebral O2 delivery in ovine fetuses at 0.6 gestation. During fetal hypoxaemia, induced by reduced uterine blood flow, fetal SaO2 and PaO2 were reduced (p < 0.01) from control values of 77.0 +/- 1.6% and 27.3 +/- 1.0 mm Hg, respectively, to 28.4 +/- 3.4% and 15.6 +/- 0.6 mm Hg; fetal pHa decreased from control values of 7.37 +/- 0.01 to 7.20 +/- 0.02 at 3 h, but returned to control values before 12 h. CBF (ml/min/100 g) was 2.0- to 2.6-fold higher (p < 0.01) than control values during hypoxaemia, but only 1.7-fold higher (p < 0.01) at 3 h when pHa was lowest. Cerebral O2 delivery (ml/min/100 g) was lower (p < 0.01) than control values of 3.15 +/- 0.29 at 1.5h (2.09 +/- 0.36) and 3h (1.84 +/- 0.22) of hypoxaemia and higher 1 h after hypoxaemia had ceased (3.81 +/- 0.22, p < 0.01). We conclude that the ovine fetus at 0.6 gestation is unable to sustain increased CBF and hence maintain cerebral O2 delivery during the first 6 h of hypoxaemia, a time which coincides with acidaemia; in contrast, at 6 and 12 h of hypoxaemia, when pHa was normal, cerebral O2 delivery was similar to control values. Reduced cerebral O2 delivery during the early, acidaemic, stages of hypoxaemia may lead to impaired neural development.

背景与目标： 我们的目的是确定12小时低氧血症对0.6妊娠的绵羊胎儿脑血流量 (CBF) 和脑O2输送的影响。在胎儿低氧血症期间，由子宫血流量减少引起的胎儿SaO2和PaO2从77.0 +/- 1.6% 和27.3 +/-1.0毫米Hg的对照值分别降低到28.4 +/- 3.4% 和15.6 +/-0.6毫米Hg (p <0.01); 胎儿pHa在3小时从7.37 +/- 0.01的对照值降至7.20 +/- 0.02，但在12小时前恢复到对照值。在低氧血症期间，CBF (ml/min/100g) 比对照值高2.0至2.6倍 (p <0.01)，但在3小时pHa最低时仅高1.7倍 (p <0.01)。低氧血症1.5小时 (2.09 +/- 0.36) 和3小时 (1.84 +/- 0.22) 时，脑O2递送 (ml/min/100g) 低于3.15 +/- 0.29的对照值 (p <0.01)，低氧血症停止后1小时更高 (3.81 +/- 0.22，p <0.01)。我们得出的结论是，0.6妊娠的绵羊胎儿无法维持CBF的增加，因此在低氧血症的前6小时 (与酸血症相吻合) 中维持脑O2的输送; 相反，在低氧血症的6和12小时，当pHa正常时，脑O2输送与对照值相似。低氧血症的早期，酸血症阶段的脑O2输送减少可能导致神经发育受损。

BACKGROUND & AIMS: BACKGROUND:Different opioids have different delays (hysteresis) between their concentrations in blood and their cerebral effects. Possible mechanisms include differences in their rate of penetration into the brain and differences in their distribution volume in the brain. There have been few in vivo studies of the cerebral kinetics of opioids to differentiate these mechanisms.

METHODS:The cerebral kinetics of meperidine and alfentanil were examined using conscious sheep that were fitted with long-term monitoring equipment to measure relative changes in cerebral blood flow and opioid concentration gradients across the brain through frequent sampling of arterial and sagittal sinus blood. The data were compared using hybrid physiologic modeling with membrane-limited (consistent with mechanism 1) and flow-limited (consistent with mechanism 2) models of cerebral kinetics.

RESULTS:Alfentanil had a variable effect on relative cerebral blood flow, whereas meperidine induced a transient increase. The arteriovenous concentration gradients were small after alfentanil but large after meperidine. The flow-limited model gave acceptable descriptions of observed sagittal sinus concentrations for alfentanil and meperidine, whereas the membrane-limited model collapsed to a flow-limited model. The half-lives of equilibrium between blood and brain were 6.3 and 0.8 min for meperidine and alfentanil, respectively:

CONCLUSIONS:The rate of penetration of both opioids into the brain was rapid and not rate-limiting. Large differences in the cerebral distribution volume of meperidine and alfentanil accounted for the respective delays in their peak brain concentration relative to blood.

背景与目标： 背景 : 不同的阿片类药物在血液中的浓度与大脑作用之间具有不同的延迟 (滞后)。可能的机制包括它们渗透到大脑的速率的差异以及它们在大脑中的分布体积的差异。关于阿片类药物的脑动力学的体内研究很少，可以区分这些机制。
方法 : 使用配备了长期监测设备的有意识的绵羊检查了哌替啶和阿芬太尼的脑动力学，以通过频繁采样动脉和矢状窦血来测量整个大脑中脑血流量和阿片类药物浓度梯度的相对变化。使用混合生理模型与脑动力学的膜受限模型 (与机制1一致) 和流量受限模型 (与机制2一致) 进行数据比较。
结果 : 阿芬太尼对相对脑血流量有不同的影响，而哌替啶诱导了短暂的增加。阿芬太尼后动静脉浓度梯度较小，而哌替啶后动静脉浓度梯度较大。限流模型对观察到的阿芬太尼和哌替啶的矢状窦浓度给出了可接受的描述，而膜限流模型崩溃为限流模型。对于哌替啶和阿芬太尼，血液和大脑之间的平衡半衰期分别为6.3和0.8分钟:
结论 : 两种阿片类药物进入大脑的速率是快速的，而不是限速。哌替啶和阿芬太尼的脑分布体积差异很大，导致其峰值脑浓度相对于血液的延迟。

BACKGROUND & AIMS: :We report a case of bilateral vertebral artery (VA) dissecting aneurysm presenting subarachnoid hemorrhage (SAH). It was difficult to decide which side was responsible for SAH because the patient's symptom and head CT suggested that the left VA aneurysm had ruptured, but angiography and MRA showed an irregular pearl and string sign on the right side. He was successfully treated by trapping of the right VA dissecting aneurysm and we confirmed by intraoperative evaluation that the right VA dissecting aneurysm had ruptured. The left unruptured aneurysm decreased its size spontaneously. In the treatment of the bilateral VA dissecting aneurysms, angiography needs to be performed over and over again because contralateral unruptured aneurysm may grow or rupture due to increased hemodynamic stress. Various combinations of direct sugery with or without arterial reconstruction and endovascular treatment should be considered when treating bilateral VA dissecting aneurysms.

背景与目标： : 我们报告一例双侧椎动脉 (VA) 夹层动脉瘤，表现为蛛网膜下腔出血 (SAH)。由于患者的症状和头部CT提示左VA动脉瘤破裂，因此很难确定是哪一侧引起SAH的原因，但是血管造影和MRA在右侧显示不规则的珍珠和弦征。通过捕获右VA夹层动脉瘤成功治疗了他，我们通过术中评估确认右VA夹层动脉瘤破裂。左未破裂的动脉瘤会自发减小其大小。在双侧VA夹层动脉瘤的治疗中，由于血流动力学压力增加，对侧未破裂的动脉瘤可能会生长或破裂，因此需要一遍又一遍地进行血管造影。在治疗双侧VA夹层动脉瘤时，应考虑直接切除有或没有动脉重建以及血管内治疗的各种组合。

BACKGROUND & AIMS: STUDY OBJECTIVES:Population-based studies have demonstrated associations between sleep-disordered breathing (SDB), hypertension, and cardiovascular disease; few large-scale studies have examined associations of SDB with objective measures of cerebrovascular disease. This study tested the significance of associations of SDB with evidence of brain injury or ischemia determined by cerebral magnetic resonance imaging (MRI) studies. DESIGN:Cross-sectional and longitudinal analyses in a nested sample of Cardiovascular Health Study participants in the Sleep Heart Health Study. PARTICIPANTS:The 843 individuals (mean age 77, SD 4.3 years, 58% women) who had MRI studies as part of the Cardiovascular Health Study before and after polysomnography obtained as part of the Sleep Heart Health Study. MEASUREMENTS:A 12-channel polysomnogram was used to derive indexes of sleep-disordered breathing. Repeated MRI measurements provided indexes of infarct (presence and size) and white matter disease. Logistic regression analyses were used to model MRI changes of infarct-like lesions and white matter disease as a function of age, baseline white matter grade, and indexes of central and obstructive sleep-disordered breathing. RESULTS:Individuals who showed progression in white matter disease compared to those who did not were significantly more likely to show a Cheyne-Stokes respiration pattern and to have an increased number of central but not obstructive apneas. CONCLUSIONS:An association between change in white matter grade and measures of central sleep apnea was demonstrated that was consistent with a causal pathway in which central sleep apnea contributes to the progression of white matter disease; alternatively, central sleep apnea may be a marker of subclinical cerebrovascular or cardiovascular disease.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:The relative importance of previous diagnosis and hereditary prothrombotic risk factors for cerebral venous thrombosis (CVT) in children in determining risk of a second cerebral or systemic venous thrombosis (VT), compared with other clinical, neuroimaging, and treatment variables, is unknown. METHODS:We followed up the survivors of 396 consecutively enrolled patients with CVT, aged newborn to 18 years (median 5.2 years) for a median of 36 months (maximum 85 months). In accordance with international treatment guidelines, 250 children (65%) received acute anticoagulation with unfractionated heparin or low-molecular weight heparin, followed by secondary anticoagulation prophylaxis with low-molecular weight heparin or warfarin in 165 (43%). RESULTS:Of 396 children enrolled, 12 died immediately and 22 (6%) had recurrent VT (13 cerebral; 3%) at a median of 6 months (range 0.1-85). Repeat venous imaging was available in 266 children. Recurrent VT only occurred in children whose first CVT was diagnosed after age 2 years; the underlying medical condition had no effect. In Cox regression analyses, non-administration of anticoagulant before relapse (hazard ratio [HR] 11.2 95% CI 3.4-37.0; p<0.0001), persistent occlusion on repeat venous imaging (4.1, 1.1-14.8; p=0.032), and heterozygosity for the G20210A mutation in factor II (4.3, 1.1-16.2; p=0.034) were independently associated with recurrent VT. Among patients who had recurrent VT, 70% (15) occurred within the 6 months after onset. CONCLUSION:Age at CVT onset, non-administration of anticoagulation, persistent venous occlusion, and presence of G20210A mutation in factor II predict recurrent VT in children. Secondary prophylactic anticoagulation should be given on a patient-to-patient basis in children with newly identified CVT and at high risk of recurrent VT. Factors that affect recanalisation need further research.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) has been linked to focal reductions in cerebral blood flow (CBF) and microvascular impairments in oxygen delivery. Effective therapies that restore flow and oxygen transport to vulnerable brain regions are currently lacking. SANGUINATE is a dual-action carbon monoxide-releasing and hemoglobin-based oxygen transfer agent with efficacy in animal models of focal brain ischemia and tolerability in patients with sickle cell disease. METHODS:We performed a safety and proof-of-principle study in 12 SAH patients at risk of DCI across three escalating doses (160, 240, and 320 mg/kg). We used 15O-PET (performed at baseline, after SANGUINATE and at 24 h) to evaluate efficacy for improving CBF and restoring flow-metabolism balance (assessed by oxygen extraction fraction [OEF]) to vulnerable regions (defined as baseline OEF ≥ 0.50). RESULTS:SANGUINATE resulted in a transient rise in mean arterial pressure (116 ± 15-127 ± 13 mm Hg, p = 0.001) that normalized by 24 h and allowed three patients with DCI to be weaned off vasopressors. No adverse events were noted during infusion. Global CBF did not rise (43 ± 8-46 ± 9 ml/100 g/min) although a trend was seen at the highest dose (45 ± 7-51 ± 9, p = 0.044). However, a significant 16% rise in regional CBF associated with reduction in OEF was seen in vulnerable regions, but did not persist at 24 h. CONCLUSIONS:We demonstrated that this novel agent can improve regional CBF and may improve oxygen supply-demand balance. Clinical studies (likely with repeat dosing) are required to evaluate whether this effect can prevent DCI or cerebral infarction.

背景与目标：

BACKGROUND & AIMS: :An understanding of the time course and correlation with injury of heat shock proteins (HSPs) released during brain and/or spinal cord cellular stress (ischemia) is critical in understanding the role of the HSPs in cellular survival, and may provide a clinically useful biomarker of severe cellular stress. We have analyzed the levels of HSPs in the cerebrospinal fluid (CSF) from patients who are undergoing thoracic aneurysm repair. Blood and CSF samples were collected at regular intervals, and CSF was analyzed by enzyme-linked immunosorbent assay for HSP70 and HSP27. These results were correlated with intraoperative somatosensory-evoked potentials measurements and postoperative paralysis. We find that the levels of these proteins in many patients are elevated and that the degree of elevation correlates with the risk of permanent paralysis. We hypothesize that sequential measurement intraoperatively of the levels of the heat shock proteins HSP70 and HSP27 in the CSF can predict those patients who are at greatest risk for paralysis during thoracic aneurysm surgery and will allow us to develop means of preventing or attenuating this severe and often fatal complication.

背景与目标： : 了解大脑和/或脊髓细胞应激 (缺血) 期间释放的热休克蛋白 (hsp) 的时间过程以及与损伤的相关性对于理解hsp在细胞存活中的作用至关重要，并且可能提供临床上有用的生物标志物严重的细胞应激。我们已经分析了正在接受胸动脉瘤修复的患者的脑脊液 (CSF) 中HSPs的水平。定期收集血液和CSF样本，并通过酶联免疫吸附法分析CSF中的HSP70和hsp27。这些结果与术中体感诱发电位测量和术后瘫痪相关。我们发现许多患者中这些蛋白质的水平升高，并且升高的程度与永久性瘫痪的风险相关。我们假设，术中连续测量CSF中热休克蛋白HSP70和HSP27的水平可以预测那些在胸动脉瘤手术中瘫痪风险最大的患者，并将使我们能够开发预防或减轻这种严重且通常致命的并发症的方法。

BACKGROUND & AIMS: BACKGROUND:In addition to detecting colorectal neoplasia, abdominal computed tomography (CT) with colonography technique (CTC) can also detect unsuspected extracolonic cancers and abdominal aortic aneurysms (AAA).The efficacy and cost-effectiveness of this combined abdominal CT screening strategy are unknown. METHODS:A computerized Markov model was constructed to simulate the occurrence of colorectal neoplasia, extracolonic malignant neoplasm, and AAA in a hypothetical cohort of 100,000 subjects from the United States who were 50 years of age. Simulated screening with CTC, using a 6-mm polyp size threshold for reporting, was compared with a competing model of optical colonoscopy (OC), both without and with abdominal ultrasonography for AAA detection (OC-US strategy). RESULTS:In the simulated population, CTC was the dominant screening strategy, gaining an additional 1458 and 462 life-years compared with the OC and OC-US strategies and being less costly, with a savings of $266 and $449 per person, respectively. The additional gains for CTC were largely due to a decrease in AAA-related deaths, whereas the modeled benefit from extracolonic cancer downstaging was a relatively minor factor. At sensitivity analysis, OC-US became more cost-effective only when the CTC sensitivity for large polyps dropped to 61% or when broad variations of costs were simulated, such as an increase in CTC cost from $814 to $1300 or a decrease in OC cost from $1100 to $500. With the OC-US approach, suboptimal compliance had a strong negative influence on efficacy and cost-effectiveness. The estimated mortality from CT-induced cancer was less than estimated colonoscopy-related mortality (8 vs 22 deaths), both of which were minor compared with the positive benefit from screening. CONCLUSION:When detection of extracolonic findings such as AAA and extracolonic cancer are considered in addition to colorectal neoplasia in our model simulation, CT colonography is a dominant screening strategy (ie, more clinically effective and more cost-effective) over both colonoscopy and colonoscopy with 1-time ultrasonography.

背景与目标：

BACKGROUND & AIMS: :Our previous studies have shown that ferulic acid (4-hydroxy-3-methoxycinnamic acid, FA) inhibits intercellular adhesion molecule-1 (ICAM-1) expression in the ischemic striatum after 2 h of reperfusion in a transient middle cerebral artery occlusion model in rats. The purpose of this study is to further investigate the neuroprotective effects of FA during reperfusion after cerebral ischemia. Rats were subjected to 90 min of ischemia; they were then sacrificed after 2, 10, 24 and 36 h of reperfusion. ICAM-1 and macrophage-1 antigen (Mac-1) mRNA were detected using semi-quantitative RT-PCR at 2 h of reperfusion. Mac-1, 4-hydroxy-2-nonenal (4-HNE), 8-hydroxy-2'-deoxyguanosine (8-OHdG), active caspase 3, neuronal nuclei (NeuN) and TUNEL positive cells were measured at 2, 10, 24 and 36 h of reperfusion. FA (100 mg/kg, i.v.) administered immediately after MCAo inhibited ICAM-1 and Mac-1 mRNA expression in the striatum at 2 h of reperfusion, and reduced the number of Mac-1, 4-HNE and 8-OHdG positive cells in the ischemic rim and core at 10, 24 and 36 h of reperfusion. FA decreased TUNEL positive cells in the penumbra at 10 h, and in the ischemic boundary and core at 24 and 36 h of reperfusion. FA curtailed active caspase 3 expression in the penumbra at 10 h and restored NeuN-labeled neurons in the penumbra and ischemic core at 36 h of reperfusion. FA decreased the level of ICAM-1 mRNA and the number of microglia/macrophages, and subsequently down-regulated inflammation-induced oxidative stress and oxidative stress-related apoptosis, suggesting that FA provides neuroprotection against oxidative stress-related apoptosis by inhibiting ICAM-1 mRNA expression after cerebral ischemia/reperfusion injury in rats.

背景与目标： : 我们先前的研究表明，在大鼠短暂性大脑中动脉闭塞模型中，再灌注2小时后，阿魏酸 (4-羟基-3-甲氧基肉桂酸，FA) 抑制缺血纹状体中细胞间粘附分子-1 (ICAM-1) 的表达。目的进一步探讨FA在脑缺血再灌注过程中的神经保护作用。大鼠缺血90分钟; 然后在再灌注2、10、24和36小时后处死它们。在再灌注2 h时，使用半定量rt-pcr检测ICAM-1和巨噬细胞-1抗原 (Mac-1) mRNA。在2时测量Mac-1,4-羟基-2-壬醛 (4-HNE)，8-羟基-2 '-脱氧鸟苷 (8-OHdG)，活性半胱天冬酶3，神经元核 (NeuN) 和TUNEL阳性细胞，再灌注10、24和36小时。FA (100 mg/kg，i.v.) 后立即给予MCAo抑制了再灌注2 h时纹状体中ICAM-1和Mac-1 mRNA的表达，并减少了Mac-1,4-hne和8-OHdG阳性细胞的数量。缺血边缘和核心在10，再灌注24和36 h。FA在再灌注10 h时减少半影中的TUNEL阳性细胞，在再灌注24和36 h时减少缺血边界和核心中的TUNEL阳性细胞。FA在10小时减少了半影中的caspase 3活性表达，并在再灌注36小时恢复了半影和缺血核心中的NeuN标记神经元。FA降低了ICAM-1 mRNA的水平和小胶质细胞/巨噬细胞的数量，随后下调了炎症诱导的氧化应激和氧化应激相关的凋亡，提示FA通过抑制大鼠脑缺血/再灌注损伤后ICAM-1 mRNA的表达来提供针对氧化应激相关凋亡的神经保护。

BACKGROUND & AIMS: INTRODUCTION:The new 3 Tesla (T) magnetic resonance (MR) scanners yield improved signal-to-noise ratio and spatial resolution with superior background suppression compared to lower field strength systems. This is advantageous for MR angiograms. The purpose of our study was to compare unenhanced three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) at 3T with catheter digital subtraction angiography (DSA) in detecting unruptured intracranial aneurysms. MATERIALS AND METHODS:Out of 1375 consecutive patients who underwent unenhanced 3D TOF MRA at 3T, 15 patients with unruptured intracranial aneurysms were retrospectively identified. Nine of these 15 patients had DSA as the reference standard for comparison. Aneurysm size, location and morphology were independently assessed on both MRA and DSA by 2 radiologists. RESULTS:Seventeen aneurysms ranging in size from 1 mm to 24 mm were identified in 15 patients on MRA. DSA confirmed the aneurysms in 9 patients with good anatomical correlation compared with the MRA findings. CONCLUSIONS:3D TOF MRA at 3T has good correlation with DSA and aneurysms as small as 1 mm in size can be detected. This can be a promising, non-invasive method for aneurysm surveillance.

背景与目标：

BACKGROUND & AIMS: :This report describe a 69-year old woman with a congenital aneurysm of the non-coronary sinus of Valsalva ruptured in the right atrium, causing severe hemodynamic derangement of the right ventricle. The site of the communication between the aneurysm and the receiving chamber was accurately diagnosed by two-dimensional color flow Doppler imaging which provided more valuable preoperative information than conventional aortography.

背景与目标： : 该报告描述了一名69岁的女性，其先天性的Valsalva非冠状窦动脉瘤在右心房破裂，导致右心室严重血流动力学紊乱。通过二维彩色多普勒成像准确诊断了动脉瘤与接收室之间的通讯部位，这比传统的主动脉造影提供了更有价值的术前信息。

BACKGROUND & AIMS: :Computer simulations of layers I and II of pirifonn (olfactory) cortex indicate that this biological network can generate a series of distinct output responses to individual stimuli, such that different responses encode different levels of information about a stimulus. In particular, after learning a set of stimuli modeled after distinct groups of odors, the simulated network's initial response to a cue indicates only its group or category, whereas subsequent responses to the same stimulus successively subdivide the group into increasingly specific encoding of the individual cue. These sequences of responses amount to an automated organization of perceptual memories according to both their similarities and differences, facilitating transfer of learned information to novel stimuli without loss of specific information about exceptions. Human recognition performance robustly exhibits such multiple levels: a given object can be identified as a vehicle, as an automobile, or as a Mustang. The findings reported here suggest that a function as apparently complex as hierarchical recognition memory, which seems suggestive of higher 'cognitive' processes, may be a fundamental intrinsic property of the operation of this single cortical cell layer in response to naturally-occurring inputs to the structure. We offer the hypothesis that the network function of superficial cerebral conical layers may simultaneously acquire and hierarchically organize information about the similarities and differences among perceived stimuli. Experimental manipulation of the simulation has generated hypotheses of direct links between the values of specific biological features and particular attributes of behavior, generating testable physiological and behavioral predictions.

背景与目标： : pirifonn (嗅觉) 皮层I和II层的计算机模拟表明，该生物网络可以对单个刺激产生一系列不同的输出响应，因此不同的响应可以编码有关刺激的不同级别的信息。特别是，在学习了一组以不同气味组为模型的刺激之后，模拟网络对提示的初始响应仅指示其组或类别，而对相同刺激的后续响应则将该组依次细分为各个提示的日益特定的编码。根据它们的相似性和差异性，这些响应序列相当于感知记忆的自动组织，从而有助于将学习的信息转移到新颖的刺激中，而不会丢失有关异常的特定信息。人类识别性能稳健地表现出这样多个层次: 给定的对象可以被识别为车辆，汽车或野马。此处报道的发现表明，与分层识别记忆一样明显复杂的功能，似乎暗示了更高的 “认知” 过程，这可能是响应自然发生的输入而使该单个皮质细胞层运行的基本固有属性。结构。我们提出了这样的假设，即浅表脑圆锥层的网络功能可以同时获取并分层组织有关感知刺激之间的异同的信息。模拟的实验操作产生了特定生物学特征的值与行为的特定属性之间直接联系的假设，从而产生了可测试的生理和行为预测。