基于CTA和眼底成像观察颈内动脉狭窄程度与视网膜血管管径的关系

目的 分析颈内动脉（ICA）狭窄程度与同侧视网膜血管管径的关系,探讨通过观察视网膜血管管径改变评估ICA狭窄的准确性及可行性。方法 基于CTA和眼底成像技术,分析243例患者单侧ICA狭窄程度和同侧视网膜血管管径资料,根据ICA最大狭窄率（R_max）将患者分为无狭窄、轻度狭窄、中度狭窄和重度狭窄共4组,分析视网膜血管管径的组间差异及其与ICA狭窄程度的相关性。结果 中、重度狭窄组的视网膜中央静脉管径（CRVE）较无狭窄和轻度狭窄组明显增宽（P均< 0.05）,4组间视网膜中央动脉管径（CRAE）和动静脉管径比值（AVR）差异无统计学意义（P均> 0.05）。R_max与同侧CRVE呈正相关（r=0.27,P < 0.01）,与AVR呈负相关（r=-0.16,P < 0.05）,与CRAE无相关性（P > 0.05）。CRVE是同侧R_max的影响因素（B=0.243,P < 0.01）,但模型的调整R²较小（0.173）。以229.5 μm为最佳临界值,CRVE诊断ICA中重度狭窄的ROC曲线下面积为0.619,敏感度和特异度为80.3%、40.1%。结论 CRVE对ICA狭窄程度的评估与预测具有一定价值。     

动态增强磁共振成像定量评估健康志愿者胰腺灌注的可行性

目的 探讨动态增强磁共振成像（DCE-MRI）量化评估胰腺灌注的可行性。方法 将68名健康志愿者分为青年组、中年组和老年组。对所有志愿者均行DCE-MRI,将数据传至Research-DCEMRI Tool诊断分析工作站,计算胰腺灌注的定量参数：容积转运常数（K^trans）、间质-血浆速率常数（K_ep）、间质容积（V_e）和血浆容积（V_p）。采用两独立样本t检验和单因素方差分析评估不同性别、年龄组和胰腺部位的灌注参数。结果 不同性别志愿者K^trans、K_ep、V_e和V_p差异均无统计学意义（P均>0.05）;老年组V_e高于青年组和中年组（P=0.036、0.001）;胰头区V_p高于胰体部和胰尾部（P=0.011、0.023）。结论 DCE-MRI可无创、较稳定、定量评估胰腺灌注情况。胰腺DCE-MRI定量灌注参数不随性别差异而不同,但随年龄和胰腺部位的不同而有差异。     

动态增强MRI鉴别诊断前列腺中央腺体T2WI低信号病变

目的 观察动态增强MRI （DCE-MRI）定量及半定量参数鉴别诊断前列腺中央腺体T2WI低信号病变的价值。方法 收集59例存在前列腺中央腺体T2WI低信号病变患者,其中前列腺癌患者32例（前列腺癌组）,前列腺增生伴慢性炎症患者15例（增生伴慢性炎症组）,高级别上皮内瘤变（HGPIN）患者12例（HGPIN组）,测量并比较其DCE-MRI定量及半定量参数：容积转运常数（K^trans）、速率常数（K_ep）、血管外细胞外容积分数（V_e）、对比剂血浆容积（V_p）、达峰时间（TTP）、最大浓度（Conc_max）、最大斜率（Slope_max）和时间-浓度曲线下面积（AUTC）,绘制ROC曲线,分析各参数诊断前列腺癌的效能。结果 前列腺癌组、增生伴慢性炎症组与HGPIN组间K_trans、K_ep、V_e、V_p、TTP及Slope_max差异均有统计学意义（P均<0.05）,其中前列腺癌组与HGPIN组间K^trans、K_ep、V_e、Slope_max及TTP差异均有统计学意义（P均<0.05）,前列腺癌组与增生伴慢性炎症组间V_p及TTP差异有统计学意义（P均<0.05）,HGPIN组与增生伴慢性炎症组间K^trans、K_ep、V_p及TTP差异均有统计学意义（P均<0.05）。ROC曲线显示TTP、K^trans及K_ep值诊断前列腺癌的曲线下面积（AUC）分别为0.743、0.735和0.721,两两比较差异均无统计学意义（P均>0.05）,但均大于V_e值诊断前列腺癌的AUC （P均<0.05）。结论 DCE-MRI参数TTP、K^trans和K_ep可于前列腺中央腺体T2WI低信号病变中有效鉴别诊断前列腺癌。     

动态增强MRI鉴别诊断不典型乳腺癌与纤维腺瘤

目的 探讨动态增强MRI（DCE-MRI）定量参数对不典型乳腺癌和纤维腺瘤的鉴别诊断价值。方法 收集经病理证实的不典型乳腺癌30例（不典型乳腺癌组）和纤维腺瘤32例（纤维腺瘤组）患者。对所有患者均进行DCE-MR检查,获取血流动力学参数容量转移常数（K_trans）、速率常数（K_ep）、血管外细胞外间隙容积分数（V_e）、血浆分数（V_p）,比较两组各参数的统计学差异,并评价其诊断效能。结果 不典型乳腺癌组K_trans、K_ep、V_e、V_p分别为（1.49±0.55）min^-1、（0.70±0.02）min^-1、0.78±0.19、0.26±0.13,纤维腺瘤组K_trans、K_ep、V_e、V_p分别为（0.64±0.23）min^-1、（0.30±0.23）min^-1、0.63±0.25、0.33±0.14;两组间K_trans、V_e、K_ep差异有统计学意义（P均<0.01）,V_p差异无统计学意义（P=0.05）。K_trans、K_ep、V_e诊断不典型乳腺癌和纤维腺瘤的曲线下面积分别为0.94、0.88、0.68,敏感度为86.7%、86.7%、83.3%,特异度为93.7%、81.2%、46.9%。结论 DCE-MRI可准确评估病变的微循环,对纤维腺瘤和不典型乳腺癌的诊断及鉴别诊断具有较高的临床应用价值。     

不同月经状态女性正常子宫动态增强MRI定量参数变化特性及其临床意义

目的 探讨不同月经状态女性正常子宫动态增强MRI定量参数值的特点及其临床意义。方法 收集我院46例不同月经状态女性资料,均行动态增强MR检查,测量子宫内膜、结合带及肌层定量参数值,包括体积转运常数（K^trans）、速率转运常数（K_ep）及体积分数（V_e）。根据不同月经状态将受试者分为绝经前和绝经后（n=14）。采用单因素方差或秩和检验比较子宫不同层面、不同月经状态的定量参数。结果 相同子宫层面,不同月经状态子宫内膜K^trans、K_ep值及子宫结合带V_e值总体比较差异有统计学意义（P均<0.05）;子宫内膜绝经后K^trans、K_ep值与分泌期和增殖期、分泌期K_ep值与增殖期差异均有统计学意义（P均<0.05）;结合带增殖期V_e值与绝经后间差异有统计学意义（P<0.05）。相同的月经状态,子宫内膜、结合带及肌层的K^trans值、K_ep值及V_e值差异均有统计学意义（P均<0.05）;子宫各层面分泌期K^trans值两两比较差异均有统计学意义（P均<0.05）,子宫结合带和肌层的增殖期和绝经后K^trans值与子宫内膜同一月经状态差异有统计学意义（P均<0.05）;除绝经后结合带与肌层间K_ep值差异无统计学意义,子宫各层面同一月经状态K_ep值两两比较差异均有统计学意义（P<0.05）。结论 采用动态增强MRI定量参数评判子宫疾病时应考虑不同月经状态下K^trans、K_ep和V_e的变化。     

一体化18F-FDG PET/MR血流代谢显像评估慢性单侧头颈动脉狭窄

目的 观察一体化¹⁸F-PET/MR血流代谢显像评估单侧头颈动脉狭窄的价值。方法 纳入68例慢性单侧头颈动脉狭窄患者,记录其美国国立卫生研究院卒中量表（NIHSS）及改良Rankin量表（mRS）评分;采用一体化PET/MR同步采集MR结构像、动脉自旋标记图像和¹⁸F-FDG PET图像,基于血流、代谢图像获取并比较幕上病变侧血流减低区、代谢减低区、血流代谢同步减低区及其各项指标,分析其与临床神经功能评分的相关性。结果 68例患者中,与血流减低区比较血流代谢同步减低区脑血流量（CBF）更低（P<0.001）、不对称指数（AI）更高（P<0.001）;血流代谢同步减低区与代谢减低区标准摄取值比值（SUVR）差异无统计学意义（P=0.548）,但前者AI更高（P<0.001）。同步减低区体积比与NIHSS、mRS均呈正相关（r_s=0.507、0.467,P均<0.001）,SUVR AI与NIHSS、mRS均呈正相关（r_s=0.337、0.317,P均<0.05）。结论 一体化PET/MR可检出慢性单侧头颈动脉狭窄患者脑血流和脑葡萄糖代谢异常。     

DCE-MRI定量参数全域直方图鉴别诊断乳腺导管原位癌与乳腺导管原位癌伴微浸润

目的 探讨动态增强MRI（DCE-MRI）定量参数全域直方图鉴别诊断乳腺导管原位癌（DCIS）与 DCIS伴微浸润（DCIS-Mi）的价值。方法 收集41例DCIS-Mi和37例DCIS患者,术前行DCE-MRI,计算容积转运常数（K^trans）、速率常数（K_ep）、血浆容积分数（V_p）,并记录其全域直方图参数,包括平均值、中位数及10%、25%、50%、75%、90%分位数（P₁₀、P₂₅、P₅₀、P₇₅、P₉₀）。比较DCIS-Mi和DCIS组间各参数差异,并分析最佳参数的诊断效能。结果 DCIS-Mi组K^trans参数中的平均值及各百分位数,K_ep参数中的平均值、中位数、P₅₀、P₇₅、P₉₀,V_p参数中的平均值、中位数、P₂₅、P₅₀、P₇₅均高于DCIS组（P均<0.05）。Logistic回归结果显示K^trans平均值、K^trans-P₂₅、K^trans-P₅₀、K^trans-P₇₅、K^trans-P₉₀、K_ep-P₅₀、K_ep-P₇₅、K_ep-P₉₀、V_p平均值、V_p-P₇₅为诊断DCIS-Mi的最佳变量,且其诊断DCIS-Mi的ROC曲线AUC均>0.80。联合变量Logistic回归模型具有最高的AUC（0.968）,其临界值、敏感度和特异度分别为2.152、0.962和0.947。结论 DCE-MRI全域直方图分析能量化反映肿瘤特征,准确诊断及鉴别诊断乳腺DCIS与DCIS-Mi。     

一体化18F-FDG PET/MR评估缺血性脑血管病

目的 探讨一体化¹⁸F-FDG PET/MR显像对于慢性缺血性脑血管病的应用价值。方法 对10名成年健康志愿者及17例慢性单侧颈内动脉（ICA）或大脑中动脉（MCA）闭塞患者行一体化¹⁸F-FDG PET/MR检查。由2名医师分析图像，定量分析和比较健康志愿者左侧与右侧不同脑区、慢性缺血性脑血管病患者脑梗死患侧与对侧相应区域及脑梗死周围区与对侧相应区域间平均ADC值（ADC_mean）、平均标准化摄取值（SUV_mean）及最大标准化摄取值（SUV_max）的差异。结果 10名健康志愿者MRI均未见异常，¹⁸F-FDG脑代谢图像清晰，各脑区代谢分布对称；左侧与右侧额叶、顶叶、颞叶、枕叶ADC_mean、SUV_mean、SUV_max差异均无统计学意义（P均>0.05）。17例慢性缺血性脑血管病MRI均可见脑梗死灶，¹⁸F-FDG脑代谢图显示患侧均较对侧相应区域ADC_mean、SUV_mean、SUV_max明显减低（P均<0.01）；脑梗死周围区与对侧相应区域比较ADC_mean、SUV_mean、SUV_max亦明显减低（P均<0.01）。结论 利用一体化¹⁸F-FDG PET/MR检查可同时获得脑结构和脑代谢综合信息，全面评价慢性缺血性脑血管病。     

动态对比增强MRI定量参数分级诊断胶质瘤:Meta分析

目的 评价动态对比增强MRI （DCE-MRI）定量参数容积转运常数（K^trans）、血管外细胞外容积分数（V_e）和血浆容积分数（V_p）分级诊断脑胶质瘤的价值。方法 于PubMed、Embase、CNKI、万方、维普数据库检索截止至2017年10月发表的有关DCE-MRI对胶质瘤分级诊断的中英文文献,以Meta分析方法评价DCE-MRI对胶质瘤的分级诊断效能。结果 共纳入27篇文献（中文13篇,英文14篇）、1 079例患者。DCE-MRI定量参数K^trans、V_e、V_p对胶质瘤分级诊断的汇总敏感度为0.86、0.85、0.81,汇总特异度为0.83、0.85、0.79,对应汇总ROC曲线的AUC为0.91、0.92、0.86。结论 K^trans、V_e、V_p对胶质瘤术前分级诊断具有较高诊断效能,其中K^trans、V_e可信度较高。     

比较乳腺动态增强MRI定量和半定量血流动力学参数鉴别乳腺良恶性病变

目的 比较乳腺动态增强MRI定量和半定量血流动力学参数鉴别诊断乳腺病变良恶性的效能。方法 采用杂合动态增强MR序列对59例患者共66个乳腺病变进行扫描，获得半定量参数和定量参数。半定量参数为时间-信号强度曲线（TIC）、初始增强曲线下面积（IAUGC）、最大增强斜率（MaxSlope）、对比增强比率（CER）及正向增强积分（PEI）；定量参数为前向容积转移常数（K^trans）、反向容积转移常数（K_ep）和每单位体积组织的血管外细胞外间隙容积（V_e）。以非参数检验比较良恶性病变间各参数的差异，并绘制ROC曲线，分析其诊断效能。结果 66个乳腺病变中，恶性31个（恶性组），良性35个（良性组），2组间K^trans、K_ep、TIC、IAUGC、MaxSlope差异均有统计学意义（P均<0.05），V_e、PEI、CER差异无统计学意义（P均>0.05）；K^trans、K_ep、TIC、IAUGC、MaxSlope的AUC均>0.7。半定量参数联合诊断乳腺病变良恶性的AUC较单个参数均有显著提高（P均<0.05）；定量参数联合后的AUC较K^trans无显著提高（P=0.134），较K_ep和V_e有显著提高（P均<0.001）。半定量联合与定量参数联合诊断诊断乳腺病变良恶性的AUC差异无统计学意义（P=0.614）。结论 K^trans、K_ep、TIC、IAUGC及MaxSlope对鉴别诊断乳腺良恶性病变具有较高效能；多参数联合，乳腺动态增强MRI半定量和定量参数诊断效能相似。     

The age‐related reduction in cerebral blood flow affects vertebral artery more than internal carotid artery blood flow

Ageing reduces cerebral blood flow (CBF), while mean arterial pressure (MAP) becomes elevated. According to ‘the selfish brain’ hypothesis of hypertension, a reduction in vertebral artery blood flow (VA) leads to increased sympathetic activity and thus increases MAP. In twenty‐two young (24 ± 3 years; mean ± SD) and eleven elderly (70 ± 5 years) normotensive men, duplex ultrasound evaluated whether the age‐related reduction in CBF affects VA more than internal carotid artery (ICA) blood flow. Pulse‐contour analysis evaluated MAP while near‐infrared spectroscopy determined frontal lobe oxygenation and transcranial Doppler middle cerebral artery mean blood velocity (MCA V_mean). During supine rest, MAP (90 ± 13 versus 78 ± 9 mmHg; P<0·001) was elevated in the older subjects while their frontal lobe oxygenation (68 ± 7% versus 77 ± 7%; P<0·001), MCA V_mean (49 ± 9 versus 60 ± 12 cm s^?1; P = 0·016) and CBF (754 ± 112 versus 900 ± 144 ml min^?1; P = 0·004) were low reflected in VA (138 ± 48 versus 219 ± 50 ml min^?1; P<0·001) rather than in ICA flow (616 ± 96 versus 680 ± 120 ml min^?1; P = 0·099). In conclusion, blood supply to the brain and its oxygenation are affected by ageing and the age‐related decline in VA flow appears to be four times as large as that in ICA and could be important for the age‐related increase in MAP.     

The effect of phenylephrine on arterial and venous cerebral blood flow in healthy subjects

Aim: Sympathetic regulation of the cerebral circulation remains controversial. Although intravenous phenylephrine (PE) infusion reduces the near‐infrared spectroscopy (NIRS)‐determined measure of frontal lobe oxygenation (S_cO₂) and increases middle cerebral artery mean blood velocity (MCA V_mean), suggesting α‐adrenergic‐mediated cerebral vasoconstriction, this remains unconfirmed by evaluation of arterial and venous cerebral blood flow. Methods: We determined S_cO₂, MCA V_mean, and right internal carotid artery (ICA) and internal jugular venous (IJV) blood flow (duplex ultrasound) during infusion of PE in eight supine young healthy men [26 (3) years, 177 (7) cm and 74 (8) kg; mean (SD)]. Results: Compared with saline, during infusion of PE, mean arterial pressure increased 26 ± 3% (mean ± SE) and MCA V_mean by 4·8 ± 1·9% (P<0·05), while S_cO₂ decreased by 13·7 ± 3·7% (P<0·05) with no significant changes in the arterial oxygen or carbon dioxide tensions. ICA blood flow did not change significantly in response to PE administration (351 ± 12 versus 373 ± 21 ml min^?1; P = 0·236), while IJV blood flow increased (443 ± 57 versus 507 ± 58 ml min^?1; P = 0·023). Conclusions: These findings confirm that PE induces a reduction in S_cO₂ measured by NIRS and causes an increase in MCA V_mean indicative of cerebral arterial vasoconstriction, although ICA was preserved and IJV increased. These results suggest that a decrease in S_cO₂ during infusion of PE reflects an altered cerebral contribution of arterial versus venous blood to the NIRS signal, although we cannot rule out that an effect of PE on skin blood flow is important.     

Tympanic membrane temperature decreases during head up tilt: relation to frontal lobe oxygenation and middle cerebral artery mean blood flow velocity

Introduction: Changes in blood flow influence temperature of surrounding tissues. Since the internal carotid artery (ICA) and internal jugular vein (IJV) neighbor the tympanic membrane, changes in their blood flow most likely determine changes in tympanic membrane temperature (TMT). We sought to evaluate the relationship between changes during a head-up tilt (HUT) induced reduction in cerebral blood flow (CBF) and TMT.

Methods: Ten male subjects (age 19–28 years) underwent 50° HUT until presyncope. A non-contact infrared sensor in the ear canal targeted the tympanic membrane. Changes in CBF were monitored by transcranial Doppler which determined the mean blood flow velocity in the middle cerebral artery (MCA V_mean) and by near infrared spectroscopy assessed frontal lobe oxygenation (S_cO₂), while skin blood flow (SkBF) was evaluated by laser Doppler flowmetry.

Results: During HUT, TMT decreased by 0.6?°C (median; range 0.2 to 1.6?°C) related to a decrease in MCA V_mean (51.0?±?6.7 to 34.3?±?5.8?cm/sec (mean?±?SD); r?=?0.518, p?=?.002) and S_cO₂ (78.6?±?5.4% to 69.0?±?5.7%; r?=?0.352, p?=?.043), but not to SkBF (120?±?78 to 69?±?37 PU; r?=?0.245, p?=?.142).

Conclusion: During an orthostatic challenge TMT decreases and the decrease is related to a reduction in CBF as indicated by MCA V_mean and S_cO₂, but not to SkBF. We consider TMT holds potential for non-invasive assessment of changes in cerebral perfusion.     

三维伪连续及血管选择性动脉自旋标记技术预测颈动脉内膜切除术后脑过度灌注

目的 评价三维伪连续动脉自旋标记（3D-pcASL）及血管选择性动脉自旋标记（tASL）技术预测颈动脉内膜切除术（CEA）后脑过度灌注的价值。方法 纳入29例CEA后颈总动脉及颈内动脉（ICA）起始段重度狭窄患者,采用3D-pcASL和tASL技术测量手术前后大脑中动脉供血区脑血流量（CBF）及各供血区灌注体积（PV）,计算总灌注体积（PV_总）及术侧CBF差值比（DR_CBF）;比较手术前、后PV_双侧ICA、PV_总及CBF_术侧的差异。根据DR_CBF将患者分为过度灌注组（n=6）及无过度灌注组（n=23）,比较术前PV_双侧ICA、PV_总和CBF_术侧差异。绘制受试者工作特征（ROC）曲线,计算曲线下面积（AUC）,评价术前CBF_术侧、PV_总预测术后发生过度灌注的效能。结果 CEA术前,过度灌注组CBF_术侧明显低于无过度灌注组,PV_总明显小于无过度灌注组（P均<0.05）;术后CBF_术侧较术前增加,PV_术侧ICA升高,PV_对侧ICA下降（P均<0.05）。根据术前CBF_术侧及PV_总预测术后发生过度灌注的AUC分别为0.942及0.790。结论 3D-pcASL及tASL可用于无创获得脑血流灌注并直观观察、测量侧支循环情况;术前CBF及PV_总预测CEA术后发生过度灌注的效能较高。     

亚急性期脑梗死的体素内不相干运动扩散加权成像

目的 探讨体素内不相干运动（IVIM）成像评价亚急性期脑梗死弥散和灌注情况的价值。方法 回顾性分析35例亚急性期脑梗死患者的MR影像资料,包括常规DWI、IVIM成像及三维动脉自旋标记（3D-ASL）序列检查。通过常规DWI序列获得ADC图,IVIM序列获得纯水分子扩散系数（D）图、灌注相关扩散系数（D^*）图、灌注分数（f）图,3D-ASL序列获得脑血流量（CBF）图。分别测量脑梗死灶及对照侧镜像区ADC值、D值、D^*值、f值、CBF值及其相对值（rADC、rD、rD^*、rf、rCBF）。比较脑梗死灶与对照侧镜像区各参数的差异,并分析rADC值与rD、rD^*、rf值的相关性及rCBF值与rD、rD^*、rf值的相关性。结果 脑梗死灶ADC、D、D^*、f、CBF值均较对照侧镜像区减低（P均<0.05）。rADC值与rD、rf值呈正相关（r=0.687、0.601,P=0.005、0.018）;rCBF值与rf值呈正相关（r=0.581,P=0.022）。结论 IVIM成像能同时提供亚急性期脑梗死的灌注及弥散信息,有助于进一步阐明亚急性期脑梗塞的机制。     

磁共振三维稳态构成干扰序列和相位对比电影序列鉴别非肿瘤性脑积水

目的 探讨MR三维稳态构成干扰（3D-CISS）序列和相位对比电影（cine PC）序列鉴别诊断非肿瘤性脑积水的价值。方法 选取常规MR平扫及增强扫描显示脑室系统扩大的非肿瘤性脑积水患者65例及健康志愿者30名（对照组）,对中脑导水管区进行3D-CISS和cine PC序列扫描。依据3D-CISS序列所见中脑导水管有无梗阻,将患者分为梗阻组和交通组,动态播放矢状位cine PC图像,观察各组中脑导水管处脑脊液（CSF）流动情况;对轴位cine PC测得的中脑导水管处CSF流速、流量与对照组进行统计学分析。结果 3D-CISS序列清晰显示22例中脑导水管梗阻（梗阻组）,43例无梗阻（交通组）。矢状位cine PC图像示梗阻组仅2例中脑导水管见微弱CSF流动信号,余均无明显CSF流动;而交通组CSF流动信号明显。轴位cine PC测得交通组中脑导水管CSF流速和流量较对照组增多（P均<0.05）。结论 3D-CISS序列结合cine PC序列可无创定性、定量观察CSF流动,有助于鉴别非肿瘤性脑积水的类型。     

动态磁敏感对比增强MRI和动态对比增强MRI鉴别诊断胶质瘤复发和放射性脑损伤

目的 探讨动态磁敏感对比增强MRI（DSC-MRI）及动态对比增强MRI（DCE-MRI）在鉴别脑胶质瘤术后放化疗后复发和放射性脑损伤中的临床应用价值。方法 对19例经临床病理确诊为脑胶质瘤患者在术后、放化疗前、放化疗后定期行DSC及DCE检查,得到相关的血流动力学参数值并将灌注成像影像诊断结果与临床最终诊断结果对照,分析各灌注参数在鉴别诊断中的价值。结果 11例为胶质瘤复发,8例为放射性脑损伤。胶质瘤复发患者的rCBF、rCBV、K_trans、V_e及riAUC值均明显高于放射性脑损伤患者（P均<0.05）;而K_ep、V_p值在胶质瘤复发或放射性脑损伤患者差异无统计学意义（P=0.37、0.22）。K_trans联合rCBV共同诊断,并、串联试验中鉴别诊断的敏感度分别为90.9%、72.7%;特异度分别为62.5%、100%。结论 DCE及DSC均可鉴别肿瘤复发或放射性脑损伤。K_trans、riAUC及rCBV诊断效能略高于V_e及rCBF,联合应用rCBV及K_trans可提高诊断正确率。     

Brain Blood Flow and Velocity

Objective. Because transcranial Doppler sonography (TCD) is unable to measure arterial diameter, it remains unproven whether the changes in cerebral blood velocity it measures are representative of changes in cerebral blood flow (CBF). Our study was designed to compare velocity changes with flow changes measured by two magnetic resonance imaging (MRI) techniques, perfusion MRI and arterial spin labeling (ASL), using flavanol‐rich cocoa to induce CBF changes in healthy volunteers. Methods. We enrolled 20 healthy volunteers aged 62 to 80 years (mean, 73 years). Each was studied at baseline and after drinking standardized servings of cocoa for 7 to 14 days. Results. Changes in middle cerebral artery (MCA) flow by TCD were significantly correlated with changes in perfusion assessed by gadolinium‐enhanced MRI (r = 0.63; P < .03). Measurements with ASL showed a stronger correlation with borderline significance. Conclusions. Changes in flow velocity in the MCA associated with drinking cocoa were highly correlated with changes in CBF measured by the two MRI techniques using the tracer gadolinium and ASL. These results validate Doppler measurements of CBF velocity as representative assessments of CBF.     

Effect of epidural anaesthesia on dorsal pedis arterial diameter and blood flow

Summary. In nine subjects the influence of low (LE: blockade at or below the umbilicus; Th. 10) and high epidural anaesthesia (HE: block above the umbilicus) on vascular tone was evaluated by high frequency ultrasound (20 mHz) determined luminal diameter and a Doppler (8 mHz) assessment of mean blood flow velocity (V_mean) in the dorsalis pedis artery. The LE was induced by 0–5% bupivacain through a catheter at L₃-L₄, and HE was established by further infusion. Resting blood pressure and heart rate were not affected by LE or HE. One subject developed selective thoracic anaesthesia, and another was blocked on the contralateral side only. In the seven adequately blocked subjects, the luminal diameter of the dorsalis pedis artery increased from 1.70 (1.25–1.93) to 1.90 (1.75–2.23) mm during LE (+12%) and further to 2.08 (1.83–2.96) mm during HE (22%; P<0.05). The V_mean was similar during control (7 [4–26] cm s^-1) and LE (12 [4–55] cm s^-1), but increased during HE to 35 (12–78) cm s^-1 (+500%; P<0.05). Thus, arterial blood flow was higher during LE (21 [7–98] ml min^-1; +263%) and HE (94 [21–177] ml min^-1; +1175%) than at rest (8 [7–36] ml min^-1; P<0.05). This study quantified the importance of sympathetic nerve activity for vascular tone and in turn blood flow in an artery of a resting human limb, as the diameter and V_mean increased with progressive epidural anaesthesia.     

肝硬化胆囊壁的高频超声分型与门静脉主干及右支血流动力学的关系

目的 探讨肝硬化胆囊壁的不同分型与门静脉主干及右支血流动力学变化的关系.方法 采用高频超声联合二维及彩色超声观察肝硬化组(69例)和对照组(30名)的胆囊壁分型、厚度、门静脉主干内径(D_(pv))、门静脉主干血流速度(V_(pv))、门静脉主干血流量(Q_(pv))、门静脉右支内径(D_(rpv))、门静脉右支血流速度(V_(rpv))、门静脉右支血流量(Q_(rpv)).同时根据胆囊壁的不同分型将69例肝硬化患者分为胆囊壁不厚亚组、单纯增厚亚组和双边亚组,对比肝硬化各组与对照组以上检测指标的差异.结果 各组间胆囊壁厚度均存在差异(P<0.05);D_(pv)除胆囊壁不厚亚组与单纯增厚亚组间差异无统计学意义外,其余各组间差异均有统计学意义(P<0.01);V_(pv)仅单纯增厚亚组与对照组、双边亚组与对照组间差异有统计学意义(P<0.01);Q_(pv)在双边亚组与其余各组间差异有统计学意义(P<0.05).D_(rpv)、Q_(rpv)各组间差异均无统计学意义;V_(rpv)对照组分别与单纯增厚亚组及双边亚组间差异有统计学意义(P<0.05).肝硬化组与对照组Q_(rpv)/Q_(pv)比值差异无统计学意义(P>0.05).胆囊壁厚度与D_(pv)呈正相关(r=0.886,P<0.01).结论 肝硬化时高频超声下胆囊壁的不同分型与门静脉主干血流动力学变化关系密切,而与门静脉右支血流动力学变化无相关性;胆囊静脉回流受阻并非肝硬化门静脉高压胆囊壁变化主要的血流动力学原因,其发生可能有更内在的机制.