椎动脉MR血流定量测定研究

目的 探讨Philips Intera Achieva 1.5T MR椎动脉流量、流速的正常值.方法 对63例正常椎动脉行MR相位对比法(2D-QFLOW序列)扫描,采用流动分析软件,对椎动脉血流定量测定.结果 63例受检者中30例为等势椎动脉,33例为非等势椎动脉,30例等势椎动脉血流测量结果:左侧椎动脉平均流量(1.74±0.54)ml/s,右侧为(1.60±0.47)ml/s(P＞0.05);左侧椎动脉平均流速(13.53±3.10)cm/s,右侧为(12.82±3.36)cm/s(P＞0.05);左侧椎动脉收缩期峰值流速(38.99±6.81)cm/s,右侧为(36.78±6.72)cm/s(P＜0.05);椎动脉相位速度图与心动周期的关系为正弦波关系,等势椎动脉管径宽度与流量呈正相关,与流速成负相关.结论 建立Philips Intera Achieva 1.5T磁共振等势椎动脉流速、流量等的正常值.     

后循环缺血的MR电影相位对比法血流定量研究

目的:探讨MR电影相位对比法测量后循环缺血患者双侧椎动脉血流流速、血流量等血流动力学参数的准确性及后循环缺血的原因。方法:28例经临床诊断为后循环缺血的患者及5例同年龄组健康志愿者,使用头部线圈和周围脉搏门控技术,采用MR电影相位对比法测量双侧椎动脉的血流动力学参数,并与经颅多普勒(TCDU)检查,结果进行比较,同时分析椎动脉血流量与血管狭窄程度的相关性。结果:MR电影相位对比和TCDU两种技术所测量的双侧椎动脉流速呈高度相关(左侧r=0.887,P=0.013;右侧r=0.785,P=0.027)。MR电影相位对比法测得病变组左右椎动脉平均流速分别为(16.16±7.99)和(15.72±9.92)cm/s,平均血流量分别为(66.63±45.23)和(68.57±38.84)ml/min。MR电影相位对比法所测血流量正常对照组与后循环缺血组之间差异有统计学意义。椎动脉血流量与血管狭窄程度无明显相关性(r=-0.144,P=0.654)。结论:使用MR电影相位对比法可无创性准确评价后循环缺血患者血流动力学改变,后循环的平均椎动脉血流量与血管狭窄程度低度相关。     

屏气相位对比MRI评价正常人冠状动脉血流储备

目的　研究屏气相位对比ＭＲ（ＰＣＭＲ） 技术测定正常人冠状动脉血流储备（ＣＦＲ） 的可行性。方法　健康志愿者１５ 例（男１２ 例,女３ 例）。采用快速屏气Ｋ空间分段ＰＣＭＲ技术,测定冠状动脉左前降支（ＬＡＤ）静息状态和静注潘生丁负荷状态下的舒张期峰值血流速度、容积流率及ＣＦＲ。结果基础状态ＬＡＤ容积流率为（３５－４±１３－３） ｍｌ／ｍｉｎ,静注潘生丁后明显增加至（１５５－４ ±６６－８） ｍｌ／ｍｉｎ（Ｐ＜０－０１）, 平均ＣＦＲ为４－４±０－７３。基础状态ＬＡＤ峰值流速为（２２－５±３－９）ｃｍ ／ｓ, 静注潘生丁后明显增加至（６３－８±１６－７）ｃｍ／ｓ（ Ｐ＜ ０－０１）, 两者比值为２－９±０－７２ 。结论　该研究表明采用屏气ＰＣＭＲＩ流速编码技术可以定量测定正常人冠状动脉容积流率、峰值流速,从而评价ＣＦＲ。     

MR成像技术的K空间与脉冲序列

ＭＲ成像技术的Ｋ空间与脉冲序列ＴｈｅＫ－ｓｐａｃｅａｎｄＲＦＰａｌｓｅＳｅｑｕｅｎｃｅｉｎＭＲＩＴｅｃｈ－ｎｉｑｕｅ杜先懋李澄何玲杜芳周龙平扬州市第一人民医院影像科２２５００１ＭＲ成像已得到迅速普及，ＭＲ技术发展的一个重要问题在于对Ｋ空间的引入及理解...     

颈内—后交通小动脉瘤的3D PC MRA评价

评价三维相位对比法磁共振血管成像（３Ｄ ＰＣ ＭＲＡ）显示颈内－后交通小动脉瘤的能力。材料和方法，对８例疑颅内血管性病变患者在ＧＥ Ｖｅｃｔｒａ０．５Ｔ超导系统上进行３Ｄ ＰＣ ＭＲＡ检查，并与ＣＡＧ／ＤＳＡ结果对照，以矢状在ＳＥＴ１ＷＩ为定位像，采用最短ＴＥ、３０－４０ｃｍ／ｓ的编码流速等参数运用３ＤＰＣ法，采集范围包括颈内动脉虹吸部和Ｗｉｌｌｉｓ图像进行分析。结果：经ＣＡＧ／ＤＳＡ证实右侧颈内     

MR相位速度图及多普勒超声对椎动脉血流动力学的对比性研究

目的 评价ＭＲ相位速度图检测椎动脉血流动力学的价值及其诊断椎动脉狭窄的准确性。材料与方法 测量３２列患者的椎动脉直径、流速及最大返流速度并与经颅多普勒超声（ＴＣＤ）进行比较,通过ｔ检验判断椎动脉狭窄患者与对照组之间有无差异以及ｘ＾２检验评判ＭＲ相位速度图测量椎动脉狭窄的准确性和特异性。结果 ＭＲ相位速度图与ＴＣＤＦ的检测结果具有一致性（ｘ＾２＝０．５,Ｐ〉０．０５）;２０例椎动脉狭窄患者的椎动脉流     

MRI电影相位对比与超声对照对正常志愿者餐前、餐后门静脉血流定量研究

目的:采用MRI电影相位对比法(Cine PC MRI)对正常志愿者餐前、餐后门静脉血流动力学进行定量测量,并与多普勒超声(DUS)对照.方法:健康志愿者26例,男16例,女10例.分别于空腹和进食1000cal食物1h后定量测量门静脉血流.结果:电影相位对比法及多普勒超声(DUS)测量正常志愿者餐后门静脉血流参数较餐前明显增加(P＜0.01),电影法门静脉流速增长为(34.11±16.76)%,流量增长为(45.87±16.22)%;DUS餐后门静脉流速较餐前增长(29.11±15.55)%,流量增长(35.54±18.77)%.对餐前门静脉血流量行相位对比MRI与超声相关性分析,两者相关性较好(r=0.606,P＜0.01).结论:PC MRI与DUS均可反映餐前、餐后门静脉血流的变化;Cine PC MRI反映门静脉血流的变化更接近人体的生理状态.     

静脉注射Gd－DOTA后在膝关节内的弥散：MRI评价

静脉注射Ｇｄ－ＤＯＴＡ后在膝关节内的弥散：ＭＲＩ评价ＩｎｔｒａａｒｔｉｃｕｌａｒＤｉｆｆｕｓｉｏｎｏｆＧｄ－ＤＯＴＡａｆｔｅｒＩｎｔｒａｖｅｎｏｕｓＩｎｊｅｃｔｉｏｎｉｎｔｈｅＫｎｅｅ：ＭＲＩｍａｇｉｎｇＥｖａｌｕａｔｉｏｎ￥Ｊ．－Ｌ．Ｄｒａｐｅ；ｅ...     

婴儿晚发性维生素K缺乏颅内并发症的CT表现(附8例报告)

婴儿晚发性维生素Ｋ缺乏颅内并发症的ＣＴ表现（附８例报告）Ｉｎｔｒａ－ｃｒａｎｉａｌＣｏｍｐｌｉｃａｆｉｏｎｉｎＩｎｆａｎｔｗｉｔｈＤｅｌａｙｅｄＶｉｔＫＤｅｆｉｃｉｅｎｃｙ：ＣＴＭａｎｉｆｅｓｔａｔｉｏｎ（ＡＲｅｐｏｒｔｏｆ８Ｃａｓｅｓ）胡爱妹姚郁林...     

MRA诊断单冠状动脉畸形一例

ＭＲＡ诊断单冠状动脉畸形一例李立伟张挽时刘朝中鲁晓燕我们应用屏气下心电门控脂肪抑制Ｋ空间分段采集快速梯度回波（ｂｒｅａｔｈ－ｈｏｌｄｆａｔ－ｓｕｐｐｒｅｓｓｅｄＥＣＧ－ｇａｔｅｄｔｕｒｂｏ－ＦＬＡＳＨ，ｗｉｔｈＫ－ｓｐａｃｅｓｅｇｍｅｎｔａｔｉｏｎ）...     

Assessment of coronary flow reserve with fast cine phase contrast magnetic resonance imaging: comparison with measurement by Doppler guide wire.

Fast cine phase contrast magnetic resonance imaging (fast cine phase contrast MRI) can measure phasic coronary flow velocity in humans. The purpose of this study was to compare the coronary flow velocity reserves measured by MR IMAGING with those obtained by Doppler guide wire. Nineteen patients with ischemic or valvular heart disease were studied. Fast cine phase contrast MR images of the left anterior descending (LAD) artery were acquired during breath-hold time in the basal state and after administration of dipyridamole. Flow velocity in the LAD artery was also measured with Doppler guide wire before and after venous injection of dipyridamole in all subjects. Flow velocity in the coronary artery measured with MR IMAGING in the basal state (12.5 +/- 4.9 cm/sec) was significantly lower than that obtained with Doppler guide wire (32.4 +/- 12.1 cm/sec, P < 0.01). However, MR assessments of coronary flow velocity reserve showed a good linear correlation with those measured by Doppler guide wire (r = 0.91). In conclusion, fast cine phase contrast MR imaging is a useful technique, which can provide a noninvasive assessment of flow reserve ratios in patients with coronary artery disease. J. Magn. Reson. Imaging 1999;10:563-568.     

Fast magnetic resonance imaging of the heart.

Fast MR imaging techniques have multiple applications for evaluation of cardiac disease. Cine MRI and MR tagging have been shown to be highly accurate and reproducible in evaluating regional and global myocardial function. Segmented k-space cine MRI and echo-planar imaging (EPI) can considerably improve time efficiency and thereby the clinical utility of these techniques. Double IR fast spin-echo sequences enable breath-hold acquisition of T2 weighted MRI with good suppression of the blood signal. Myocardial perfusion can be assessed with fast dynamic MRI after administration of contrast media. Multi-shot EPI improves temporal resolution and also provides full coverage of the left ventricle. Substantial progress has been made in respiratory gated 3D coronary artery MR angiography with navigator echoes. The newer approaches for coronary arterial imaging including breath-hold three-dimensional segmented EPI and high resolution spiral MRI may further improve clinical usefulness of coronary MR angiography. Assessment of coronary blood flow and flow reserve with phase contrast MRI has the potential for the non-invasive evaluating of the presence and significance of stenosis in the native coronary artery and bypass grafts. Fast cardiac MRI may emerge as a cost effective modality for comprehensive assessments of both cardiac morphology, function, blood flow and perfusion.     

Contrast-enhanced 2D cine phase MR angiography for measurement of basilar artery blood flow in posterior circulation ischemia

BACKGROUND AND PURPOSE: Dizziness is a symptom that develops with internal ear disturbances and with dysfunctions of the brain stem and cerebellum, in particular with blood flow disturbances of the brain stem and cerebellum (posterior circulation ischemia [PCI]). Patients with PCI often present with various neurologic signs and symptoms. To examine the usefulness of contrast-enhanced 2D cine phase MR angiography in the diagnosis of PCI, we examined quantitative blood flow of the basilar artery in patients with PCI who had primarily complained of dizziness. METHODS: We quantitatively measured the blood flow volume rate of the basilar artery by using a contrast-enhanced 2D cine phase MR angiographic technique in 21 patients diagnosed with PCI and in 16 age- and sex-matched control participants. RESULTS: Maximum and mean average flow velocities of the basilar artery in the PCI group were significantly lower than those of the control group (29.2 +/- 9.2 cm/s versus 38.5 +/- 8.2 cm/s [P <.005] and 18.0 +/- 5.6 cm/s versus 22.6 +/- 5.0 cm/s [P <.01], respectively). The flow volume rates of the basilar arteries were also significantly lower in the PCI group (103.3 +/- 37.3 mL/min versus 148.8 +/- 40.0 mL/min [P <.001]). CONCLUSION: The flow volume rate of the basilar artery in patients with PCI during intermittent ischemic attacks with dizziness was chronically reduced compared with that in the control participants. This suggests that flow volume rates may influence the development of the clinical signs and symptoms of PCI. We think that contrast-enhanced 2D cine phase MR angiography is a valuable method for the diagnosis of PCI.     

Blood flow dynamics in the vertebrobasilar system: correlation of a transparent elastic model and MR angiography.

PURPOSETo describe the flow patterns in a model of the vertebrobasilar artery and use these observations to explain the appearance of the flow on the MR images.METHODSWe created an anatomically precise, transparent elastic model of the human vertebrobasilar artery containing a basilar tip aneurysm and perfused the model with non-Newtonian fluid which has similar rheologic properties to blood. Flow patterns in the vessels were directly observed. MR angiogram images were obtained with commercially available two-dimensional time-of-flight, three-dimensional time-of-flight, and 3-D phase-contrast MR angiographic pulse sequences, and they were correlated with the directly seen flow patterns. Quantitative flow velocity measurements were performed with 2-D cine phase-contrast MR angiography and correlated with the flow measured with an electromagnetic flow meter.RESULTSVisualization studies showed the dye stream patterns in the vertebrobasilar arteries to be extremely complex and variable. During the MR experiments we found that often the same segment of a vessel could appear very different depending on the pulse sequence. In some instances, the model experiments helped to explain the MR appearance of the vessels. Flow profiles measured with 2-D cine phase contrast were found to be consistent with those measured directly with an electromagnetic flow meter.CONCLUSIONClear elastic models can be used to duplicate the flow in human cranial vessels and thus provide a unique means to observe these flow patterns directly. The flow patterns helped to explain the variation in appearance of the vessels and the artifacts with different MR angiography pulse sequences. The artifacts depend on both the geometry of the vessel and the flow pattern within it. Two-dimensional cine phase-contrast MR provides temporal flow field information that is directly related to physiological information about flow volumes and velocity patterns.     

颅内疾病对导水管脑脊液流量的影响

目的：探讨用磁共振相位对比电影(PC cine)对导水管脑脊液定量测量的临床应用价值。方法：将35例中枢神经系统不同疾病分三组，用PC cine方法进行导水管脑脊液流量测量。结果：在脑血管病组伴白质改变时导水管流量增加；梗阻性脑积水导水管流量减少，流动波形异常；交通性脑积水导水管流量增加，波形圆钝。结论：磁共振PC cine方法测量导水管脑脊液流量简单易行，可为临床提供更多的影像信息。     

Peak blood flow measurement of coronary sinus by cine phase contrast MR imagings: comparison between breath-hold and respiratory compensation techniques.

The aim of this study was to assess the feasibility of cine phase contrast (PC) magnetic resonance (MR) imaging for the peak blood flow measurement of the coronary sinus. Conventional PC imaging demonstrated the coronary sinus clearly and the significantly higher peak flow compared with the corresponding values measured with breath-hold fast cine PC imaging techniques at end-inspiration and end-expiration. This study showed the feasibility of conventional cine PC imaging with respiratory compensation in measurement of coronary sinus blood flow.     

Effect of flip angle on volume flow measurement with nontriggered phase‐contrast MR: In vivo evaluation in carotid and basilar arteries

Purpose

To evaluate the effect of flip angle on volume flow rate measurements obtained with nontriggered phase‐contrast magnetic resonance imaging (MRI) in vivo.

Materials and Methods

We prospectively measured volume flow rates of the bilateral internal carotid artery and the basilar artery with cine and nontriggered phase‐contrast MRI. For nontriggered phase‐contrast imaging, flip angles of 4, 15, 60, and 90° were used for 40 volunteers and of 8, 15, and 30° for 54 volunteers. Lumen boundaries were semiautomatically determined by pulsatility‐based segmentation using cine phase‐contrast MRI. Identical lumen boundaries were used for nontriggered phase‐contrast imaging.

Results

The ratio of volume flow rate obtained with nontriggered phase‐contrast imaging to that obtained with cine phase‐contrast imaging significantly increases with an increase in the flip angle. The mean ratios lie within a relatively narrow range of ±15% with a wide range of flip angles of 8–90°. As the flip angle increases, ghost artifacts become prominent and signal‐to‐noise and contrast‐to‐noise ratios increase.

Conclusion

Flip angles between 8 and 60° are most appropriate for nontriggered phase‐contrast MR measurements in the internal carotid and the basilar artery. J. Magn. Reson. Imaging 2009;29:1218–1223. © 2009 Wiley‐Liss, Inc.     

Influence of blood-pool contrast media on MR imaging and flow measurements in the presence of pulmonary arterial stents in swine

PURPOSE: To compare the effects of various stents on magnetic resonance (MR) imaging flow volume measurements and to determine the value of a blood-pool MR imaging contrast medium in assessment of vascular stents. MATERIALS AND METHODS: In 11 pigs, six nitinol stents (Memotherm), four platinum stents (NuMed), and one elgiloy stent (Wallstent) were placed in the main pulmonary artery under x-ray fluoroscopic guidance. MR imaging was performed 3 months after stent placement before and after injection of NC100150 contrast medium. Blood flow volumes were assessed with velocity-encoded cine MR imaging through and next to the stent. The signal-to-noise ratio and width of susceptibility artifacts of the stents also were determined. Measurements were analyzed with the paired Student t test and Bland-Altman test, where appropriate. RESULTS: Blood flow volumes measured through the nitinol and platinum stents disclosed no significant difference between velocity-encoded cine MR imaging measurements through and next to the stent. On cine MR images, small susceptibility artifacts were observed around the nitinol and platinum stents. Signal-to-noise ratio in the stent lumen was reduced in nitinol and platinum stents when compared with that next to the stent. The elgiloy stent produced severe susceptibility artifacts, making measurement of flow volumes impossible. NC100150 injection caused no significant effect on flow volume measurements. It improved the signal-to-noise ratio of the pulmonary arterial lumen outside and, to a lesser extent, inside the stent. CONCLUSION: Assessment of morphology and flow volumes through nitinol and platinum stents is feasible with MR imaging. Blood-pool contrast media provide persistent signal enhancement in the pulmonary artery and, to a lesser extent, in the lumina of nitinol and platinum stents.     

Blood flow in major cerebral arteries measured by phase-contrast cine MR.

PURPOSETo measure mean blood flow in individual cerebral arteries (carotid, basilar, anterior cerebral, middle cerebral, and posterior cerebral) using a cine phase contrast MR pulse sequence.METHODSTen healthy volunteers (22 to 38 years of age) were studied. The cine phase-contrast section was positioned perpendicular to the vessel of interest using oblique scanning planes. This pulse sequence used a velocity encoding range of 60 to 250 cm/sec. From the velocity and area measurements on the cine images, mean blood flow was calculated in milliliters per minute and milliliters per cardiac cycle. In the same subjects, transcranial Doppler measurements of blood velocity in these same vessels were also obtained.RESULTSThere was no difference in blood flow in the paired cerebral arteries. Carotid arteries had mean blood flow in the range of 4.8 +/- 0.4 ml/cycle, the basilar artery 2.4 +/- 0.2 ml/cycle, the middle cerebral artery 1.8 +/- 0.2 ml/cycle, the distal anterior cerebral artery 0.6 +/- 0.1 ml/cycle, and the posterior cerebral artery 0.8 +/- 0.1 ml/cycle. Overall, there was poor correlation between MR-measured and transcranial Doppler-measured peak velocity.CONCLUSIONAlthough careful attention to technical detail is required, mean blood flow measurements in individual cerebral vessels is feasible using a cine phase-contrast MR pulse sequence.     

Popliteal and tibioperoneal arteries: feasibility of two-dimensional time-of-flight MR angiography and phase velocity mapping.

To assess the feasibility of using magnetic resonance (MR) angiography and velocity-encoded cine MR imaging to evaluate morphology and function in the popliteal and tibioperoneal arteries, the profiles of blood flow velocity measured with velocity-encoded cine MR were compared with those measured with color-coded sonography. Two-dimensional time-of-flight MR angiography was performed in the popliteal and tibioperoneal arteries of 10 healthy subjects; velocity-encoded cine MR and color-coded sonography were performed above and below the trifurcation. The velocity waveforms acquired with velocity-encoded cine MR and color-coded sonography correlated well and showed a typical triphasic pattern. At peak systole in the popliteal artery, spatial maximum and spatial mean velocities measured with velocity-encoded cine MR were 42.29 cm/sec +/- 9.55 (standard deviation) and 27.7 cm/sec +/- 5.8, respectively; the peak velocity measured with color-coded sonography was 44.2 cm/sec +/- 12.3. It is concluded that use of both MR angiography and velocity-encoded cine MR should be considered for identification of arterial stenoses and assessment of the hemodynamic importance of peripheral vascular stenoses.