Global left ventricular perfusion: noninvasive measurement with cine MR imaging and phase velocity mapping of coronary venous outflow.

Velocity and volumetric flow of left ventricular venous outflow in the distal coronary sinus were measured with magnetic resonance (MR) velocity mapping techniques in 24 healthy men. A total of 16-21 velocity maps were acquired throughout the cardiac cycle. To determine the accuracy of the MR velocity-mapping pulse sequence, measurements were obtained with a flow phantom. Mean blood flow was 144 mL/min +/- 62 (standard deviation); mean velocity, 2.1 cm/sec +/- 1.0; and mean cross-sectional area, 1.2 cm2. Phasic measurements revealed a biphasic flow pattern in the coronary sinus, with a first peak in systole (257 mL/min +/- 174) and a second peak in early diastole (1,090 mL/min +/- 487). The cross-sectional area varied between 0.5 cm2 +/- 0.2 at end diastole and 1.9 cm2 +/- 0.6 in systole, a finding that suggests a capacitance function for venous outflow. Mean blood flow measurements were in agreement with measurements obtained invasively in previous studies. It is concluded that MR velocity mapping can enable noninvasive measurement of coronary venous outflow and global left ventricular perfusion and may become clinically useful in assessment of coronary blood flow reserve.     

Assessment of regional left ventricular long-axis motion with MR velocity mapping in healthy subjects

The pattern of left ventricular long-axis motion during early diastole was assessed with magnetic resonance (MR) velocity mapping in 31 healthy volunteers. Regional long-axis velocity varied with time and position around the ventricle. During systole, the base descended toward the apex. The greatest magnitude of long-axis velocity occurred during early diastole. The lateral wall had the highest velocity (140 mm/sec ± 40 [mean ± standard deviation]); the anterior and inferior walls had lower velocities (96 mm/sec ± 27 and 92 mm/sec ± 34, respectively). The inferoseptal area consistently had the lowest velocities (87 mm/sec ± 40). Absolute values of peak early-diastolic velocity declined with age (r = ?.64, P <.001). Peak early-diastolic velocity was not dependent on heart rate (r =.014, P =.94). Regional variations in left ventricular wall motion were seen. MR velocity mapping is a useful technique for assessing regional left ventricular long-axis heart function.     

正常人体心室舒张功能生理性变化特点的超声研究

目的观察正常人体心室舒张功能的演变规律，探讨心室舒张功能生理性减退的基本界限。方法本项目运用无创性超声成像技术，对正常人心室舒张功能进行了血流动力学检测。240名自愿接受体检者．按年龄分为少年组、青年组、中年组和老年组，采用二维超声检测心腔内径，M型超声检测舒张期心室壁弛张速度，频谱多普勒检测左右房室瓣及肺静脉口血流速度以及流速比值，彩色多普勒显示舒张期心室血流充盈时相及持续时间。结果二尖瓣、三尖瓣以及肺静脉口血流的多项参数与年龄增长呈高度相关。正常人心室舒张功能特点是：青少年期为完全正常期．中年期为顺应性减低期，老年期为舒张功能减低期。心室舒张功能的减退左室先于右室。结论正常人心室舒张功能随年龄增长存在生理性减退。     

肥厚型心肌病心功能异常的磁共振电影成像分析

目的 应用磁共振电影成像（ｃｉｎｅ－ＭＲＩ）方法探讨肥厚型心肌病的左心室功能的变化。方法 １２例肥厚型心肌病患者,行ＭＲ快速自旋回波（ＴＳＥ）多层面平扫和ｃｉｎｅ－ＭＲＩ检查,用ＡＲＧＵＳ专用心功能分析软件分析射血分数、心肌增厚率、心腔（左心室）容积及时间－容积变化曲线等参数。结果 （１）肥厚型心肌病主要累及左心室前、侧壁及室间隔,肥厚心肌的心肌增厚率显著低于正常心肌（ｔ＝１５．１,Ｐ〈０．０１）     

Myocardial velocity gradient imaging by phase contrast MRI with application to regional function in myocardial ischemia

Velocity-encoded phase contrast magnetic resonance imaging (MRI) has the potential to quantify regional myocardial contractile function with a sensitivity to motion comparable to implanted ultrasonic crystals. An MRI sequence and post-processing algorithm were developed to measure myocardial velocity gradients on a 1.5 T MRI scanner. These methods were validated on a rotating phantom and applied to dogs before (n = 11) and during prolonged coronary occlusion (n = 5). In phantom validation studies, the average absolute error corresponded to motion equivalent to 0.03 ± 0.04 mm (mean ± SD) during the repetition time of the experiment. Rigid body corrections during post-processing significantly simplified the interpretation of myocardial velocity vectors. In vivo, rigid body motion contributes substantially to the recorded myocardial velocities in systole and diastole and can give the false impression of regional wall motion abnormalities. After rigid body correction, normal systolic and diastolic velocity vectors in short-axis views of the left ventricle were primarily directed toward the center of the left ventricle. Transmural radial strain rate was 2.0 ± 0.6 sec⁻¹ during systole and −3.6 ± 1.1 sec⁻¹ during early diastole in normal canine hearts. Ischemic myocardium was easily discriminated from normal left ventricle by velocity-encoded phase contrast MRI both qualitatively and quantitatively (P < 0.01 in systole and P < 0.05 in early diastole). Although the myocardial velocity images have a spatial resolution on the order of a millimeter, the velocity encoding describes the mechanical consequences of focal myocardial ischemia with sensitivity to submillimeter displacement of the pixels. The three-dimensional nature of velocity-encoded MRI is particularly well suited to the study of the complex motion of the heart in vivo. Magn Reson Med 42:98–109, 1999. © 1999 Wiley-Liss, Inc.     

Spiral phase velocity mapping of left and right coronary artery blood flow: correction for through-plane motion using selective fat-only excitation

PURPOSE: To develop a method of correcting both right and left coronary artery flow velocities for the through-plane motion of the vessel, in order to allow details in the temporal flow profiles to be viewed. MATERIALS AND METHODS: The methods developed use selective excitation and velocity mapping of the epicardial fat surrounding the artery, either in a separate acquisition (temporal resolution = 22 msec) or interleaved with the water-excitation acquisition (temporal resolution = 44 msec) used to determine coronary blood flow velocities. The two methods were compared in 10 right and 13 left coronary arteries in healthy volunteers. RESULTS: For the right coronary arteries, correction for through-plane motion significantly reduces the mean systolic flow velocity (75.3 mm/second vs. 90.0 mm/second, P < 0.01), while the mean diastolic flow velocity is unchanged (96.8 mm/second vs. 94.5 mm/second, P = ns). The resulting profiles are biphasic, with approximately equal flow in systole and diastole. For the left arteries, correction for through-plane motion reduces the mean systolic flow velocity (25.0 mm/second vs. 72.8 mm/second, P < 0.001), resulting in the expected diastolic predominant flow profiles. For the right arteries, there were no significant differences in the mean systolic and mean diastolic velocities after correction with the separate fat-excitation acquisition, and after correction the poorer temporal resolution combined water excitation/fat excitation acquisition. However, for the left coronary arteries, the combined water excitation/fat excitation acquisition resulted in a slight reduction in the mean diastolic velocity (121.5 mm/second vs. 130.9 mm/second, P < 0.05). CONCLUSION: Selective excitation of the surrounding epicardial fat enables through-plane correction of both left and right coronary flow velocities, enabling the temporal details of flow velocity to be viewed.With a combined WE/FE acquisition, this can be performed without extending the study duration; however, the reduced temporal resolution and temporal mismatch of the excitations results in a blunting of rapidly changing flow profiles. As such, it may be less suitable for the left coronary artery, which has a greater range of through-plane motion than the right, and correction using separate WE and FE acquisitions, or the adjacent myocardium, may be preferable.     

超声检测小儿贫血的心功能改变

目的 :检测贫血患儿心功能及动态变化。方法 :采用心脏超声及多普勒组织显像 (DTI)检查 2 5例贫血患儿心指数 (CI)、射血分数 (EF)、二尖瓣环收缩期及舒张早期运动速度 (MVR SV及MVR DEV)、左室后壁心肌收缩期及舒张期运动速度 (MSV及MDV)并动态与配对对照组比较。结果 :观察 1组CI及MVR SV较对照组显著增加 ,观察 2组MVR DEV及MDV较对照组显著降低。结论 :贫血患儿开始可出现收缩功能代偿增加 ,长期未治贫血患儿可出现心功能失代偿 ,首先表现为舒张功能减低。     

肥厚型心肌病的磁共振影像诊断应用初探

目的 评价肥厚型心肌病的磁共振影像诊断价值。材料与方法 ２０例肥厚型心肌病患者,行磁共振ＴＳＥ多层面平扫和磁共振电影（ｃｉｎｅ－ＭＲＩ）检查,用ＡＲＧＵＳ专用心功能分析软件分析左室心肌质量、各节段心壁厚度及心肌增厚率等参数。结果 （１）肥厚型心肌病主要累及室间隔及左室前、侧壁,呈非对称分布,肥厚心肌与左室后下壁比率≥１．５。（２）肥厚心肌的心肌增厚率显著低于正常心肌（Ｐ〈０．０１）。（３）梗阻型左     

Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR

Objective:

Obtaining new details of radial motion of left ventricular (LV) segments using velocity-encoding cardiac MRI.

Methods:

Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Cine images for navigator-gated phase contrast velocity mapping were acquired using a black blood segmented κ-space spoiled gradient echo sequence with a temporal resolution of 13.8 ms. Peak systolic and diastolic radial velocities as well as radial velocity curves were obtained for 16 ventricular segments.

Results:

Significant differences among peak radial velocities of basal and mid-ventricular segments have been recorded. Particular patterns of segmental radial velocity curves were also noted. An additional wave of outward radial movement during the phase of rapid ventricular filling, corresponding to the expected timing of the third heart sound, appeared of particular interest.

Conclusion:

The technique has allowed visualization of new details of LV radial wall motion. In particular, higher peak systolic radial velocities of anterior and inferior segments are suggestive of a relatively higher dynamics of anteroposterior vs lateral radial motion in systole. Specific patterns of radial motion of other LV segments may provide additional insights into LV mechanics.

Advances in knowledge:

The outward radial movement of LV segments impacted by the blood flow during rapid ventricular filling provides a potential substrate for the third heart sound. A biphasic radial expansion of the basal anteroseptal segment in early diastole is likely to be related to the simultaneous longitudinal LV displacement by the stretched great vessels following repolarization and their close apposition to this segment.Advances in cardiac imaging techniques have allowed evaluation of new details of the complex pattern of left ventricular (LV) motion. Using high temporal resolution cardiovascular MR with myocardial velocity-encoding techniques, we previously performed a detailed analysis of rotational and longitudinal motions of the left ventricle, correlating them with the orientation or cardiomyocyte aggregates within the LV wall.^1,2 However, accurate evaluation of radial motion is equally important. For example, radial wall motion abnormalities have been detected in patients with diabetes³ and hypertrophic cardiomyopathy,⁴ whereas radial dyssynchrony is almost universal in patients with heart failure.⁵ The purpose of this study was to obtain new details of global and regional radial wall motion of the left ventricle using the cardiac MR high temporal resolution myocardial velocity-encoding technique.^6,7 Considering recent interest in myocardial multilayer measurements, which provide more layer-specific information about the functional state of the myocardium at different levels,^8–13 separate calculations of all myocardial velocities and their corresponding peak times for the inner (endocardial), middle (transmural) and outer (epicardial) layers of the LV wall were performed.     

Multiphasic cardiac magnetic resonance imaging: normal regional left ventricular wall thickening

Magnetic resonance imaging (MRI) is a completely noninvasive method for visualizing cardiovascular anatomy but has had limited use for assessment of cardiac function. The authors evaluated the use of gated MRI for the quantification of regional myocardial contraction. Nine normal subjects underwent gated MRI of five transverse sections (7 mm thickness) through the left ventricle at five intervals in the cardiac cycle using a new technique called rotating gated sequence. All five sections were examined, and the section that best demonstrated the midportion of the left ventricle in its maximum dimension was used to obtain measurement. This technique permitted assessment of regional wall thickening of various regions of the left ventricle in different phases of the cardiac cycle. The extent and percentage of wall thickening were calculated from measurements of the septum and anterior and lateral left ventricular wall in end-diastole and end-systole. The calculated mean values for extent and percentage of wall thickening for the septum were 0.40 cm and 40%; for the anterior wall, 0.61 cm and 73%; and for the lateral wall, 0.53 cm and 57%, respectively. A limitation of the current technique in wall thickness measurements is that the transverse MR plane of section is not perpendicular to the long axis of the left ventricle. Consequently, such oblique sections through the left ventricle may give inaccurate absolute wall thickness measurements but can provide reliable estimate of regional wall thickening dynamics. The ability to define left ventricular wall thickness and function without contrast media provides a noninvasive technique for the detection of segmental left ventricular myocardial dysfunction in ischemic heart disease.     

Effects of ventricular insertion sites on rotational motion of left ventricular segments studied by cardiac MR

Objective:

Obtaining new details for rotational motion of left ventricular (LV) segments using velocity encoding cardiac MR and correlating the regional motion patterns to LV insertion sites.

Methods:

Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Peak rotational velocities and circumferential velocity curves were obtained for 16 ventricular segments.

Results:

Reduced peak clockwise velocities of anteroseptal segments (i.e. Segments 2 and 8) and peak counterclockwise velocities of inferoseptal segments (i.e. Segments 3 and 9) were the most prominent findings. The observations can be attributed to the LV insertion sites into the right ventricle, limiting the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments as viewed from the apex. Relatively lower clockwise velocities of Segment 5 and counterclockwise velocities of Segment 6 were also noted, suggesting a cardiac fixation point between these two segments, which is in close proximity to the lateral LV wall.

Conclusion:

Apart from showing different rotational patterns of LV base, mid ventricle and apex, the study showed significant differences in the rotational velocities of individual LV segments. Correlating regional wall motion with known orientation of myocardial aggregates has also provided new insights into the mechanisms of LV rotational motions during a cardiac cycle.

Advances in knowledge:

LV insertion into the right ventricle limits the clockwise rotation of anteroseptal LV segments and the counterclockwise rotation of inferoseptal segments adjacent to the ventricular insertion sites. The pattern should be differentiated from wall motion abnormalities in cardiac pathology.Assessment of regional rotation patterns of the left ventricular (LV) wall improves the understanding of the systolic and diastolic ventricular function [1]. Cardiac echocardiography with speckle tracking performed in healthy individuals demonstrated large regional differences in the rotation of individual LV segments. For example, significant rotational differences of inferoseptal segments compared with anterolateral segments were reported at the LV base and papillary level [1]. Small regional differences were also recorded at the apical level [1]. Recent developments in cardiac imaging techniques have helped in assessing rotational patterns of LV segments in patients with cardiac pathology. Thus, patients with an atrial septal defect and pulmonary hypertension demonstrated higher average counterclockwise peak rotation of basal LV segments, lower peak rotations of posterior, inferior and posteroseptal walls at the LV base and delayed average interval time of rotational motion [2]. In patients with hypertrophic cardiomyopathy, a reduced cardiac rotation of the posterior region and a reduced radial displacement of the inferior septal zone were recorded [3]. In dog models, occlusion of left anterior descending or left circumflex arteries had a pronounced effect on apex rotation [4]. Under controlled pre-ischaemic conditions, a linear relationship between the apex rotation and the segment length was recorded during ejection and a different steeper relationship during the isovolumic relaxation. In regionally ischaemic segments, this relationship became non-linear for both ejection and isovolumic relaxation [4]. Because the affected myocardial segments may vary depending on the occluded coronary vessel, knowledge about the normal pattern of rotational motion of individual segments becomes increasingly important.The cause of regional differences in rotational pattern of ventricular segments is likely to be multifactorial and determined by regional ventricular anatomy and dynamics. For example, in a study assessing regional rotational patterns of individual LV segments using speckle tracking echocardiography, Gustafsson et al [1] reported that the diastolic untwist matches the phases of both the E-wave and the A-wave and seems to be related to the intraventricular pressure differences. We hypothesise that the insertion sites of the left ventricle and the cardiac fixation points tethering the heart to the mediastinum in close proximity with the left ventricle may particularly influence the rotational pattern of adjacent LV segments. In the present study, we aimed to correlate the potential differences in rotational velocities of individual LV segments with ventricular insertion sites or major heart vessels located in close proximity with the left ventricle. Considering recent interest in myocardial multilayer measurements, which provide more layer-specific information about the functional state of myocardium at different levels [5–10], separate measurements of rotational myocardial velocities for the inner (endocardial), middle (transmural) and outer (epicardial) layers of the LV wall were performed for 16 ventricular segments.     

Cardiac tissue Doppler in steroid users

Anabolic steroids cause a variety of side effects, among them a slight concentric left ventricular hypertrophy. The objective of the present study was to clarify if they also induce alterations in left ventricular function. 14 male body builders with substantial intake of anabolic steroids (users) were examined by standard echocardiography and cardiac tissue Doppler imaging. They were compared to 11 steroid-free strength athletes (non-users) and 15 sedentary control subjects. Users showed an increased left ventricular muscle mass index. The ratio of peak transmitral blood flow velocities during early diastolic filling and atrial contraction did not differ between groups (users: 1.4 +/- 0.3; non-users: 1.7 +/- 0.5; controls: 1.4 +/- 0.4). In contrast an analogous tissue Doppler parameter, the ratio of myocardial velocities during early and late ventricular filling in the basal septum, was significantly lower in users (1.2 +/- 0.4) when compared to non-users (1.6 +/- 0.5) or controls (1.6 +/- 0.6). The velocity gradient during myocardial E-wave in the posterior wall showed significantly lower values in users (3.8 +/- 1.3 1/s) as compared to controls (5.8 +/- 2.5 1/s). There were no differences in systolic function. Summarizing strength athletes abusing anabolic steroids show negative alterations in diastolic function.     

Left ventricular function evaluation using radionuclide methods in the intensive coronary care unit

We describe an adapted first-transit (FT) technique to perform left ventricular ejection fraction (LVEF) measurements on patients with Swan-Ganz catheters in the intensive cardiac care unit (ICCU). The radionuclide is introduced directly into the right pulmonary artery through the catheter. High-quality images of the left ventricle are obtained owing to minimal activity in the right ventricle and left lung. LVEF measurements obtained by FT compared well with measurements obtained from gated blood pool studies (r = 0.91) but gave consistently lower values. The adapted FT method improves LVEF determination and left-ventricular wall motion evaluation in the ICCU patient.     

MR黑血和白血技术诊断肥厚型心肌病的价值

目的：研究MR黑血和白血技术在诊断肥厚型心肌病中的价值。方法：采用心脏MR黑血和白血技术及多平面成像方式，对15例临床拟诊为肥厚型心肌病的患者进行检查。结果：MR黑白技术提供病变部位、厚度、信号、心腔形态、大小等信号。白血技术能反映心肌的运动，流出道有无狭窄及程度，二尖瓣有无返流等情况。多平面成像更全面了解病变的部位和范围，避免漏诊。MR的基本特征有室壁肥厚、心肌信号不均匀、左心室流出道狭窄、心肌运动不均匀、二尖瓣少量返流和心包积液等。结论：MR黑白和白血技术对肥厚型心肌病的诊断能提供更为准确、全面的影像学信息。     

三平面组织同步成像定量评价冠心病患者左心室节段非同步运动

目的 探讨三平面组织同步成像技术定量评价冠心病患者左心室节段收缩非同步性运动及其与左心室收缩功能的关系.资料与方法 34例冠心病患者和35例正常对照者,应用三平面组织同步成像技术获得心尖四腔切面组织速度图,获取左心室6个壁共12个节段的收缩期达峰时间(Tp)、达峰速度(Vp),并计算Tp、Vp的标准差(Tp-SD、Vp-SD)及12个节段中任意2个节段Tp、Vp的最大差值( Tp-maxD、Vp-maxD).同时采用Simpson双平面法测量左室射血分数(LVEF)、左室舒张末期容积(LVESV)、左室收缩末期容积(LVEDV).结果 冠心病组LVEDV、LVESV较正常对照组增加,LVEF较正常对照组减小,差异均有统计学意义(P＜ 0.001).与正常对照组相比,冠心病组Tp、Tp-SD、Tp-maxD均明显延迟,Vp、Vp-SD、Vp-maxD均明显降低(P＜0.001);Tp与LVEF呈负相关(r=-0.559,P＜0.001);Vp与LVEF呈正相关(r=0.801,P＜ 0.001).结论 三平面组织同步成像可用于定量评价冠心病患者左心室非同步运动,Tp、Tp-SD、Tp-maxD、Vp、Vp-SD、Vp-maxD 可作为定量评价左室收缩运动同步性的有效指标,且左室运动同步性异常加重左室收缩功能异常.     

心腔内超声评价心脏结构和左室收缩功能的实验研究

目的:研究心腔内超声探查心脏结构和评价左室收缩功能的方法。方法:AcuNav心腔内超声导管置于健康犬右房、右室,二维图像显示左右心腔、心瓣膜、肺静脉、冠状动脉、主动脉、肺动脉等结构,彩色及频谱多普勒记录血流状况。开胸制作犬急性心肌缺血再灌注模型,观察室壁运动和左室射血分数改变。结果:所有目标结构及血流均获得清晰显示,未发生导管相关的严重并发症。心腔内超声示心肌缺血再灌注过程中前壁厚度、增厚率、左室射血分数动态改变。结论:心腔内超声可安全、清晰地显示心脏结构和血流状态,并评价左室收缩功能。     

Gated MR imaging of the heart: intracardiac signals in patients and healthy subjects

The appearance of intraluminal signal in the cardiac chambers, the descending aorta, and blood vessels was studied in healthy subjects and patients with myocardial disease on first and second spin-echo gated magnetic resonance images. Signal was present in the cardiac chambers and the aorta at various phases of the cardiac cycle when physiological or pathological slow flow conditions are expected in healthy subjects and in patients. Healthy individuals tended to show signal in the ventricles and aorta during end-diastole, and signal was less likely to be present at higher heart rates and in systolic images. In patients with regional or global left ventricular dysfunction, intraventricular signal tended to persist into systole. Surprisingly, intraventricular signal was not present with increased frequency adjacent to infarcted regions of the myocardial wall. Thus, the mere presence of intracavitary signal cannot be used as an indicator of either regional or global cardiac contraction abnormalities. In the left atrium, signal was often present during systole. Physical factors determining the appearance of signal of flowing blood are discussed in an Appendix.     

射频导管消融犬左束支电位对心脏电机械活动的影响

目的 探讨射频导管消融犬左束支电位(LBP)对心脏传导及心功能的影响,以及犬左束支传导阻滞(LBBB)模型的制备方法.方法 应用射频消融导管在10只实验犬左心室内膜标测到LBP处进行消融,观察能否成功制备犬LBBB模型以及其对心脏传导的影响.对成功复制LBBB的模型犬应用超声心动图比较LBBB前后心脏收缩功能及舒张功能的变化.结果 10只犬接受LBP处消融后,8只(80％)成功制备LBBB模型.消融靶点处心房与心室电压比值＜1:10,局部记录的LBP至心室电位间期为17.1±3.2(12～22)ms,消融后QRS波宽度由52.8±4.8ms增至100.5±11.1ms(P＜0.001),而PR间期、AH间期、HV间期无明显变化.另外2只犬在LBP至心室电位间期分别为30ms、32ms处消融,导致完全性房室传导阻滞.8只犬发生LBBB后超声心动图检查示:收缩功能指标左室射血分数和主动脉血流速度积分降低(P＜0.05);舒张功能指标E/A下降为＜1,伴有等容舒张时间和二尖瓣减速时间延长(P＜0.05);出现显著室间与室内不同步,表现为间隔后壁运动延迟及左右心室射血前期时间差明显延长(P＜0.001).结论 射频导管消融左束支电位可导致LBBB,是制备犬LBBB模型成功率较高的方法,但有发生完全性房室传导阻滞的危险.LBBB即刻可导致左室激动延迟,左右室间及左室内收缩不同步,左心室收缩及舒张功能降低.     

Fetal echocardiography during the 2nd half of pregnancy. Biometry and functional approach

Fetal cardiac biometry was conducted in the TM mode, after real time anatomical outlining of the plane of the four cardiac cavities, on 48 recordings of supposedly normal pregnancies of 23 to 39 weeks of amenorrhoea. Ten measurements were made for each patient, in an immediately subvalvular plane perpendicular to the septum (dimensions of the two ventricular cavities, of the wall of the two ventricles, and of the septum, in diastole and systole respectively). Functional results derived from this data showed that the difference between diastolic and systolic values for ventricular diameters increased with term, the ratio of the diastolic diameter of the right ventricle (RV) to that of the left ventricle (LV) was a constant: 1.23 +/- 0.12, and the size of the RV was always superior to that of the LV (+ + +). Alson noted was that percentage shortening of the LV was superior to that of the RV, and mean percentage thickenings of the RV and septum were inferior to that of the LV. A further observation was that interpretation of the kinetic of the septum requires precise knowledge of the plane of the section in relation to "the pivot point".     

Normal flow patterns of intracranial and spinal cerebrospinal fluid defined with phase-contrast cine MR imaging

A phase-contrast cine magnetic resonance (MR) imaging technique was used to study normal dynamics of cerebrospinal fluid (CSF) in 10 healthy volunteers and four patients with normal MR images. This pulse sequence yielded 16 quantitative flow-encoded images per cardiac cycle (peripheral gating). Flow encoding depicted craniocaudal flow as high signal intensity and caudo-cranial flow as low signal intensity. Sagittal and axial images of the head, cervical spine, and lumbar spine were obtained, and strategic sites were analyzed for quantitative CSF flow. The onset of CSF systole in the subarachnoid space was synchronous with the onset of systole in the carotid artery. CSF systole and diastole at the foramen of Monro and aqueduct were essentially simultaneous. The systolic and diastolic components were different in the subarachnoid space, where systole occupied approximately 40% and diastole 60% of the cardiac cycle, compared with the ventricular system, where they were equal. This difference results in systole in the intracranial and spinal subarachnoid spaces preceding that in the ventricular system; the same is true for diastole. The fourth ventricle and cisterna magna serve as mixing chambers. The high-velocity flow in the cervical spine and essentially no flow in the distal lumbar sac indicate that a portion of the capacitance necessary in this essentially closed system resides in the distal spinal canal.