心梗部位对超声多普勒左室舒张功能测定的影响

目的 :观察心梗患者缺血部位不同对常规超声多普勒左室舒张功能检测指标的影响。资料与方法 :以核素心肌扫描显像为定位标准 ,将 84例急性、陈旧性心肌梗塞患者按缺血部位不同分成 :(1)前壁心梗 ,(2 )间壁心梗 ,(3 )下 (后 )壁心梗 ,(4 )侧壁心梗 ,(5 )广泛前壁 ,(6)前壁伴下壁及侧壁心梗 ,(7)心尖部室壁瘤形成 7组 ;观察了描述左室舒张功能的超声多普勒二尖瓣口血流速度指标 E/A比值和核素心血池造影左室峰值充盈率 LVPFR在各分组中的变化。结果 :缺血范围较局限的左室前壁、间壁及侧壁心梗组之间的 L VPFR测值无明显差别 ,分别为 (1.82± 0 .48)、(2 .0 7± 0 .79)、(2 .18± 0 .90 ) EDV/S,但多明显高于下 (后 )壁、广泛前壁、室壁瘤及左室壁多个部位缺血组 ,其 LVPFR分别为 (1.63± 0 .3 3 )、(1.2 2± 0 .68)、(1.45± 0 .43 )、(1.15± 0 .3 8) EDV/S,而后 4组之间的 L VPFR测值差别不显著 ;单有左室前壁、间壁缺血的心梗组的 E/A比值也高于左室下 (后 )壁、广泛前壁、多部位心肌缺血的心梗组 ,其 E/A比值分别为 1.17± 0 .3 1、1.0 9±0 .2 6、0 .78± 0 .2 8、0 .80± 0 .5 1、0 .81± 0 .3 1;除下 (后 )壁心梗组外 ,其它各组的 E/A比值与室壁瘤形成组差别不显著 ,后者的 E/A比值为 1.0 2± 0 .     

双室再同步起搏治疗充血性心功能衰竭近期疗效

目的　本研究旨在观察双室再同步起搏治疗严重的充血性心功能衰竭疗效。方法　 2 0 0 1年 4月～ 2 0 0 2年 11月在我科住院患者 10例 ,男 8例 ,女 2例 ,年龄 4 2～ 74岁 ,其中缺血性心肌病 5例 ,扩张型心肌病 4例 ,酒精性心肌病 1例。心功能NYHA分级 :Ⅲ级 5例 ,Ⅳ级 5例。病史超过半年 ,均用多种抗心衰药物治疗效果不佳。所有患者超声心动图示左室舒张末期内径 >6 0mm ,左室射血分数 <0 .4 ,并伴有轻中度二尖瓣返流 ,QRS波≥ 130ms 9例 ,QRS波等于 12 0ms 1例。植入InSync(80 4 0型 )三腔 (右房、右室、左室 )起搏器 ,左室起搏导线通常放置在心侧静脉和后侧静脉 ,均达到最满意的起搏参数。根据Ritter公式放置最佳房室传导间期 ,以保证最大舒张期充盈。结果　所有患者均成功植入起搏器 ,9例患者接受起搏治疗后 3个月随访 ,1例缺血性心肌病患者手术后 1个月死于肾功能衰竭。 9例患者临床评估结果为 :心功能术前 3.4± 0 .5级 ,术后 3个月为 1.5± 0 .7级 (P <0 .0 1)。心衰症状得分术前为 8.11± 3.2 9,术后为 1.4 4± 1.74(P <0 .0 1) ,ECG示QRS波术前为 (172± 32 )ms ,术后为 (14 9± 2 3)ms(P >0 .0 5 )。超声心动图检查左室舒张末期直径术前 6 7± 6 .7mm ,术后为 (6 3± 6 )mm (P <0 .0 5 ) ,左室     

前负荷改变对二尖瓣环DTI频谱波形的影响对肾透析患者的观察

目的　了解前负荷变化对多普勒组织成像二尖瓣环运动速度波形测量的影响。方法　利用多普勒 组织成像对21例肾透析患者透析前后二尖瓣环间隔、侧壁、前壁、下壁、前间隔、后壁6个位点的运动速度波 形进行了测量。结果　与透析前比较,透析后21例患者的血压、左室内径、左室容量、左室射血分数值及左心 排血量均无明显改变,但患者的体重多有减轻[(59.34±11.08)/(56.00±9.77)kg,P<0.05],心率加快 [(78.95±14.36)/(84.33±10.26)bpm,P<0.05];反映左室舒张功能的二尖瓣口血流波形指标减低 [(1.08±0.63)/(0.88±0.59),P<0.05],其中二尖瓣口舒张早期血流峰值减低明显[(81.71±24.94)/ (70.25±18.77)cm/s,P<0.05]、二尖瓣口舒张晚期(房缩期)血流峰值变化不大[(76.95±23.18)/(79.19± 14.83)cm/s,P>0.05];二尖瓣环处平均e波波幅减低[(7.05±3.23)/(6.12±3.01)cm/s]、平均a波变化 甚小[(8.68±4.55)/(8.83±2.67)cm/s,P>0.05]、平均e/a比值减小[(0.86±0.46)/(0.75±0.54),P< 0.05);二尖瓣环处平均s波没有明显改变[(7.01±4.76)/(6.95±3.81)cm/s,P>0.05]。结论　由于透析 并不能显著改善肾功能不全患者的心肌收缩与舒张状况,考虑到心率、前负荷变化所带来的测量影响,肾功能     

介入超声印压系统对活体舒张心肌黏弹性的检测作用

目的 探讨介入超声印压系统(IUIS)对活体心脏舒张期舒张心肌黏弹性的检测作用.方法 应用IUIS以印压法对陈旧性心肌梗死模型组(OMI组,n=8)和假手术组(n=8)犬在舒张期进行印压蠕变实验,以三参量固体黏弹性模型拟合实验数据,提取舒张心肌瞬时弹性模量(E1)、松弛模量(E∞)、蠕变弹性模量(E2)、黏性阻尼系数(η)等黏弹性参数,并进行比较.结果 OMI组E1、E∞、E2、η参数(分别为27.81±6.74kPa、17.87±3.59kPa、49.54±14.35kPa、1.97±0.78Pa.s)与假手术组(分别为6.78±2.43kPa、4.52±1.56kPa、16.82±12.37kPa、0.66±0.40Pa.s)比较均明显增加,差异有统计学意义(P<0.05).结论 IUIS系统及其印压蠕变实验方法 可用于活体舒张心肌黏弹性的评估.三参量固体黏弹性模型可用于描述舒张心肌蠕变特性.梗死心肌弹性模量和黏性阻力增加.     

DTI检测缺血心肌左室舒张功能损伤特征的研究

目的　利用DTI技术研究缺血心肌左室舒张功能损伤特征。方法　对 2 4例疑似冠心病患者进行冠脉造影 ,在造影前后同步检测左室压力和左室后壁心肌舒张期运动速度的变化。结果　心肌缺血后左室舒张最低压显著升高 (P <0 0 5 ) ,而左室?p/dt、LVEDP和T常数无明显变化 ;心肌缺血后舒张早期左室后壁心肌运动速度明显下降 (P <0 0 1) ,晚期运动速度无明显变化 ;心肌缺血时左室后壁心肌舒张早期心内膜运动速度显著下降(P <0 0 1) ,心内 外膜速度梯度负值增大 (P <0 0 1)。结论　心内膜对缺血最敏感 ,缺血首先使舒张期心内膜运动速度下降 ,导致舒张早期室壁运动减弱 ,舒张功能异常。     

超声心动图对慢性心衰患者心室再同步化的评价

研究目的　通过超声心动图来评价表示心室内及心室间同步化的参数 ,探讨在慢性心衰合并左束支传导阻滞的患者中 ,何种情况得益于双心室再同步起搏 (CRT)最多。背景资料　双心室再同步起搏已成为治疗慢性顽固性心衰的有效方法之一 ,但其疗效的原因是多因素的 ,目前还没有一个统一的标准用来评价何种情况得益于CRT最多。研究方法　研究对象包括 8例 (男 4例 ,女 4例 ,平均年龄 6 8岁 )顽固性心衰患者 (3例为扩张性心肌病 ,5例为缺血性心肌病 ) ,均合并左束支传导阻滞 (QRS时限≥ 14 0ms ,房室传导时间平均为 2 0 1ms) ,采用多普勒超声心动图测量表示心室内及心室间机械活动不同步的参数。在CRT前及术后 1个月之内分别测量左室舒张末期容积指数 (LVEDVI)和左室收缩末期容积指数 (LVESVI) ,患者的LVESVI下降至少在 15 %以上 ,方可认为有效。结果　双心室再同步起搏治疗明显降低左室的容积(LVEDVI从 (15 0± 5 3)ml/m2 下降至 (119± 37)ml/m2 ,P <0 .0 0 0 1;LVESVI从 (116± 4 3)ml/m2 下降至 (85± 2 9)ml/m2 ,P <0 .0 0 0 1)。同时 ,在有效组 ,其CRT前患者的室间隔与左室后壁收缩运动延迟时间 (SP WMD)明显延长 ;在所以的表示左室内不同步的参数中 ,只有QRS时限及SPWMD与LVESVI的下降显著相关 (相关系数     

缺氧对大鼠心肌细胞钙通道的影响

目的 :研究缺氧对急性分离的大鼠心肌细胞L型钙通道电活动的影响 ;方法 :运用膜片钳技术的细胞吸附式方式记录心肌细胞L型钙通道的单通道电流 ;结果 :缺氧后 ,心肌细胞L型钙通道平均开放时间由 ( 2 .5 1± 1 .3 8)ms增加到 ( 6.42± 1 .97)ms,平均关闭时间由 ( 42 .83± 1 0 .92 )ms减为 ( 3 0 .3 4± 5 .1 1ms) ;平均开放概率由 0 .0 5 4± 0 .0 1 8变为 0 .2 2 1± 0 .0 2 7;结论 :缺氧后心肌细胞L型钙通道开放时间延长 ,开放概率增大 ,Ca2 +大量内流引起细胞内钙超载也将成为心肌缺氧损伤的机制之一     

正常中脑导水管脑脊液流动磁共振定量研究

目的 :运用磁共振相位对比电影法非侵袭性测量中脑导水管脑脊液流动方向、流速及流量改变情况。方法 :测量 15例正常志愿者 (年龄 2 1～ 4 7岁 ,平均 31 4岁 )中脑导水管脑脊液流动情况 ,在正中矢状位T1WI图像上选择垂直于导水管层面 ,编码速率 2 0cm/s。测量相应层面导水管截面积 ,计算相应导水管区脑脊液流量 ,并研究在一个心动周期内CSF流动改变情况。结果 :正常中脑导水管脑脊液流动在一个心动周期内表现为双向流动 ,即收缩期向下流动和舒张期向上流动 ,收缩期平均向下峰流速和舒张期平均向上峰流速分别为 12 6 7± 3 5 8mm/s和 11 5 8± 3 96mm/s,平均向下及向上流量分别为 1 311± 0 74 0ml/min(0 0 18± 0 0 12ml/心动周期 )和 1 0 6 8± 0 5 6 8ml/min(0 0 14± 0 0 0 9ml/心动周期 ) ,平均净流量为 0 2 6 0± 0 2 4 9ml/min(0 0 0 4± 0 0 0 4ml/心动周期 ) ;脑脊液向下流动平均最大峰速发生在一个心动周期的R波后平均 18%时间点 (心动周期的 5 7ms,平均心动周期 85 7ms) ,向上最大峰流速出现在心动周期的 87%时间点 (心动周期的6 86ms,平均心动周期 85 7ms) ,而逆向流动发生在R波后平均 4 4 %～ 5 8%时间点 (心动周期的 343～ 4 5 7ms,平均心动周期85 7ms)。结论 :磁共振相位对比     

卡维地洛治疗扩张型心肌病心力衰竭的疗效观察

目的　观察卡维地洛对扩张型心肌病 (DCM)心力衰竭 (CHF)的临床疗效。方法　 6 0例DCM并心力衰竭患者在利尿剂、洋地黄、ACEI及硝酸盐制剂治疗的基础上 ,随机分为卡维地洛治疗组及常规治疗组 (每组 30例 )。治疗前及 4月启用超声心动图测左室缩短分数 (FS) ,射血分数 (EF)、左室舒张末内径 (LVDD)、室间隔厚度 (IVS)和左室后壁厚度 (LVPW)。结果　治疗 4月后 ,两组心功能明显改善。卡维地洛组LVDD[6 1.5± 6 .6与 6 7.3± 6 .2 ,P <0 .0 5 ]、EF[4 8± 9.7与 4 0 .3± 6 .2 ,P <0 .0 5 ]、D/T[4 .1± 0 .7与 4 .6± 0 .5 ,P <0 .0 5 ]显著改善。结论　卡维地洛能显著改善DCM心力衰竭心功能及心肌重构     

海洛因海绵状白质脑病影像学对比分析

目的　对海洛因海绵状白质脑病患者的MRI、CT、单光子发射计算机体层摄影术 (singlephotonemissioncomputerizedtomography ,SPECT)脑显像与经颅多普勒超声 (transcranialDopplersonography,TCD)表现进行对比分析。方法　共观察 1 7例海洛因海绵状白质脑病患者 ,其中对 1 2例患者单行颅脑MRI ,2例单行CT ,3例同时行MRI和CT检查 ;9例行SPECT检查 ;1 1例行TCD检查 ,并设TCD对照组。结果　MRI或CT :全部患者幕上半球脑白质、小脑半球、内囊后肢及膝部、胼胝体压部及膝部 ,部分患者中脑、桥脑见双侧、对称性异常改变。 5例CT表现为上述白质区对称性低密度 ;1 5例MRI均表现为T1 WI呈低信号 ,T2 WI及水抑制成像呈高信号。SPECT :以白质为主的放射性稀疏或缺损 ,脑白质区扩大 ;灰质区亦存在不同程度的多发低供血灶 :颞叶 9例 ;顶叶 7例 ;小脑 7例 ;基底神经核 5例 ;枕叶 4例。TCD :收缩峰变尖 ,脑前循环与后循环舒张期血流速度 [分别为 (35 0± 9 7)cm/s,(2 3 4±5 2 )cm/s]均较对照组 [分别为 (43 2± 7 5)cm/s,(2 7 6± 5 0 )cm/s]显著降低 (P <0 0 1 ) ;脉动指数(分别为 1 0 4 0± 0 2 30 ,1 0 63± 0 331 )较对照组 (分别为 0 751± 0 0 92 ,0 70 8± 0 1 0 3)明显增高 (P <0 0 1 )。结论　CT或M     

Flow profiles in the left anterior descending and the right coronary artery assessed by MR velocity quantification: effects of through-plane and in-plane motion of the heart.

PURPOSE: The purpose of this work was to compare the temporal profiles of volume flow in the left anterior descending artery (LAD) and the right coronary artery (RCA) and to assess the effect of through-plane and in-plane myocardial motion. METHOD: In eight healthy volunteers, MR phase-difference velocity quantification was applied with prospective ECG triggering, pixel size of 1.16 x 0.98 mm2 (LAD) or 1.25 x 0.98 mm2 (RCA), velocity sensitivity of 40 cm/s, and data acquisition time window of 64 ms for LAD (3 ky lines per heartbeat) and 24 ms for RCA. In-plane motion was measured from the magnitude images. RESULTS: In the LAD, systolic peak and mean flow values were 0.94+/-0.28 and 0.30 +/-0.22 ml/s, respectively. Diastolic peak and mean flows were 2.42+/-0.56 and 1.38+/-0.43 ml/s. The systolic to diastolic ratio was 0.37+/-0.12 for peak flow and 0.22+/-0.15 for mean flow. Mean flow through the cardiac cycle was 59.1+/-15.0 ml/min. In the RCA, systolic peak and mean flow values were 1.96+/-0.69 and 0.74+/-0.31 ml/s, respectively. Diastolic peak and mean flows were 1.80+/-0.53 and 0.83+/-0.20 ml/s. The systolic to diastolic ratio was 0.97+/-0.58 for peak flow and 0.85+/-0.39 for mean flow. Mean flow through the cardiac cycle was 38.4+/-10.8 ml/min. The in-plane velocity of the coronary artery cross-section was 6.4+/-1.8 cm/s for the LAD and 14.9 +/-4.0 cm/s for the RCA (given by peak values in diastole). CONCLUSION: It is confirmed noninvasively with MR that the LAD shows a predominantly diastolic flow, whereas the RCA shows about equal flow values in systole and diastole. Through-plane motion correction is required for assessing the true flow patterns. The in-plane velocities of the coronary artery cross-sections imply a maximum data acquisition time window, estimated at 58 ms for the LAD and at 23 ms for the RCA.     

Echocardiographic evaluation of left ventricular diastolic function in patients with aortic valve stenosis

Impairment of left ventricular diastolic function in aortic valve stenosis occurs very early and precedes the impairment of systolic function. Aim was to examine left ventricular diastolic function and its association with severity of myocardial hypertrophy and clinical picture. The paper comprised 78 patients with isolated aortic valve stenosis in whom were performed ultrasonography and catheterization. No significant differences in parameters of diastolic filling were observed in patients with mild hypertrophy and preserved systolic function compared to healthy subjects. In patients with moderate myocardial hypertrophy, left ventricular filling was decreased in an early diastole (Emax 51 +/- 5 cm/s, Evti 6.4 +/- 1.1 cm) and increased in late diastole (Amax 88 +/- 11 cm/s, Avti 11.4 +/- 1.8 cm), while deceleration time was prolonged (DT 171 +/- 32 ms). Pulmonary vein flow was decreased during diastole (Dmax 33 +/- 5 cm/s, Dvti 7.6 +/- 2 cm). Pseudonormalization of flow through mitral valve was observed in patients with pronounced hypertrophy of left ventricular wall (mass > 180 g/m2): increase of the velocity during the phase of fast left ventricular filling (Emax 72 +/- 13 cm/s, Evti 9.8 +/- 2.1 cm), decrease during atrial contraction (Amax 31 +/- 6 cm/s, Avti 3.7 +/- 0.4 cm), reduction in deceleration time (DT 116 +/- 11 ms), while pulmonary vein flow velocity was increased during the early diastole (Dmax 64 +/- 17 cm/s, Dvti 10.7 +/- 2.2 cm). Likewise, significant correlation between clinical picture and type of blood flow through mitral valve was observed.     

MR phase-shift velocity mapping of mitral and pulmonary venous flow

Mitral and pulmonary venous flows are important indexes in the evaluation of left ventricular diastolic function and in the assessment of mitral valve disease. We used MR phase-shift velocity mapping to measure mitral and pulmonary venous flow velocity in 10 healthy volunteers and mitral flow velocity in 5 patients with mitral valve stenosis. Normal mitral flow shows two positive peaks: one during early ventricular diastole and the other during atrial contraction. Peak mitral flow velocity (mean +/- SD) in early diastole was 68 +/- 12 cm/s and during atrial contraction 39 +/- 10 cm/s. The ratio of peak mitral flow velocity in early diastole to that during atrial contraction was 1.9 +/- 0.6. In patients with mitral valve stenosis, the initial high flow velocity persisted through diastole. Peak mitral flow velocity of patients with mitral valve stenosis correlated well with values obtained from Doppler echocardiography. Pulmonary venous flow showed two positive peaks: one during ventricular systole and the other in ventricular diastole. A small backflow during atrial contraction was noticed. Peak systolic velocity in the right lower pulmonary vein was 47 +/- 11 cm/s, peak diastolic velocity was 40 +/- 9 cm/s, and peak backflow velocity was 14 +/- 3 cm/s. Magnetic resonance velocity mapping is a noninvasive technique for the evaluation of time-related flow velocity patterns and for quantitative measurement of mitral and pulmonary venous blood flow velocity.     

Simultaneous measurement of blood and myocardial velocity in the rat heart by phase contrast MRI using sparse q-space sampling

PURPOSE: To measure cardiac blood flow patterns and ventricular wall velocities through the cardiac cycle in anesthetized Wistar Kyoto (WKY) rats. MATERIALS AND METHODS: A gradient-echo cine pulse sequence incorporating pulsed field gradients (PFGs) provided phase contrast (PC) motion encoding. We achieved a range of velocity sensitivity that was sufficient to measure simultaneously the large flow velocities within the cardiac chambers and aortic outflow tract (up to 70 cm s(-1) during systole), and the comparatively small velocities of the cardiac wall (0-3 cm s(-1)). A scheme of sparsely sampling q-space combined with a probability-based method of velocity calculation permitted such measurements along three orthogonal axes, and yielded velocity vector maps in all four chambers of the heart and the aorta, in both longitudinal and transverse sections, for up to 12 time-points in the cardiac cycle. RESULTS: Left ventricular systole was associated with a symmetrical laminar flow pattern along the cardiac axis, with no appearance of turbulence. In contrast, blood showed a swirling motion within the right ventricle (RV) in the region of the pulmonary outflow tract. During left ventricular diastole a plume of blood entered the left ventricle (LV) from the left atrium. The ventricular flow patterns could also be correlated with measurements of left ventricular wall motion. The greatest velocities of the ventricular walls occurred in the transverse cardiac plane and were maximal during diastolic refilling. The cardiac wall motion in the longitudinal axis demonstrated a caudal-apical movement that may also contribute to diastolic refilling. CONCLUSION: The successful measurements of blood and myocardial velocity during normal myocardial function may be extended to quantify pathological cardiac changes in animal models of human cardiac disease.     

In vivo quantitative three-dimensional motion mapping of the murine myocardium with PC-MRI at 17.6 T.

This work presents a method that allows for the assessment of 3D murine myocardial motion in vivo at microscopic resolution. Phase-contrast (PC) magnetic resonance imaging (MRI) at 17.6 T was applied to map myocardial motion in healthy mice along three gradient directions. High-resolution velocity maps were acquired at three different levels in the murine myocardium with an in-plane resolution of 98 mum, a slice thickness of 0.6 mm, and a temporal resolution of 6 ms. The applied PC-MRI method was validated with phantom experiments that confirmed the correctness of the method with deviations of <1.7%. Myocardial in-plane velocities between 0.5 cm/s and 2.2 cm/s were determined for the healthy murine myocardium. Through-plane velocities of 0.1-0.83 cm/s were measured. Velocity data was also used to calculate the myocardial twist angle during systole at different slices in the short-axis view.     

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.     

Segmental myocardial velocities in dilated cardiomyopathy with and without left bundle branch block

Purpose:

To quantify three‐directional left ventricular (LV) myocardial velocities and intraventricular synchrony in dilated cardiomyopathy (DCM) with and without left bundle branch block (LBBB) using MR tissue phase mapping (TPM).

Materials and Methods:

Regional velocities were assessed by TPM (spatial/temporal resolution = 1.3 × 1.3 mm² × 8 mm/14 ms) in DCM patients with (n = 12) and without LBBB (n = 7) compared with age‐matched volunteers (n = 20). For the evaluation the AHA 16‐segment and an extended LV visualization model was used.

Results:

Radial velocities in DCM patients were reduced in 75% (systole) and in 94% (diastole) (P = 0.0001 – P = 0.0360), long‐axis velocities in 31% (systole) and in 75% (diastole) of the 16 segments compared with controls (P = 0.0001 – P = 0.0310). LBBB resulted in inferolaterally delayed diastolic long‐axis velocities (P = 0.0012 – P = 0.0464) and shortened TTP for septal systolic radial velocities (P = 0.0002). Intra‐ventricular radial systolic TTP differed up to 150 ms between segments in patients with LBBB (89 ms without LBBB, 34 ms in volunteers) reflecting an increased dyssynchrony. LV twist was altered in all patients with reduced and delayed systolic and diastolic peak velocities.

Conclusion:

TPM identified previously not described alterations of the spatial distribution and timing of all myocardial velocities in patients with DCM and LBBB. This may help to optimize therapy management in future. J. Magn. Reson. Imaging 2013;37:119–126. © 2012 Wiley Periodicals, Inc.     

Aortic distensibility and left ventricular diastolic functions in endurance athletes

Aortic elastic properties are important determinants of left ventricular function. The aim of this study was to determine left ventricular diastolic function and aortic distensibility in endurance athletes. Thirty male runners and thirty age-matched healthy male controls took part in the study. All subjects underwent echocardiographic examination and cardiopulmonary exercise testing. Measurements included LV cavity dimension, standard and tissue Doppler parameters, and aortic diameter, 3 cm above aortic valve, at systole and diastole. Maximal oxygen uptake in athletes was higher than in controls. The aortic distensibility index was found to be higher in athletes compared with controls (5.37 +/- 1.50 vs. 3.37 +/- 1.48 cm (2) . dynes (-1) . 10 (-6), p < 0.001). While the aortic stiffness index in athletes was significantly lower than in controls (2.77 +/- 0.28 vs. 3.43 +/- 0.41, p < 0.001). Furthermore, transmitral early peak velocity (E) and late peak velocity (A), peak velocity of myocardial systolic wave (S (m)), early (E (m)) and atrial (A (m)) diastolic waves in athletes were higher than in controls. It seemed that the association of E (m) velocity with aortic distensibility was stronger than that of other LV parameters (coefficient = 0.74, p < 0.001) by using multiple linear regression. Increased aortic distensibility in endurance-trained athletes may cause better diastolic function as a physiological cardiovascular adaptation factor.     

Black-blood T2* technique for myocardial iron measurement in thalassemia

PURPOSE: To compare the effectiveness and reproducibility of a new black-blood sequence vs. a conventional bright-blood gradient-echo T2* sequence for myocardial iron overload measurement in thalassemia. MATERIALS AND METHODS: Twenty thalassemia patients were studied. Black-blood sequence images were acquired in diastole after a double inversion recovery (DIR) preparation pulse. Bright-blood sequence images were acquired in both early systole and late diastole. The data were randomized and the T2* analysis was performed blindly by two independent observers. RESULTS: The T2* values from the black-blood sequence were comparable to those of the conventional bright-blood sequence (25.7 +/- 12.9 msec vs. 26.4 +/- 14.2 msec in early systole, P = 0.44; and 25.2 +/- 13.1 msec in late diastole, P = 0.41). The coefficient of variation (CV) for black-blood image T2* analysis was 4.1% compared with 8.9% (early systole P = 0.03) and 7.8% (late diastole P = 0.05) for bright-blood image analysis. CONCLUSION: The black-blood T2* technique yields high-contrast myocardial images, provides clearly depicted myocardial borders, and avoids blood signal contamination of the myocardium while yielding improvements in interobserver variability.     

Elimination of errors caused by first-order aliasing in velocity encoded cine-MR measurements of postoperative jets after aortic coarctation: in vitro and in vivo validation

The aim of this study was to evaluate a velocity-encoded cine-MR (VEC-MR) sequence in measuring flow velocities up to two times the velocity encoding value (VENC) in a flow phantom and to validate the method for assessing poststenotic jet velocities in postoperative patients after aortic coarctation. In vitro, a flow phantom was used (0.5T; TR/TE: 51/8 ms, flip angle=30 degrees, FOV=280 mm, 128x256 matrix VENC 40 or 80 cm/s). On binary images, maximum flow velocities (V(max)) were calculated with a region of interest (ROI, 8 pixels). With aliasing, V(max) was calculated by VENC+(V(aliasing)). In vivo, 16 postoperative patients after aortic coarctation underwent double-oblique VEC-MR imaging through the aortic arch (ECG triggering, 16 phases/RR, TR=600-800 ms, flow-encoding cranio-caudal, VENC=2 m/s). Peak systolic velocities were measured and transthoracic Doppler echocardiography (TTDE) was performed. In vitro, there were excellent correlations for MR velocity measurements with and without aliasing ( r=0.99) and for true and MR-derived flow velocities ( r=0.99). In vivo, there was good correlation between VEC-MR and TTDE-assessed V(max) values in the aorta at the former coarctation site ( r=0.90, n=16). Aliasing occurred in 13 patients. VEC-MR is a useful modality for assessing jet velocities in the follow-up of patients after aortic coarctation. Despite of aliasing, accurate velocity measurements up to two times VENC are possible using binary images.