Quantification of left ventricular function and mass in heart transplant recipients using dual-source CT and MRI: initial clinical experience

The purpose of this study was to compare LV function and mass quantification derived from cardiac dual-source CT (DSCT) exams with those obtained by MRI in heart transplant recipients. Twelve heart transplant recipients who underwent cardiac DSCT and MRI examination were included. Double-oblique short-axis 8-mm slice thickness images were evaluated. Left ventricular ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, cardiac output and myocardial mass were manually assessed for each patient by two blinded readers. A systematic overestimation of all left ventricular volumes by DSCT when compared with MRI was observed. Mean difference was 16.58 +/- 18.61 ml for EDV, 4.9 4 +/- 6.84 ml for ESV, 11.64 +/- 13.58 ml for SV and 5.73 +/- 1.14 l/min for CO. Slightly lower values for left ventricular ejection fraction with DSCT compared with MRI were observed (mean difference 0.34 +/- 3.18%, p = 0.754). Correlation between DSCT and MRI for left ventricular mass was excellent (rho = 0.972). Bland and Altman plots and CCC indicated good agreement between DSCT and MRI left ventricular function and mass measurements. The interobserver correlation was good. In conclusion, DSCT accurately estimates left ventricular ejection fraction, volumes and mass in heart transplant recipients.     

Global left-ventricular function assessment using dual-source multidetector CT: effect of improved temporal resolution on ventricular volume measurement

The purpose was to compare global left-ventricular (LV) function parameters measured with cine MRI with results from multiphase dual-source CT (DSCT) using 10 and 20 reconstruction phases. Twenty-eight patients with suspected or known CAD underwent DSCT coronary angiography. LV end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fraction (EF) were determined using LV segmentation and selection of specific phases from DSCT image sets reconstructed either at 5% or 10% steps through the R-R interval. Cine MRI served as the reference investigation. Threshold-based 3D-segmentation was feasible in all DSCT data sets. EDV and ESV were underestimated by DSCT, but showed excellent correlation (Pearson's correlation coefficient 0.95/0.97) to values obtained with MRI. Using data from 5% DSCT image reconstructions instead of 10% phase reconstructions, the position of the ED and ES phase was changed in 16 of 28 patients; ESVs were to found to be slightly smaller, whereas EDV were slightly larger, resulting in a systematic overestimation of LV EF by 1.9% (p = 0.56). Threshold-based 3D segmentation enables accurate and reliable DSCT determination of global LV function with excellent correlation to cine MRI. Minor differences in LV EF indicate that both modalities are virtually interchangeable, even if the number of reconstructed phases is limited to 10% phase reconstructions.     

Assessment of global left and right ventricular function using dual-source computed tomography (DSCT) in comparison to MRI: an experimental study in a porcine model

OBJECTIVE: We sought to evaluate the ability of retrospectively ECG-gated dual-source computed tomography (DSCT) to assess left (LV) and right ventricular (RV) functional parameters in comparison to 1.5 T magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ten domestic pigs (60 kg) underwent both contrast-enhanced cardiac DSCT and cardiac MRI using standardized examination protocols under general anesthesia. From manually drawn endocardial and epicardial contours, LV and RV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), peak filling rate (PFR), peak ejection rate (PER), time to peak ejection (TPE), and time to peak filling (TPF) were calculated by means of dedicated analysis software. LV and RV functional parameters were analyzed using Bland-Altman plots, Student t test, and Pearson's correlation coefficient. RESULTS: Both left and right ESV and EDV, SV and EF determined with DSCT correlated well with MR imaging results (left, r = 0.98/0.92/0.82/0.98; right, r = 0.90/0.94/0.96/0.94). PER, PFR, TPE, TPF, and MM showed only a moderate to low correlation (left, r = 0.67/0.37/0.23/0.35/0.57; right, r = 0.78/0.69/0.12/0.11/0.44). PER and PFR were significantly underestimated by DSCT when compared with MRI. CONCLUSIONS: Retrospectively ECG-gated DSCT correctly depicts end-systole and can accurately determine LV and RV volumes, SV, and EF in comparison to MRI. DSCT showed a significant underestimation of PER and PFR in comparison to MRI.     

Assessment of left ventricular parameters in orthotopic heart transplant recipients using dual-source CT and contrast-enhanced echocardiography: Comparison with MRI

Objectives

To establish the accuracy and reliability of cardiac dual-source CT (DSCT) and two-dimensional contrast-enhanced echocardiography (CE-Echo) in estimating left ventricular (LV) parameters with respect to cardiac magnetic resonance imaging (CMR) as the reference standard.

Methods

Twenty-five consecutive heart transplant recipients (20 male, mean age 62.7 ± 10.4 years, mean time since transplantation 8.1 ± 5.9 years) were prospectively recruited. Two blinded readers independently assessed LV ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), and stroke volume (SV) for each patient after manual tracing of the endo- and epicardial contours in DSCT, CE-Echo and CMR cine images. Student's t-test for paired samples for differences, and Bland and Altman plots and Lin's concordance-correlation coefficients (CCC) for agreement were calculated.

Results

There was no statistical difference between left ventricular parameters determined by DSCT and CMR. CE-Echo resulted in significant underestimation of left ventricular volumes (mean difference EDV: 15.94 ± 14.19 ml and 17.1 ± 17.06 ml, ESV: 8.5 ± 9.3 and 7.32 ± 9.14 ml with respect to DSCT and CMR), and overestimation of EF compared with the cross-sectional imaging modalities (3.78 ± 8.47% and 2.14 ± 8.35% with respect to DSCT and CMR). Concordance correlation coefficients for LV parameters using DSCT and CMR were higher (CCC ≥ 0.75) than CCC values observed between CE-Echo and DSCT- or CMR-derived data (CCC ≥ 0.54 and CCC ≥ 0.49, respectively). Interobserver agreement was higher for DSCT and CMR values (CCC ≥ 0.72 and CCC ≥ 0.87, respectively).

Conclusion

In orthotopic heart transplantation cardiac DSCT allows accurate and reliable estimation of LV parameters compared with CMR, whereas CE-Echo seems to be insufficient to obtain precise measurements.     

Quantitative analysis of cardiac left ventricular variables obtained by MRI at 3 T: a pre- and post-contrast comparison

Short-axis cine images are acquired during cardiac MRI in order to determine variables of cardiac left ventricular (LV) function such as ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and LV mass. In cardiac perfusion assessments this imaging can be performed in the temporal window between first pass perfusion and the acquisition of delayed enhancement images in order to minimise overall scanning time. The objective of this study was to compare pre- and post-contrast short-axis LV variables of 15 healthy volunteers using a two-dimensional cardiac-gated segmented cine true fast imaging with steady state precession sequence and a 3.0 T MRI unit in order to determine the possible effects of contrast agent on the calculated cardiac function variables. Image analysis was carried out using semi-automated software. The calculated mean LV mass was lower when derived from the post-contrast images, relative to those derived pre-contrast (102 vs 108.1 g, p<0.0001). Small but systematic significant differences were also found between the mean pre- and post-contrast values of EF (69.4% vs 68.7%, p<0.05), EDV (142.4 vs 143.7 ml, p<0.05) and ESV (44.2 vs 45.5 ml, p<0.005), but no significant differences in SV were identified. This study has highlighted that contrast agent delivery can influence the numerical outcome of cardiac variables calculated from MRI and this was particularly noticeable for LV mass. This may have important implications for the correct interpretation of patient data in clinical studies where post-contrast images are used to calculate LV variables, since LV normal ranges have been traditionally derived from pre-contrast data sets.     

双源CT在主动脉瓣置换术前左心功能评价中的应用

目的:以磁共振成像(MRI)为金标准,用双源CT(DSCT)定量评价左心功能,探讨DSCT在主动脉瓣置换术前左心功能评价中的应用价值.方法:选取临床诊断主动脉瓣病变欲行主动脉瓣置换术的患者21例,全部病例均行DSCT和MRI心功能分析检查.由有经验的2位放射科医生独立进行,结果以均数士标准差表示.两种仪器间测量值应用配对样本t检验及相关分析检验,同一仪器测量值的差异相互关系用组内相关系数描述,P ＜0.05为有统计学意义.结果:DSCT和MRI两种方法测量的心功能指标差异无统计学意义,舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)、左室射血分数(EF)相关性高,r值(EDV)=0.93,r值(ESV)=0.94,r值(SV)=0.89,r值(EF)=0.85.EDV均值:DSCT＞ MRI;ESV均值:DSCT＞ MRI;SV均值:DSCT＞ MRI; EF均值:DSCT＞ MRI.同一仪器三次测量值的差异相互关系(ICC值):MRI测量的EDV、ESV、SV、EF值的ICC值在0.8～1之间;DSCT测量的EDV、ESV、SV、EF值的ICC值在0.6～0.75之间.结论:DSCT在左心室收缩功能定量评价方面准确、可靠,重复性好,并可在不增加放射剂量的前提下,一次DSCT冠状动脉造影检查同时评估冠状动脉狭窄情况和左心室收缩功能,能够为临床主动脉瓣置换术前评估及制订手术方案提供更多重要的参考信息.     

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 ± 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 ± 41.9 ml and 54.9 ± 29.6 ml, respectively, compared with 132.1 ± 40.8 ml EDV and 57.6 ± 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement −46.1/+53.6), while ESV was underestimated by 2.6 ml (−36.6/+31.4). Mean EF was 61.6 ± 12.4% in DSCT and 57.9 ± 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at −14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication. S. Busch and T. Johnson contributed equally to this study.     

中国人心脏房室腔内径及左右心室功能正常参数的MRI研究

目的 使用MRI测量中国正常成人心脏各房室腔内径及心功能参数.方法 共269名正常志愿者,无线矢量心电门控下,采用单次激发半傅立叶快速自旋回波与真实稳态自由进动序列,分别获得标准心脏各长轴及短轴切面二维体层及电影图像.由2名医师独立分析MRI,分别测量心脏各房室腔径线及心功能后处理分析,获得包括射血分数(EF)、舒张末容积(EDV)、收缩末容积( ESV)及心肌质量(CM)等心功能参数.男性与女性相对应参数做非配对的t检验.结果 所有志愿者均完成MR扫描,平均扫描时间(15 ±3) min.心脏各房室腔主要参数为:左心房前后径(2.87±0.77) cm,右心房径(垂直于房间隔,3.61 ±0.57)cm,左心室舒张末横径(4.97±0.52) cm,右心室舒张末横径(2.65±0.48) cm,心功能主要参数为:左心室EF (60.62±7.08)％、EDV( 128.27±32.16) ml、ESV(46.02±15.72) ml、CM( 82.97±24.03)g;右心室EF (47.73±6.50)％、EDV(115.37±26.71) ml、ESV(67.7±21.07) ml、CM(48.24±13.42)g.除左心室ESV(P =0.144)、EDV指数(P=0.714)、ESV指数(P =0.113)、心脏指数(P=0.199)及右心室EF值(P=0.296)和ESV指数(P =0.093)男女差异无统计学意义外,其余各指标性别间差异均有统计学意义(P＜0.01).结论 MRI以其高度的可重复性可获得正常中国人心脏形态与功能信息.     

Assessment of left ventricular function and mass in patients undergoing computed tomography (CT) coronary angiography using 64-detector-row CT: comparison to magnetic resonance imaging

PURPOSE: To quantify left ventricular function and mass derived from retrospectively ECG-gated 64-detector-row computed tomography coronary angiography data sets in comparison to cine magnetic resonance (MR) imaging as the reference standard. We hypothesized that the administration of beta-blockers prior to multidetector computed tomography (MDCT) coronary angiography has a significant impact on left ventricular functional parameters. MATERIAL AND METHODS: Multiplanar reformations in the short-axis orientation were calculated from axial contrast-enhanced CT images in 21 patients (16 male, five female; age range 41-75 years, mean 64.3+/-6.8 years) referred for CT coronary angiography. Patients whose heart rates exceeded 60 bpm received 5 mg bisoprolol orally 1 hour before the MDCT examination. In case of insufficient heart-rate reduction, up to four vials (20 mg) of metoprolol were injected intravenously. The end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and left ventricular mass (LVM) of the reformatted images were analyzed compared to volumetric measurements based on continuous short-axis steady-state free-precession cine MR sequences (TR 3 ms, TE 1.5 ms, FA 60 degrees ). RESULTS: On average, each patient received 15.5 mg metoprolol (range 0-20 mg) and 3.85 mg bisoprolol (range 0-5 mg). The mean heart rate was 56+/-5 bpm during CT and 73+/-9 bpm during MRI examination. This difference was statistically significant (P<0.05). Mean EDV and ESV measured on MDCT were significantly higher compared to MR (MDCT vs. MR: EDV 164.2+/-52.5 vs. 144.2+/-46.7 ml, ESV 77.3+/-46.6 vs. 63.8+/-47.3 ml; P<0.05). Mean EF and CO derived from MDCT images were significantly lower compared to MR (MDCT vs. MR: EF 55.4+/-11.8 vs. 59.3+/-15.4%, CO 4822+/-779 vs. 5755+/-1267 ml; P<0.05). Mean SV and LVM were not significantly different between both methods (MDCT vs. MR: SV 86.8+/-18.1 vs. 80.3+/-15.6 ml, P = 0.44; LVM 132.4+/-42.5 vs. 138.7+/-39.1 g, P = 0.31). CONCLUSION: Left ventricular volumes assessed by the newest-generation MDCT scanners are significantly higher compared with MRI, whereas ejection fraction and cardiac output are significantly lower in MDCT. This appears to be a result of the frequent application of beta-blockers prior to MDCT examinations.     

Gender and strain variations in left ventricular cardiac function and mass determined with magnetic resonance imaging at 7 tesla in adult mice

OBJECTIVES: We sought to assess with magnetic resonance imaging (MRI) the influence of strain type and gender on left ventricular (LV) global function and mass in 3 inbred mouse strains with a normal cardiac phenotype. MATERIALS AND METHODS: A total of 30 mice from 3 inbred strains (C57BL/6, 29S2/SvPasCrl, and C3HFeJ) were studied on a 7.05-T MR scanner using ECG-triggered cine sequences. LV mass and volumes were calculated with inclusion and exclusion of papillary muscles (PMs) in the LV wall. RESULTS: Significant differences were found with strain and gender (P < 0.001), with strain-effect but no gender-effect for ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV). There were no differences in LV mass between strains but lower values in female mice except in the C3H strain. The exclusion of PMs led to the relative underestimation of EF (-6.1%) and of LV mass (-6.4 mg) and the relative overestimation of EDV (6.3 microL) and ESV (5.3 microL). Inter- and intraobserver reproducibility was better when PMs were included. CONCLUSION: The use of MRI demonstrates cardiac interstrain and gender-related phenotypic diversities that are essential factors to consider when building genomic databases and designing studies.     

Evaluation of left ventricular volumes and ejection fraction by gated myocardial perfusion SPECT versus cardiac MRI

It is stated that cardiac MRI imaging can provide accurate estimation of left ventricular (LV) volumes and ejection fraction (EF). The purpose of this study was to evaluate the accuracy of gated myocardial perfusion SPECT for assessment of LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF, using cardiac MRI as the reference methods/(methodology). Gated myocardial perfusion SPECT images were analyzed with two different quantification software, QGS and 4D-MSPECT. Thirty-four consecutive patients were studied. Myocardial perfusion SPECT and cardiac MRI had excellent intra/interobserver reproducibility. Correlation between the results of gated myocardial perfusion SPECT and cardiac MRI were high for EDV and EF. However, ESV and EDV were significantly underestimated by gated myocardial perfusion SPECT compared to cardiac MRI. Moreover, gated myocardial perfusion SPECT overestimated EF for small heart. One reason for the difference in volumes and EF is the delineation of the endocardial border. Cardiac MRI has higher spatial resolution. We should understand the differences of volumes and EF as determined by gated myocardial perfusion SPECT and cardiac MRI.     

体重指数对中国成年男性左心结构和功能影响的心血管MRI研究

目的应用心血管磁共振(cardiovascular magnetic resonance,CMR)评价体重指数(body mass index,BMI)对中国成年男性左心结构和功能的影响。方法选取2010年10月~2018年3月行CMR检查的男性体检者共420例,年龄30~50岁,按体重指数(BMI)分为三组,正常体重组(<24 kg/m²)164例、超重组(24.0~27.9 kg/m²)190例和肥胖组(≥28.0 kg/m²)66例。应用1.5T Siemens Magnetom Essenza和GE磁共振扫描仪进行CMR检查,应用CVI⁴²(v5.6.2,Canada)软件包进行心脏结构及功能参数的测量,将乳头肌纳入心肌质量,不计入心室容积;心室容积包含心室流出道,逐层勾画出左室心内膜、心外膜轮廓后计算得出以下参数:左心室舒张末期容积(EDV)、收缩末期容积(ESV)、射血分数(EF)、每搏输出量(SV)、心输出量(CO)、心肌质量(LVM)及经体表面积(BSA)校正的值:EDVI=EDV/BSA、ESVI=ESV/BSA、LVMI=LVM/BSA,左心室心肌质量容积比LVM/EDV。结果CO、LVM、LVM/EDV与BMI呈正相关(P<0.05)。与正常体重组比较,超重组及肥胖组EDV、SV显著增加,超重组EF较正常体重组增大(P<0.05)。经BSA校正,超重组ESVI、LVMI及肥胖组EDVI、ESVI、LVMI均与正常体重组差异有统计学意义(P<0.05),而超重与肥胖组两组间及ESV各组间差异无统计学意义(P=0.42)。结论BMI增加可使EDV、CO、SV、EF及LVM改变,且超重未达肥胖时,即可引起左心室重构、影响左心收缩功能;BSA可校正部分由BMI增加导致的左心结构功能参数改变的差异。     

时间-空间相关成像技术评估中孕期胎儿心功能的初步研究

目的 评估时间-空间相关成像( STIC)技术在中孕期胎儿心功能检查中的应用.资料与方法 110例孕20～27+6周胎儿常规超声筛查心脏无异常,用STIC技术扫描获得胎儿心脏整个心动周期的容积数据,存盘后采用体器官计算机辅助分析软件(VOCAL)进行脱机分析,手动描画出心室舒张末期容积(EDV)、收缩末期容积(ESV).计算心室的每搏量(SV)、心排血量(CO)、射血分数(EF),评价SV、CO、EF与孕龄的相关性.结果 110例胎儿中,94例(85.5％)获得满意的心脏容积数据.左、右心室SV从孕20周的(0.33±0.06) ml和(0.40±0.07) ml增加至孕27+6周的(1.13±0.11) ml和(1.29±0.11) ml,左、右心室CO从孕20周的( 49.66±8.10) ml/min和(59.96±9.43) ml/min增加至孕27+6周的(163.51±17.68) ml/min和(187.57±15.98) ml/min;左、右心室SV和CO随孕龄增加而增加,与孕龄呈正相关(左心室SV及CO r=0.93,P＜0.05.右心室:SV r =0.95,P＜0.05; CO r=0.94,P＜0.05).左、右心室EF分别为(49.48±4.12)％和(51.07±4.00)％,与孕龄无明显相关性(r=0.02、0.04,P＞ 0.05).结论 STIC技术能较为准确客观地测量胎儿心室容积,评价胎儿心功能,有望成为胎儿心功能检查的一种新方法.     

Abnormal response to inotropic stimulation in young asymptomatic type I diabetic patients demonstrated by serial gated myocardial perfusion SPECT imaging

Purpose In subjects without underlying cardiac disease dobutamine is known to enhance systolic LV function and LV relaxation. As end-systolic (ES) and end-diastolic (ED) volumes (V) can be derived from gated SPECT we intent to study these volumes and their response to dobutamine in order to have a better understanding of the mechanism by which stroke volume (SV) increases during dobutamine infusion. We intent to do this in normal controls and in young diabetic subjects.Methods After injection of sestamibi, serial gated SPECT were obtained at baseline, and during low doses of dobutamine infusion in 12 asymptomatic type I diabetic patients, and in 12 age matched controls. LV EDV, ESV, SV and EF were calculated with the QGS program.Results Gated SPECT showed comparable LV EF and SV in both groups at rest. There was a significant increase in LVEF and SV during dobutamine infusion but in the diabetic patients the increase in SV was due to a decrease in ESV from 25±5 to 20±6 ml/m2 (p=0.002) and no change in EDV. In normal controls, the increase in EF was due to an increase in EDV from 69±10 to 73±12 ml/m2 (p=0.002) with no significant change in ESV.Conclusion These data confirm the presence of subclinical abnormalities of diastolic function in asymptomatic type I diabetic patients and show differences in adaptation to inotropic stimulation in order to preserve the increase in stroke volume and LV ejection fraction.     

Assessment of left ventricular function and mass in dual-source computed tomography coronary angiography: Influence of beta-blockers on left ventricular function: Comparison to magnetic resonance imaging

Purpose

To quantify left ventricular (LV) function and mass (LVM) derived from dual-source computed tomography (DSCT) and the influence of beta-blocker administration compared to cardiac magnetic resonance imaging (CMR).

Methods

Thirty-two patients undergoing cardiac DSCT and CMR were included, where of fifteen received metoprolol intravenously before DSCT. LV parameters were calculated by the disc-summation method (DSM) and by a segmented region-growing algorithm (RGA). All data sets were analyzed by two blinded observers. Interobserver agreement was tested by the intraclass correlation coefficient.

Results.

1. Using DSM LV parameters were not statistically different between DSCT and CMR in all patients (DSCT vs. CMR: EF 63 ± 8% vs. 64 ± 8%, p = 0.47; EDV 136 ± 36 ml vs. 138 ± 35 ml, p = 0.66; ESV 52 ± 21 ml vs. 52 ± 22 ml, p = 0.61; SV 83 ± 22 ml vs. 87 ± 19 ml, p = 0.22; CO 5.4 ± 0.9 l/min vs. 5.7 ± 1.2 l/min, p = 0.09, LVM 132 ± 33 g vs. 132 ± 33 g, p = 0.99).2. In a subgroup of 15 patients beta-blockade prior to DSCT resulted in a lower ejection fraction (EF), stroke volume (SV), cardiac output (CO) and increase in end systolic volume (ESV) in DSCT (EF 59 ± 8% vs. 62 ± 9%; SV 73 ± 17 ml vs. 81 ± 15 ml; CO 5.7 ± 1.2 l/min vs. 5.0 ± 0.8 l/min; ESV 52 ± 27 ml vs. 57 ± 24 ml, all p < 0.05).3. Analyzing the RGA parameters LV volumes were not significantly different compared to DSM, whereas LVM was higher using RGA (177 ± 31 g vs. 132 ± 33 g, p < 0.05). Interobserver agreement was excellent comparing DSM values with best agreement between RGA calculations.

Conclusion

Left ventricular volumes and mass can reliably be assessed by DSCT compared to CMR. However, beta-blocker administration leads to statistically significant reduced EF, SV and CO, whereas ESV significantly increases. DSCT RGA reliably analyzes LV function, whereas LVM is overestimated compared to DSM.     

Stereological estimation of left-ventricular volumetric and functional parameters from multidetector-row computed tomography data

This study aims to optimize the stereological method for estimating left-ventricular (LV) parameters from retrospectively electrocardiography-gated 16-row MDCT and to compare stereological estimations with those by MRI. MDCT was performed in 17 consecutive patients with known or suspected coronary disease. Stereological measurements based on point counting were optimized by determining the appropriate distance between grid points. LV parameters were evaluated by standard CT analysis using a semi-automatic segmentation method. Two independent observers evaluated the reproducibility of the stereological method. End-diastolic volume (EDV) and end-systolic volume (ESV) estimations with a coefficient of error below 5% were obtained in a mean time of 2.3 +/- 0.5 min with a point spacing of 25 and 15 pixels, respectively. The intra- and interobserver variability for estimating LV parameters was 2.6-4.4 and 4.9-8.2%, respectively. MRI estimations were highly correlated with those by standard CT analysis (R > 0.82) and stereology (R > 0.84). Stereological method significantly overestimated EDV and ESV compared to MRI (EDV: P = 0.0011; ESV: P = 0.0013), whereas for stroke volume (SV) and ejection fraction (EF), no difference was observed (P > 0.05). For standard CT analysis and MRI, significant differences were found except for SV and EF (EDV: P = 0.0008; ESV: P = 0.0004; EF: P = 0.051; SV: P = 0.064). The time-efficient optimized stereological method enables the reproducible evaluation of LV function from MDCT.     

电影磁共振图像评定运动员心脏形态与功能

本文对瑞典10名耐力运动员(耐力组,长跑7人,游泳3人),10名举重运动员(力量组)及10名健康无训练者(对照组)进行了心脏电影磁共振图像与最大吸氧量的测试。结果表明:1)从左室舒末容量、左室编末容量、心搏量、左室心肌重量、最大吸氧量、最大通气量等指标来看,无论是其绝对实测值,还是其按体表面积或体重校正计算的相对值,耐力组均非常显著地大于其它二组。力量组除了左室心肌重量及左室心肌重量/左室舒末容量比值略有增高外(P<0.05),其余各指标与对照组比较均无显著性差异。2)左室舒末容量、心搏量、左室心肌重量及最大通气量四指标均与最大吸氧量呈高度正相关关系,相关系数依次为0.88,0.85,0.81,0.76,各相关系数均有高度显著性(P<0.001)。3)本文各组的左室心肌重量的电影磁共振图像测定值低于以往多数类似研究对象的超声心动图测定值。文章指出,电影磁共振图像技术是评定左室心肌重量与左室容量十分准确可靠的无创性检查新方法。本文首先报道了运动员心脏电影磁共振部分指标正常测量值。     

Dual-source cardiac CT imaging with improved temporal resolution: Impact on image quality and analysis of left ventricular function

In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system's superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62+/-8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42+/-0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function.     

The effects of denervation and acute rejection on left ventricular volumes measured by radionuclide ventriculography following cardiac transplantation in the chacma baboon

Seven baboons underwent autotransplantation of the heart or heart and both lungs (group A). Eleven allografts were performed (group B) (nine orthotopic heart transplants and two en bloc transplants of the heart and both lungs). Radionuclide ventriculography was performed both pretransplant and at intervals posttransplant in all animals, and provided measurements of ejection fraction (EF) and left ventricular volumes (LVv) (end-diastolic volume [EDV], end-systolic volume [ESV], and stroke volume [SV]). In seven animals, a total of 20 endomyocardial biopsies were taken. Correlation was made between histopathological features of acute rejection seen on endomyocardial biopsy and changes in EF and LVv measured by radionuclide imaging. A significant increase of 12% in the EF (P less than 0.01) and significant falls in the LVv were observed in all animals (groups A and B) on the first posttransplant day, presumably a result of total cardiac denervation. EDV was reduced by 50% (P less than 0.005), ESV by 62% (P less than 0.0001), and SV by 43% (P less than 0.0001). In autografted baboons (group A) EF and LVv showed no further changes until reinnervation of the heart had occurred, when they reverted to pretransplant levels. In the allografted baboons (group B) further significant reductions in the LVv occurred as acute cardiac rejection progressed. From the first post-transplant day to the time of the final study before the animals' death, the EF decreased by 10% (P less than 0.01), the EDV by 38% (P less than 0.005), and SV by 73% (P less than 0.003): the decrease in ESV did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)     

回顾性心电门控多层螺旋CT对急性肺栓塞右心室功能障碍及溶栓前后右心室功能变化的评价

目的 应用ECG门控MSCT前瞻性对中心型急性肺动脉栓塞(APE)患者右心功能障碍及静脉溶栓前后右心功能变化进行评价.方法 96名可疑APE患者进行了ECG门控MSCT胸痛三联检查,25例确诊为中心型肺栓塞.行胸痛三联检查无心肺疾患且性别、年龄匹配的25例作为对照组.APE患者于静脉溶栓后复查MSCT,评价右心功能恢复情况.测量参数包括横断面舒张期的右心室(RV)及左心室(LV)短轴最大内径,RV及LV舒张末期容积(EDV)、收缩末期容积(ESV)、射血分数(EF)、主肺动脉/主动脉直径比.应用单因素方差分析,如果有统计学意义,则采用两两组间q检验.结果 对照组的右心室EDV、ESV、EF值、收缩末期RV/LV容积比、横断面RV/LV内径比及主肺动脉/主动脉直径比分别为(15O.5±24.1)ml、(71.5±18.5)ml、(53.5±4.2)%、1.08±0.04、1.01±0.04及0.99±0.02,中心型APE患者溶栓前以上各值分别为(190.3±16.2)ml、(128.1±13.2)ml、(32.7±3.6)%、2.00±0.26、1.30±0.09及1.34±0.11,溶栓后分别为(159.2±21.5)ml、(80.7±9.4)ml、(49.2±5.9)%、1.22±0.25、1.02±0.02及1.02±0.11.中心型APE患者与对照组比较,右心室ESV(q=6.28,P<0.01)及EDV均增大(q=7.59,P<0.01),EF减小(q=4.82,P<0.01),收缩末期RV/LV容积比增大(q=6.04,P<0.01),横断面RV/LV内径比(q=4.43,P<0.01)及主肺动脉/主动脉直径比增大(q=4.36,P<0.01),左心室EDV减小.中心型APE患者静脉溶栓后,与溶栓前比较,右心室ESV(q=5.03,P<0.01)及EDV减小(q=6.11,P<0.01),EF增加(q=6.29,P<0.01),收缩末期RV/LV容积比减小(q=4.74,P<0.01),横断面RV/LV内径比(q=3.83,P<0.01)及主肺动脉/主动脉直径比减小(q=3.46,P<0.01),左心室EDV增大(q=4.01,P<0.01).结论 回顾性ECG门控MSCT胸痛三联检查可同时检测APE和测量左右心功能,排除其他胸痛疾病,评价溶栓疗效.