Novel phase-based noise reduction strategy for quantification of left ventricular function and mass assessment by cardiac CT: Comparison with cardiac magnetic resonance

Background

Tube current modulation in retrospective ECG gated cardiac computed tomography (CT) results in increased image noise and may reduce the accuracy of left ventricular (LV) ejection fraction (EF) and mass assessment.

Objective

To examine the effects of a novel CT phase-based noise reduction (NR) algorithm on LV EF and mass quantification as compared to cardiac magnetic resonance (CMR).

Methods

In 40 subjects, we compared the LV EF and mass between CT and CMR. In a subset of 24 subjects with tube current modulated CT, the effect of phase-based noise reduction strategies on contrast-to-noise ratio (CNR) and the assessment of LV EF and mass was compared to CMR.

Results

There was excellent correlation between CT and CMR for EF (r = 0.94) and mass (r = 0.97). As compared to CMR, the limits of agreement improved with increasing strength of NR strategy. There was a systematic underestimation of LV mass by CT compared to CMR with no NR (−10.3 ± 10.1 g) and low NR (−10.3 ± 12.5 g), but was attenuated with high NR (−0.5 ± 8.3 g). Studies without NR had lower CNR compared to low and high NR at both the ES phase and ED phase (all p < 0.01).

Conclusions

A high NR strategy on tube current modulated functional cardiac CT improves correlation of EF compared to CMR and reduces variability of EF and mass evaluation by increasing the CNR. In an effort to reduce radiation dose with tube current modulation, this strategy provides better image quality when LV function and mass quantification is needed.     

Benefit of combining quantitative cardiac CT parameters with troponin I for predicting right ventricular dysfunction and adverse clinical events in patients with acute pulmonary embolism

Objective

To prospectively evaluate the diagnostic accuracy of quantitative cardiac CT parameters alone and in combination with troponin I for the assessment of right ventricular dysfunction (RVD) and adverse clinical events in patients with acute pulmonary embolism (PE).

Materials and results

This prospective study had institutional review board approval and was HIPAA compliant. In total 83 patients with confirmed PE underwent echocardiography and troponin I serum level measurements within 24 h. Three established cardiac CT measurements for the assessment of RVD were obtained (RV/LV_axial, RV/LV_4-CH, and RV/LV_volume). CT measurements and troponin I serum levels were correlated with RVD found on echocardiography and adverse clinical events according to Management Strategies and Prognosis in Pulmonary Embolism Trial-3 (MAPPET-3 criteria. 31 of 83 patients with PE had RVD on echocardiography and 39 of 83 patients had adverse clinical events. A RV/LV_volume ratio > 1.43 showed the highest area under the curve (AUC) (0.65) for the prediction of adverse clinical events when compared to RV/LV_axial, RV/LV_4Ch and troponin I. The AUC for the detection of RVD of RV/LV_axial, RV/LV_4Ch, RV/LV_volume, and troponin I were 0.86, 0.86, 0.92, and 0.69, respectively. Combination of RV/LV_axial, RV/LV_4Ch, RV/LV_volume with troponin I increased the AUC to 0.87, 0.87 and 0.93, respectively.

Conclusion

A combination of cardiac CT parameters and troponin I measurements improves the diagnostic accuracy for detecting RVD and predicting adverse clinical events if compared to either test alone.     

持续非卧床腹膜透析患者左心室肥厚与血清N-末端脑钠素原水平的关系

目的探讨持续非卧床腹膜透析（CAPD）患者左心室肥厚（LVH）与血清N-末端脑钠素原（NT-proBNP）水平的关系。方法连续入选32例接受CAPD治疗1年以上患者,超声心动图检查测算左心室心肌质量指数（LVMI）;根据LVMI将入选者分为左心室肥厚组和左心室正常组,双抗体夹心酶标免疫法测定两组患者血清NT-proBNP水平。结果入选CAPD患者中,左心室肥厚组17例,左心室正常组15例,左心室肥厚组血清NT-proBNP（6234.21±854.43）pg/ml较左心室正常组血清NT-proBNP（2456.23±576.98）pg/ml水平明显升高（P〈0.01）,且NT-proBNP水平与LVMI呈正相关（r=0.625,P〈0.01）,NT-proBNP诊断LVH的ROC曲线下面积为0.912。结论 CAPD合并LVH患者血清NT-proBNP水平明显升高,与LVMI呈正相关且有诊断价值,NT-proBNP可能是预测CAPD患者合并LVH的一个新指标。     

Cardiac troponin T and creatine kinase predict mid-term infarct size and left ventricular function after acute myocardial infarction: a cardiac MR study

Purpose:

To assess the relation of cardiac troponin T (cTnT) and creatine kinase (CK) release with infarct size and left ventricular function evaluated during the subacute phase as well as four months after acute myocardial infarction (AMI) by contrast‐enhanced MRI (CE‐MRI).

Materials and Methods:

CMR of 80 patients (68 male, mean age 54.2 ± 11.7 years) was performed within 8 days and 4 months after first acute ST‐elevation AMI with successful primary angioplasty. CK and cTnT concentrations were determined serially from admission to day 4 after symptom onset.

Results:

All single time‐points, estimated average release and peak concentrations of CK and cTnT markers correlated significantly with acute and mid‐term infarct size (r = 0.43 to 0.79, all P < 0.001), ejection fraction (EF%) (r = ?0.42 to ?0.58, all P < 0.002) as well as with end‐systolic volume (ESV) (r = 0.32 to 0.57, all P < 0.002) at all times of assessment. Patients with cTnT concentrations below the cutoff value of 3.26 μg/L measured 48 h after AMI‐related symptom onset had a significant improvement in global (EF: P < 0.0001) myocardial function during the study period, whereas in those with cTnT ≥ 3.26 μg/L, functional recovery did not occur (P = 0.09).

Conclusion:

All single, mean and maximum concentrations of cTnT and CK measured within the first 4 days after AMI permit an accurate prediction of infarct size and left ventricular function as determined in the acute phase as well as four months after AMI by CE‐MRI. J. Magn. Reson. Imaging 2011;33:847–854. © 2011 Wiley‐Liss, Inc.

     

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.     

Ethnic differences in coronary anatomy,left ventricular mass and CT-derived fractional flow reserve

BackgroundStudies have observed higher incidence of cardiovascular mortality in South Asians (SA), and lower prevalence in East Asians (EA), compared with Caucasians. These observations are not entirely explained by ethnic differences in cardiovascular risk factors and mechanistic factors such as variations in cardiac anatomy and physiology may play a role. This study compared ethnic differences in CT-assessed left ventricular (LV) mass, coronary anatomy and non-invasive fractional flow reserve (FFRCT).MethodsThree-hundred symptomatic patients (age 59 ± 7.9, male 51%) underwent clinically-mandated CT-coronary-angiography (CTA) were matched for age, gender, BMI and diabetes (100 each ethnicity). Assessment of coronary stenosis, luminal dimensions and vessel dominance was performed by independent observers. LV mass, coronary luminal volume and FFRCT were quantified by blinded core-laboratory. A sub-analysis was performed on patients (n = 187) with normal/minimal disease (0–25% stenosis).ResultsStenosis severity was comparable across ethnic groups. EA demonstrated less left-dominant circulation (2%) compared with SA (8.2%) and Caucasians (10.1%). SA compared with EA and Caucasians demonstrated smallest indexed LV mass, coronary luminal volumes and dimensions. EA compared with Caucasians had comparable indexed LV mass, coronary luminal dimensions and highest luminal volumes. The latter was driven by higher prevalence of right-dominance including larger and longer right posterior left ventricular artery. FFR_CT in the left anterior descending artery (LAD) was lowest in SA (0.87) compared with EA (0.89; P = 0.009) and Caucasians (0.89; P < 0.001), with no difference in other vessels. All observed differences were consistent in patients with minimal disease.ConclusionThis single-centre study identified significant ethnic differences in CT-assessed LV mass, coronary anatomy and LAD FFR_CT. These hypotheses generating results may provide a mechanistic explanation for ethnic differences in cardiovascular outcomes and require validation in larger cohorts.     

Comparison of T2* relaxation times of articular cartilage of the knee in elite professional football players and age-and BMI-matched amateur athletes

ObjectiveRecent investigation has underlined the potential of quantitative MR imaging to be used as a complementary tool for the diagnosis of cartilage degeneration at an early state. The presented study analyses T2* relaxation times of articular cartilage of the knee in professional athletes and compares the results to age- and BMI (Body Mass Index)-matched healthy amateur athletes.Materials and methods22 professional football players and 22 age- and BMI-matched individuals were underwent knee Magnetic Resonance Imaging (MRI) at 3T including qualitative and quantitative analysis. Qualitative analysis included e.g. meniscal tears, joint effusion and bone edema. For quantitative analysis T2* (22 ET: 4.6-53.6 ms) measurements in 3D data acquisition were performed. Deep and superficial layers of 22 predefined cartilage segments were analysed. All data sets were postprocessed using a dedicated software tool. Statistical analysis included Student t-test, confidence intervals and a random effects model.ResultsIn both groups, T2* relaxation times were significantly higher in the superficial compared to the deep layers (p < 0.001). Professional athletes had significantly higher relaxation times in eight superficial and three deep cartilage layers in the predefined cartilage segments (p < 0.05). Highly significant differences were found in the weight-bearing segments of the lateral superficial femoral condyle (p < 0.001).ConclusionElevated T2* values in cartilage layers of professional football players compared to amateur athletes were noted. The effects seem to predominate in superficial cartilage layers.     

高原肺水肿治疗前后血清心肌肌钙蛋白T的变化

目的 探讨诊断和判别高原肺水肿（ＨＡＰＥ）状态的新指标。方法 在海拔３７００ｍ处对８例ＨＡＰＥ患者在治疗前及临床治愈后分别测定血清肌酸激酶同功酶（ＣＫ－ＭＢ）和ｃＴｎＴ两项指标。结果 ＨＡＰＥ患者血清ＣＫ－ＭＢ和ｃＴｎＴ临床治愈后较治疗前均降低,二者间的差别有非常显著性意义（Ｐ〈０．０１）。结论 ＨＡＰＥ时存在心肌损伤,血清ｃＴｎＴ是一项具有高灵敏度、高特异性的血清心肌损伤标志物,对ＨＡＰＥ的诊断、病情分析有一定的价值。     

冠心病患者左室Tei指数与左室心肌质量的相关性分析

目的:探讨冠心病患者左室Tei指数与左室心肌质量的相关性。方法:应用脉冲多普勒超声测量34例冠心病患者和34例正常人的左室Tei指数,并进行比较。应用实时三维超声心动图(RT-3DE)测量34例冠心病患者的左室心肌质量(LVM)、左室心肌质量指数(LVMI),分析冠心病患者Tei指数与LVM、LVMI的相关性。结果:冠心病患者的Tei指数明显大于正常对照组(P<0.001)。冠心病患者Tei指数的升高与LVM和LVMI的增加呈正相关(r=0.784,r=0.808)。结论:冠心病患者Tei指数与LVM密切相关,可以综合反映冠心病患者左室功能。     

不同海拔高血压患者血CGRP、ADM、MPO及BNP含量的相关性研究

目的：探讨不同海拔的高血压患者血降钙素基因相关肽（calcitonin gene-related pep-tide,CGRP）、肾上腺髓质素（adrenomedulin,ADM）、髓过氧化物酶（myeloperox-idase,MPO）、脑钠肽（brain natriuretic peptide,BNP）浓度的变化,以期对高血压的诊断、治疗和预后判断提供理论依据。方法：采用放射免疫法测定血浆CGRP、ADM含量,用比色法测定血清MPO含量,用Triage荧光免疫分析仪测定BNP含量。结果：高海拔及西宁地区高血压组患者血CGRP含量分别低于同海拔正常对照组（均P〈0.05）;高海拔及西宁地区高血压患者血ADM、MPO、BNP含量分别高于同海拔正常对照组（均P〈0.05）;高原地区高血压组及正常组血CGRP含量分别低于西宁地区高血压组及正常组（均P〈0.05）;高原地区高血压组及正常组ADM、BNP含量分别高于西宁地区高血压组及正常组（均P〈0.05）;高原地区高血压组及正常组血清MPO含量分别与西宁地区高血压组及正常组比较均无显著性差异（均P〉0.05）。结论：高海拔地区人群CGRP含量降低,ADM、MPO及BNP升高,这种趋势在高血压患者中更为明显,提示：海拔高度影响高原居住人群的血管活性物质分泌,可能是高原不适应,导致血压升高的因素之一。     

二维、实时三维超声心动图对冠心病患者左室心肌质量的评价

目的:探讨二维超声心动图(2DE)、实时三维超声心动图(RT-3DE)在定量评价冠心病患者左室心肌质量(LVM)的价值。方法:分别采用2DE和RT-3DE测量34例冠心病患者LVM和左室心肌质量指数(LVMI),并进行比较。结果:2DE测定的LVM和LVMI大于RT-3DE测值,2种方法测值之间差异有统计学意义(P0.05)。结论:RT-3DE能准确测量冠心病患者LVM,2DE高估冠心病患者LVM。     

慢性心力衰竭患者血脂、血浆NT-ProBNP、CTnI和hs-CRP水平测定的临床分析

目的 测定慢性心力衰竭（CHF）患者的血脂、血浆N氨基末端脑钠肽前体（NT-ProBNP）、心肌肌钙蛋白I（CTnI）和高敏C反应蛋白（hs-CRP）水平并进行临床分析。 方法 采用生化法、荧光免疫分析法和放射免疫分析法测定165例CHF患者和60名正常对照者的血脂和血浆NT-ProBNP、CTnI和hs-CRP水平,并进行比较性分析。 结果 165例CHF患者血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）和高密度脂蛋白胆固醇（HDL-C）水平较60名正常对照者明显降低（TC：tⅡ=2.214,P＜0.05;tⅢ=2.873,P＜0.01;tⅣ=3.146;P＜0.01;TG：tⅡ=2.167,P＜0.05;tⅢ=2.863,P＜0.01;tⅣ=3.063,P＜0.01;LDL-C：tⅡ=2.147,P＜0.05;tⅢ=2.056,P＜0.05;tⅣ=2.184,P＜0.05;HDL-C：tⅡ=2.137,P＜0.05;tⅢ=2.256,P＜0.05;tⅣ=3.148,P＜0.01）。在生物标志物的测定中,165例CHF患者的血浆NT-ProBNP、CTnI和hs-CRP水平与正常对照者之间的差异有统计学意义（NT-proBNP：tⅡ=2.096,P＞0.05;tⅢ=2.813,P＜0.01;tⅣ＝4.135,P＜0.001;CTnI：tⅡ=2.736,P＜0.01;tⅢ=2.962,P＜0.01;tⅣ=3.816,P＜0.001;hs-CRP：tⅡ＝2.103,P＜0.05;tⅢ＝2.956,P＜0.01;tⅣ＝4.452,P＜0.001）,而且随左心室射血功能（LVEF）的降低而逐步升高。 结论 CHF患者血脂水平（TC、TG、LDL-C和HDL-C）随LVEF的降低而降低,具有血脂代谢紊乱的现象;血浆生物标志物水平（NT-ProBNP、CTnI和hs-CRP）随LVEF的降低而升高。     

Congenital left ventricular wall abnormalities in adults detected by gated cardiac multidetector computed tomography: Clefts, aneurysms, diverticula and terminology problems

Objectives

Our aim was to evaluate congenital left ventricular wall abnormalities (clefts, aneurysms and diverticula), describe and illustrate imaging features, discuss terminology problems and determine their prevalence detected by cardiac CT in a single center.

Materials and methods

Coronary CT angiography images of 2093 adult patients were evaluated retrospectively in order to determine congenital left ventricular wall abnormalities.

Results

The incidence of left ventricular clefts (LVC) was 6.7% (141 patients) and statistically signi?cant difference was not detected between the sexes regarding LVC (P = 0.5). LVCs were single in 65.2% and multiple in 34.8% of patients. They were located at the basal to mid inferoseptal segment of the left ventricle in 55.4%, the basal to mid anteroseptal segment in 24.1%, basal to mid inferior segment in 17% and septal–apical septal segment in 3.5% of cases. The cleft length ranged from 5 to 22 mm (mean 10.5 mm) and they had a narrow connection with the left ventricle (mean 2.5 mm). They were contractile with the left ventricle and obliterated during systole. Congenital left ventricular septal aneurysm that was located just under the aortic valve was detected in two patients (0.1%). No case of congenital left ventricular diverticulum was detected.

Conclusion

Cardiac CT allows us to recognize congenital left ventricular wall abnormalities which have been previously overlooked in adults. LVC is a congenital structural variant of the myocardium, is seen more frequently than previously reported and should be differentiated from aneurysm and diverticulum for possible catastrophic complications of the latter two.     

慢性心力衰竭患者血清心肌肌钙蛋白I和室性心律失常严重性的关系

目的　研究慢性心力衰竭(chronicheartfailure ,CHF)患者血清心肌肌钙蛋白I(cTnI)和室性心律失常严重性的关系。方法　本研究包括2 18例CHF患者,入院时抽血进行cTnI分析,根据血清cTnI将患者分为2组:cTnI阳性组(cTnI>或=0 .0 5ng ml)和cTnI阴性组(cTnI<0 .0 5ng ml)。急性心肌梗死和心肌炎等可引起cTnI升高的疾病除外。用2 4hHolter监测评估室性心律失常的严重性,事先确定室性心律失常严重性负荷指标。结果　2组患者的室性心律失常的危险因素水平相同。cTnI阳性CHF患者的所有室性心律失常的测量指标明显高于cTnI阴性CHF患者。平均每小时成对性室早(2 6±2 .6vs17±2 .9,P =0 .0 3)、平均每小时单发室早总数(182±2 7vs 15 3±2 8,P =0 .0 2 )和2 4小时室性心动过速发作次数(5 3±4 .7vs 2 4±5 .8,P =0 .0 1)都有明显差异。在包含临床变量和药物治疗的多变量分析中,cTnI和上述指标的肯定关系依然存在,他们的P值分别是0 .0 30、0 .0 35、0 .0 31。经多变量logistic回归分析,形成室性心动过速的危险在cTnI阳性组明显增高,校正比数比是2 .4 1(95 4 %CI,1.34to 3.4 2 ,p =0 .0 0 4 )。结论　CHF患者血清cTnI具有促室性心律失常的作用;这种作用可能是心衰自身不断发展的机制     

Quantification of left ventricular function and mass in cardiac Dual-Source CT (DSCT) exams: comparison of manual and semiautomatic segmentation algorithms

The purpose of our study was to evaluate reliability of left ventricular (LV) function and mass quantification in cardiac DSCT exams comparing manual contour tracing and a region-growing-based semiautomatic segmentation analysis software. Thirty-three consecutive patients who underwent cardiac DSCT exams were included. Axial 1-mm slices were used for the semiautomated technique, and short-axis 8-mm slice thickness multiphase image reconstructions were the basis for manual contour tracing. Left ventricular volumes, ejection fraction and myocardial mass were assessed by both segmentation methods. Length of time needed for both techniques was also recorded. Left ventricular functional parameters derived from semiautomatic contour detection algorithm were not statistically different from manual tracing and showed an excellent correlation (p<0.001). The semiautomatic contour detection algorithm overestimated LV mass (180.30±44.74 g) compared with manual contour tracing (156.07±46.29 g) (p<0.001). This software allowed a significant reduction of the time needed for global LV assessment (mean 174.16±71.53 s, p<0.001). Objective quantification of LV function using the evaluated region-growing-based semiautomatic segmentation analysis software is feasible, accurate, reliable and time-effective. However, further improvements are needed to equal results achieved by manual contour tracing, especially with regard to LV mass quantification.     

Quantification of left ventricular volumes and ejection fraction from gated <Superscript>99m</Superscript>Tc-MIBI SPECT: validation of an elastic surface model approach in comparison to cardiac magnetic resonance imaging, 4D-MSPECT and QGS

Purpose The segmentation algorithm ESM based on an elastic surface model was validated for the assessment of left ventricular volumes and ejection fraction from ECG-gated myocardial perfusion SPECT. Additionally, it was compared with the commercially available quantification packages 4D-MSPECT and QGS. Cardiac MRI was used as the reference method. Methods SPECT and MRI were performed on 70 consecutive patients with suspected or proven coronary artery disease. End-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were derived from SPECT studies by using the segmentation algorithms ESM, 4D-MSPECT and QGS and from cardiac MRI. Results ESM-derived values for EDV and ESV correlated well with those from cardiac MRI (correlation coeffients R = 0.90 and R = 0.95, respectively), as did the measurements for LVEF (R = 0.86). Both EDV and ESV were slightly overestimated for larger ventricles but not for smaller ventricles; LVEF was slightly overestimated irrespective of ventricle size. The above correlation coefficients are comparable to those for the 4D-MSPECT and QGS segmentation algorithms. However, results obtained with the three segmentation algorithms are not interchangeable. Conclusion The ESM algorithm can be used to assess EDV, ESV and LVEF from gated perfusion SPECT images. Overall, the performance was similar to that of 4D-MSPECT and QGS when compared with cardiac MRI. Results obtained with the three tested segmentation methods are not interchangeable, so that the same algorithm should be used for follow-up studies and control subjects.