Assessment of global left ventricular function: comparison of cardiac multidetector-row computed tomography with angiocardiography

Severity of mitral stenosis and left ventricular mechanics: a speckle tracking study

BACKGROUND

It has been shown that mitral stenosis (MS) impairs left ventricular (LV) systolic function; however, this issue has not been studied comprehensively. We aimed to evaluate the role of 2D strain in the assessment of subclinical LV systolic dysfunction in patients with MS.

METHODS

Seventy-two patients with isolated MS (mild, moderate and severe) and 31 healthy control subjects constituted the study population. 2D echocardiography images were obtained from LV apical 4-chamber (4C), long axis (LAX), and 2-chamber (2C) views. Peak longitudinal strain and strain rate (Sr) were obtained from 4C, LAX, and 2C views. Global strain and Sr were calculated by averaging the three apical views.

RESULTS

There were no significant differences in LV ejection fraction and LV systolic or diastolic dimensions between the groups. Patients with MS had significantly lower LV longitudinal strain and Sr measurements than the control group. In addition, there were no significant differences in MS subgroups with respect to LV strain and Sr measurements.

CONCLUSION

We demonstrated that patients with MS had lower LV functions using 2D strain imaging, and this is independent of the hemodynamic severity of MS. In the detection of subclinical LV dysfunction in patients with MS, 2D strain imaging appears to be useful.

PET/CT challenge for the non-invasive diagnosis of coronary artery disease

This review will focus on the clinical potential of PET/CT for the characterization of cardiovascular diseases. We describe the technical challenges of combining instrumentation with very different imaging performance and discuss the clinical applications in the field of cardiology.

Semi-automatic assessment of global left ventricular function and left ventricular parameters with dual-source computed tomography: comparison with invasive angiography

This study assesses the global left ventricular function and volumes using dual-source computed tomography (DSCT) with improved temporal resolution (83 ms) by use of a semi-automatic software tool in comparison to invasive angiography (IVA). One hundred patients scheduled for invasive coronary angiography because of suspected or known coronary artery disease (80 men; 20 women, mean age 62 +/- 10 years) were additionally examined by DSCT. Global left ventricular function (LVF), left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), and stroke volume (SV) were calculated by the use of semi-automatic post-processing software and results compared with those of IVA. Bland-Altman analysis revealed a good concordance between DSCT and IVA in terms of LVF: Pearson's r 0.78, confidence interval [CI] 0.68-0.86, P < 0.0001, bias 7.1% +/- 9.1%. The same was true for LVESV (Pearson's r 0.78, CI 0.67-0.85, P < 0.0001, bias 15.0 +/- 21.0 ml), whereas the agreement for LVEDV and SV was only moderate (LVEDV: Pearson's r 0.59, CI 0.43-0.72, P < 0.0001, bias 13.0 +/- 18.1 ml; SV: Pearson's r 0.47, CI 0.28-0.62, P < 0.0001, bias -1.4 +/- 28.4 ml). Semi-automatic evaluation of left ventricular parameters with DSCT revealed good correlation for LVF and LVESV, whereas LVEDV and SV showed only a moderate correlation. Moreover, LVF is systematically underestimated by DSCT.

Accuracy of the long-axis area-length method for the measurement of left ventricular volumes and ejection fraction using multidetector computed tomography

BACKGROUND

Multidetector computed tomography (MDCT) is useful for assessing left ventricular (LV) volumes and function. Validation has mainly been carried out using Simpson's method of summing up consecutive short-axis areas. Because the latter method is time-consuming, many users prefer using a quicker method, based on a single view or a pair of views.

OBJECTIVES

To evaluate the accuracy of the long-axis area-length method (AL), which has not been validated for MDCT, using Simpson's method as the gold standard, as well as right anterior oblique LV angiography as a clinical standard.

METHODS

Twenty-three patients admitted with acute chest pain were clinically evaluated with electrocardiogram-gated MDCT and invasive LV angiography. MDCT-based end-diastolic, end-systolic and stroke volumes, and ejection fraction (EF) were calculated using Simpson's method, biplane AL and single-plane AL. For LV angiography, EF was calculated using single-plane AL.

RESULTS

A Bland-Altman analysis showed a close agreement between biplane AL and Simpson's method for EF, with 1% underestimation, 95% CI of +/-11% and a correlation of 0.89. For end-diastolic, end-systolic and stroke volumes, overestimations of 7 mL, 4 mL and 2 mL, and 95% CI of +/-27 mL, +/-15 mL and +/-26 mL, respectively were found. Correlation coefficients were 0.95, 0.97 and 0.82, respectively. Comparisons with LV angiography were considerably weaker. The vertical long-axis AL method by MDCT correlated better with both LV angiography and Simpson's method than the horizontal long-axis AL method.

CONCLUSIONS

The biplane AL method gives results for EF, which correspond closely with the more cumbersome Simpson's method, although volumes are slightly overestimated.

Quantitative 4-dimensional volumetric analysis of left ventricle in ischemic heart disease by 64-slice computed tomography: a comparative study with invasive left ventriculogram

OBJECTIVE

To elucidate the usefulness of CT in evaluating left ventricular (LV) volumes and ejection fraction (EF) in ischemic heart disease (IHD), we compared 64-slice CT with conventional left ventriculography (CLVG).

MATERIALS AND METHODS

71 subjects with suspected or confirmed IHD underwent ECG-gated enhanced CT before or after cardiac catheterization. End-diastolic volume (EDV) and end-systolic volume (ESV) of LV were selected in 20 phases of R-R interval of ECG, and data sets were reconstructed to determine EDV, ESV, SV, and EF of LV using a multislice area summation method; in CLVG these parameters were calculated from the right anterior oblique 30-degree projection.

RESULTS

Correlation coefficients between CT and CLVG for EDV, ESV, SV, and EF were 0.759, 0.895, 0.550, and 0.836, respectively (P<0.01). In 35 subjects without apical asynergy of LV wall motion, correlation coefficients between CT and CLVG were 0.77, 0.91, 0.63, and 0.87 respectively (P<0.01); in 36 subjects, with apical asynergy, the correlation coefficients were 0.751, 0.875, 0.503, and 0.738, respectively (P<0.01). The limits of agreement of all parameters were wider in the subjects with apical asynergy of LV wall motion than the subjects without.

CONCLUSION

There was good correlation between EDV, ESV, SV, and EF estimated by CT and those by CLVG, but CT tended to overestimate EDV and ESV and underestimate EF. In subjects with apical asynergy of LV wall motion, estimates of EF were less correlated between CT and CLVG and the limits of agreement of all parameters were wider than in those without. These discrepancies may come from the capability of CT to estimate LV wall asynergy 3-dimensionally and more accurately.

Estimation of global and regional cardiac function using 64-slice computed tomography: A comparison study with echocardiography, gated-SPECT and cardiovascular magnetic resonance

BACKGROUND

Sixty-four-slice multidetector spiral computed tomography (CT) has improved temporal resolution and reduced acquisition time. We aimed to evaluate the functional analysis using 64-slice CT comparing with echocardiography, electrocardiographically gated single-photon emission tomography (SPECT) and cardiovascular magnetic resonance (CMR).

METHODS

Six-three patients (77.4+/-18.6 bpm) underwent 64-slice CT and CMR (echocardiography in 55; SPECT in 33) within 2 weeks were retrospectively reviewed. The left ventricular volumetric data from different methods were compared with CMR. Regional wall motion was compared between CT and CMR in a 17-segment and 4-point system (1=normal to 4=akinesis/dyskinesis).

RESULTS

Ejection fraction (EF), end-diastolic volume (EDV) and end-systolic volume (ESV) by CT agreed well with CMR (bias+/-SD, -0.22%+/-4.18, r=0.97;-0.59 mL+/-15.21, r=0.98; 1.09 mL+/-10.61, r=0.99) over a wide range of left ventricular (LV) function (EF 18-76% by CMR). Our results also showed good correlation of EF measured by CT and echocardiography (r=0.87) or SPECT (r=0.91, all P<0.0001); however, standard deviation of EF difference between CT and CMR was significantly less than echocardiography or SPECT (P<0.005). For regional wall motion, an exact agreement of 97% (kappa=0.91) was found between CT and CMR.

CONCLUSION

Sixty-four-slice CT agreed well with CMR in LV function assessment, and had a superior accuracy than echocardiography and SPECT on EF estimation. Sixty-four-slice CT is considered a clinically acceptable and robust method to evaluate LV function.

Clinical value of multidetector CT coronary angiography as a preoperative screening test before non-coronary cardiac surgery

OBJECTIVE

Myocardial scintigraphy and/or conventional angiography (CA) are often performed before cardiac surgery in an attempt to identify unsuspected coronary artery disease which might result in significant cardiac morbidity and mortality. Multidetector CT coronary angiography (MDCTCA) has a recognised high negative predictive value and may provide a non-invasive alternative in this subset of patients. The aim of this study was to evaluate the clinical value of MDCTCA as a preoperative screening test in candidates for non-coronary cardiac surgery.

METHODS

132 patients underwent MDCTCA (Somatom Sensation 16 Cardiac, Siemens) in the assessment of the cardiac risk profile before surgery. Coronary arteries were screened for > or = 50% stenosis. Patients without significant stenosis (Group 1) underwent surgery without any adjunctive screening tests while all patients with coronary lesions > or = 50% at MDCTCA (Group 2) underwent CA.

RESULTS

16 patients (12.1%) were excluded due to poor image quality. 72 patients without significant coronary stenosis at MDCTCA were submitted to surgery. 30 out of 36 patients with significant (> or = 50%) coronary stenosis at MDCTCA and CA underwent adjunctive bypass surgery or coronary angioplasty. In 8 patients, MDCTCA overestimated the severity of the coronary lesions (> 50% MDCTCA, < 50% CA). No severe cardiovascular perioperative events such as myocardial ischaemia, myocardial infarction or cardiac failure occurred in any patient in Group 1.

CONCLUSIONS

MDCTCA seems to be effective as a preoperative screening test prior to non-coronary cardiac surgery. In this era of cost containment and optimal care of patients, MDCTCA is able to provide coronary vessel and ventricular function evaluation and may become the method of choice for the assessment of a cardiovascular risk profile prior to major surgery.

[Evaluation of cardiac function with 32DAS MDCT--fundamental examination]

Cardiac images were taken in altered pulse counts on a pulsating cardiac phantom, revolving speed of X-ray tube, image reconstructing mode, and beam pitch with 32 DAS MDCT. The objective of this study was to determine whether conditions of image taking affect calculated values of ejection fraction (EF). Moreover, the EF values measured by left ventriculography (LVG) and by coronary computed tomography (CT) were compared using clinical data of 4 patients who underwent both coronary CT and LVG. On evaluating the pulsating cardiac phantom images, the EF values measured by coronary CT were generally smaller than those measured by LVG. On evaluation of the pulsating cardiac phantom images, the values of end-diastolic volume (EDV) and end-systolic volume (ESV) measured by coronary CT were smaller than those measured by LVG. On the contrary, the EF values measured by coronary CT were bigger than those measured by LVG. The maximal difference between the EF values measured by LVG and those measured by coronary CT was approximately 10% based upon the values measured by LVG.

Comprehensive cardiac CT study: evaluation of coronary arteries, left ventricular function, and myocardial perfusion--is it possible?

With advances in multidetector computed tomography (MDCT) technology, the new generation of 64-slice MDCT scanners with submillimeter collimation and a faster gantry rotation allows imaging of the entire heart in a single breath-hold with excellent temporal and spatial resolution. This potentially permits a comprehensive assessment of coronary anatomy, left ventricular function, and myocardial perfusion. As will be seen in this review of the current literature regarding 16- and 64-slice MDCT, there is great promise for a comprehensive cardiac computed tomography (CT) study. The available data support the notion that CT coronary angiography may be an alternative to invasive coronary angiography in symptomatic patients with a low to intermediate likelihood of having coronary artery disease. By use of the same data acquired for CT coronary angiography, evaluation of global and regional left ventricular function and myocardial perfusion can be added to the MDCT evaluation without additional exposure to contrast medium or radiation and may provide a more conclusive cardiac workup in these patients. The potential applications and limitations of coronary stenosis detection, global and regional left ventricular function, and myocardial perfusion assessment by MDCT will be reviewed. The full potential of cardiac MDCT is just beginning to be realized.

Indications for Coronary and Cardiac Computed Tomographic Angiography

Cardiovascular disease remains the leading cause of death and disability in the developed world. Over the last several years, many noninvasive imaging techniques have been used to enhance the diagnosis of cardiac disease. One of these advances, multidetector computed tomographic angiography (CTA), has transformed computed tomography from a single-slice transaxial imaging modality to a true 3-dimensional imaging technique with the ability to acquire submillimeter volumetric data. These benefits enable novel applications of CTA for the assessment of cardiac and coronary anatomy that were not previously possible. In this report, we discuss evolving indications for coronary CTA, noncoronary cardiac CTA, and several potential future indications for cardiac CTA.

MDCT of Right Ventricular Function: Comparison of Right Ventricular Ejection Fraction Estimation and Equilibrium Radionuclide Ventriculography, Part 1

OBJECTIVE

The aim of this study was to calculate right ventricular ejection fraction by use of ECG-gated MDCT and to compare the results with those of equilibrium radionuclide ventriculography.

SUBJECTS AND METHODS

Forty-nine consecutively examined patients (30 men, 19 women; mean age, 59 years) with known or suspected right ventricular dysfunction secondary to bronchopulmonary (n = 30) or pulmonary vascular (n = 19) disease underwent ECG-gated 16-MDCT angiography of the heart (rotation time, 0.42 second; 120 kV; 300 mAs; collimation, 12 x 0.75 mm; pitch, 0.2) after CT angiographic examination of the entire thorax according to a standard protocol. Biphasic administration of a 30% contrast agent was systematically performed (phase 1, 90 mL at 3 mL/s; phase 2, 30 mL at 1.5 mL/s); no patient received additional medication. Right ventricular ejection fraction was calculated after two reviewers in consensus determined the reconstruction windows and segmentation of the right ventricular cavity on a series of diastolic and systolic short-axis images. The results were compared with those of equilibrium radionuclide ventriculography.

RESULTS

At data acquisition, the mean (+/- SD) heart rate of the study group was 82 +/- 13.87 beats per minute (BPM) (range, 51-115 BPM). ECG showed a sinus rhythm in 30 (61%) of the patients and irregular cardiac rhythm in 19 (39%) of the patients. Agreement between the two techniques was estimated by intraclass correlation coefficient (0.77), the method of Bland and Altman (limits of concordance, -14.9 and 13.7), and percentage of variability between two measurements expressed by mean absolute percentage error (12.1%). The estimated effective dose for heart examination was 7.48 mSv with CT and 5 mSv with scintigraphy. The mean effective dose for the chest and heart CT examinations was 11.64 mSv.

CONCLUSION

Right ventricular ejection fraction can be reliably estimated with 16-MDCT in unselected patients.

Thick Maximum Intensity Projections for the Assessment of Left Ventricular Function With 64-Slice Computed Tomography

OBJECTIVE

The objective of this study was to assess the accuracy of thick maximum intensity projections (MIP) from computed tomography (CT) data sets mimicking projection images from biplane ventriculography for evaluation of left ventricular (LV) parameters.

MATERIALS AND METHODS

Fifty-eight patients underwent 64-slice CT. Multiphase images were reconstructed in 10% steps of the RR interval. MIP images (70-mm thickness) of the contrast-enhanced LV in fixed 30 degrees right anterior oblique (RAO)/60 degrees left anterior oblique (LAO) and in adapted short-/long-axis planes were reconstructed. LV parameters were calculated using the area-length method formula. Three-dimensional assessment with semiautomated software served as reference standard.

RESULTS

Use of thick MIP reconstructions had a high intermethod reliability (86-94%) compared with the 3-dimensional approach. Smaller measurement errors were found for thick MIP reconstructions in adapted short-/long-axis planes. A significant projection error (3.0%, P < 0.001) of thick MIP reconstructions was found using fixed 30 degrees RAO/60 degrees LAO compared with adapted short-/long-axis reconstructions.

CONCLUSION

Thick MIP reconstructions with adapted short-/long-axis planes allow an accurate assessment of LV parameters compared with the established 3-dimensional method.