Assessment of left ventricular function: comparison of cardiac multidetector-row computed tomography with two-dimension standard echocardiography for assessment of left ventricular function

The Potential Role of Cardiac CT in the Evaluation of Patients With Known or Suspected Cardiomyopathy: From Traditional Indications to Novel Clinical Applications

After 15 years from its advent in the clinical field, coronary computed tomography (CCTA) is now widely considered as the best first-step test in patients with low-to-moderate pre-test probability of coronary artery disease. Technological innovation was of pivotal importance for the extensive clinical and scientific interest in CCTA. Recently, the advent of last generation wide-coverage CT scans paved the way for new clinical applications of this technique beyond coronary arteries anatomy evaluation. More precisely, both biventricular volume and systolic function quantification and myocardial fibrosis identification appeared to be feasible with last generation CT. In the present review we would focus on potential applications of cardiac computed tomography (CCT), beyond CCTA, for a comprehensive assessment patients with newly diagnosed cardiomyopathy, from technical requirements to novel clinical applications.

Analysis of left ventricular function, left ventricular outflow tract and aortic valve area using computed tomography: Influence of reconstruction parameters on measurement accuracy

Objectives:

Computed tomography (CT) allows reproducible assessment of left ventricular (LV) function, left ventricular outflow tract area (LVOT_area) and aortic valve area (AVA). We evaluated the influence of image reconstruction parameters on these measurements.

Methods:

We analyzed 45 contrast-enhanced, retrospectively ECG-gated CT datasets acquired on a third-generation dual source system. A standard filtered-back-projection data set (20 cardiac phases (5% steps, 0–95%), 0.6-mm-slice thickness, 512 × 512 matrix) and eight reconstructions with modified slice thickness (1–8 mm), number of cardiac phases (5, 10), matrix size (256×256) and an iterative reconstruction (IR) algorithm were obtained. LV parameters (ejection fraction (EF), stroke volume (SV), end-diastolic (EDV), end-systolic volumes (ESV)), LVOT_area and AVA were assessed.

Results:

Differences in LV parameters, LVOT_area and AVA, were only minimal between standard reconstructions and those with modified matrix size, IR algorithm and ≤2 mm slice thickness, while reconstructions with 8-mm slice thickness significantly overestimated SV (p < 0.001) and EDV (p = 0.016). AVA planimetry in reconstructions with ≥5 mm slice thickness was not feasible in 56% of patients. A decrease in the number of reconstructed phases (10 or 5) underestimated EF, SV, EDV, LVOT_area and AVA and overestimated ESV.

Conclusions:

Modifications of reconstruction parameters (except a slice thickness ≤2 mm) have only a marginal effect on LV, LVOT_area and AVA assessment. However, a reduced number of reconstructions per cardiac cycle may significantly influence measurements.

Advances in knowledge:

Substantial modifications in number of reconstructions per cardiac cycle significantly affect the assessment of LV function, LVOT_area and AVA also in modern CT scanners.

Global left ventricular function assessment by ECG-gated multi-detector CT (MDCT): revised role in relation to 2D transthoracic echocardiography

Background

An accurate and reproducible way for determining the left ventricular function is crucial to provide diagnostic and prognostic aspects of the pump activity of the heart. The MDCT of the heart can be that modality. We compared the 128 MDCT of fifty patients with their 2D echocardiography performed on the same day.

Results

Mean EF, ESV, EDV, and LV mass were 61.22 ± 9.50%, 70.23 ± 38.35, 172.22 ± 53.57, 164.63 ± 52.57 respectively on MDCT, and 61.14 ± 10.90%, 72.13 ± 32.69, 173.76 ± 62.45, 198.32 ± 72.54 respectively on echocardiography with moderate correlation in EF and good correlation in ventricular volumes (p < 0.05) using linear regression analysis. A Bland-Altman analysis showed that MDCT had slightly lower LFEF, LVESV, and LVEDV values with mean value of differences of 0.8, 2.4, and 2.28 respectively.

Conclusion

It is reasonable to use MDCT alone to assess LV function in patients already underwent coronary CT angiography.

Role of cardiac CTA in estimating left ventricular volumes and ejection fraction

Left ventricular ejection fraction (LVEF) is an important predictor of cardiac outcome and helps in making important diagnostic and therapeutic decisions such as the treatment of different types of congestive heart failure or implantation of devices like cardiac resynchronization therapy-defibrillator. LVEF can be measured by various techniques such as transthoracic echocardiography, contrast ventriculography, radionuclide techniques, cardiac magnetic resonance imaging and cardiac computed tomographic angiography (CTA). The development of cardiac CTA using multi-detector row CT (MDCT) has seen a very rapid improvement in the technology for identifying coronary artery stenosis and coronary artery disease in the last decade. During the acquisition, processing and analysis of data to study coronary anatomy, MDCT provides a unique opportunity to measure left ventricular volumes and LVEF simultaneously with the same data set without the need for additional contrast or radiation exposure. The development of semi-automated and automated software to measure LVEF has now added uniformity, efficiency and reproducibility of practical value in clinical practice rather than just being a research tool. This article will address the feasibility, the accuracy and the limitations of MDCT in measuring LVEF.

Chamber dimensions and functional assessment with coronary computed tomographic angiography as compared to echocardiography using American Society of Echocardiography guidelines

Background:

The correlation between normal cardiac chamber linear dimensions measured during retrospective coronary computed tomographic angiography as compared to transthoracic echocardiography using the American Society of Echocardiography guidelines is not well established.

Methods:

We performed a review from January 2005 to July 2011 to identify subjects with retrospective electrocardiogram-gated coronary computed tomographic angiography scans for chest pain and transthoracic echocardiography with normal cardiac structures performed within 90 days. Dimensions were manually calculated in both imaging modalities in accordance with the American Society of Echocardiography published guidelines. Left ventricular ejection fraction was calculated on echocardiography manually using the Simpson’s formula and by coronary computed tomographic angiography using the end-systolic and end-diastolic volumes.

Results:

We reviewed 532 studies, rejected 412 and had 120 cases for review with a median time between studies of 7 days (interquartile range (IQR_25,75) = 0–22 days) with no correlation between the measurements made by coronary computed tomographic angiography and transthoracic echocardiography using Bland–Altman analysis. We generated coronary computed tomographic angiography cardiac dimension reference ranges for both genders for our population.

Conclusion:

Our findings represent a step towards generating cardiac chamber dimensions’ reference ranges for coronary computed tomographic angiography as compared to transthoracic echocardiography in patients with normal cardiac morphology and function using the American Society of Echocardiography guideline measurements that are commonly used by cardiologists.

Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR

Objectives

To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters.

Methods

Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced-steady state free precession) SAX sequence for MR, and evaluated using dedicated software.

Results

CT and MR images showed good agreement: LV EF (Ejection Fraction) (52 ± 14% for CT vs. 52 ± 14% for MR; r = 0.73; p > 0.05); RV EF (47 ± 12% for CT vs. 47 ± 12% for MR; r = 0.74; p > 0.05); LV EDV (End Diastolic Volume) (74 ± 21 ml/m² for CT vs. 76 ± 25 ml/m² for MR; r = 0.59; p > 0.05); RV EDV (84 ± 25 ml/m² for CT vs. 80 ± 23 ml/m² for MR; r = 0.58; p > 0.05); LV ESV (End Systolic Volume)(37 ± 19 ml/m² for CT vs. 38 ± 23 ml/m² for MR; r = 0.76; p > 0.05); RV ESV (46 ± 21 ml/m² for CT vs. 43 ± 18 ml/m² for MR; r = 0.70; p > 0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups.

Conclusions

Cardiac CT provides accurate and reproducible LV and RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR.

Key Points

• Cardiac-CT is able to provide Left and Right Ventricular function.

• Cardiac-CT is accurate as MR for LV and RV volume assessment.

• Cardiac-CT can provide accurate evaluation of coronary arteries and LV and RV function.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-011-2345-6) contains supplementary material, which is available to authorized users.

Effects of propranolol on the left ventricular volume of normal subjects during CT coronary angiography

OBJECTIVE

The purpose of this study is to determine the effects of propranolol on the left ventricular (LV) volume during CT coronary angiography.

MATERIALS AND METHODS

The LV volume of 252 normal Chinese subjects (126 subjects with propranolol medication and 126 age- and gender-matched Chinese subjects without medication) was estimated using 64 slices multi-detector CT (MDCT). The heart rate difference was analyzed by the logistic linear regression model with variables that included gender, age, body height, body weight, systolic blood pressure (SBP), diastolic blood pressure (DBP) and the dosage of propranolol. The following global LV functional parameters were calculated: the real-end diastolic volume (EDV), the real-end systolic volume (ESV) and the real-ejection fraction (EF).

RESULTS

The female subjects had a greater decrease of heart rate after taking propranolol. The difference of heart rate was negatively correlated with the dosage of propranolol. The real-EDV, the real-ESV and the real-EF ranged from 48.1 to 109 mL/m², 6.1 to 57.1 mL/m² and 41% to 88%, respectively. There was no significant difference in the SBP and DBP between the groups without and with propranolol medication (123 ± 17 and 80 ± 10 mmHg; 120 ± 14 and 80 ± 11 mmHg, respectively). The real-EDV showed no significant difference between these two groups, but the real-ESV and real-EF showed significant differences between these two groups (69.4 ± 9.3 and 70.6 ± 8.9 mL/m²; 23.5 ± 5.7 and 25.6 ± 3.7 mL/m², 66.5 ± 5.1% and 63.5 ± 4.6%, respectively).

CONCLUSION

The difference of heart rate is significantly influenced by gender and the dosage of propranolol. Propranolol will also increase the ESV, which contributes to a decreased EF, while the SBP, DBP and EDV are not statistically changed.

Comparison of global left ventricular function using 20 phases with 10-phase reconstructions in multidetector-row computed tomography

To compare the measurement of global left-ventricular (LV) function parameters of 64-slice multidetector-row computed tomography (MDCT) between 20- and 10-reconstruction phases. Fifty five patients with suspected or known coronary artery disease underwent 64-slice MDCT. LV end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were measured from MDCT data sets using threshold-based volume segmentation and reconstruction at every 5% (20 phases) and 10% (10 phases) step through the R-R interval. These global functional parameters were compared to those obtained via two-dimensional transthoracic echocardiography (2D-TTE), considering the reference standard. The required time for CT data analysis was checked. Agreement for parameters of LV global function was determined using Pearson's correlation coefficient (r) and Bland-Altman analysis. LV volumes (EDV(-5%) 87.5 ± 17.1 ml, EDV(-10%) 87.7 ± 16.3 ml; ESV(-5%) 32.4 ± 10.6 ml, ESV(-10%) 31.9 ± 9.9 ml; SV(-5%) 55.1 ± 10.5 ml, SV(-10%) 55.8 ± 9.9 ml; mean ± SD) and EF (EF(-5%) 63.4 ± 6.2%, EF(-10%) 63.9 ± 5.8%) did not differ significantly between the 20- and 10 phase reconstructions, and evidenced good to excellent correlation (r = 0.786-0.896, all P < 0.001) with the 2D-TTE results. The mean required time for CT data analysis in the 20- and 10 phase reconstructions were 15.5 ± 4.0 and 7.3 ± 2.5 min. Within MDCT, using 10-phase image reconstruction is sufficient to evaluate LV volumes and EF, and is also more time-effective than 20-phase reconstruction.

Assessment of global function of left ventricle with dual-source CT in patients with severe arrhythmia: a comparison with the use of two-dimensional transthoracic echocardiography

To evaluate the agreement between dual-source computed tomography (DSCT) and two-dimensional transthoracic echocardiography (2D-TTE) with respect to the assessment of global left ventricular (LV) function in patients with severe arrhythmia. With 2D-TTE serving as the reference method, we performed both DSCT and 2D-TTE, at an interval of less than 2 days, in 54 patients with severe arrhythmia (average heart rate difference >30 beats per min) before open heart surgery for evaluation of valvular heart disease (VHD) and coronary artery disease. DSCT was performed using retrospective electrocardiography (ECG) without dose modulation. Ten phases of the cardiac cycle were analyzed for identification of end-diastolic and end-systolic phases with ECG-editing. Pearson's correlation coefficient (r) and Bland-Altman analysis were used to determine agreement for parameters of LV global function. Correlation between DSCT and 2D-TTE measurements was good or excellent in terms of the values of the LV ejection fraction (51.0 ± 11.4% vs. 55.8 ± 11.6%; r = 0.8), LV end-diastolic volume (179.5 ± 98.6 ml vs. 152.1 ± 73.8 ml; r = 0.95), LV end-systolic volume (90.7 ± 60.7 ml vs. 69.1 ± 46.8 ml; r = 0.90), and LV stroke volume (89.0 ± 48.1 ml vs. 82.9 ± 37.3 ml; r = 0.89). Left ventricular ejection fraction measured using DSCT was less than that measured using 2D-TTE by an average of -4.8 ± 7.3%. Dual-source CT with ECG editing can provide results comparable to those of 2D-TTE for assessment of LV global function in patients with severe arrhythmia.

Assessment of left ventricular ejection fraction and regional wall motion with 64-slice multidetector CT: a comparison with two-dimensional transthoracic echocardiography

The aim of this study was to compare the measurement of left ventricular ejection fraction (LVEF) and regional wall motion using 64-slice multidetector CT (MDCT) with that using two-dimensional transthoracic echocardiography (2D-TTE) in a heterogeneous patient population. In 126 patients with angina pectoris, acute myocardial infarction, chronic myocardial infarction, atypical chest pain without coronary artery disease or valvular heart disease, 64-slice MDCT was performed using retrospective electrocardiography gating without dose modulation. 20 phases of the cardiac cycle were analysed to identify the end-diastolic and end-systolic phases and to assess regional LV wall motion. For these measurements, 2D-TTE served as the reference standard. MDCT and 2D-TTE were performed within 10 days of each other. An excellent correlation between MDCT and 2D-TTE was shown for the evaluation of LVEF (59.2+/-11% vs 57.9+/-10%, respectively; r = 0.87). LVEF was slightly overestimated by MDCT, when compared with 2D-TTE, by an average of 1.4+/-5.6%. Good agreement was obtained between the use of the two techniques, with 94% of the segments scored identically on both modalities (kappa = 0.70). MDCT had a sensitivity of 97% and a specificity of 82% when compared with 2D-TTE as the reference standard. In conclusion, the use of 64-slice MDCT can provide comparable results to those using 2D-TTE for LVEF and regional wall motion assessment in a heterogeneous population.

Real-time three-dimensional echocardiographic left ventricular systolic assessment: side-by-side comparison with 64-slice multi-detector cardiac computed tomography

AIMS

To investigate by real-time 3D echocardiography (RT3DE) and cardiac computed tomography (CCT) the analysis of left ventricle ejection fraction (LVEF) and volumes.

METHODS AND RESULTS

A total of 67 patients (37 males, 55 +/- 11 years) were studied prospectively by RT3DE and by 64-slice CCT. RT3DE data: LVEF ranged from 30 to 78.6% (63.1 +/- 7.33); left ventricular end-diastolic volume (LVEDV) from 44.1 to 210 (104.9 +/- 29.7) mL; left ventricular end-systolic volume (LVESV) from 11.4 to 149 ( 38.9 +/- 19.3) mL. CCT data: LVEF ranged from 28 to 86% (66 +/- 8.4); LVEDV from 51 to 212 (110.3 +/- 31.2) mL; LVESV from 7 to 152 (38.2 +/- 19.2) mL. Correlations relative to RT3DE and CCT were: LVEF (r: 0.79, P < 0.0001); LVEDV (r: 0.82, P < 0.0001); and LVESV (r: 0.91, P < 0.0001).

CONCLUSION

It was observed adequate correlation between RT3DE and CCT ventricular systolic function and geometry assessment.