Left ventricular function studied with MDCT

Deep learning-based whole-heart segmentation in 4D contrast-enhanced cardiac CT

Automatic cardiac chamber and left ventricular (LV) myocardium segmentation over the cardiac cycle significantly extends the utilization of contrast-enhanced cardiac CT, potentially enabling in-depth assessment of cardiac function. Therefore, we evaluate an automatic method for cardiac chamber and LV myocardium segmentation in 4D cardiac CT. In this study, 4D contrast-enhanced cardiac CT scans of 1509 patients selected for transcatheter aortic valve implantation with 21,605 3D images, were divided into development (N = 12) and test set (N = 1497). 3D convolutional neural networks were trained with end-systolic (ES) and end-diastolic (ED) images. Dice similarity coefficient (DSC) and average symmetric surface distance (ASSD) were computed for 3D segmentations at ES and ED in the development set via cross-validation, and for 2D segmentations in four cardiac phases for 81 test set patients. Segmentation quality in the full test set of 1497 patients was assessed visually on a three-point scale per structure based on estimated overlap with the ground truth. Automatic segmentation resulted in a mean DSC of 0.89 ± 0.10 and ASSD of 1.43 ± 1.45 mm in 12 patients in 3D, and a DSC of 0.89 ± 0.08 and ASSD of 1.86 ± 1.20 mm in 81 patients in 2D. The qualitative evaluation in the whole test set of 1497 patients showed that automatic segmentations were assigned grade 1 (clinically useful) in 98.5%, 92.2%, 83.1%, 96.3%, and 91.6% of cases for LV cavity and myocardium, right ventricle, left atrium, and right atrium. Our automatic method using convolutional neural networks performed clinically useful segmentation across the cardiac cycle in a large set of 4D cardiac CT images, potentially enabling in-depth assessment of cardiac function.

Clinical utility of early postoperative cardiac multidetector computed tomography after coronary artery bypass grafting

We evaluated the clinical utility of early postoperative cardiac computed tomography (CT) for evaluating left ventricular (LV) function and predicting prognosis in patients who had undergone coronary artery bypass grafting (CABG). Of the 205 patients who underwent CABG from March 2011 to December 2014, 136 underwent early postoperative cardiac CT (within 30 days after CABG) and were enrolled as the study population. The baseline and postoperative follow-up echocardiographic findings, major adverse cardiac events (MACE), and death were recorded for a follow-up period (mean, 5.9 ± 1.1 years). Functional cardiac CT parameters were compared to echocardiographic measurements. The associations between cardiac CT findings and functional recovery and prognosis were evaluated by logistic regression analyses. The LVEF measured via cardiac CT was significantly higher (56.2 ± 11.5% vs. 61.9 ± 12.9%; p = 0.0002) compared to those via early postoperative echocardiography, but the wall motion score index (WMSI) was not significantly different (1.23 ± 0.33 vs. 1.21 ± 0.28, p = 0.5041) between the two methods. During the follow-up period, 17 patients (12.5%) died and 40 (29.4%) developed MACE. Both the LVEF and WMSI measured with early postoperative echocardiography (p = 0.0202 and odds ratio [OR] = 5.0171, p = 0.0039, respectively), and cardiac CT (OR = 0.9625, p = 0.0091 and OR = 14.3605, p = 0.0001, respectively) predicted MACE OR = 0.9630, but only the WMSI, measured using cardiac CT, predicted all-cause death (OR = 10.6017, p = 0.0035). In CABG patients, LVEF and the WMSI measured with early postoperative cardiac CT were comparable with echocardiography and predicted the development of MACE and all-cause death.

Cardiac left ventricular myocardial tissue density, evaluated by computed tomography and autopsy

BACKGROUND

Left ventricular mass (LVM) is an independent risk factor for the prediction of cardiac events. Its assessment is a clinically important diagnostic procedure in cardiology and may be performed by Computed Tomography (CT). The aim of this study was to assess the correlation between the cardiac left ventricular shell volume (LVShV) determined by postmortem Computed Tomography (PMCT) and the anatomic LVM obtained at autopsy and to calculate the myocardial tissue density.

METHODS

A total of 109 deceased individuals were examined with a 64-slice CT scanner and LVShV was determined. At autopsy, the left ventricle was dissected and weighted. The correlation between LVShV and the anatomic LVM was analysed. Asymmetric left ventricular (LV) hypertrophy was recorded. Inter-observer variability was evaluated, and a density value for myocardial tissue was calculated.

RESULTS

The mean age of the deceased was 55 ± 16 years, and 58% was men. We found 30 cases of asymmetric LV hypertrophy. A highly positive correlation existed between LVShV and anatomic LVM (r = 0.857; p < 0.0001), regardless of hypertrophy, asymmetric hypertrophy and gender. The mean difference in the inter-observer variability for LVShV assessment was - 4.4 ml (95% CI: -26.4; 17.6). A linear regression analysis was performed, resulting in a value of 1.265 g/ml for myocardial tissue density. Applying the hitherto used myocardial tissue density of 1.055 g/ml underestimated the anatomic LVM by 18.1% (p < 0.0001).

CONCLUSION

PMCT is a helpful tool for the assessment of LVM, and LVShV is highly correlated with LVM as assessed by subsequent autopsy. The correlation between the two was independent of gender, hypertrophy and LV asymmetric hypertrophy. We found a higher myocardial tissue density of 1.265 g/ml compared to previous studies. We show that PMCT combined with autopsy may contribute not only to anatomical but also clinical knowledge.

Dose levels and image quality of second-generation 128-slice dual-source coronary CT angiography in clinical routine

OBJECTIVES

To compare radiation exposure and image quality of second-generation 128-slice dual-source CT (DSCT) coronary angiography (cCTA) protocols.

MATERIALS AND METHODS

We retrospectively analyzed data from four groups with 25 patients, each examined by one of the following DSCT cCTA protocols: prospectively ECG-gated high-pitch (group 1) or sequential (group 2) acquisition, retrospectively ECG-gated acquisition in dual-energy (DECT, group 3) or dual-source (group 4) mode. CT dose index volume, dose length product, estimated radiation dose, contrast-to-noise- and signal-to-noise-ratios were compared. Subjective image quality was rated by two observers blinded to the protocols.

RESULTS

High-pitch DSCT showed a mean estimated radiation dose of 1.27 ± 0.62 mSv, significantly (p < 0.01) lower than sequential (2.04 ± 0.94 mSv), dual-energy (3.97 ± 1.29 mSv) or dual-source (8.11 ± 4.95 mSv) acquisition. Image noise showed no statistical difference (p > 0.91), ranging from 15.2 ± 4.4 (group 2) up to 24.5 ± 22.0 (group 4). Each protocol showed diagnostic image quality in at least 98.1 % of evaluated coronary segments without significant differences (p > 0.05).

CONCLUSIONS

Prospectively ECG-gated DSCT protocols enable cCTA with significant dose reduction and consistently diagnostic image quality. In patients requiring retrospectively ECG-gated DSCT for functional analysis or due to arrhythmia, dual-energy mode should be preferred over dual-source mode as it significantly decreases estimated dose without compromising image quality.

Korean guidelines for the appropriate use of cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Improvement of automated right ventricular segmentation using dual-bolus contrast media injection with 256-slice coronary CT angiography

RATIONALE AND OBJECTIVES

To investigate the effect of dual-bolus contrast media injection (dual-CM) on the accuracy of automated right ventricular (RV) segmentation on coronary computed tomography angiography (CCTA).

MATERIALS AND METHODS

A total of 104 patients with suspected and known coronary artery disease underwent 256-slice CCTA with retrospective electrocardiographic (ECG) gating. The patients were divided into 51 patients who underwent single-bolus CM injection (single-CM) and 53 patients who underwent dual-CM. The dual-CM method consisted of an initial bolus of CM followed by an injection of dilute CM with saline (CM:saline, 1:9). Three-dimensional CCTA images were automatically segmented into the RV, left ventricle (LV), and myocardium using commercially available software (Comprehensive Cardiac Analysis; Philips Medical Systems, Cleveland, OH). Prevalence and locations of segmentation errors were compared between single-CM and dual-CM. Segmentation errors were defined as segment deviation of >1 cm from the actual ventricular margin.

RESULTS

Prevalence of segmentation errors was significantly lower with dual-CM than with single-CM in the diastolic phase (4/41 vs. 20/41, respectively; P < .01), and there was no difference between the two methods in the systolic phase (2/12 vs. 2/10, respectively). With dual-CM and single-CM, the locations of segmentation errors were mostly the RV wall (4/53 and 18/51, respectively) and secondly the LV wall (2/53 and 9/51, respectively).

CONCLUSIONS

Dual-CM improved the accuracy of automated ventricular segmentation using diastolic data from 256-slice CCTA.

CT-scan images preprocessing and segmentation to improve bioprosthesis leaflets morphological analysis

The visualization of bioprosthesis leaflet morphology might help to better understand the underlying mechanism of dysfunction in degenerated aortic bioprosthesis. Because today such visualization of bioprosthesis leaflet morphology is intricate to impossible with other imaging techniques, we hypothesized that the processing of multi-detector CT images would allow better visualization of the prosthetic valve leaflets after biological aortic valve replacement. The purpose of our study was to prospectively evaluate patients with a degenerated aortic bioprosthesis, waiting for reoperation, by using 64-slice CT to evaluate prosthetic leaflets morphology. A semi-automatic segmentation of pre-operative tomodensitometric images was conducted, using 2 different implementations of the region growing algorithm. Here we report all segmentation steps (selection of the region of interest, filtering, segmentation). Studied degenerated aortic bioprostheses were represented by two Carpentier-Edwards Supra Annular Valve (porcine leaflets), one Edwards Perimount (pericardial leaflets) and one Medtronic Mosaic (porcine leaflets). Both segmentation methods (Isotropic Region Growing and Stick Region Growing) allowed a semi-automatic segmentation with 3D reconstruction of all bioprosthetic components (stent, leaflets, degeneration/calcifications). Explanted bioprosthesis CT images were also processed and used as reference. Segmentation results were compared by means of quantitative criteria. Semi-automatic segmentation using region growing algorithm seems to provide an interesting approach for the morphological characterization of degenerated aortic bioprostheses. We believe that in the next future CT scan images segmentation may play an important role to better understand the mechanism of dysfunction in failing aortic bioprostheses. Moreover, bioprostheses 3D reconstructions could be integrated into preoperative planning tools to optimize valve-in-valve procedure.

Assessment of global left ventricular function with dual-source computed tomography in patients with valvular heart disease

BACKGROUND

Left ventricular (LV) function is a vital parameter for prognosis, therapy guidance, and follow-up of cardiovascular disease. Dual-source computed tomography (DSCT) provides an accurate analysis of global LV function.

PURPOSE

To assess the performance of DSCT in the determination of global LV functional parameters in comparison with cardiovascular magnetic resonance (CMR) and two-dimensional transthoracic echocardiography (2D-TTE) in patients with valvular heart disease (VHD).

MATERIAL AND METHODS

A total of 111 patients (58 men, mean age 49.9 years) with known VHD and who underwent DSCT, 2D-TTE, and CMR a period of 2 weeks before undergoing valve surgery were included in this study. LV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) were calculated by DSCT using the threshold-based technique, by 2D-TTE using a modified Simpson's method, and by CMR using Simpson's method. Agreement for parameters of LV global function was determined with the Pearson's correlation coefficient (r) and Bland-Altman analysis. All the DSCT and CMR data-sets were assessed independently by two readers.

RESULTS

Fifty of the total 111 patients had aortic VHD, 29 patients had mitral VHD, and 32 patients had mixed aortic and mitral VHD. An excellent inter-observer agreement was seen for the assessment of global LV function using DSCT (r = 0.910-0.983) and CMR (r = 0.854-0.965). An excellent or good correlation (r = 0.93, 0.95, 0.87, and 0.71, respectively, P < 0.001) was noted between the DSCT and 2D-TTE values for EDV, ESV, SV, and EF. EDV (33.7 mL, P < 0.001), ESV (12.1 mL, P < 0.001), SV (21.2 mL, P < 0.001), and EF (1.6%, P = 0.019) were significantly overestimated by DSCT when compared with 2D-TTE. An excellent correlation (r = 0.96, 0.97, 0.91, and 0.94, respectively, P < 0.001) between DSCT and CMR was seen in the evaluation of EDV, ESV, SV, and EF. EDV (15.9 mL, P < 0.001), ESV (7.3 mL, P < 0.001), and SV (8.5 mL, P < 0.001) were significantly underestimated, but EF (1.1%, P = 0.002) was significantly overestimated by DSCT when compared with CMR.

CONCLUSION

Our study showed that DSCT measurements of global LV function using the threshold-based technique were highly reproducible and compared more favorably with CMR measurements using Simpson's method than those of 2D-TTE using the modified Simpson's method. DSCT enables accurate quantification of global LV function in patients with VHD.

The emerging role of magnetic resonance imaging and multidetector computed tomography in the diagnosis of dilated cardiomyopathy

Magnetic resonance imaging and multidetector computed tomography are new imaging methods that have much to offer clinicians caring for patients with dilated cardiomyopathy. In this article we briefly describe the clinical, pathophysiological and histological aspects of dilated cardiomyopathy. Then we discuss in detail the use of both imaging methods for measurement of chamber size, global and regional function, for myocardial tissue characterisation, including myocardial viability assessment, and determination of arrhythmogenic substrate, and their emerging role in cardiac resynchronisation therapy.

Informatics in radiology: postprocessing pitfalls in using CT for automatic and semiautomatic determination of global left ventricular function

Recent advances in technical capabilities of computed tomographic (CT) scanners, including an increasing number of detector rows, improved spatial and temporal resolution, and the development of retrospective gating, have allowed the acquisition of four-dimensional (4D) datasets of the beating heart. As a result, the heart can be visualized in different phases and CT datasets can be used to assess cardiac function. Many software packages currently exist that allow automatic or semiautomatic evaluation of left ventricular function on the basis of 4D CT datasets. The level of automation varies from extensive, completely manual segmentation by the user to fully automatic evaluation of left ventricular function without any user interaction. Although the reproducibility of functional parameter assessment is reported to be high and intersoftware variability low for larger groups of patients, significant differences can exist among measurements obtained with different software tools from the same dataset. Thus, careful review of automatically or semiautomatically obtained results is required.

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.

Novel techniques for assessment of left ventricular systolic function

The evaluation of left ventricular systolic function is one of the most common reasons for referral for a non-invasive cardiac imaging study. In addition to its diagnostic and prognostic value, an assessment of ejection fraction can also be used to guide medical and device therapy. Thus, obtaining an accurate and reproducible assessment of LVEF is essential for patient management. This review will focus on novel multi-modality techniques used for the quantification of left ventricular systolic function. Emerging echocardiography techniques such as three-dimensional echocardiography and strain imaging and their incremental role over traditional 2D imaging will be discussed. In addition, new developments expanding nuclear imaging techniques' evaluation of left ventricular systolic function will be reviewed. Finally, an overview of advances in imaging techniques such as cardiac magnetic resonance and cardiac computed tomography, which now allow for an accurate and highly reproducible assessment of LVEF, will be presented.

Accuracy of different reconstruction intervals to quantify left ventricular function and mass in cardiac computed tomography examinations

PURPOSE

To compare the accuracy of cardiac dual-source CT (DSCT) reconstructions obtained at 5% and 10% of the cardiac cycle and MRI for quantifying global left ventricular (LV) function and mass in heart transplant recipients.

MATERIAL AND METHODS

We prospectively included 23 heart transplant recipients (21 male, mean age 60±11.7 years) who underwent cardiac DSCT and MRI examinations. We compared LV parameters on cardiac DSCT reconstructions obtained at 5% (0%-95%) and 10% (0%-90%) intervals of the cardiac cycle and on double-oblique short-axis MR images. We determined ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and myocardial mass using commercially available semiautomated segmentation analysis software for DSCT datasets and conventional manual contour tracing for MR studies.

RESULTS

Using different reconstruction intervals to quantify LV parameters at DSCT resulted in non-significant differences (P>.05). Compared to MRI, DSCT slightly overestimated LV-EDV, ESV, and mass when both 5% (11.5±25.1ml, 6.8±10.9ml, and 28.3±21.6g, respectively) and 10% (mean difference 15.3±26.3ml, 7.4±11.5ml, and 29.3±18.7g, respectively) reconstruction intervals were used. DSCT and MRI estimates of EF and SV were not significantly different.

CONCLUSION

In heart transplant recipients, DSCT allows reliable quantification of LV function and mass compared with MRI, even using 10% interval reconstructions.

Left atrial volume by real-time three-dimensional echocardiography: validation by 64-slice multidetector computed tomography

BACKGROUND

Left atrial (LA) enlargement has been acknowledged as a significant predictor of cardiovascular morbidity and mortality.

METHODS

To evaluate the accuracy of two-dimensional and three-dimensional echocardiography for determining LA volume, LA volume measurements by echocardiography were compared with those measured by 64-slice multidetector computed tomography (MDCT) as a reference standard.

RESULTS

Fifty-seven consecutive patients (mean age, 66 ± 11 years; 59% men) referred to echocardiography and MDCT on the same day were prospectively evaluated. LA volume by three-dimensional echocardiography was correlated closely with that by MDCT (r = 0.95, P < .0001), with 8% underestimation. LA volume by two-dimensional echocardiography was correlated less well with that measured by MDCT (r = 0.86, P < .0001) and consistently underestimated LA volume by 19%, particularly as the left atrium enlarged.

CONCLUSIONS

LA volume assessment by three-dimensional echocardiography was correlated closely with that measured by MDCT, albeit with an 8% underestimation. Three-dimensional echocardiography is a feasible noninvasive method to evaluate LA volume.

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.

Assessment of pulmonary hypertension what CT and MRI can provide

RATIONALES AND OBJECTIVES

Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging.

CONCLUSIONS

CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.

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.

Simple area-based measurement for multidetector computed tomography to predict left ventricular size

OBJECTIVE

Measures of left ventricular (LV) mass and dimensions are independent predictors of morbidity and mortality. We determined whether an axial area-based method by computed tomography (CT) provides an accurate estimate of LV mass and volume.

METHOD

A total of 45 subjects (49% female, 56.0 +/- 12 years) with a wide range of LV geometry underwent contrast-enhanced 64-slice CT. LV mass and volume were derived from 3D data. 2D images were analysed to determine LV area, the direct transverse cardiac diameter (dTCD) and the cardiothoracic ratio (CTR). Furthermore, feasibility was confirmed in 100 Framingham Offspring Cohort subjects.

RESULTS

2D measures of LV area, dTCD and CTR were 47.3 +/- 8 cm(2), 14.7 +/- 1.5 cm and 0.54 +/- 0.05, respectively. 3D-derived LV volume (end-diastolic) and mass were 148.9 +/- 45 cm(3) and 124.2 +/- 34 g, respectively. Excellent inter- and intra-observer agreement were shown for 2D LV area measurements (both intraclass correlation coefficients (ICC) = 0.99, p < 0.0001) and could be confirmed on non-contrast CT. The measured 2D LV area was highly correlated to LV volume, mass and size (r = 0.68; r = 0.73; r = 0.82; all p < 0.0001, respectively). On the other hand, CTR was not correlated to LV volume, mass, size or 2D LV area (all p > 0.27).

CONCLUSION

Compared with traditionally used CTR, LV size can be accurately predicted based on a simple and highly reproducible axial LV area-based measurement.

Computed tomography of the coronary arteries in diagnosis

IMPORTANCE OF THE FIELD

Cardiac computed tomography (CT) has recently emerged as a non-invasive alternative to catheter angiography for the assessment of coronary artery disease. Rapid technological advances have rendered coronary CT angiography to a robust, accurate and fast imaging modality to assess coronary artery disease in selected patients. The list of further indications in which cardiac CT is an appropriate test remains a topic of discussion.

AREAS COVERED IN THIS REVIEW

This review discusses the main literature available on the use of cardiac CT in the indications considered appropriate in the 2006 Appropriateness Criteria by the American College of Radiology with special emphasis on the temporal trends in the utilization of cardiac CT in clinical practice and in the opinion of the experts, and provides an outlook on how cardiac CT might evolve in the future.

WHAT THE READER WILL GAIN

The reader will gain insight into the strengths and shortcomings of CT of the coronary arteries in coronary artery diagnosis and will learn why cardiac CT is appropriate in some indications but not in others.

TAKE HOME MESSAGE

Recent research in cardiac CT has substantially improved the evaluation of the coronary arteries with CT, and the list of indications cardiac CT is appropriate for might expand further in the coming years.

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.

Value of Cardiac CT in Patients With Heart Failure

Multidetector CT (MDCT) with 64-slice capability continues to gain momentum for cardiovascular imaging. Beyond images of coronary arteries, it also provides reliable information on left ventricular structure and function, cardiac venous anatomy, the pulmonary venous system, and right ventricular function-all aspects important in the management of heart failure patients. Potential unique applications in heart failure include cardiac dyssynchrony evaluation, assessing cardiomyopathies, and post-transplant annual follow-up. This review details the multiple applications and limitations of MDCT in the heart failure population, including comparison with other commonly used imaging modalities such as echocardiography and MRI.

Quantitative analysis of left ventricular function as a tool in clinical research. Theoretical basis and methodology

The usefulness the left ventricular ejection fraction as a surrogate endpoint in clinical trials has been confirmed by numerous studies. However, if this approach is to be applied successfully, images must be acquired in a rigorously controlled manner, and it is advisable to use measurement units that have been specifically developed for quantitative analysis of the imaging parameters obtained with current imaging techniques. This review summarizes what is now known about the left ventricular ejection fraction and left ventricular volumes, discusses the importance of measurement units in image analysis, and describes the different imaging techniques available. Finally, there is a discussion of how to select the best imaging technique for specific clinical applications.