Two-phase reconstruction for the assessment of left ventricular volume and function using retrospective ECG-gated MDCT: comparison with echocardiography

Peculiarities of cardio-respiratory relationships in qualified athletes with different types of heart rhythm regulation according to respiratory maneuver data

Introduction

Our goal was to determine the differences in changes in cardiovascular and cardiorespiratory interaction indicators during a respiratory maneuver with a change in breathing rate in athletes with different types of heart rate regulation.

Methods

The results of a study of 183 healthy men aged 21.2 ± 2.3 years, who were systematically involved in various sports, were analyzed. According to the results of the analysis of the HRV study during spontaneous breathing, the athletes were divided into 4 groups taking into account the type of heart rate regulation (HRR). Group 1 (with type I) consisted of 53 people, group 2 (with type II)-29 people, group 3 (with type III)-85 people, group 4 (with type IV)-16 people. The methodology for studying the cardiorespiratory system included combined measurements of the respiratory and cardiovascular system activity indicators in a sitting position using a spiroarteriocardiorhythmograph. The duration of the study was 6 min.

Results

According to changes in cardiorespiratory and cardiovascular interaction indicators during controlled breathing with a frequency of 6 and 15 per minute (CR6 and CR15), it is shown that with a pronounced predominance of parasympathetic influences (type IV) in conditions of excessive cardiorespiratory control and moderate hyperventilation, differences in changes in arterial baroreflex sensitivity (δBRLF and δBRHF) are noted in comparison with other HRR. Athletes with type IV at CR6 in δBRLF significantly differ from athletes with type III (p = 0.026) and do not differ from athletes with type II (p = 0.141). In δBRHF significantly (p = 0.038 and p = 0.043)-from athletes with types I and II. It is shown that with the predominance of sympathetic influences (types I and II), the reactivity of BRS (δBRLF and δBRHF) in response to moderate hyperventilation (CR15) is significantly lower. Changes in the Hildebrandt index and the volume synchronization index additionally differentiate HRR associated with a moderate and pronounced predominance of sympathetic and parasympathetic influences.

Conclusion

The use of a respiratory maneuver in a combined study of the cardiorespiratory system in the conditions of current control of athletes showed informativeness in the differentiation of HRR types and states of functional overstrain.

Cardiorespiratory dynamics during respiratory maneuver in athletes

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation.

Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6 min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25 Hz).

Results: Performing a breathing maneuver at breathing 0.1 Hz and breathing 0.25 Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators–TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators–TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative.

Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Cardiorespiratory dynamics during respiratory maneuver in athletes

Introduction: The modern practice of sports medicine and medical rehabilitation requires the search for subtle criteria for the development of conditions and recovery of the body after diseases, which would have a prognostic value for the prevention of negative effects of training and rehabilitation tools, and also testify to the development and course of mechanisms for counteracting pathogenetic processes in the body. The purpose of this study was to determine the informative directions of the cardiorespiratory system parameters dynamics during the performing a maneuver with a change in breathing rate, which may indicate the body functional state violation. Methods: The results of the study of 183 healthy men aged 21.2 ± 2.3 years who regularly engaged in various sports were analyzed. The procedure for studying the cardiorespiratory system included conducting combined measurements of indicators of activity of the respiratory and cardiovascular systems in a sitting position using a spiroarteriocardiograph device. The duration of the study was 6 min and involved the sequential registration of three measurements with a change in breathing rate (spontaneous breathing, breathing at 0.1 Hz and 0.25 Hz). Results: Performing a breathing maneuver at breathing 0.1 Hz and breathing 0.25 Hz in comparison with spontaneous breathing leads to multidirectional significant changes in heart rate variability indicators-TP (ms2), LF (ms2), LFHF (ms2/ms2); of blood pressure variability indicators-TPDBP (mmHg2), LFSBP (mmHg2), LFDBP (mmHg2), HFSBP (mmHg2); of volume respiration variability indicators - LFR, (L×min-1)2; HFR, (L×min-1)2; LFHFR, (L×min-1)2/(L×min-1)2; of arterial baroreflex sensitivity indicators - BRLF (ms×mmHg-1), BRHF (ms×mmHg-1). Differences in indicators of systemic hemodynamics and indicators of cardiovascular and respiratory systems synchronization were also informative. Conclusion: According to the results of the study, it is shown that during performing a breathing maneuver with a change in the rate of breathing, there are significant changes in cardiorespiratory parameters, the analysis of which the increments made it possible to determine of the changes directions dynamics, their absolute values and informative limits regarding the possible occurrence of the cardiorespiratory interactions dysregulation.

Comparative features of the immediate impact of manual therapy traction manipulations on the cardiorespiratory system of men and women

Purpose: the aim of this study was to determine the principal differences of changes in the cardiorespiratory system activity under the influence of traction manipulations in the thoracic spine of men and women. Material & Methods: the 26 adults were involved in the study, including 18 women aged 39.6±12.1 years and 8 men aged 36.3±8.3 years. All patients were diagnosed with osteochondrosis of the thoracic spine, which was confirmed by radiographic examination. The study of the cardiorespiratory system was conducted in the first procedure of SMT before and after the use of traction manipulations directly in the physician office. The integrated method of studying the cardiorespiratory system defined as spiroarteriocardiorhythmography (SACR) was used. It simultaneously records the heart rate, rhythms of systolic and diastolic pressure at each heartbeat and respiratory rhythms, which provides significant time savings to determine the functional state of the heart, vessels and respiration, as well as to identify the important parameters of their interaction. Results: characterizing the changes in the cardiorespiratory system as a whole under the influence of traction manipulations on the thoracic spine, it should be noted that men and women had some significant unidirectional changes in HR (min–1), CO (dm3), CI (dm3/m2), IH (n. u.), which are determined primarily by the decrease in HR (min–1) under the influence of traction manipulations. As to the men, the significant effects were more related to the impact on the contractile function of the heart, which was confirmed by the improvement of the electrical systole of the ventricles (QTC, s), the increase in the activity of the effects of the parasympathetic branch of the ANS on the cardiac rhythm (HF, ms2) and a certain increase in the stroke index within the normative values (SI, cm3/m2), then to the women the significant effects were more related to the influence on the breathing pattern and vascular tone. Thus, characteristic and positive effects in women can be considered a decrease in the variability of diastolic blood pressure in the very-low-frequency range (VLFDBP, mmHg2), which is combined with a decrease in the total power of diastolic pressure variability (TPDBP, mmHg2) and an increase in the total peripheral vascular resistance (GPVR, dyn/s/cm−5). Conclusions: summarizing the results of the impact of traction manipulations in the thoracic spine on the cardiorespiratory system of men and women, it can be stated that their effect is different and has features associated with the use of different mechanisms. For men, the predominant effect is on the heart contractile function, and for women it is on the respiratory system and autonomous regulation of vascular tone.

Comparative features of the immediate impact of manual therapy traction manipulations on the cardiorespiratory system of men and women

Purpose: the aim of this study was to determine the principal differences of changes in the cardiorespiratory system activity under the influence of traction manipulations in the thoracic spine of men and women. Material & Methods: the 26 adults were involved in the study, including 18 women aged 39.6±12.1 years and 8 men aged 36.3±8.3 years. All patients were diagnosed with osteochondrosis of the thoracic spine, which was confirmed by radiographic examination. The study of the cardiorespiratory system was conducted in the first procedure of SMT before and after the use of traction manipulations directly in the physician office. The integrated method of studying the cardiorespiratory system defined as spiroarteriocardiorhythmography (SACR) was used. It simultaneously records the heart rate, rhythms of systolic and diastolic pressure at each heartbeat and respiratory rhythms, which provides significant time savings to determine the functional state of the heart, vessels and respiration, as well as to identify the important parameters of their interaction. Results: characterizing the changes in the cardiorespiratory system as a whole under the influence of traction manipulations on the thoracic spine, it should be noted that men and women had some significant unidirectional changes in HR (min–1), CO (dm3), CI (dm3/m2), IH (n. u.), which are determined primarily by the decrease in HR (min–1) under the influence of traction manipulations. As to the men, the significant effects were more related to the impact on the contractile function of the heart, which was confirmed by the improvement of the electrical systole of the ventricles (QTC, s), the increase in the activity of the effects of the parasympathetic branch of the ANS on the cardiac rhythm (HF, ms2) and a certain increase in the stroke index within the normative values (SI, cm3/m2), then to the women the significant effects were more related to the influence on the breathing pattern and vascular tone. Thus, characteristic and positive effects in women can be considered a decrease in the variability of diastolic blood pressure in the very-low-frequency range (VLFDBP, mmHg2), which is combined with a decrease in the total power of diastolic pressure variability (TPDBP, mmHg2) and an increase in the total peripheral vascular resistance (GPVR, dyn/s/cm−5). Conclusions: summarizing the results of the impact of traction manipulations in the thoracic spine on the cardiorespiratory system of men and women, it can be stated that their effect is different and has features associated with the use of different mechanisms. For men, the predominant effect is on the heart contractile function, and for women it is on the respiratory system and autonomous regulation of vascular tone.

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.

Evaluation of a commercial cardiac motion phantom for dual-energy chest radiography

Misregistration due to cardiac motion causes artifacts in two-exposure dual-energy subtraction images, in both the soft-tissue-only image and the bone-only image. Two previous investigations have attempted to avoid misregistration artifacts by using cardiac gating of the first and second exposures. The severity of misregistration was affected by the heart rate, the time interval between the low- and high-energy exposures, the total duration of the two exposures, and the phase of the cardiac cycle at the start of the exposure sequence. We sought to determine whether a commercial phantom with a simulated beating heart can be used to investigate the factors affecting misregistration in dual-energy chest radiography. We made dual-energy images of the phantom in postero-anterior orientation using the indirect digital radiography system (GE XQ/i). We acquired digital images at heart rates between 40 beats per minute and 120 beats per minute and transferred them to a computer, where the area of the artifact on the silhouette of the heart was measured from both soft-tissue-only and bone-only images. For comparison, we measured misregistration in clinical dual-energy subtraction images by the same method. Generally speaking, without synchronization of the exposure sequence with the cardiac cycle, the area of the misregistration artifact increased with heart rate for both the phantom and clinical images. However, the phantom exaggerated the magnitude of misregistration relative to clinical images. Although this phantom was designed for horizontal operation and computed tomography imaging, it can be used in an upright configuration to simulate heart motion for investigation of dual-energy misregistration artifacts and control.

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.

Incremental prognostic value of left ventricular function analysis over non-invasive coronary angiography with multidetector computed tomography

BACKGROUND

The purpose of this study was to determine the prognostic value of computed tomography coronary angiography (CTA)-derived left ventricular (LV) function analysis and to assess its incremental prognostic value over the detection of significant stenosis using CTA.

METHODS

In 728 patients (400 males, mean age 55 ± 12 years) with known or suspected CAD, the presence of significant stenosis (≥ 50% stenosis) and LV function were assessed using CTA. LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV), and LV ejection fraction (LVEF) were calculated. LV function was assessed as a continuous variable and using cutoff values (LVEDV > 215 mL, LVESV > 90 mL, LVEF < 49%). The following events were combined in a composite end-point: all-cause mortality, non-fatal myocardial infarction, and unstable angina pectoris requiring hospitalization.

RESULTS

On CTA, a significant stenosis was observed in 221 patients (30%). During follow-up [median 765 days, 25-75th percentile: 493-978] an event occurred in 45 patients (6.2%). After multivariate correction for clinical risk factors and CTA, LVEF < 49% and LVESV > 90 mL were independent predictors of events with an incremental prognostic value over clinical risk factors and CTA.

CONCLUSIONS

The present results suggest that LV function analysis provides independent and incremental prognostic information beyond anatomic assessment of CAD using CTA.

Evaluation of left atrial volumes using multidetector computed tomography: comparison with echocardiography

Objective

To prospectively assess the relationship between the two different measurement methods for the evaluation of left atrial (LA) volume using cardiac multidetector computed tomography (MDCT) and to compare the results between cardiac MDCT and echocardiography.

Materials and Methods

Thirty-five patients (20 men, 15 women; mean age, 60 years) underwent cardiac MDCT angiography for coronary artery disease. The LA volumes were measured using two different methods: the two dimensional (2D) length-based (LB) method measured along the three-orthogonal planes of the LA and the 3D volumetric threshold-based (VTB) method measured according to the threshold 3D segmentation of the LA. The results obtained by cardiac MDCT were compared with those obtained by echocardiography.

Results

The LA end-systolic and end-diastolic volumes (LAESV and LAEDV) measured by the 2D-LB method correlated well with those measured by the 3D-VTB method using cardiac MDCT (r = 0.763, r = 0.786, p = 0.001). However, there was a significant difference in the LAESVs between the two measurement methods using cardiac MDCT (p < 0.05). The LAESV measured by cardiac MDCT correlated well with measurements by echocardiography (r = 0.864, p = 0.001), however with a significant difference (p < 0.01) in their volumes. The cardiac MDCT overestimated the LAESV by 22% compared to measurements by echocardiography.

Conclusion

A significant correlation was found between the two different measurement methods for evaluating LA volumes by cardiac MDCT. Further, cardiac MDCT correlates well with echocardiography in evaluating the LA volume. However, there are significant differences in the LAESV between the two measurement methods using cardiac MDCT and between cardiac MDCT and echocardiography.

Assessment of global left ventricular function and volumes with 320-row multidetector computed tomography: A comparison with 2D-echocardiography

BACKGROUND

Multidetector computed tomography (MDCT) has been demonstrated as a feasible imaging modality for noninvasive assessment of coronary artery disease and left ventricular (LV) function. Recently, 320-row systems have become available with 16 cm anatomical coverage allowing image acquisition of the entire heart within a single heartbeat. The purpose of this study was to evaluate the accuracy of 320-row MDCT in the assessment of global LV function compared to two-dimensional (2D) echocardiography as the standard of reference.

METHODS AND RESULTS

A head-to-head comparison between 320-row MDCT and 2D-echocardiography was performed in 114 patients (68 men; mean age 62 +/- 13 years) who were clinically referred for MDCT coronary angiography. The entire heart was imaged in a single heartbeat, using prospective dose modulation. LV end-diastolic volumes (LVEDV) and LV end-systolic volumes (LVESV) were determined and the LV ejection fraction (LVEF) was derived. Average LVEF was 60 +/- 10% (range 26-78%) as determined on MDCT, compared with 59 +/- 10% (range 25-77%) on 2D-echocardiography. Evaluation of LVEF by linear regression analysis showed a good correlation between MDCT and 2D-echocardiography (r(2) = .87; P < .001). Good correlations between MDCT and 2D-echocardiography were demonstrated for the assessment of LVEDV (r(2) = .91; P < .001) and LVESV (r(2) = .94; P < .001). At Bland-Altman analysis, mean differences (+/-SD) of 7.3 +/- 12.1 mL (P < .05) and 1.8 +/- 7.4 mL (P < .05) were observed between MDCT and 2D-echocardiography for LVEDV and LVESV, respectively. LVEF was slightly overestimated with MDCT (.9 +/- 3.6%; P < .05).

CONCLUSIONS

Accurate assessment of LV function and volumes is feasible with single heartbeat 320-row MDCT in patients referred for MDCT coronary angiography.

Novel clinical applications of state-of-the-art multi-slice computed tomography

Recent years have witnessed a rapid development of multi-slice computed tomography (MSCT) technology. The number of detector rows has increased from 4-slices to the current availability of 64-slice and even 320-slice systems. In addition, images are acquired with thinner slices and faster rotation times resulting in substantially improved image quality and diagnostic accuracy. Simultaneously, effective dose reduction acquisition techniques have been developed allowing considerable reduction of the radiation dose. Conceivably, these advancements may allow further expansion of the use of MSCT beyond the visual assessment of the presence or absence of significant coronary artery disease. Indeed, a particular advantage of the technique is that in addition to evaluation of the coronary arteries it also allows assessment of cardiac structures and function. The purpose of the current review is to discuss several novel applications of cardiac MSCT, including stenosis quantification, atherosclerotic plaque imaging and prognostification as well as imaging of left ventricular function, aortic and mitral valve anatomy using state-of-the-art technology.

Usefulness of 64-slice multidetector computed tomography as an initial diagnostic approach in patients with acute chest pain

BACKGROUND

Recently, multidetector computed tomography (MDCT) has been proposed as an accurate diagnostic tool to evaluate for coronary artery disease. However, the role of MDCT as part of the initial diagnostic for evaluating acute chest pain is less well established.

METHODS

We prospectively enrolled patients presenting with acute chest pain to the emergency department (ED) and risk stratified them based on the pretest probability for an acute coronary syndrome (ACS): (1) very low, (2) low, (3) intermediate, (4) high, and (5) very high or definite. After exclusion of very low and very high risk patients, 268 patients were randomized to either immediate 64-slice cardiac MDCT or a conventional diagnostic strategy. Number of admissions, ED and hospital length of stay (LOS), and major adverse cardiac events over 30 days of follow-up were compared between the strategies based on the pretest probability for ACS.

RESULTS

The number of patients ultimately diagnosed with an ACS did not differ between the 2 strategies. Emergency department LOS and total admissions were not different between strategies. Patients in the MDCT-based strategy had a decreased hospital LOS (P = .049) and fewer admissions deemed unnecessary (P = .007). Reductions in unnecessary admissions were more prominent in intermediate-risk patients (P = .015). None of the patients discharged from the ED in the MDCT-based strategy experienced major adverse cardiac events at follow-up.

CONCLUSION

Use of an MDCT-based strategy in the ED as part of the initial diagnostic approach for patients presenting with acute chest pain is safe and efficiently reduces avoidable admissions in patients with an intermediate pretest probability for ACS.

Quantitative assessment of ventricular function using three-dimensional SSFP magnetic resonance angiography

PURPOSE

To evaluate three-dimensional (3D), free-breathing, steady-state free precession (SSFP) magnetic resonance angiography (MRA) for volumetric assessment of ventricular function.

MATERIALS AND METHODS

In 18 subjects (mean age = 21.5 years) 3D datasets of the heart and great vessels were acquired using an ECG-triggered, free-breathing SSFP technique with a T2-preparation prepulse. Data were acquired during end-systole (ES) and end-diastole (ED) for assessment of stroke volumes (SVs). Through-plane flow measurements of the great arteries were performed as well as 2D-cine SSFP imaging for comparison. For image analysis of the 3D SSFP datasets a simplex mesh model was used. Papillary muscles were excluded from ventricular volumes using thresholds. Intra- and interobserver variability (Bland-Altman analysis) and correlations (Pearson's coefficient) between volumetric and flow measurements were assessed.

RESULTS

ES and ED datasets were acquired successfully in all subjects. The best correlation was observed between flow vs. 3D SSFP SV for the LV (r = 0.85, mean difference = -1.0 mL) and the RV (r = 0.89, mean difference = -2.2 mL) with high intra- (LV: r = 0.93; RV: r = 0.94) and interobserver (LV: r = 0.91; RV: r = 0.93) reproducibility.

CONCLUSION

3D SSFP datasets combined with semiautomatic segmentation algorithms allow highly accurate and reproducible assessment of left (LV) and right ventricular (RV) SVs in free-breathing subjects.

Left Ventricular Functional Analysis Using 64-Slice Multidetector Row Computed Tomography: Comparison with Left Ventriculography and Cardiovascular Magnetic Resonance

OBJECTIVE

The progress in computed tomography (CT) has improved temporal resolution and shortened the acquisition time. We compared cardiac function using 64-slice CT with left ventriculography (LVG) and cardiovascular magnetic resonance (CMR).

METHODS

A head-to-head comparison between CT, LVG and CMR was performed in 41 patients. In global LV function, CMR served as the reference. Regional wall motion was compared in a 5-point scoring system.

RESULTS

CT had excellent intra- and interobserver reproducibility. Ejection fraction, end-diastolic and end-systolic volumes by CT were closely correlated with CMR (r = 0.95, 0.96 and 0.98, respectively), while LVG underestimated LV volumes (p < 0.01). The standard deviation of ejection fraction difference between CT and CMR was significantly lower than that between LVG and CMR (p = 0.0015). In regional function, there were good agreements of 94.8% (kappa = 0.82) between CT and LVG and 94.5% (kappa = 0.84) between CT and CMR. The intermethod agreements in mild hypokinesis using CT tended to be lower.

CONCLUSION

An excellent correlation was observed between CT and CMR in the LV function over a wide range of heart rates. However, even though 64-slice CT tended to be less sensitive in detecting mild hypokinesis, it still showed excellent concordance in advanced regional abnormalities.

Assessment of left ventricular volumes and ejection fraction with 16-slice multi-slice computed tomography; comparison with 2D-echocardiography

BACKGROUND

In recent years, multi-slice computed tomography (MSCT) has emerged as a rapidly expanding modality for non-invasive assessment of coronary artery disease. Simultaneously, left ventricular (LV) function can be evaluated although this is not yet a routine component of an MSCT examination. Accordingly, the purpose of the present study was to validate assessment of LV function with MSCT using 2D-echocardiography in a large cohort of patients.

METHODS

In 70 patients (57 male, 13 female), 16-slice MSCT was performed (Toshiba Aquilion 16, Japan) followed by retrospective analysis of global LV function. For these measurements, 2D-echocardiography served as the standard of reference.

RESULTS

For LV volumes, excellent correlations for both end-diastolic volume (EDV) (r=0.97) and end-systolic volume (ESV) (r=0.98) were obtained by linear regression analysis. At Bland-Altman analysis, mean differences (+/-standard deviations) of -1.4 ml+/-11.3 ml and -3.0 ml+/-7.7 ml were observed between MSCT and 2D-echocardiography for LV EDV and LV ESV respectively. As a result, LV EF was slightly overestimated with MSCT (1.7%+/-4.9%, P<0.05). Correlation between the two techniques was excellent (r=0.91).

CONCLUSION

In a large cohort of patients, an excellent correlation was observed between 16-slice MSCT and 2D-echocardiography in the evaluation of LV volumes and EF. The addition of LV function analysis to the anatomical MSCT data may potentially enhance the diagnostic and prognostic value of the technique.

Assessment of Cardiac Function Using Multidetector Row Computed Tomography

In patients with suspected or documented heart disease, a precise quantitative and qualitative assessment of cardiac function is critical for clinical diagnosis, risk stratification, management and prognosis. Cardiac CT is increasingly being used in diagnosis of coronary artery disease. Initially multi-detector row computed tomography (MDCT) was used chiefly for detecting coronary artery stenosis and assessment of cardiac morphology. Electron beam computed tomography has been shown to provide a highly accurate ejection fraction (+/-1%), with 50 ms image acquisition per image. Retrospective electrocardiographic gating allows for image reconstruction in any phase of the cardiac cycle. Thus, end systolic and end diastolic images can be produced to assess ventricular volumes and function. Despite lower temporal resolution than electron beam computed tomography, the ability of MDCT to assess ejection fraction is preserved. In the assessment of cardiac function, MDCT has been shown to be in good agreement with echocardiography, cineventriculography, single photon emission computed tomography and magnetic resonance imaging. The fast technical development of scanner hardware along with multisegmental image reconstruction has led to rapid improvement of spatial and temporal resolution and significantly faster cardiac scans. The same data that is acquired for MDCT angiography can also be used for evaluation of cardiac function. Considering contrast media application, radiation exposure, and limited temporal resolution, MDCT solely for analysis of cardiac function parameters seems not reasonable at the present time. However, because the data is already obtained during coronary evaluation, the combination of noninvasive coronary artery imaging and assessment of cardiac function with MDCT is a suitable approach to a conclusive cardiac workup in patients with suspected coronary artery disease. MDCT seems suitable for assessment of cardiac function by MDCT when results are held in comparison to magnetic resonance imaging as the reference standard. Given the radiation dose and contrast requirement, referring a patient to MDCT only for evaluation of function is not warranted, but rather adds important clinical information to the already acquired data during retrospective triggering for MDCT angiography.