Global longitudinal strain assessment by computed tomography in severe aortic stenosis patients - Feasibility using feature tracking analysis

Comprehensive Myocardial Assessment by Computed Tomography: Impact on Short-Term Outcomes After Transcatheter Aortic Valve Replacement

BACKGROUND

Quantification of myocardial changes in severe aortic stenosis (AS) is prognostically important. The potential for comprehensive myocardial assessment pre-transcatheter aortic valve replacement (TAVR) by computed tomography angiography (CTA) is unknown.

OBJECTIVES

This study sought to evaluate whether quantification of left ventricular (LV) extracellular volume-a marker of myocardial fibrosis-and global longitudinal strain-a marker of myocardial deformation-at baseline CTA associate with post-TAVR outcomes.

METHODS

Consecutive patients with symptomatic severe AS between January 2021 and June 2022 who underwent pre-TAVR CTA were included. Computed tomography extracellular volume (CT-ECV) was derived from septum tracing after generating the 3-dimensional CT-ECV map. Computed tomography global longitudinal strain (CT-GLS) used semi-automated feature tracking analysis. The clinical endpoint was the composite outcome of all-cause mortality and heart failure hospitalization.

RESULTS

Among the 300 patients (80.0 ± 9.4 years of age, 45% female, median Society of Thoracic Surgeons Predicted Risk of Mortality score 2.80%), the left ventricular ejection fraction (LVEF) was 58% ± 12%, the median CT-ECV was 28.5% (IQR: 26.2%-32.1%), and the median CT-GLS was -20.1% (IQR: -23.8% to -16.3%). Over a median follow-up of 16 months (IQR: 12-22 months), 38 deaths and 70 composite outcomes occurred. Multivariable Cox proportional hazards model, accounting for clinical and echocardiographic variables, demonstrated that CT-ECV (HR: 1.09 [95% CI: 1.02-1.16]; P = 0.008) and CT-GLS (HR: 1.07 [95% CI: 1.01-1.13]; P = 0.017) associated with the composite outcome. In combination, elevated CT-ECV and CT-GLS (above median for each) showed a stronger association with the outcome (HR: 7.14 [95% CI: 2.63-19.36]; P < 0.001).

CONCLUSIONS

Comprehensive myocardial quantification of CT-ECV and CT-GLS associated with post-TAVR outcomes in a contemporary low-risk cohort with mostly preserved LVEF. Whether these imaging biomarkers can be potentially used for the decision making including timing of AS intervention and post-TAVR follow-up will require integration into future clinical trials.

Multimodality Imaging in Aortic Stenosis: Beyond the Valve - Focusing on the Myocardium

Current guidelines of aortic stenosis (AS) management focus on valve parameters, LV systolic dysfunction, and symptoms; however, emerging data suggest that there may be benefit of aortic valve replacement before it becomes severe by present criteria. Myocardial assessment using novel multimodality imaging techniques exhibits subclinical myocardial injury and remodeling at various stages before guideline-directed interventions, which predicts adverse outcomes. This raises the question of whether implementing serial myocardial assessment should become part of the standard appraisal, thereby identifying high-risk patients aiming to minimize adverse outcomes.

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Multimodality Imaging in Aortic Stenosis: Beyond the Valve - Focusing on the Myocardium

Current guidelines of aortic stenosis (AS) management focus on valve parameters, LV systolic dysfunction, and symptoms; however, emerging data suggest that there may be benefit of aortic valve replacement before it becomes severe by present criteria. Myocardial assessment using novel multimodality imaging techniques exhibits subclinical myocardial injury and remodeling at various stages before guideline-directed interventions, which predicts adverse outcomes. This raises the question of whether implementing serial myocardial assessment should become part of the standard appraisal, thereby identifying high-risk patients aiming to minimize adverse outcomes.

Cardiac CT in CRT as a Singular Imaging Modality for Diagnosis and Patient-Tailored Management

Between 30-40% of patients with cardiac resynchronization therapy (CRT) do not show an improvement in left ventricular (LV) function. It is generally known that patient selection, LV lead implantation location, and device timing optimization are the three main factors that determine CRT response. Research has shown that image-guided CRT placement, which takes into account both anatomical and functional cardiac properties, positively affects the CRT response rate. In current clinical practice, a multimodality imaging approach comprised of echocardiography, cardiac magnetic resonance imaging, or nuclear medicine imaging is used to capture these features. However, with cardiac computed tomography (CT), one has an all-in-one acquisition method for both patient selection and the division of a patient-tailored, image-guided CRT placement strategy. This review discusses the applicability of CT in CRT patient identification, selection, and guided placement, offering insights into potential advancements in optimizing CRT outcomes.

Feasibility of Coronary CT Angiography-derived Left Ventricular Long-Axis Shortening as an Early Marker of Ventricular Dysfunction in Transcatheter Aortic Valve Replacement

Purpose

To evaluate the value of using left ventricular (LV) long-axis shortening (LAS) derived from coronary CT angiography (CCTA) to predict mortality in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR).

Materials and Methods

Patients with severe AS who underwent CCTA for preprocedural TAVR planning between September 2014 and December 2019 were included in this retrospective study. CCTA covered the whole cardiac cycle in 10% increments. Image series reconstructed at end systole and end diastole were used to measure LV-LAS. All-cause mortality within 24 months of follow-up after TAVR was recorded. Cox regression analysis was performed, and hazard ratios (HRs) are presented with 95% CIs. The C index was used to evaluate model performance, and the likelihood ratio χ² test was performed to compare nested models.

Results

The study included 175 patients (median age, 79 years [IQR, 73-85 years]; 92 men). The mortality rate was 22% (38 of 175). When adjusting for predictive clinical confounders, it was found that LV-LAS could be used independently to predict mortality (adjusted HR, 2.83 [95% CI: 1.13, 7.07]; P = .03). In another model using the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM), LV-LAS remained significant (adjusted HR, 3.38 [95 CI: 1.48, 7.72]; P = .004), and its use improved the predictive value of the STS-PROM, increasing the STS-PROM C index from 0.64 to 0.71 (χ² = 29.9 vs 19.7, P = .001). In a subanalysis of patients with a normal LV ejection fraction (LVEF), the significance of LV-LAS persisted (adjusted HR, 3.98 [95 CI: 1.56, 10.17]; P = .004).

Conclusion

LV-LAS can be used independently to predict mortality in patients undergoing TAVR, including those with a normal LVEF.Keywords: CT Angiography, Transcatheter Aortic Valve Implantation/Replacement (TAVI/TAVR), Cardiac, Outcomes Analysis, Cardiomyopathies, Left Ventricle, Aortic Valve Supplemental material is available for this article. © RSNA, 2022See also the commentary by Everett and Leipsic in this issue.

Association of baseline and change in global longitudinal strain by computed tomography with post-transcatheter aortic valve replacement outcomes

AIMS

Transcatheter aortic valve replacement (TAVR) procedural planning requires computed tomography angiography (CTA) which allows for the assessment of left ventricular global longitudinal strain (CTA-LVGLS). There is, however, limited data on the feasibility of CTA-LVGLS, and its prognostic value. This study sought to evaluate the incremental prognostic value of baseline CTA-LVGLS, change in CTA-LVGLS after TAVR, and their association with post-TAVR outcomes.

METHODS AND RESULTS

A total of 431 patients who underwent multiphasic gated CTA using dual-source system for TAVR planning at baseline and 1-month follow-up were included [median (interquartile range) age, 83 (77-87) years; 44% female, STS-PROM score: 3.3 (2.3-5.1)%, Echo-left ventricular ejection fraction (LVEF): 60 (55-65)%, CTA-LVGLS: -18.0 (-21.6 to -14.2)%, feasible in 97% of patients]. CTA-LVGLS was measured using dedicated feature-tracking software. Over a median follow-up of 19 (13-27) months, 99 endpoints of all-cause death or heart failure hospitalization occurred. The relative hazard of the endpoint increased as baseline CTA-LVGLS worsened with -18.2% as the threshold for higher events (P = 0.005). After adjustment for baseline characteristics, CTA-LVGLS remained associated with the endpoint [hazard ratio (HR) (95% confidence interval, CI), 1.08 (1.03-1.14); P = 0.005] and incrementally improved prognostication (C-index difference, 0.026). Although CTA-LVGLS improved after TAVR [-18.3 (-21.6 to -14.3)% vs. -18.7 (-21.9 to -15.4)%, P < 0.001], patients without CTA-LVGLS improvement had higher risk of the endpoint than those with improvement or preserved baseline global longitudinal strain [HR (95% CI), 1.92 (1.19-3.12); P = 0.008].

CONCLUSIONS

In this predominantly low-risk TAVR cohort of patients, mostly with normal LVEF, assessment of CTA-LVGLS is highly feasible improving risk stratification by providing independent and incremental prognostic value over clinical and echocardiographic characteristics.

Postoperative evaluation of left ventricular global strain using cardiac computed tomography in pediatric patients with congenital heart disease: A comparison with echocardiography

PURPOSE

We explored the feasibility and reproducibility of cardiac computed tomography (CCT)-derived left ventricular (LV) global strain in postoperative children
with congenital heart disease (CHD) and compared its correlation and agreement with transthoracic echocardiography (TTE).

METHODS

Fifty-one patients (28 males, 23 females) were included who underwent clinically indicated retrospective electrocardiography-triggered CCT. and all patients underwent additional TTE on the same day. LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were measured. Correlations of global strains between CCT and TTE were assessed using Pearson's correlation coefficient. Intra-class correlation coefficients (ICC) were used to assess CCT intra-observer and inter-observer reproducibility.

RESULTS

GLS and GCS were not significantly different between CCT and TTE (GLS: -23.54 ± 3.24 vs. -23.85 ± 3.72, respectively, p = 0.415; GCS: -28.21 ± 3.55 vs. -28.79 ± 3.69, respectively, p = 0.155). GRS was significantly different between CCT and TTE (60.79 ± 15.11 vs. 41.73 ± 4.27, respectively, p < 0.001). There was good correlation between CCT- and TTE-derived GLS (r = 0.70, p < 0.001) and GCS (r = 0.68, p < 0.001), but GRS showed no correlation between CCT and TTE (r = 0.09, p = 0.54). CCT-derived global strain showed good intra- and inter-observer reproducibility (ICC = 0.86-0.92), except the inter-observer reproducibility for GRS (ICC = 0.77).

CONCLUSIONS

CCT was feasible for postoperative evaluation of LV global strain in pediatric patients with CHD with sufficient reproducibility. CCT-derived global strain can provide additional information in selected CHD patients with poor acoustic windows and who are intolerant to or have contraindications for cardiac magnetic resonance.

Feasibility of CT-derived myocardial strain measurement in patients with advanced cardiac valve disease

To explore the feasibility of CT-derived myocardial strain measurement in patients with advanced cardiac valve disease and to compare it to strain measurements derived from transthoracic echocardiography (TTE). 43 consecutive patients with advanced cardiac valve disease and clinically indicated retrospectively gated cardiac CTs were retrospectively analyzed. The longitudinal, circumferential as well as radial systolic strain were determined in all patients utilizing a commercially available CT strain software. In 36/43 (84%) patients, CT-derived longitudinal strain was compared to speckle-tracking TTE. Pearson’s correlation coefficients as well as Bland–Altman analysis were used to compare the CT-derived strain measurements to TTE. The intra- and inter-reader-reliability of the CT-derived strain measurements were assessed by intra-class correlation coefficients (ICCs). Strain measurements were feasible in all patients. CT-derived global longitudinal strain (GLS) correlated moderately with TTE-derived GLS (r = 0.6, p < 0.001). A moderate correlation between CT-derived GLS and CT-derived left ventricular ejection fraction was found (LVEF, r = − 0.66, p = 0.036). Bland–Altman analysis showed a systematic underestimation of myocardial strain by cardiac CT compared to TTE (mean difference: − 5.8%, 95% limit of agreement between − 13.3 and 1.8%). Strain measurements showed an excellent intra- and inter-reader-reliability with an intra-reader ICC of 1.0 and an inter-reader ICC of 0.99 for GLS measurements. CT-derived myocardial strain measurements are feasible in patients with advanced cardiac valve disease. They are highly reproducible and correlate with established parameters of strain measurements. Our results encourage the implementation of CT-derived strain measurement into clinical routine.

The Journal of Cardiovascular Computed Tomography: 2020 Year in review

The purpose of this review is to highlight the most impactful, educational, and frequently downloaded articles published in the Journal of Cardiovascular Computed Tomography (JCCT) for the year 2020. The JCCT reached new records in 2020 for the number of research submissions, published manuscripts, article downloads and social media impressions. The articles in this review were selected by the Editorial Board of the JCCT and are comprised predominately of original research publications in the following categories: Coronavirus disease 2019 (COVID-19), coronary artery disease, coronary physiology, structural heart disease, and technical advances. The Editorial Board would like to thank each of the authors, peer-reviewers and the readers of JCCT for making 2020 one of the most successful years in its history, despite the challenging circumstances of the global COVID-19 pandemic.

Quantitative analysis of three-dimensional left ventricular global strain using coronary computed tomography angiography in patients with heart failure: Comparison with 3T cardiac MR

PURPOSE

The objective of this study was to investigate whether three dimentional (3D)- Coronary CT angiography (CCTA)- feature tracking (FT) can measure global myocardial strain of the left ventricle (LV) in patients with heart failure using cardiac MR (CMR) as reference.

METHODS

Consecutive patients (n = 44) with variable degrees of heart failure who underwent an ECG-gated CCTA and CMR within 24 h were included. Both modalities were compared for 2D/3D LV global radial strain (2D/3D-GRS), circumferential strain (2D/3D-GCS), longitudinal strain (2D/3D-GLS) and conventional functional parameters.

RESULTS

Compared to CMR, CCTA-derived 3D-GLS and LVEF showed no significant difference (p > 0.05). Bland-Altman plots showed a small bias (0.3 %) between CCTA-derived 3D-GLS and CMR 3D-GLS. Close correlations were observed between the two modalities regarding LV global strain (3D-GRS, r = 0.89; 3D-GCS, r = 0.86; 3D-GLS, r = 0.79, respectively, p < 0.001 for all). However, CCTA-derived 3D-GRS and 3D-GCS were statistically different compared with CMR. CCTA-derived 3D-GLS had an inverse correlation with CCTA-LVEF(r=-0.75, p < 0.05). Intraobserver agreements for CCTA-derived 3D-global strain were good (ICC = 0.856 for 3D-GLS, ICC = 0.741 for 3D-GCS and ICC = 0.762 for 3D-GRS). 2D global strain showed statistical differences between the two modalities (p＜0.05 for all), but close correlations were observed regarding 2D LV global strain (2D-GRS, r = 0.80; 2D-GCS, r = 0.81; 2D-GLS, r = 0.81, respectively, p < 0.001 for all). The average radiation dose-long-product (DLP) of CCTA was 387.86 ± 89.3 mGy*cm.

CONCLUSION

CCTA-derived 3D-GLS can provide both reliable and interchangeable results for quantitative assessment of myocardial mechanical changes in HF patients compared to CMR with good intra-observer agreement.

Identification of Subclinical Myocardial Dysfunction and Association with Survival after Transcatheter Mitral Valve Repair

BACKGROUND

Transcatheter mitral valve repair (TMVr) using edge-to-edge mitral valve clip is effective for patients with mitral regurgitation (MR) and high or prohibitive surgical risk. Global longitudinal strain (GLS) allows evaluation of subclinical myocardial dysfunction, but its incremental clinical utility into risk stratification, beyond traditional clinical parameters, is unknown in patients treated with TMVr. We sought to evaluate the association of baseline GLS with 1-year all-cause mortality in patients treated with TMVr using edge-to-edge mitral valve clip.

METHODS

We analyzed 155 patients who underwent transcatheter edge-to-edge mitral valve clip implantation (mean age, 83 ± 7 years; 48% were women; mean left ventricular ejection fraction, 56% ± 10%, Society of Thoracic Surgeons Predicted Risk of Mortality score for repair, 6.62% ± 5.22%). Baseline left ventricular GLS was obtained by two-dimensional speckle-tracking echocardiography, averaging 18 segments from three apical views. Receiver operating characteristic analyses were used to assess the GLS cut point associated with all-cause mortality. Multivariable models with Cox regression tested its relationship after adjustment for baseline comorbidities.

RESULTS

During a median follow-up of 316 days, all-cause deaths occurred in 30 patients at a median of 156 days after TMVr. The area under the curve of preoperative GLS associated with the outcome was 0.60, with a cutoff point of -14.5%. Baseline GLS > -14.5% was associated with 1-year mortality (hazard ratio = 2.50; 95% CI, 1.20-5.21; P = .02) before and after adjustment for baseline characteristics. After accounting for baseline characteristics, patients with GLS > -14.5% had worse 1-year mortality than those with GLS ≤ -14.5% (χ²P < .001). In nested Cox proportional hazards models, the addition of baseline GLS to Society of Thoracic Surgeons Predicted Risk of Mortality score, left ventricular ejection fraction, and the etiology of MR significantly increased the model χ² value (χ² = 12.32).

CONCLUSIONS

Baseline GLS is independently associated with 1-year all-cause mortality in patients who undergo TMVr, and its assessment improves risk stratification in these patients.

Left ventricular global longitudinal strain in bicupsid aortic valve patients: head-to-head comparison between computed tomography, 4D flow cardiovascular magnetic resonance and speckle-tracking echocardiography

Left ventricular global longitudinal strain (LVGLS) analysis is a sensitive measurement of myocardial deformation most often done using speckle-tracking transthoracic echocardiography (TTE). We propose a novel approach to measure LVGLS using feature-tracking software on the magnitude dataset of 4D flow cardiovascular magnetic resonance (CMR) and compare it to dynamic computed tomography (CT) and speckle tracking TTE derived measurements. In this prospective cohort study 59 consecutive adult patients with a bicuspid aortic valve (BAV) were included. The study protocol consisted of TTE, CT, and CMR on the same day. Image analysis was done using dedicated feature-tracking (4D flow CMR and CT) and speckle-tracking (TTE) software, on apical 2-, 3-, and 4-chamber long-axis multiplanar reconstructions (4D flow CMR and CT) or standard apical 2-, 3-, and 4-chamber acquisitions (TTE). CMR and CT GLS analysis was feasible in all patients. Good correlations were observed for GLS measured by CMR (− 21 ± 3%) and CT (− 20 ± 3%) versus TTE (− 20 ± 3%, Pearson’s r: 0.67 and 0.65, p < 0.001). CMR also correlated well with CT (Pearson’s r 0.62, p < 0.001). The inter-observer analysis showed moderate to good reproducibility of GLS measurement by CMR, CT and TTE (Pearsons’s r: 0.51, 0.77, 0.70 respectively; p < 0.05). Additionally, ejection fraction (EF), end-diastolic and end-systolic volume measurements (EDV and ESV) correlated well between all modalities (Pearson’s r > 0.61, p < 0.001). Feature-tracking GLS analysis is feasible using the magnitude images acquired with 4D flow CMR. GLS measurement by CMR correlates well with CT and speckle-tracking 2D TTE. GLS analysis on 4D flow CMR allows for an integrative approach, integrating flow and functional data in a single sequence. Not applicable, observational study.

Characteristics of the left ventricular three-dimensional maximum principal strain using cardiac computed tomography: reference values from subjects with normal cardiac function

OBJECTIVES

This study evaluated the characteristics of left ventricular maximum principal strain (LV-MPS) using cardiac CT in subjects with normal LV function.

METHODS

Of 973 subjects who underwent retrospective electrocardiogram-gated cardiac CT using a third-generation dual-source CT without beta-blocker administration, 31 subjects with preserved LV ejection fraction ≥ 55% assessed by echocardiography without coronary artery stenosis and cardiac pathology were retrospectively identified. CT images were reconstructed every 5% (0-95%) of the RR interval. LV-MPS and the time to peak (TTP) were analyzed using the 16-segment model and compared among three levels (base, mid, and apex) and among four regions (anterior, septum, inferior, and lateral) using the Steel-Dwass test. The intra- and inter-observer reproducibilities for LV-MPS were calculated using intraclass correlation coefficients (ICCs).

RESULTS

The intra- and inter-observer ICCs (95% confidence interval) for peak LV-MPS were 0.96 (0.94-0.97) and 0.94 (0.92-0.96), respectively. The global peak LV-MPS (median, inter-quantile range) was 0.59 (0.55-0.72). The regional LV-MPS significantly increased in the order of the basal (0.54, 0.49-0.59), mid-LV (0.57, 0.53-0.65), and apex (0.68, 0.60-0.84) (p < 0.05, in each), and was significantly higher in the lateral wall (0.66, 0.60-0.77), while that in the septal region (0.47, 0.44-0.54) was the lowest among the four LV regions (all p < 0.05). No significant difference in TTP was seen among the myocardial levels and regions.

CONCLUSION

CT-derived LV-MPS is reproducible and quantitatively represents synchronized myocardial contraction with heterogeneous values in subjects with normal LV function.

KEY POINTS

• CT-derived left ventricular maximum principal strain analysis allows highly reproducible quantitative assessments of left ventricular myocardial contraction. • In subjects with normal cardiac function, the peak value of CT-derived left ventricular maximum principal strain is the highest in the apical level and in the lateral wall and the lowest in the septum. • The regional peak left ventricular maximum principal strain shows intra-ventricular heterogeneity on a per-patient basis, but myocardial contraction is globally synchronized in subjects with normal cardiac function seen on cardiac CT.

Role of advanced left ventricular imaging in adults with aortic stenosis

This review focuses on the available data regarding the utility of advanced left ventricular (LV) imaging in aortic stenosis (AS) and its potential impact for optimising the timing of aortic valve replacement. Ejection fraction is currently the only LV parameter recommended to guide intervention in AS. The cut-off value of 50%, recommended for decision-making in asymptomatic patients with AS, is currently under debate. Several imaging parameters have emerged as predictors of disease progression and clinical outcomes in this setting. Global longitudinal LV strain by speckle tracking echocardiography is useful for risk stratification of asymptomatic patients with severe AS and preserved LV ejection fraction. Its prognostic value was demonstrated in these patients, but further work is required to define the best thresholds to aid the decision-making process. The assessment of myocardial fibrosis is the most studied application of cardiac magnetic resonance in AS. The detection of replacement fibrosis by late gadolinium enhancement offers incremental prognostic information in these patients. Clinical implementation of this technique to optimise the timing of aortic valve intervention in asymptomatic patients is currently tested in a randomised trial. The use of T1 mapping techniques can provide an assessment of interstitial myocardial fibrosis and represents an expanding field of interest. However, convincing data in patients with AS is still lacking. All these imaging parameters have substantial potential to influence the management decision in patients with AS in the future, but data from randomised clinical trials are awaited to define their utility in daily practice.

Prognostic Influence of Feature Tracking Multidetector Row Computed Tomography-Derived Left Ventricular Global Longitudinal Strain in Patients with Aortic Stenosis Treated With Transcatheter Aortic Valve Implantation

Computed tomography plays a central role in the evaluation of patients with severe aortic stenosis who underwent transcatheter aortic valve implantation (TAVI). Advances in left ventricular (LV) analysis with multidetector row computed tomography (MDCT) permit measurement of LV global longitudinal strain (GLS). The present study aimed at evaluating the association between feature tracking (FT) MDCT derived LV GLS and all-cause mortality in patients treated with TAVI. A total of 214 patients with severe aortic stenosis (51% male, 80 ± 7 years) who underwent TAVI and with dynamic MDCT data allowing LV GLS measurement with novel FT algorithm were included. LV GLS was measured at baseline and were divided according to a previously published cut-off value of LV GLS associated with all-cause mortality (≤-14% [more preserved LV systolic function] vs >-14% [more impaired LV systolic function]). Patients were followed for the occurrence of all-cause mortality. Mean FT MDCT-derived LV GLS was -12.5 ± 4%. During a median follow-up of 45 months (interquartile range: 29 to 62 months), 67 (31%) patients died. The cumulative rate of all-cause mortality for the patients with FT MDCT-derived LV GLS ≤-14% was 15% versus28% for the patients with FT MDCT-derived LV GLS >-14%, Log rank p = 0.001). FT MDCT-derived LV GLS was independently associated with all-cause mortality (hazard ratio: 0.851; 95% confidence interval: 0.772 to 0.937; p = 0.001). In conclusion, impaired FT MDCT-derived LV GLS is independently associated with all-cause mortality in patients treated with TAVI. Besides aortic valve area and calcification, FT MDCT-derived LV GLS is an important prognostic marker.

Automated 4-dimensional regional myocardial strain evaluation using cardiac computed tomography

Evaluation of myocardial regional function is generally performed by visual "eyeballing" which is highly subjective. A robust quantifiable parameter of regional function is required to provide an objective, repeatable and comparable measure of myocardial performance. We aimed to evaluate the clinical utility of novel regional myocardial strain software from cardiac computed tomography (CT) datasets. 93 consecutive patients who had undergone retrospectively gated cardiac CT were evaluated by the software, which utilizes a finite element based tracking algorithm through the cardiac cycle. Circumferential (CS), longitudinal (LS) and radial (RS) strains were calculated for each of 16 myocardial segments and compared to a visual assessment, carried out by an experienced cardiologist on cine movies of standard "echo" views derived from the CT data. A subset of 37 cases was compared to speckle strain by echocardiography. The automated software performed successfully in 93/106 cases, with minimal human interaction. Peak CS, LS and RS all differentiated well between normal, hypokinetic and akinetic segments. Peak strains for akinetic segments were generally post-systolic, peaking at 50 ± 17% of the RR interval compared to 43 ± 9% for normokinetic segments. Using ROC analysis to test the ability to differentiate between normal and abnormal segments, the area under the curve was 0.84 ± 0.01 for CS, 0.80 ± 0.02 for RS and 0.68 ± 0.02 for LS. There was a moderate agreement with speckle strain. Automated 4D regional strain analysis of CT datasets shows a good correspondence to visual analysis and successfully differentiates between normal and abnormal segments, thus providing an objective quantifiable map of myocardial regional function.

Assessment of Global Longitudinal and Circumferential Strain Using Computed Tomography Feature Tracking: Intra-Individual Comparison with CMR Feature Tracking and Myocardial Tagging in Patients with Severe Aortic Stenosis

In this study, we used a single commercially available software solution to assess global longitudinal (GLS) and global circumferential strain (GCS) using cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) feature tracking (FT). We compared agreement and reproducibility between these two methods and the reference standard, CMR tagging (TAG). Twenty-seven patients with severe aortic stenosis underwent CMR and cardiac CT examinations. FT analysis was performed using Medis suite version 3.0 (Leiden, The Netherlands) software. Segment (Medviso) software was used for GCS assessment from tagged images. There was a trend towards the underestimation of GLS by CT-FT when compared to CMR-FT (19.4 ± 5.04 vs. 22.40 ± 5.69, respectively; p = 0.065). GCS values between TAG, CT-FT, and CMR-FT were similar (p = 0.233). CMR-FT and CT-FT correlated closely for GLS (r = 0.686, p < 0.001) and GCS (r = 0.707, p < 0.001), while both of these methods correlated moderately with TAG for GCS (r = 0.479, p < 0.001 for CMR-FT vs. TAG; r = 0.548 for CT-FT vs. TAG). Intraobserver and interobserver agreement was excellent in all techniques. Our findings show that, in elderly patients with severe aortic stenosis (AS), the FT algorithm performs equally well in CMR and cardiac CT datasets for the assessment of GLS and GCS, both in terms of reproducibility and agreement with the gold standard, TAG.