Impact of chest wall deformity on cardiac function by CMR and feature-tracking strain analysis in paediatric patients with Marfan syndrome

Free-Breathing Compressed Sensing Cine Cardiac MRI for Assessment of Left Ventricular Strain by Feature Tracking in Children

BACKGROUND

Cardiac MRI feature-tracking (FT) with breath-holding (BH) cine balanced steady state free precession (bSSFP) imaging is well established. It is unclear whether FT-strain measurements can be reliably derived from free-breathing (FB) compressed sensing (CS) bSSFP imaging.

PURPOSE

To compare left ventricular (LV) strain analysis and image quality of an FB CS bSSFP cine sequence with that of a conventional BH bSSFP sequence in children.

STUDY TYPE

Prospective.

SUBJECTS

40 children able to perform BHs (cohort 1 [12.1 ± 2.2 years]) and 17 children unable to perform BHs (cohort 2 [5.2 ± 1.8 years]).

FIELD STRENGTH/SEQUENCE

3T, bSSFP sequence with and without CS.

ASSESSMENT

Acquisition times and image quality were assessed. LV myocardial deformation parameters were compared between BH cine and FB CS cine studies in cohort 1. Strain indices and image quality of FB CS cine studies were also assessed in cohort 2. Intraobserver and interobserver variability of strain parameters was determined.

STATISTICAL TESTS

Paired t-test, Wilcoxon signed-rank test, intraclass correlation coefficient (ICC), and Bland-Altman analysis. A P-value <0.05 was considered statistically significant.

RESULTS

In cohort 1, the mean acquisition time of the FB CS cine study was significantly lower than for conventional BH cine study (15.6 s vs. 209.4 s). No significant difference were found in global circumferential strain rate (P = 0.089), global longitudinal strain rate (P = 0.366) and EuroCMR image quality scores (P = 0.128) between BH and FB sequences in cohort 1. The overall image quality score of FB CS cine in cohort 2 was 3.5 ± 0.5 with acquisition time of 14.7 ± 2.1 s. Interobserver and intraobserver variabilities were good to excellent (ICC = 0.810 to 0.943).

DATA CONCLUSION

FB CS cine imaging may be a promising alternative technique for strain assessment in pediatric patients with poor BH ability.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.

Myocardial deformation characteristics assessed by cardiovascular magnetic resonance feature tracking in a healthy Chinese population

Purpose

To explore global/regional myocardial deformation across various layers, vascular distributions, specific levels and distinct walls in healthy individuals using cardiovascular magnetic resonance feature tracking (CMR-FT).

Methods

We selected a cohort of 55 healthy participants and CMR cine images were used to obtain the left ventricular (LV) peak longitudinal, circumferential, radial strains (LS, CS, RS). The characteristics of normal LV strain in various layers (endocardium, myocardium, epicardium), territories [left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA)], levels (basal, middle, apical) and walls (anterior, septum, inferior, lateral) were compared.

Results

The absolute values of the LV global LS and CS gradually decreased from endocardium to epicardium. The absolute LV global RS (65.7 ± 47.7%) was maximum relative to LS (-22.0 ± 10.8%) and CS (-22.8 ± 7.7%). The absolute values of the LCX territorial strain were the largest compared with the LAD and RCA territorial strains. Regional RS, endo-CS and endo-LS gradually increased from the basal to the apical level. The LV lateral walls had the highest strain values (CS, LS, and RS).

Conclusions

Variations in normal LV strain values across various layers, territories, levels, and walls were observed, suggesting the necessity for careful clinical interpretation of these strain values. These findings also partially revealed the complexity of normal cardiac mechanics.

Longitudinal follow-up by MR angiography reveals progressive dilatation of the distal aorta after aortic root replacement in Marfan syndrome

OBJECTIVES

To define and compare growth rates of the distal aorta in Marfan patients with and without aortic root replacement using serial MR angiography (MRA).

METHODS

We retrospectively included 136 Marfan patients with a total of 645 MRAs who underwent a median of five MRAs (range: 2-13) at 1.5 T and 3 T in annual intervals. Of these, 41 patients (34.8 ± 12 years) had undergone aortic root replacement. The remaining 95 patients (29.0 ± 17 years) still had a native aorta and served as the control group. Thoracic aortic diameters were independently measured at eleven predefined levels. Estimated growth rates were calculated using a mixed effects model adjusted for sex, age, BMI, and medication.

RESULTS

Marfan patients with aortic root replacement revealed the highest mean estimated growth rate in the proximal descending aorta (0.77 mm/year, CI: 0.31-1.21). Mean growth rates at all levels of the distal thoracic aorta were significantly higher in patients with aortic root replacement (0.28-0.77 mm/year) when compared to patients without aortic root replacement (0.03-0.07 mm/year) (all p < 0.001). Antihypertensive medication, gender, and BMI had no significant impact on the distal aortic growth rates.

CONCLUSION

Distal thoracic aortic diameters increase at a significantly higher rate in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. Further studies are warranted to investigate if the increased growth rate of the distal thoracic aorta after aortic root replacement is caused by altered hemodynamics due to the rigid aortic root graft or due to the general genetic disposition of post-operative Marfan patients.

CLINICAL RELEVANCE STATEMENT

High growth rates of the distal aorta after aortic root replacement underline the need for careful life-long aortic imaging of Marfan patients after aortic root replacement.

KEY POINTS

• Aortic growth rates in Marfan patients with aortic root replacement are highest in the mid-aortic arch, the proximal- and mid-descending aorta. • Growth rates of the distal thoracic aorta are significantly higher in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. • Antihypertensive medication, gender, and BMI have no significant impact on distal aortic growth rates in Marfan patients.

Association of Pectus Excavatum With Ventricular Remodelling and Mitral Valve Abnormalities in Marfan Syndrome

Background: Marfan syndrome (MFS) is an inherited connective tissue disorder. Pectus excavatum (PEX) is common in MFS. The purpose was to evaluate the association of PEX with cardiovascular manifestations of MFS, biventricular size and function. Methods: MFS adults undergoing cardiac MRI were retrospectively evaluated. Exclusion criteria were incomplete cardiac MRI, significant artifacts, co-existent ischaemic or congenital heart disease. Haller Index (HI) ≥3.25 classified patients as PEX positive (PEX+) and PEX negative (PEX-). Cardiac MRI analysis included assessment of mitral valve prolapse (MVP), mitral annular disjunction (MAD), biventricular volumetry and aortic dimensions. Results: 212 MFS patients were included, 76 PEX+ and 136 PEX- (HI 8.3 ± 15.2 vs 2.3 ± 0.5, P < .001). PEX+ were younger (33.4 ± 12.0 vs 38.1 ± 14.3 years, P = .02) and similar in sex distribution (55% vs 63% male, P = .26) compared to PEX-. MVP and MAD were more frequent in PEX+ vs PEX- (43/76 [57%] vs 37/136 [27%], P < .001; 44/76 [58%] vs 50/136[37%], P = .003, respectively). PEX+ had higher right ventricular end-diastolic and end-systolic volumes (RVEDVi 92 ± 17mL/m2 vs 84 ± 22mL/m2, P = .04; RVESVi 44 ± 10 mL/m2 vs 39 ± 14 mL/m2, P = .02), lower RV ejection fraction (RVEF 52 ± 5% vs 55 ± 6%, P = .01) compared to PEX-. Left ventricular (LV) volumes, LVEF and aortic dimensions were similar. Conclusion: MFS adults with PEX have higher frequency of cardiac manifestations including MV abnormalities, increased RV volumes and lower RVEF compared to those without PEX. Awareness of this association is important for all radiologists who interpret aortic CT or MRI, where HI can be easily measured. PEX in MFS may suggest more severe disease expression necessitating careful screening for MV abnormalities and outcomes surveillance.

State-of-the-art myocardial strain by CMR feature tracking: clinical applications and future perspectives

Based on conventional cine sequences of cardiac magnetic resonance (CMR), feature tracking (FT) is an emerging tissue tracking technique that evaluates myocardial motion and deformation quantitatively by strain, strain rate, torsion, and dyssynchrony. It has been widely accepted in modern literature that strain analysis can offer incremental information in addition to classic global and segmental functional analysis. Furthermore, CMR-FT facilitates measurement of all cardiac chambers, including the relatively thin-walled atria and the right ventricle, which has been a difficult measurement to obtain with the reference standard technique of myocardial tagging. CMR-FT objectively quantifies cardiovascular impairment and characterizes myocardial function in a novel way through direct assessment of myocardial fiber deformation. The purpose of this review is to discuss the current status of clinical applications of myocardial strain by CMR-FT in a variety of cardiovascular diseases. KEY POINTS: • CMR-FT is of great value for differential diagnosis and provides incremental value for evaluating the progression and severity of diseases. • CMR-FT guides the early diagnosis of various cardiovascular diseases and provides the possibility for the early detection of myocardial impairment and additional information regarding subclinical cardiac abnormalities. • Direct assessment of myocardial fiber deformation using CMR-FT has the potential to provide prognostic information incremental to common clinical and CMR risk factors.

Acute impact of an endurance race on biventricular and biatrial myocardial strain in competitive male and female triathletes evaluated by feature-tracking CMR

Objectives

Cardiac adaptation in endurance athletes is a well-known phenomenon, but the acute impact of strenuous exercise is rarely reported on. The aim of this study was to analyze the alterations in biventricular and biatrial function in triathletes after an endurance race using novel feature-tracking cardiac magnetic resonance (FT-CMR).

Methods

Fifty consecutive triathletes (45 ± 10 years; 80% men) and twenty-eight controls were prospectively recruited, and underwent 1.5-T CMR. Biventricular and biatrial volumes, left ventricular ejection fraction (LVEF), FT-CMR analysis, and late gadolinium imaging (LGE) were performed. Global systolic longitudinal (GLS), circumferential (GCS), and radial strain (GRS) were assessed. CMR was performed at baseline and following an endurance race. High-sensitive troponin T and NT-proBNP were determined. The time interval between race completion and CMR was 2.3 ± 1.1 h (range 1–5 h).

Results

Post-race troponin T (p < 0.0001) and NT-proBNP (p < 0.0001) were elevated. LVEF remained constant (62 ± 6 vs. 63 ± 7%, p = 0.607). Post-race LV GLS decreased by tendency (− 18 ± 2 vs. − 17 ± 2%, p = 0.054), whereas GCS (− 16 ± 4 vs. − 18 ± 4%, p < 0.05) and GRS increased (39 ± 11 vs. 44 ± 11%, p < 0.01). Post-race right ventricular GLS (− 19 ± 3 vs. − 19 ± 3%, p = 0.668) remained constant and GCS increased (− 7 ± 2 vs. − 8 ± 3%, p < 0.001). Post-race left atrial GLS (30 ± 8 vs. 24 ± 6%, p < 0.0001) decreased while right atrial GLS remained constant (25 ± 6 vs. 24 ± 6%, p = 0.519).

Conclusions

The different alterations of post-race biventricular and biatrial strain might constitute an intrinsic compensatory mechanism following an acute bout of endurance exercise. The combined use of strain parameters may allow a better characterization of ventricular and atrial function in endurance athletes.

Key Points

• Triathletes demonstrate a decrease of LV global longitudinal strain by tendency and constant RV global longitudinal strain following an endurance race.

• Post-race LV and RV global circumferential and radial strains increase, possibly indicating a compensatory mechanism after an acute endurance exercise bout.

• Subgroup analyses of male triathletes with focal myocardial fibrosis did not demonstrate alterations in biventricular and biatrial strain after an endurance race.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08401-y.

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking-All About the Left Ventricle?

Purpose of Review

Cardiac magnetic resonance-feature-tracking (CMR-FT)-based deformation analyses are key tools of cardiovascular imaging and applications in heart failure (HF) diagnostics are expanding. In this review, we outline the current range of application with diagnostic and prognostic implications and provide perspectives on future trends of this technique.

Recent Findings

By applying CMR-FT in different cardiovascular diseases, increasing evidence proves CMR-FT-derived parameters as powerful diagnostic and prognostic imaging biomarkers within the HF continuum partly outperforming traditional clinical values like left ventricular ejection fraction. Importantly, HF diagnostics and deformation analyses by CMR-FT are feasible far beyond sole left ventricular performance evaluation underlining the holistic nature and accuracy of this imaging approach.

Summary

As an established and continuously evolving technique with strong prognostic implications, CMR-FT deformation analyses enable comprehensive cardiac performance quantification of all cardiac chambers.