Quantification of myocardial strain in patients with isolated left ventricular non-compaction and healthy subjects using deformable registration algorithm: comparison with feature tracking

Measurement of Abdominal Aortic Aneurysm Strain Using MR Deformable Image Registration: Accuracy and Relationship to Recent Aneurysm Progression

BACKGROUND

Management of asymptomatic abdominal aortic aneurysm (AAA) based on maximum aneurysm diameter and growth rate fails to preempt many ruptures. Assessment of aortic wall biomechanical properties may improve assessment of progression and rupture risk. This study aimed to assess the accuracy of AAA wall strain measured by cine magnetic resonance imaging (MRI) deformable image registration (MR strain) and investigate its relationship with recent AAA progression.

METHODS

The MR strain accuracy was evaluated in silico against ground truth strain in 54 synthetic MRIs generated from a finite element model simulation of an AAA patient's abdomen for different aortic pulse pressures, tissue motions, signal intensity variations, and image noise. Evaluation included bias with 95% confidence interval (CI) and correlation analysis. Association of MR strain with AAA growth rate was assessed in 25 consecutive patients with >6 months of prior surveillance, for whom cine balanced steady-state free-precession imaging was acquired at the level of the AAA as well as the proximal, normal-caliber aorta. Univariate and multivariate regressions were used to associate growth rate with clinical variables, maximum AAA diameter (D max ), and peak circumferential MR strain through the cardiac cycle. The MR strain interoperator variability was assessed using bias with 95% CI, intraclass correlation coefficient, and coefficient of variation.

RESULTS

In silico experiments revealed an MR strain bias of 0.48% ± 0.42% and a slope of correlation to ground truth strain of 0.963. In vivo, AAA MR strain (1.2% ± 0.6%) was highly reproducible (bias ± 95% CI, 0.03% ± 0.31%; intraclass correlation coefficient, 97.8%; coefficient of variation, 7.14%) and was lower than in the nonaneurysmal aorta (2.4% ± 1.7%). D max ( β = 0.087) and MR strain ( β = -1.563) were both associated with AAA growth rate. The MR strain remained an independent factor associated with growth rate ( β = -0.904) after controlling for D max .

CONCLUSIONS

Deformable image registration analysis can accurately measure the circumferential strain of the AAA wall from standard cine MRI and may offer patient-specific insight regarding AAA progression.

Myocardial Strain Measurements Derived From MR Feature-Tracking: Influence of Sex, Age, Field Strength, and Vendor

BACKGROUND

Cardiac magnetic resonance feature tracking (CMR-FT) is a novel technique for assessing myocardial deformation and dysfunction. However, a comprehensive assessment of normal values of strain parameters in all 4 cardiac chambers using different vendors is lacking.

OBJECTIVES

This study aimed to characterize the normal values for myocardial strain in all 4 cardiac chambers and identify factors that contribute to variations in FT strain through a systematic review and meta-analysis of the CMR-FT published reports.

METHODS

The investigators searched PubMed, Embase, and Scopus for myocardial strains of all 4 chambers measured by CMR-FT in healthy adults. The pooled means of all strain parameters were generated using a random-effects model. Subgroup analyses and meta-regressions were performed to identify the sources of variations.

RESULTS

This meta-analysis included 44 studies with a total of 3,359 healthy subjects. The pooled means of left ventricular global longitudinal strain (LV-GLS), LV global radial strain, and LV global circumferential strain (GCS) were -18.4% (95% CI: -19.2% to -17.6%), 43.7% (95% CI: 40.0%-47.4%), and -21.4% (95% CI: -22.3% to -20.6%), respectively. The pooled means of left atrial (LA)-GLS (corresponding to total strain, passive strain, and active strain) were 34.9% (95% CI: 29.6%-40.2%), 21.3% (95% CI: 16.6%-26.1%) and 14.3% (95% CI: 11.8%-16.8%), respectively. The pooled means of right ventricular (RV)-GLS and right atrial global longitudinal total strain were -24.0% (95% CI: -25.8% to -22.1%) and 36.3% (95% CI: 15.5%-57.0%), respectively. Meta-regression identified field strength (P < 0.001; I2 = 98.6%) and FT vendor (P < 0.001; I2 = 98.5%) as significant confounders contributing to heterogeneity of LV-GLS. The variations of LA-GLSactive were associated with regional distribution (P < 0.001; I2 = 97.3%) and FT vendor (P < 0.001; I2 = 97.4%). Differences in FT vendor were attributed to variations of LV-GCS and RV-GLS (P = 0.02; I2 = 98.8% and P = 0.01; I2 = 93.8%).

CONCLUSIONS

This study demonstrated the normal values of CMR-FT strain parameters in all 4 cardiac chambers in healthy subjects. Differences in FT vendor contributed to the heterogeneity of LV-GLS, LV-GCS, LA-GLSactive, and RV-GLS, whereas sex, age, and MR vendor had no effect on the normal values of CMR-FT strain measurements.

Utilizing Artificial Intelligence-Based Deformable Registration for Global and Layer-Specific Cardiac MRI Strain Analysis in Healthy Children and Young Adults

RATIONALE AND OBJECTIVES

The absence of published reference values for multilayer-specific strain measurement using cardiac magnetic resonance (CMR) in young healthy individuals limits its use. This study aimed to establish normal global and layer-specific strain values in healthy children and young adults using a deformable registration algorithm (DRA).

MATERIALS AND METHODS

A retrospective study included 131 healthy children and young adults (62 males and 69 females) with a mean age of 16.6 ± 3.9 years. CMR examinations were conducted using 1.5T scanners, and strain analysis was performed using TrufiStrain research prototype software (Siemens Healthineers, Erlangen, Germany). Global and layer-specific strain parameters were extracted from balanced Steady-state free precession cine images. Statistical analyses were conducted to evaluate the impact of demographic variables on strain measurements.

RESULTS

The peak global longitudinal strain (LS) was -16.0 ± 3.0%, peak global radial strain (RS) was 29.9 ± 6.3%, and peak global circumferential strain (CS) was -17.0 ± 1.8%. Global LS differed significantly between males and females. Transmural strain analysis showed a consistent pattern of decreasing LS and CS from endocardium to epicardium, while radial strain increased. Basal-to-apical strain distribution exhibited decreasing LS and increasing CS in both global and layer-specific analysis.

CONCLUSION

This study uses DRA to provide reference values for global and layer-specific strain in healthy children and young adults. The study highlights the impact of sex and age on LS and body mass index on RS. These insights are vital for future cardiac assessments in children, particularly for early detection of heart diseases.

Myocardial Mechanics and Associated Valvular and Vascular Abnormalities in Left Ventricular Noncompaction Cardiomyopathy

Left ventricular (LV) non-compaction (LVNC) is a rare genetic cardiomyopathy due to abnormal intra-uterine arrest of compaction of the myocardial fibers during endomyocardial embryogenesis. Due to the partial or complete absence of LV compaction, the structure of the LV wall shows characteristic abnormalities, including a thin compacted epicardium and a thick non-compacted endocardium with prominent trabeculations and deep intertrabecular recesses. LVNC is frequently associated with chronic heart failure, life-threatening ventricular arrhythmias, and systemic embolic events. According to recent findings, in the presence of LVNC, dysfunctional LV proved to be associated with left atrial volumetric and functional abnormalities and consequential dilated and functionally impaired mitral annulus, partly explaining the higher prevalence of regurgitation. Although the non-compaction process morphologically affects only the LV, signs of remodeling of the right heart were also detected. Moreover, dilation and stiffening of the aorta were present. The aim of the present detailed review was to summarize findings regarding changes in cardiac mechanics, valvular abnormalities, and vascular remodeling detected in patients with LVNC.

Value of cardiac magnetic resonance feature tracking technology in the differential diagnosis of isolated left ventricular noncompaction and dilated cardiomyopathy

Background

This study explored the value of myocardial strain in the differential diagnosis of isolated left ventricular myocardial noncompaction (ILVNC) and dilated cardiomyopathy (DCM) using cardiac magnetic resonance (CMR) feature tracking technology.

Methods

This retrospective analysis was performed on consecutive patients (25 with ILVNC, 30 with DCM, and 30 healthy controls) presenting to Shanxi Cardiovascular Hospital. All ILVNC patients met echocardiographic and CMR criteria for ventricular non-compaction. All patients with DCM met the 2016 American Heart Association and 2018 Chinese Medical Association Cardiovascular Branch diagnostic criteria. cvi42 software (Circle Cardiovascular Imaging) was used to measure radial, circumferential, and longitudinal strain (LS) globally and in segments of the left ventricle. Analysis of variance was used to compare strains among groups and among different segments within the same group. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of different parameters in ILVNC and DCM.

Results

Basal circumferential strain was lower in the DCM than in the ILVNC group (P=0.05). Both median and apical LS were lower in the ILVNC than in DCM group (P=0.02 and P=0.01, respectively). ROC curves showed that apical LS was the most effective in distinguishing ILVNC from DCM [area under the curve (AUC) =0.883; P<0.001; 95% CI: 0.850-0.977]. Comparing strains among different segments within the same group revealed that in DCM, the circumferential and LS of the apex were higher than those of the basal segment, which is consistent with the pattern in healthy controls; however, has no such regular pattern was seen in ILVNC.

Conclusions

Myocardial strain parameters are of considerable value in the differential diagnosis of ILVNC and DCM. Differences in patterns between ILVNC and DCM can be sensitively identified, providing more comprehensive information for early clinical diagnosis.

Comparison of left ventricular global and segmental strain parameters by cardiovascular magnetic resonance tissue tracking in light-chain cardiac amyloidosis and hypertrophic cardiomyopathy

Background

Apical sparing of left ventricular (LV) strain can occur in light-chain cardiac amyloidosis (AL-CA). We employed indicators of the strain ratio of the apex to base (RAB) and the relative apical sparing of strain (RAS) on the basis of LV global and segmental strain to distinguish AL-CA from hypertrophic cardiomyopathy (HCM).

Methods

In all, 36 AL-CA patients, 37 HCM patients, and 36 healthy controls underwent 3.0 T cardiac magnetic resonance (CMR) examination. We compared LV strain parameters from CMR tissue tracking (CMR-TT), including global and segmental peak radial strain (PRS), peak circumferential strain (PCS), and peak longitudinal strain (PLS); the peak systolic strain rate in radial, circumferential, and longitudinal directions (PSSR_R, PSSR_C, PSSR_L); and the peak diastolic strain rate in radial, circumferential, and longitudinal directions (PDSR_R, PDSR_C, PDSR_L). We also assessed the values of RAB and RAS. Differences in all groups were compared using an independent t-test and a nonparametric rank sum test.

Results

In the comparison of global strain parameters, all the peak strain, systolic, and diastolic peak strain rates of the AL-CA group significantly decreased compared with those of the HCM and healthy control groups (all P<0.001). The values of PSSR in all directions were lower in the AL-CA than in the HCM patients (PSSR_R, P<0.001; PSSR_C, P=0.004; PSSR_L, P=0.010) . In the analysis of segmental strain parameters, all peak strains in the basal segment showed significant differences between the AL-CA and HCM groups (all P<0.001). Some strain rate parameters in the basal segment were also noted to be significantly different (PSSR_R, P<0.001; PSSR_L, P<0.001; PDSR_R, P=0.015; PDSR_C, P=0.020). Both the RAB and RAS of peak strain in all directions showed significant differences between the AL-CA and HCM groups (all P<0.001). The RAB of the radial and circumferential PSSR showed statistical differences between the 2 groups (P<0.001 and P=0.001). The RAS in the radial direction of both the PSSR and PDSR was statistically different (P=0.003 and P=0.012).

Conclusions

The CMR-TT technique can be used to quantitatively compare global and segmental strain differences between AL-CA and HCM. In addition, RAB and RAS are reliable parameters for assessing the apical sparing pattern and thus, for distinguishing AL-CA from HCM.