Biventricular Myocardial Strain Analysis in Patients with Pulmonary Arterial Hypertension Using Cardiac Magnetic Resonance Tissue-Tracking Technology

To evaluate both left and right ventricular (LV and RV) function in patients with pulmonary arterial hypertension (PAH) using cardiac magnetic resonance tissue-tracking (CMR-TT) technology and explore its clinical value. Methods: A total of 79 participants (including 47 patients with PAH and 32 healthy controls) underwent cardiac magnetic resonance imaging (CMRI) with a short-axis balanced steady-state free precession (SSFP) sequence. The biventricular cardiac function parameters and strain parameters were obtained by postprocessing with CVI42 software. A comparative analysis was performed between the LV and RV strain parameters in all PAH patients and in PAH patients with reduced or preserved cardiac function. Results: The results showed preferable repeatability of CMR-TT in analyzing the global radial strain (GRS), circumferential strain (GCS), and longitudinal strain (GLS) of the left and right ventricles in the PAH group. The GRS, GCS, and GLS of the left and right ventricles except for LV GRS (LVGRS) of PAH patients were significantly lower than those of healthy controls (p < 0.05 for all). The GRS and GCS of the left and right ventricles showed a moderate correlation in the PAH group (r = 0.323, p = 0.02; r = 0.301, p = 0.04, respectively). PAH patients with preserved RV function (n = 9) showed significantly decreased global and segmental RS, CS, and LS of the right ventricles than healthy controls (p < 0.05 for all), except for basal RVGCS (RVGCS-b, p = 0.996). Only the LVGLS was significantly different between the PAH patients with preserved LV function (n = 32) and the healthy controls (−14.23 ± 3.01% vs. −16.79 ± 2.86%, p < 0.01). Conclusions: As a nonradioactive and noninvasive technique, CMR-TT has preferable feasibility and repeatability in quantitatively evaluating LV and RV strain parameters in PAH patients and can be used to effectively detect early biventricular myocardial damage in patients with PAH.

Real-world clinical validity of cardiac magnetic resonance tissue tracking in primitive hypertrophic cardiomyopathy

OBJECTIVE

Cardiac magnetic resonance (CMR) is an uncontested diagnostic tool for identifying and assessing hypertrophic cardiomyopathy (HCM) patients. Concerning the necessity to identify valid prognosticators for predicting the individual risk of clinical evolution, this study aimed to evaluate the clinical validity of CMR tissue tracking (TT) analysis in patients affected by primitive HCM in a real-world setting.

METHODS

This historical prospective study included 33 patients. Diagnostic validity and clinical validation were assessed for strain values. CMR-TT diagnostic validity was studied comparing HCM patients with healthy control groups and phenotypic presentation of HCM. The impact of strain values and all phenotypic disease characteristics were assessed in a long-term follow-up study.

RESULTS

The inter-reading agreement was good for all strain parameters. Significant differences were observed between the control group and HCM patients. Similarly, hypertrophic and LGE + segments showed lower deformability than healthy segments. The AUC of predictive model, including conventional risk factors for MACE occurrence and all strain values, reached 98% of diagnostic concordance (95% CI .94-1; standard error: .02; p value .0001), compared to conventional risk factors only (86%; 95% CI .73-99; standard error: .07; p value .002).

CONCLUSION

In patients with primitive HCM, CMR-TT strain proves high clinical validity providing independent and non-negligible prognostic advantages over clinical features and traditional CMR markers.

[Evaluating Cardiac Function of Tree Shrew (Tupaiabelangeri) using CMR at 7T with 2D Tissue Tracking]

OBJECTIVE

To determine the potential value of the two-dimensional (2D) cardiac magnetic resonance imaging (CMR) tissue tracking (CMR-TT) method in assessing the cardiac function of tree shrew at 7T.

METHODS

Healthy adult tree shrews (male, n=8) and spraguedawley rats(male, n=8) were selected for this study. CMR was performed to acquire the short-axis images of left ventricle at 7T using the same appropriative coil and cine sequence for all experimental animals. The CMR images were processed using the professional cardiac analysis software, calculating ejection fraction (EF), radial peak sysolic strain (Err), circumferential peak sysolic strain (Ecc), radial peak sysolic displacement (DR), and LVM/BM 〔the ratio of left ventricular mass (LVM) to body mass (BM)〕.

RESULTS

Cine imaging for the tree shrews was 100% successful following the CMR protocol for the rats, with clearly visible main segments of cardiac. Significant differences in EF, Err, Ecc and DR were found between the two groups of animals (P < 0.01). The tree shrews has lower EF, Err and Ecc than the rats. Err and Ecc appeared in the fifteenth phase in left ventriclar systole in the tree shrews, compared with the tenth phase in the rats.The tree shrews also had higher LVM/BM than the rats.

CONCLUSION

The cardiac function of tree shrew can be assessed using the 2D CMR-TT method despite significant differences across species.