Assessment of biventricular function in Patients with chronic mountain sickness by cardiac magnetic resonance T1 mapping and feature tracking technique

Objective: Chronic mountain sickness (CMS) is also known as high-altitude maladaptation syndrome [1] . When the more severe stages of this disease, high-altitude pulmonary hypertension and right ventricular enlargement are commonly found. The cardiac magnetic resonance feature tracking (CMR-FT) and T1mapping can analyze quantitatively bi-ventricular strain in CMS patients and facilitate myocardium impairment early in CMS . Materials and methods 38 individuals including 20 healthy controls and 18 CMS patients who underwent cardiac magnetic resonance (CMR) with Steady-State Free Precession (SSFP) sequences and T1mapping.Biventricular myocardial function measures and strain variables were acquired after post-processing with the CVI42 tool. Based on T1 and ECV maps acquired using a modified Look Locker inversion recovery approach, the pre/post-enhancemant T1 and ECV values of the biventricles were determined. The parameters linked to the total biventricular systolic strain were assessed using conventional cine images and tissue tracking analytic techniques. Results (1) CMR-FT results: Global circumferential strain(GCS), Global radial strain(GRS), and Global longitudinal strain(GLS) were significantly lower in both ventricular in CMS patients than in healthy controls (all p < 0.05). GRS and GCS showed moderate correlation in the left and right ventricles in the CMS group (r = 0.671, p = 0.002; r = 0.597, p = 0.009, respectively) .This shows that their onset time may be earlier than the decline time of left ventricular ejection fraction(LVEF)and right ventricular ejection fraction(RVEF). (2) T1 mapping results: For the right ventricle, pre/post enhancement T1 values and ECV were higher in CMS patients than in controls whole native T1 values were 1374.3 ± 157.6ms, vs 1164.6 ± 60.1ms;whole post T1 values were 551.7 ± 42.2ms vs 485.1 ± 17.2ms and ECV values were 34.2 ± 6.8% vs 25.2 ± 3.6%; the differences were significant (p < 0.05). The results show that their onset time may be earlier than the decline time of left ventricular ejection fraction(LVEF)and right ventricular ejection fraction(RVEF), indicating that myocardium is impaired in CMS. Conclusions For the quantitative evaluation of biventricular strain parameters and ventricular myocardial fibrosis in patients with CMS, CMR-FT and mapping procedures are practicable and repeatable. They may also efficiently identify early biventricular damage in individuals with CMS.