Native myocardial T1 mapping in pulmonary hypertension: correlations with cardiac function and hemodynamics

Abstract

ObjectivesTo analyze alterations in left ventricular (LV) myocardial T1 times in patients with pulmonary hypertension (PH) and to investigate their associations with ventricular function, mass, geometry and hemodynamics.MethodsFifty-eight patients with suspected PH underwent right heart catheterization (RHC) and 3T cardiac magnetic resonance imaging. Ventricular function, geometry and mass were derived from cine real-time short-axis images. Myocardial T1 maps were acquired by a prototype modified Look-Locker inversion-recovery sequence in short-axis orientations. LV global, segmental and ventricular insertion point (VIP) T1 times were evaluated manually and corrected for blood T1.ResultsSeptal, lateral, global and VIP T1 times were significantly higher in PH than in non-PH subjects (septal, 1249 ± 58 ms vs. 1186 ± 33 ms, p < 0.0001; lateral, 1190 ± 45 ms vs. 1150 ± 33 ms, p = 0.0003; global, 1220 ± 52 ms vs. 1171 ± 29 ms, p < 0.0001; VIP, 1298 ± 78 ms vs. 1193 ± 31 ms, p < 0.0001). In PH, LV eccentricity index was the strongest linear predictor of VIP T1 (r = 0.72). Septal, lateral and global T1 showed strong correlations with VIP T1 (r = 0.81, r = 0.59 and r = 0.75, respectively).ConclusionsIn patients with PH, T1 times in VIPs and in the entire LV myocardium are elevated. LV eccentricity strongly correlates with VIP T1 time, which in turn is strongly associated with T1 time changes in the entire LV myocardium.Key Points • Native T1 mapping detects left ventricular myocardial alterations in pulmonary hypertension • In pulmonary hypertension, native T1 times at ventricular insertion points are increased • These T1 times correlate strongly with left ventricular eccentricity • In pulmonary hypertension, global and segmental myocardial T1 times are increased • Global, segmental and ventricular insertion point T1 times are strongly correlated

Cardiac magnetic resonance T1 mapping. Part 1: Aspects of acquisition and evaluation

“…Whereas, generally, female native T1 and ECV values have been found to tend to exceed corresponding male values (Table 1) As myocardium contains blood, alterations of the substantially varying native T1 time of blood should alter myocardial native T1 time. Different studies reported correlations between blood and myocardial native T1 times in normal subjects [47,51,57,75]. The slopes of corresponding regression lines might be employed to normalize myocardial native T1 values to a common blood T1 time, which leads to a reduction of the spread of myocardial native T1 normal ranges [47,57,58].…”

The left ventricle undergoes biomechanical and gene expression changes in response to increased right ventricular pressure overload

“…When looking in the LV, the septum and the inter‐ventricular sulcus also revealed slight but significantly elevated fibrosis in PAB animals, relative to sham animals, with some perivascular fibrosis even visible in the LV free wall, but to a much lesser extent than in the RV. This is supported by MRI studies in patients with pulmonary hypertension that have shown elevated T1 times in the entire LV, which is correlated with changes in the eccentricity index (Reiter et al, ). The aforementioned computational studies in our lab have suggested a potential mechanism by showing that increased RV pressure overload causes increased LV myocardial stress (Kheyfets et al, ), which is a biomechanical initiator for fibroblast activation (Espeland, Lunde, B, Gullestad, & Aakhus, ).…”

“…Previous research from our group and elsewhere have documented biomechanical and structural changes (Dufva et al, ; Reiter et al, ) within the LV of patients with pressure overload in the RV‐PA axis. However, it was unclear if this was a result of biomechanical or biochemical signaling.…”

Cardiac magnetic resonance T1 mapping. Part 2: Diagnostic potential and applications

“…Increased native T1 values at the ventricular insertion points (Fig. 13), which are closely related to the frequently observed focal patterns of LE in patients with right heart pressure overload [86,87], could represent a potential non-contrast diagnostic marker in patients with suspicion of pulmonary hypertension [88,92].…”

“…In contrast to systemic hypertension without LV hypertrophy, pulmonary hypertension was found to be associated with increased native LV and RV myocardial T1 and ECV regardless of the underlying disease etiology [88][89][90][91][92]. Increased native T1 values at the ventricular insertion points (Fig.…”