Native Magnetic Resonance T1-Mapping Identifies Diffuse Myocardial Injury in Hypothyroidism

Abstract

Background and AimHypothyroidism (HT) is characterized by thyroid hormone deficiencies, which can lead to diffuse myocardial interstitium lesions in patients with HT. Myocardial longitudinal relaxation time (T1) mapping is a potential diagnostic tool for quantifying diffuse myocardial injury. This study aimed to assess the usefulness of T1 mapping in identifying myocardial involvement in HT, and determine the relationship between T1 values and myocardial function.MethodsA cross-sectional study was conducted with 30 untreated HT patients alongside 23 age- and sex-matched healthy controls. All subjects underwent cardiac magnetic resonance (CMR) with non-contrast (native) T1 mapping using a modified Look-Locker inversion-recovery (MOLLI) sequence to assess the native T1 values of myocardium and cardiac function.ResultsNative myocardial T1 values were significantly increased in HT patients, especially those with pericardial effusion (p < 0.05), compared with healthy controls. In addition, significantly reduced peak filling rate (PFR) and prolonged peak filling time (PFT) were obtained (p < 0.05) in HT patients compared with controls. Furthermore, stroke volume (SV) and cardiac index (CI) were significantly lower in HT patients than controls (all p < 0.05). Interestingly, native T1 values were negatively correlated with free triiodothyronine (FT3), PFR, SV and CI (all p < 0.05).ConclusionDiffuse myocardial injuries are common in HT patients, and increased T1 values are correlated with FT3 and cardiac function impairment. These findings indicate that T1 mapping might be useful in evaluating myocardial injuries in HT patients.

Effects of short‐term levothyroxine therapy on myocardial injuries in patients with severe overt hypothyroidism: Evidence from a cardiac MRI Study

“…More important, expansion of the collagen matrix increases the volume of distribution, leading to combined native T 1 augmentation . A previous study has revealed that T 1 values are significantly increased in patients with HT, particularly in cases with pericardial effusion . Furthermore, T 1 mapping has exploited slight changes in T 1 values to permit the measurement of early improvement after treatment.…”

“…10 This MRI sequence has been used already in a clinical setting and showed increased noncontrast T 1 values with impaired peak filling rate (PFR) in patients with newly diagnosed overt HT, which may reflect the presence of myocardial interstitial fibrosis, edema lesions, and then diastolic dysfunction in the low-FT3 heart. 11 Jellis et al have also confirmed that fibrosis is one of the important contributors to the pathogenesis of myocardial relaxation abnormalities. 12 In recent decades, the effects of levothyroxine treatment in patients with HT have mainly focused on myocardial structure and function according to the echocardiography or MRI using a late gadolinium enhancement imaging technique.…”

“…Myocardial longitudinal relaxation time ( T 1 ) mapping is an emerging technique that permits the assessment and quantification of diffuse myocardial interstitial fibrosis and has a high diagnostic performance for detection of myocardial edema . This MRI sequence has been used already in a clinical setting and showed increased noncontrast T 1 values with impaired peak filling rate (PFR) in patients with newly diagnosed overt HT, which may reflect the presence of myocardial interstitial fibrosis, edema lesions, and then diastolic dysfunction in the low‐FT3 heart . Jellis et al have also confirmed that fibrosis is one of the important contributors to the pathogenesis of myocardial relaxation abnormalities …”

Left ventricular end‐diastolic strain rate recovered in hypothyroidism following levothyroxine replacement therapy: A strain rate imaging study

“…Global SRivr and SRe are primarily dependent on LV relaxation, while SRa, which occurs at late diastole, should be subject more to LV compliance. Compliance is influenced by myocardial stiffness and extracellular matrix, which has been detected in hypothyroidism using CMR . Therefore, the finding of a decreased late diastolic myocardial deformation (SRa) in untreated hypothyroidism is consistent with abnormal extracellular matrix alteration.…”

“…8 Compliance is influenced by myocardial stiffness and extracellular matrix, which has been detected in hypothyroidism using CMR. 23,24 Therefore, the finding of a decreased late diastolic myocardial deformation (SRa) in untreated hypothyroidism is consistent with abnormal extracellular matrix alteration.…”