Abstract
The objective of this study was to assess the relationship between imaging surrogates for diffuse fibrosis and myocardial dysfunction. Thirty-six New Zealand white rabbits were classified into two groups: a control group (n = 18) and an alloxan-induced diabetes mellitus (DM) group (n = 18). For all rabbits, conventional ultrasonography, two-dimensional speckle tracking, and cardiac magnetic resonance (CMR) T1 mapping were performed; all of the rabbits were then sacrificed for Masson’s staining. The extracellular volume (ECV) was calculated from pre- and post-contrast T1 values and compared with myocardial function measured by echocardiography using Pearson’s correlation. In the DM group, ECV increased as the duration of diabetes increased, consistent with the changes in myocardial fibrosis verified by pathology. Moreover, ECV was strongly correlated with the early diastolic strain rate (r = −0.782, p < 0.001) and moderately correlated with the radial systolic peak strain (r = 0.478, p = 0.045). Thus, ECV is an effective surrogate for myocardial diffuse fibrosis on CMR imaging, and higher ECV values are associated with an increased impairment of myocardial diastolic function.
Highlights
Two-dimensional (2D) speckle tracking is an advanced, highly sensitive echocardiographic technique for the early detection of subtle diabetic myocardial dysfunction[7]
At a particular magnetic field strength, Cardiac magnetic resonance (CMR) T1 mapping can quantify the degree of fibrosis by accurately measuring the extracellular volume (ECV), which is calculated from pre- and post-contrast T1 values[11,12]
In the diabetes mellitus (DM) group, 1 rabbit died within 8 hours after the alloxan injection, 3 rabbits died after model induction, and the blood glucose levels of 2 other rabbits gradually returned to normal
Summary
Two-dimensional (2D) speckle tracking is an advanced, highly sensitive echocardiographic technique for the early detection of subtle diabetic myocardial dysfunction[7]. Because of its technical limitations, the use of an integrated backscatter ultrasound technique for the detection of diffuse myocardial fibrosis has several limitations[8]. Cardiac magnetic resonance (CMR) T1 mapping has recently been developed and uses inversion recovery, saturation recovery, and Look-Locker methods. CMR T1 mapping has better spatial and temporal resolution and can noninvasively detect diffuse myocardial fibrosis[9,10]. At a particular magnetic field strength, CMR T1 mapping can quantify the degree of fibrosis by accurately measuring the extracellular volume (ECV), which is calculated from pre- and post-contrast T1 values[11,12]. Our hypothesis was that after the induction of diabetes, rabbits will develop diffuse myocardial fibrosis that can lead to myocardial dysfunction
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