Pediatric Track Session
SCMR 22nd Annual Scientific Sessions
Cardiovascular disease is the leading cause of death in patients with Duchenne muscular dystrophy(DMD).Current research aims to investigate cardiac MRI(cMRI) biomarkers,including native(pre-contrast)T1,to evaluate microstructural remodeling.Native T1 in DMD boys acquired at 1.5T can identify myocardial changes and assess disease severity2.From pre- and post-contrast T1,extracellular volume(ECV) can be calculated and used to quantify diffuse fibrosis3.This 3T MRI study aims:1)to characterize native T1 differences between DMD and healthy controls;2)to report post-contrast T1 and ECV estimates in DMD boys;and 3)to assess myocardial heterogeneity and regional differences in DMD boys and healthy controls.
DMD boys(N=19,13.2±3.1years,BMI=24.2±5.1kg/m2,HR=97±14.5bpm) and healthy boys(N=16,13.5±3.1years,BMI=19.8±5.9kg/m2,HR=76±18.5bpm) were prospectively enrolled (IRB-approved,informed consent) and underwent 3T cMRI.T1 measurements were acquired with a Motion Corrected MOLLI 5(3)3(pre-contrast) and 4(1)-3(1)-(2)(post-contrast) sequence.Contrast was only administered to DMD boys.Post-contrast images were acquired~10 minutes after contrast injection.Pre- and post-contrast T1 maps were combined with the patient’s hematocrit to calculate an ECV map.All maps were used to determine global and septal measurements for the left ventricular(LV) myocardium(FIG.1).Group-wise comparisons were performed with a two-tailed t-test.Multiple regression assessed the dependency of age,heart rate(HR),and BMI on pre- and post-contrast T1 in DMD (pre-contrast for healthy).Data is reported as median(IQR) and as standard deviation(SD) for assessing heterogeneity.
DMD boys exhibited increased native T1[1334(60)ms,1290(51)ms,p<0.001,FIG.2A] and increased SD[131(37)ms,85(26)ms,p<0.001] when compared to healthy controls.Multiple regression showed no significant dependency of native and post-contrast T1 on age,HR,and BMI in the healthy nor DMD groups.However,HR and BMI were both higher in DMD[p<0.001,p=0.02] and a trend toward elevated native T1 with HR and BMI are possible(FIG2A-2C).In DMD,regional analyses showed increased native T1[1334(61)ms,1270(37)ms,p<0.001],decreased post-contrast T1[652(168)ms,697(152)ms,p<0.001],and increased ECV[30(6)%,24(4)%,p<0.001] for the entire myocardium relative to the septum(FIG3A-3C).
DMD boys have elevated native T1 compared to healthy,age-matched controls.As expected the reported 3T T1 values are longer relative to previously reported 1.5T values for DMD and healthy groups[1045ms,988ms,p=0.001]4.Hence,the reported values help establish 3T reference values for both boys with DMD and healthy subjects.Furthermore,post-contrast T1 and ECV estimates are reported here for DMD boys at 3T for the first time.Increased SD of native T1 within each DMD boy may be a marker of tissue heterogeneity.Lastly, the myocardial free wall is more affected than the septum for boys with DMD.