Pediatric Track Session
SCMR 22nd Annual Scientific Sessions
Nyasha Maforo
Graduate Student Researcher
University of California, Los Angeles
Patrick Magrath, MSc
PhD Candidate
University of California, Los Angeles
Kevin Moulin, PhD
Post-doctoral Fellow
Stanford University
Jiaxin Shao, PhD
Research Scientist
University of California, Los Angeles
Kavya Umachandran
Undergraduate Student Researcher
University of California, Los Angeles
Grace Kim, PhD
Assistant Professor
University of California
Pierangelo Renella, MD
Medical Doctor
University of California, Los Angeles
Nancy Halnon, MD
Medical Doctor
University of California, Los Angeles
Holden Wu, PhD
Assistant Professor
UCLA
Daniel Ennis, PhD
Associate Professor
Stanford University
Background:
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.
Methods:
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.
Results:
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).
Conclusion:
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.