Regional 4D Cardiac Magnetic Resonance Strain Predicts Cardiomyopathy Progression in Duchenne Muscular Dystrophy.

Abstract

Background: Cardiomyopathy (CMP) is the leading cause of death in Duchenne muscular dystrophy (DMD). Characterization of disease trajectory can be challenging, especially in early stages of CMP where onset and progression may vary. Traditional metrics from cardiovascular magnetic resonance (CMR) imaging such as LVEF (left ventricular ejection fraction) and LGE (late gadolinium enhancement) are often insufficient for assessing the pace of disease progression. We hypothesized that strain patterns from a novel 4D (3D+time) CMR regional strain analysis method can be used to predict DMD CMP progression.

Methods: We compiled 190 short-axis cine CMR image stacks for n=66 pediatric DMD patients (13.3 [10.8-16.5] years; median [interquartile range]) imaged for 3 consecutive years and computed regional strain metrics using custom-built feature tracking software. We measured regional strain parameters from the generated 4D endocardial surface mesh.

Results: Using LVEF decrease, measured two years following the initial scan, we classified patients into slow (ΔLVEF%<5; n=35) or fast (ΔLVEF%≥5; n=30) progressing groups. There was no statistical difference between the slow and fast-progressing groups in terms of standard metrics such as age, LVEF, or LGE status. However, peak basal circumferential strain (E_cc) and surface area strain (E_a) magnitudes were decreased in fast progressors (p<0.01 for all). Basal E_cc late diastolic strain rate and basal E_a late diastolic strain rate magnitude were also significantly decreased in fast progressors (p<0.01 for all).

Conclusion: Regional strain metrics from 4D CMR can be used to differentiate between slow or fast CMP progression in a longitudinal DMD cohort.