Abstract
PurposeCommon types of congenital heart disease exhibit a variety of structural and functional variations which may be accompanied by changes in the myocardial microstructure. We aimed to compare myocardial architecture from magnetic resonance diffusion tensor imaging (DTI) in preserved pathology specimens.Materials and methodsPathology specimens (n = 24) formalin-fixed for 40.8 ± 7.9 years comprised tetralogy of Fallot (TOF, n = 10), dextro-transposition of great arteries (D-TGA, n = 8) five with ventricular septal defect (VSD), systemic right ventricle (n = 4), situs inversus totalis (SIT, n = 1) and levo-TGA (L-TGA, n = 1). Specimens were imaged using a custom spin-echo sequence and segmented automatically according to tissue volume fraction. In each specimen T1, T2, fractional anisotropy, mean diffusivity, helix angle (HA) and sheet angle (E2A) were quantified. Pathologies were compared according to their HA gradient, HA asymmetry and E2A mean value in each myocardial segment (anterior, posterior, septal and lateral walls).ResultsTOF and D-TGA with VSD had decreased helix angle gradient by − 0.34°/% and remained symmetric in the septum in comparison to D-TGA without VSD. Helix angle range was decreased by 45°. It was associated with a decreased HA gradient in the right ventricular (RV) wall, i.e. predominant circumferential myocytes. The sheet angle in the septum of TOF was opposing those of the left ventricular (LV) free wall. Univentricular systemic RV had the lowest HA gradient (− 0.43°/%) and the highest HA asymmetry (75%). HA in SIT was linear, asymmetric, and reversed with a sign change at about 70% of the depth at mid-ventricle. In L-TGA with VSD, HA was asymmetric (90%) and its gradients were decreased in the septum, anterior and lateral wall.ConclusionThe organization of the myocytes as determined by DTI differs between TOF, D-TGA, L-TGA, systemic RV and SIT specimens. These differences in cardiac structure may further enlighten our understanding of cardiac function in these diverse congenital heart diseases.
Highlights
Congenital heart disease (CHD) is the most common malformation arising during fetal development, with increasing prevalence worldwide [1]
The organization of the myocytes as determined by diffusion tensor imaging (DTI) differs between Tetralogy of Fallot (TOF), Dextro-transposition of the great arteries (D-Transposition of the great arteries (TGA)), Levo-transposition of the great arteries (L-TGA), systemic right ventricle (RV) and Situs inversus totalis (SIT) specimens
Specimens DTI was performed on 24 historical formalin-fixed heart specimens, consisting of tetralogy of Fallot (TOF, n = 10), dextro transposition of the great arteries (D-TGA, n = 8), systemic right ventricle (RV) pathologies (n = 4, 2 single ventricle and two TGA with hypoplastic left ventricle (LV)), situs inversus totalis (SIT, n = 1) and levo-TGA (L-TGA, n = 1)
Summary
Congenital heart disease (CHD) is the most common malformation arising during fetal development, with increasing prevalence worldwide [1]. Advances in paediatric cardiac surgery and intensive care medicine have increased survival in the younger population and there are more adults with CHD than children [2]. These adults have a high risk of myocardial dysfunction and heart failure. Reparative or palliative surgery will provide adequate anatomical correction, it is likely that abnormalities persist within the myocardial structure [5]. Surgeries on newborns may alter the structural growth pattern, resulting in intrinsic tissue problems and regional remodeling [6, 7], leading to differences in blood flow patterns through the heart and early heart failure
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