Heterogeneity of fractional anisotropy and mean diffusivity measurements by in vivo diffusion tensor imaging in normal human hearts

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Panfilov, AV, McGill, L-A, Scott, AD, Ferreira, PF, Nielles-Vallespin, S, Ismail, T, Kilner, PJ, Gatehouse, PD, de Silva, R, Prasad, SK, Giannakidis, A ORCID: https://orcid.org/0000-0001-7403-923X, Firmin, DN and Pennell, DJ, 2015. Heterogeneity of fractional anisotropy and mean diffusivity measurements by in vivo diffusion tensor imaging in normal human hearts. PLOS ONE, 10 (7), e0132360. ISSN 1932-6203

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Official URL: http://doi.org/10.1371/journal.pone.0132360

Abstract

Background: Cardiac diffusion tensor imaging (cDTI) by cardiovascular magnetic resonance has the potential to assess microstructural changes through measures of fractional anisotropy (FA) and mean diffusivity (MD). However, normal variation in regional and transmural FA and MD is not well described.

Methods: Twenty normal subjects were scanned using an optimised cDTI sequence at 3T in systole. FA and MD were quantified in 3 transmural layers and 4 regional myocardial walls.

Results: FA was higher in the mesocardium (0.46 ±0.04) than the endocardium (0.40 ±0.04, p≤0.001) and epicardium (0.39 ±0.04, p≤0.001). On regional analysis, the FA in the septum was greater than the lateral wall (0.44 ±0.03 vs 0.40 ±0.05 p = 0.04). There was a transmural gradient in MD increasing towards the endocardium (epicardium 0.87 ±0.07 vs endocardium 0.91 ±0.08×10-3 mm2/s, p = 0.04). With the lateral wall (0.87 ± 0.08×10-3 mm2/s) as the reference, the MD was higher in the anterior wall (0.92 ±0.08×10-3 mm2/s, p = 0.016) and septum (0.92 ±0.07×10-3 mm2/s, p = 0.028). Transmurally the signal to noise ratio (SNR) was greatest in the mesocardium (14.5 ±2.5 vs endocardium 13.1 ±2.2, p<0.001; vs epicardium 12.0 ± 2.4, p<0.001) and regionally in the septum (16.0 ±3.4 vs lateral wall 11.5 ± 1.5, p<0.001). Transmural analysis suggested a relative reduction in the rate of change in helical angle (HA) within the mesocardium.

Conclusions: In vivo FA and MD measurements in normal human heart are heterogeneous, varying significantly transmurally and regionally. Contributors to this heterogeneity are many, complex and interactive, but include SNR, variations in cardiac microstructure, partial volume effects and strain. These data indicate that the potential clinical use of FA and MD would require measurement standardisation by myocardial region and layer, unless pathological changes substantially exceed the normal variation identified.

Item Type:	Journal article
Publication Title:	PLOS ONE
Creators:	Panfilov, A.V., McGill, L.-A., Scott, A.D., Ferreira, P.F., Nielles-Vallespin, S., Ismail, T., Kilner, P.J., Gatehouse, P.D., de Silva, R., Prasad, S.K., Giannakidis, A., Firmin, D.N. and Pennell, D.J.
Publisher:	Public Library of Science
Date:	2015
Volume:	10
Number:	7
ISSN:	1932-6203
Identifiers:	Number Type 10.1371/journal.pone.0132360 DOI
Rights:	This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
Divisions:	Schools > School of Science and Technology
Record created by:	Jonathan Gallacher
Date Added:	15 Mar 2018 17:07
Last Modified:	02 May 2018 15:49
URI:	https://irep.ntu.ac.uk/id/eprint/33003