Direct comparison of in-vivo and post-mortem spin-echo based diffusion tensor imaging in the porcine heart

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Background The microstructural changes following myocardial infarction (MI) can be characterised in-vivo with cardiac diffusion tensor imaging (cDTI) imaging, using mean diffusivity (MD), fractional anisotropy (FA), secondary eigenvector angle (E2A) and helix angle (HA) maps. In this study, we use cDTI to explore the microstructural differences between subendocardial and transmural chronic infarct segments. Method Twenty STEMI patients (15 men, 5 women, mean age 59) underwent 3T CMR scan at 3 months following presentation (mean interval 107 ± 18 days). Scan protocol included: second order motion compensated (M012) free-breathing spin echo DTI (3 slices, 18 diffusion directions at b-values 100s/mm2[3], 200s/mm2[3] and 500s/mm2[12], acquired resolution was 2.20x2.27x8mm3; cine gradient echo and LGE imaging. Average MD, FA, E2A and HA parameters were calculated on a 16-AHA-segmental level. HA maps were described by dividing values into left-handed HA (LHM, -90° < HA < -30°), circumferential HA (CM, -30° < HA < 30°), and right-handed HA (RHM, 30° < HA < 90°) and reported as relative proportions. Infarct segments were identified using LGE; patients were categorised according to the maximal transmurality of their infarct segments, into subendocardial (<50% LGE) or transmural (>50% LGE) MI. Results DTI acquisition was successful in all patients (acquisition time 13 ± 5mins). Ten patients had transmural MI. The results are shown in table 1. Transmurally infarcted segments had significantly lower FA (FA subendocardial MI = 0.27 ± 0.04, FA transmural MI = 0.23 ± 0.02, p < 0.01), lower E2A (E2A subendocardial MI = 47 ± 7°, E2A transmural MI = 38 ± 6°, p < 0.01) and lower proportions of right-handed cardiomyocytes (RHM subendocardial MI = 21 ± 5%, RHM transmural MI = 14 ± 5%, p < 0.01) than subendocardial infarct segments. Conclusion Compared to subendocardial MI segments, the diffusion of water molecules is more isotropic in transmurally infarcted myocardium as evidenced by lower FA values, signifying increased structural disarray. The significantly lower E2A values suggest that laminar sheetlets of transmural infarct segments remain fixed at shallower angles during systole and are unable to reach their usual contractile configuration. The lower proportions of RHM on HA maps highlight the significantly greater loss of subendocardial cardiomyocytes in transmural infarct segments. Further studies are required to assess if these segmental changes can be predictive of long-term LV remodelling.

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Spin echo versus stimulated echo diffusion tensor imaging of the in vivo human heart

Magnetic Resonance in Medicine ◽

10.1002/mrm.25998 ◽

2015 ◽

Vol 76 (3) ◽

pp. 862-872 ◽

Cited By ~ 34

Author(s):

Constantin von Deuster ◽

Christian T. Stoeck ◽

Martin Genet ◽

David Atkinson ◽

Sebastian Kozerke

Keyword(s):

Diffusion Tensor Imaging ◽

Human Heart ◽

Diffusion Tensor ◽

Spin Echo ◽

Stimulated Echo

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In vivo diffusion tensor imaging of the neonatal rat brain development

Neuropediatrics ◽

10.1055/s-0033-1347344 ◽

2013 ◽

Vol 44 (S 01) ◽

Author(s):

M Breu ◽

D Reisinger ◽

D Wu ◽

Y Zhang ◽

A Fatemi ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

Brain Development ◽

Rat Brain ◽

Diffusion Tensor ◽

Neonatal Rat ◽

Neonatal Rat Brain

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Meyer’s Loop Anatomy Demonstrated Using Diffusion Tensor MR Imaging and Fiber Tractography at 3T

Acta Medica Marisiensis ◽

10.2478/amma-2014-0045 ◽

2014 ◽

Vol 60 (5) ◽

pp. 215-222 ◽

Cited By ~ 1

Author(s):

Cristina Goga ◽

Zeynep Firat ◽

Klara Brinzaniuc ◽

Is Florian

Keyword(s):

Diffusion Tensor Imaging ◽

Diffusion Tensor ◽

Region Of Interest ◽

Fiber Tractography ◽

Brain Images ◽

3 Dimensional ◽

Software Release ◽

Magnetic Resonance Imaging Mri ◽

Meyer’S Loop

Abstract Objective: The ultimate anatomy of the Meyer’s loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer’s loop and the optic radiations. This study aims at exploring the anatomy of the Meyer’s loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer’s loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer’s loop. Two patterns of angulation of the Meyer’s loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer’s loop.

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The effect of microvascular obstruction on the myocardial microstructure: a diffusion tensor imaging study

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jeaa356.323 ◽

2021 ◽

Vol 22 (Supplement_1) ◽

Author(s):

A Das ◽

K Kelly ◽

M Aldred ◽

I Teh ◽

CK Stoeck ◽

...

Keyword(s):

Microvascular Obstruction ◽

Diffusion Tensor ◽

Spin Echo ◽

Mean Diffusivity ◽

Imaging Study ◽

Free Breathing ◽

Helix Angle ◽

Acquisition Time ◽

Heart Research

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Heart Research UK Background Diffusion tensor cardiac magnetic resonance (DT-CMR) imaging allows for characterising myocardial microstructure in-vivo using mean diffusivity (MD), fractional anisotropy (FA), secondary eigenvector angle (E2A) and helix angle (HA) maps. Following myocardial infarction (MI), alterations in MD, FA and HA proportions have previously been reported. E2A depicts the contractile state of myocardial sheetlets, however the behaviour of E2A in infarct segments, and all DTI markers in areas of microvascular obstruction (MVO) is also not fully understood. Purpose We performed spin echo DTI in patients following ST-elevation MI (STEMI) in order to investigate acute changes in DTI parameters in remote and infarct segments both with and without MVO. Method Twenty STEMI patients (16 men, 4 women, mean age 59) had acute (5 ± 2d) 3T CMR scans. CMR protocol included: second order motion compensated (M012) free-breathing spin echo DTI (3 slices, 18 diffusion directions at b-values 100s/mm2[3], 200s/mm2[3] and 500s/mm2[12], reconstructed resolution was 1.66x1.66x8mm); cine and late gadolinium enhancement (LGE) imaging. Average MD, FA, E2A HA parameters were calculated on a 16 AHA segmental level. HA maps were described by dividing values into left-handed HA (LHM, -90° < HA < -30°), circumferential HA (CM, -30° < HA < 30°), and right-handed HA (RHM, 30° < HA < 90°) and reported as relative proportions. Segments were defined as infarct (positive for LGE) and remote (opposite to the infarct). Results DTI acquisition was successful in all patients (acquisition time 13 ± 5mins). Ten patients had evidence of MVO on LGE images. MD was significantly higher in infarct regions in comparison to remote; MVO-ve infarct segments had significantly higher MD than MVO + ve infarct segments (MD remote= 1.46 ± 0.12x10-3mm2/s, MD MVO + ve = 1.59 ± 0.12x10-3mm2/s, MD MVO-ve = 1.75 ± 0.12x10-3mm2/s, ANOVA p < 0.01). FA was reduced in infarct segments in comparison to remote; MVO-ve infarct segments had significantly lower FA than MVO + ve infarct segments (FAremote= 0.37 ± 0.02, FA MVO + ve = 0.31 ± 0.02 x 10-3mm2/s, MD MVO-ve =0.25 ± 0.02, ANOVA p < 0.01). E2A values were significantly lower in infarct segments compared to remote; MVO + ve infarct segments had significantly lower values than MVO-ve. (E2A remote= 57.4 ± 5.2°, E2A MVO-ve = 46.8 ± 2.5°, E2A MVO + ve = 36.8 ± 3.1°, ANOVA p < 0.001). RHM% (corresponding to subendocardium) was significantly lower in infarct segments compared to remote; MVO + ve infarct segments had significantly lower RHM% than MVO-ve. (RHM remote= 37 ± 3%, RHM RHM MVO-ve= 28 ± 7%, MVO + ve= 8 ± 5%, ANOVA p < 0.001). Conclusion The presence of MVO results in a decrease in MD and increase in FA in comparison to surrounding infarct segments. However, the reduction in E2A and right-handed myocytes on HA in infarct segments is further exacerbated by the presence of MVO. Further study is required to investigate the underlying mechanisms for such alterations in signal intensity. Abstract Figure. A case of transmural septal MI with MVO

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