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MRI characterization of peripheral arterial chronic total occlusions at 7 Tesla with microCT and histologic validation
Journal of Cardiovascular Magnetic Resonance volume 17, Article number: P404 (2015)
Background
Current treatment guidelines recommend surgical bypass for peripheral chronic total occlusions (CTOs)[1]. Percutaneous transluminal angioplasty (PTA), however, offers a less invasive approach with improved perioperative morbidity, shorter length of hospital stay, and lower cost[2]. Not all lesions are amenable to this technique and there is a significant primary failure rate[2]. Predicting lesion crossability is difficult because current imaging techniques offer limited information with which to characterize CTOs. The ability to distinguish between hard and soft biological substances that compose a CTO can aid procedural planning and facilitate intervention. This pilot study demonstrates the ability of high resolution MRI to characterize peripheral CTO components with microCT and histologic validation.
Methods
MRI was performed on 10 excised human peripheral arterial CTO segments from 3 patients. Each sample was imaged at 7T (Bruker BioSpec preclinical MR imaging system) at high resolution (75x75x75μm voxels) to produce three-dimensional T2- and T2*-weighted images. For T2-weighted imaging, a spin-echo sequence with an echo-train length of 8 and an equivalent TE of 37 ms was used. For T2*-imaging, an ultrashort echo (UTE) sequence was used with a set of echo times: {20µs, 500µs, 1ms}. A difference image was produced by subtracting the complex signal values of the 1ms-image from those of the 20µs-image. An off-resonance map was produced using linear fits of the phase signals of the set of T2* images. The T2-weighted image, T2*-difference-image, and off-resonance map were used together to differentiate between lesion components. Each sample was imaged with microCT at high resolution (5x5x5μm voxels) to identify calcium. Samples were then decalcified during histologic processing. H&E staining was used to identify microlumina, smooth muscle cells, blood, and residual calcium. Movat's pentachrome staining was used to identify elastic lamina, fibrin, collagen, cholesterol clefts, and proteoglycan.
Conclusions
These preliminary results demonstrate the potential of high-resolution T2 and T2* imaging using UTE to characterize hard and soft lesion components in human peripheral CTOs. This provides the foundation for further work in determining the lesion crossability and procedural success rates in CTOs.
Funding
Canadian Institutes of Health Research.
References
Lovell M: Can J. Cardiol. 2009, 25: 39-45. 10.1016/S0828-282X(09)70021-2.
Adam D, et al: Lancet. 2005, 366: 1925-34.
Stone G, et al: Circulation. 2005, 112: 2364-72. 10.1161/CIRCULATIONAHA.104.481283.
Siu A, et al: Submitted to SCMR. 2014
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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
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Roy, T., Liu, G., Qi, X. et al. MRI characterization of peripheral arterial chronic total occlusions at 7 Tesla with microCT and histologic validation. J Cardiovasc Magn Reson 17 (Suppl 1), P404 (2015). https://doi.org/10.1186/1532-429X-17-S1-P404
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DOI: https://doi.org/10.1186/1532-429X-17-S1-P404