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Mitsouras D, Tao M, de Vries MR, Trocha K, Miranda OR, Vemula PK, Ding K, Imanzadeh A, Schoen FJ, Karp JM, Ozaki CK, Rybicki FJ. Early animal model evaluation of an implantable contrast agent to enhance magnetic resonance imaging of arterial bypass vein grafts. Acta Radiol 2018; 59:1074-1081. [PMID: 29378421 DOI: 10.1177/0284185117753656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Non-invasive monitoring of autologous vein graft (VG) bypass grafts is largely limited to detecting late luminal narrowing. Although magnetic resonance imaging (MRI) delineates vein graft intima, media, and adventitia, which may detect early failure, the scan time required to achieve sufficient resolution is at present impractical. Purpose To study VG visualization enhancement in vivo and delineate whether a covalently attached MRI contrast agent would enable quicker longitudinal imaging of the VG wall. Material and Methods Sixteen 12-week-old male C57BL/6J mice underwent carotid interposition vein grafting. The inferior vena cava of nine donor mice was treated with a gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-based contrast agent, with control VGs labeled with a vehicle. T1-weighted (T1W) MRI was performed serially at postoperative weeks 1, 4, 12, and 20. A portion of animals was sacrificed for histopathology following each imaging time point. Results MRI signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were significantly higher for treated VGs in the first three time points (1.73 × higher SNR, P = 0.0006, and 5.83 × higher CNR at the first time point, P = 0.0006). However, MRI signal enhancement decreased consistently in the study period, to 1.29 × higher SNR and 2.64 × higher CNR, by the final time point. There were no apparent differences in graft morphometric analyses in Masson's trichrome-stained sections. Conclusion A MRI contrast agent that binds covalently to the VG wall provides significant increase in T1W MRI signal with no observed adverse effects in a mouse model. Further optimization of the contrast agent to enhance its durability is required.
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Affiliation(s)
- Dimitrios Mitsouras
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Ming Tao
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Margreet R de Vries
- Department of Surgery, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Kaspar Trocha
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Oscar R Miranda
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Praveen Kumar Vemula
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Kui Ding
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Amir Imanzadeh
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
| | | | - Jeffrey M Karp
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - C Keith Ozaki
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Frank J Rybicki
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
- Ottawa Hospital Research Institute and Division of Medical Imaging, The Ottawa Hospital Department of Radiology, University of Ottawa, Ottawa, ON, Canada
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Mitsouras D, Vemula PK, Yu P, Tao M, Nguyen BT, Campagna CM, Karp JM, Mulkern RV, Ozaki CK, Rybicki FJ. Immobilized contrast-enhanced MRI: Gadolinium-based long-term MR contrast enhancement of the vein graft vessel wall. Magn Reson Med 2010; 65:176-83. [PMID: 20859994 DOI: 10.1002/mrm.22606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance postsurgical tissue differentiation using MRI. For small-vessel (e.g., vein graft) MRI, the direct benefit of such permanent "labeling" of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast-to-noise ratio, or a combination thereof. We demonstrate, for the first time, stable long-term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified diethylenetriaminepentaacetic acid gadolinium(3+) dihydrogen complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3 T, and its long-term stability is demonstrated during a 4-month incubation period.
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Affiliation(s)
- Dimitris Mitsouras
- Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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Rybicki FJ, Mitsouras D, Owens CD, Whitmore A, Gerhard-Herman M, Wake N, Cai T, Zhou Q, Conte MS, Creager MA, Mulkern RV. Multi-contrast high spatial resolution black blood inner volume three-dimensional fast spin echo MR imaging in peripheral vein bypass grafts. Int J Cardiovasc Imaging 2010; 26:683-91. [PMID: 20333469 DOI: 10.1007/s10554-010-9621-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 03/09/2010] [Indexed: 01/20/2023]
Abstract
The purpose of this study is to primarily evaluate the lumen area and secondarily evaluate wall area measurements of in vivo lower extremity peripheral vein bypass grafts patients using high spatial resolution, limited field of view, cardiac gated, black blood inner volume three-dimensional fast spin echo MRI. Fifteen LE-PVBG patients prospectively underwent ultrasound followed by T1-weighted and T2-weighted magnetic resonance (MR) imaging. Lumen and vessel wall areas were measured by direct planimetry. For graft lumen areas, T1- and T2-weighted measurements were compared with ultrasound. For vessel wall areas, differences between T1- and T2-weighted measurements were evaluated. There was no significant difference between ultrasound and MR lumen measurements, reflecting minimal MR blood suppression artifact. Graft wall area measured from T1-weighted images was significantly larger than that measured from T2-weighted images (P < 0.001). The mean of the ratio of T1- versus T2-weighted vessel wall areas was 1.59 (95% CI: 1.48-1.69). The larger wall area measured on T1-weighted images was due to a significantly larger outer vessel wall boundary. Very high spatial resolution LE-PVBG vessel wall MR imaging can be performed in vivo, enabling accurate measurements of lumen and vessel wall areas and discerning differences in those measures between different tissue contrast weightings. Vessel wall area differences suggest that LE-PVBG vessel wall tissues produce distinct signal characteristics under T1 and T2 MR contrast weightings.
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Affiliation(s)
- Frank J Rybicki
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA.
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Mitsouras D, Owens CD, Conte MS, Ersoy H, Creager MA, Rybicki FJ, Mulkern RV. In vivo differentiation of two vessel wall layers in lower extremity peripheral vein bypass grafts: application of high-resolution inner-volume black blood 3D FSE. Magn Reson Med 2009; 62:607-15. [PMID: 19449380 DOI: 10.1002/mrm.22037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lower extremity peripheral vein bypass grafts (LE-PVBG) imaged with high-resolution black blood three-dimensional (3D) inner-volume (IV) fast spin echo (FSE) MRI at 1.5 Tesla possess a two-layer appearance in T1W images while only the inner layer appears visible in the corresponding T2W images. This study quantifies this difference in six patients imaged 6 months after implantation, and attributes the difference to the T(2) relaxation rates of vessel wall tissues measured ex vivo in two specimens with histologic correlation. The visual observation of two LE-PVBG vessel wall components imaged in vivo is confirmed to be significant (P < 0.0001), with a mean vessel wall area difference of 6.8 +/- 2.7 mm(2) between contrasts, and a ratio of T1W to T2W vessel wall area of 1.67 +/- 0.28. The difference is attributed to a significantly (P < 0.0001) shorter T(2) relaxation in the adventitia (T(2) = 52.6 +/- 3.5 ms) compared with the neointima/media (T(2) = 174.7 +/- 12.1 ms). Notably, adventitial tissue exhibits biexponential T(2) signal decay (P < 0.0001 vs monoexponential). Our results suggest that high-resolution black blood 3D IV-FSE can be useful for studying the biology of bypass graft wall maturation and pathophysiology in vivo, by enabling independent visualization of the relative remodeling of the neointima/media and adventitia.
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Affiliation(s)
- Dimitris Mitsouras
- Department of Radiology, Applied Imaging Science Laboratory, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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Owens CD. Adaptive changes in autogenous vein grafts for arterial reconstruction: clinical implications. J Vasc Surg 2009; 51:736-46. [PMID: 19837532 DOI: 10.1016/j.jvs.2009.07.102] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 07/20/2009] [Accepted: 07/24/2009] [Indexed: 01/22/2023]
Abstract
For patients with the most severe manifestations of lower extremity arterial occlusive disease, bypass surgery using autogenous vein has been the most durable reconstruction. However, the incidence of bypass graft stenosis and graft failure remains substantial and wholesale improvements in patency are lacking. One potential explanation is that stenosis arises not only from over exuberant intimal hyperplasia, but also due to insufficient adaptation or remodeling of the vein to the arterial environment. Although in vivo human studies are difficult to conduct, recent advances in imaging technology have made possible a more comprehensive structural examination of vein bypass maturation. This review summarizes recent translational efforts to understand the structural and functional properties of human vein grafts and places it within the context of the rich existing literature of vein graft failure.
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Affiliation(s)
- Christopher D Owens
- Division of Vascular and Endovascular Surgery, University of California San Francisco, San Francisco, CA 94143, USA.
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