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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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Gasper WJ, Owens CD, Kim JM, Hills N, Belkin M, Creager MA, Conte MS. Thirty-day vein remodeling is predictive of midterm graft patency after lower extremity bypass. J Vasc Surg 2012; 57:9-18. [PMID: 22960020 DOI: 10.1016/j.jvs.2012.06.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 06/15/2012] [Accepted: 06/20/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Successful adaptation of a vein graft to an arterial environment is incompletely understood. We sought to investigate whether early vein graft remodeling is predictive of subsequent patency. METHODS A prospective longitudinal study was conducted of 67 patients undergoing lower extremity bypass with autogenous vein between February 2004 and April 2008. Preoperative blood samples were drawn for biomarkers. During the bypass operation, a 5-cm index segment of the graft was registered for serial lumen diameter measurements at 0, 1, 3, 6, 9, and 12 months using duplex ultrasound imaging. The imaging substudy analysis included patients with at least two ultrasound assessments. RESULTS Patients (55% male) were a median age of 70 years (interquartile range [IQR], 59-76 years), 40% had diabetes mellitus, 49% had critical limb ischemia, 75% were taking a statin, and 91% were taking an antiplatelet medication. Median follow-up was 32 months (IQR, 15-47 months). The median baseline high-sensitivity C-reactive protein level (hsCRP) was 3.2 mg/L (IQR, 1.4-9.7 mg/L). The average intraoperative, postimplantation vein lumen diameter was 3.9±1.0 mm, increasing to 4.7±1.1 mm at 1 month, an average 24%±27% change per patient. By 3 months, the average lumen diameter was 5.1±1.6 mm, with little subsequent change observed to 12 months. Nonwhite race, baseline hsCRP ≥5 mg/L, statin use, and initial lumen diameter were significantly associated with early (0- to 1-month) vein remodeling in a multivariable regression model. The primary patency rate for the cohort was 60%±6.3% at 2 years. Initial lumen diameter of the index segment was not associated with primary patency, whereas larger lumen diameter achieved at 1 month (≥5.1 mm) was positively associated with primary patency (log-rank, P=.03). Early (30-day) remodeling behavior was used to divide patients into "poor remodelers" (<-5% lumen diameter change, n=6), "modest remodelers" (-5% to 25% change, n=29), and "robust remodelers" (>+25% change, n=30). Early remodeling category was significantly associated with primary patency rate at 2 years (log-rank, P=.02). A multivariable Cox proportional hazards model showed that modest remodelers (hazard ratio, 3.9; 95% confidence interval, 1.02-15; P=.04) and poor remodelers (hazard ratio, 13; 95% confidence interval; P=.008) had significantly higher hazard ratios for graft failure than robust early remodelers. CONCLUSIONS Early remodeling of the arterialized vein appears to predict midterm bypass graft patency. In addition to baseline diameter, race, inflammation, hsCRP, and statin use are associated with early adaptive remodeling, but the mechanisms for these observations are not understood.
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Affiliation(s)
- Warren J Gasper
- Division of Vascular and Endovascular Surgery, Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA 94143-0222, USA
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Liu Z, Li B, Wang B, Yang Z, Wang Q, Li T, Qin D, Li Y, Wang M, Yan M. Magnetic nanoparticles modified with DTPA-AMC-rare earth for fluorescent and magnetic resonance dual mode imaging. Dalton Trans 2012; 41:8723-8. [DOI: 10.1039/c2dt30125c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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