Early animal model evaluation of an implantable contrast agent to enhance magnetic resonance imaging of arterial bypass vein grafts. (September 2018)

• Record Type: Journal Article
• Authors: Mitsouras, Dimitrios; Tao, Ming; de Vries, Margreet R; Trocha, Kaspar; Miranda, Oscar R; Vemula, Praveen Kumar; Ding, Kui; Imanzadeh, Amir; Schoen, Frederick J; Karp, Jeffrey M; Ozaki, C Keith; Rybicki, Frank J
• Is Part Of: Acta radiologica. Volume 59:Number 9(2018:Nov.)
• Page Start: 1074
• Page End: 1081
• Publication Date: 2018-09
• Subjects: Magnetic resonance imaging -- gadolinium -- image enhancement -- contrast media -- signal-to-noise ratio -- vascular grafting -- peripheral vascular diseases; Radiology, Medical -- Periodicals; Radiography, Medical -- Periodicals; Radiotherapy -- Periodicals; 616.0757
• DOI: 10.1177/0284185117753656
• Languages: English
• ISSNs: 0284-1851

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.