Typically, this is done by injecting diluted contrast media through a catheter that has engaged the coronary ostium or proximal coronary artery, leading to a strong, localized enhancement of the vessel(s) of interest. MRI has several potential advantages over X-ray fluoroscopy: MRI 1) does not expose the patient or medical team to ionizing radiation or nephrotoxic contrast agents 2) allows for two-dimensional (2D) and three-dimensional (3D) imaging with arbitrary slice orientation and thickness and 3) can obtain not only anatomic information but also physiological information, such as myocardial perfusion and flow ( 3).Ĭatheter-directed projection coronary MRA is one of the methods proposed for disease diagnosis in an interventional MRI (iMRI) setting. Recent studies have proposed catheter-directed magnetic resonance angiography (MRA) as a potential alternative to X-ray fluoroscopy for the detection and treatment of coronary artery stenoses ( 1, 2). This study demonstrates that in the future interventional MRI may be an alternative to X-ray angiography for the detection and quantification of coronary artery disease. Cross-sectional MRI accurately quantified each stenosis, with strong agreement to the measurements made using X-ray fluoroscopy (Intra-class correlation coefficient = 0.955 p < 0.05). Catheter-directed MRA successfully detected 8/9 stenoses. Line signal intensity profiles were drawn across the vessel diameter at the stenosis site and proximal to the stenosis for each data set to measure percent stenosis for each animal. The two-step protocol consisted of catheter-directed magnetic resonance angiography (MRA), which was first used to localize the stenosis, followed by MRI cross-sectional images to quantify the degree of stenosis without use of contrast agent.
Studies were conducted in 9 swine with a surgically induced stenosis in the proximal left circumflex coronary artery. The accuracy of a two-step interventional MRI protocol to quantify coronary artery disease was compared to the clinical gold standard, X-ray angiography.
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