Magnetic resonance imaging of small arteries

Magnetic resonance imaging (MRI) with receive-only surface coil technology was used to visualize and quantitative luminal diameters of small arteries in the rat. MRI measurements of normal and aneurysmal aortas, over a diameter range of 1-3 mm, were closely correlated with direct measurements made visually at laparotomy: measured differences averaged 0.16 mm, and the least-squares regression line (R2 = 0.97, P < 0.001) compared favorably to the line of equivalence, X = Y. This noninvasive but precise imaging modality demonstrates the potential value of using MRI to evaluate the diameter of small vessels, including the postoperative monitoring of arterial bypass graft patency in peripheral regions.