Serial imaging of canine myocardial infarction by in vivo nuclear magnetic resonance

Anterior infarction was produced in eight dogs to characterize serial changes in nuclear magnetic resonance signal intensity within the infarct zone. Magnetic resonance imaging was done on the day of infarction, on day 4, 5 or 6, on day 13 and day 20 using a 0.15 tesla (6.25 MHz) resistive imager. Electrocardiographically triggered spin echo (30, 45 and 60 ms echo times) and inversion recovery (400 to 500 ms inversion time) pulse sequences were employed to obtain single slice images. On day 20, the excised hearts were sectioned and examined to determine infarct location and extent. In the spin echo images, signal intensity within the ischemic zone was visibly increased in seven of the eight dogs on the day of infarction, and in all dogs by days 4 to 6. Signal intensity remained elevated in all but two dogs at day 20. With inversion recovery imaging, changes in the infarct zone were highly variable; both ill defined increases and decreases in signal intensity were noted. With a 30 ms echo time, signal intensity in the infarct zone was increased on average 29.8 +/- 24.1% above that in normal myocardium on the day of infarction. The relative signal intensity increased to 62.4 +/- 23.5% during the first 2 weeks after infarction (p less than 0.05), then decreased to 12.0 +/- 18.5% by day 20 (p less than 0.05). Similar changes were detected in the images using the 45 and 60 ms echo times. Nuclear magnetic resonance imaging therefore is able to detect regions of myocardial infarction and follow evolutionary changes in signal intensity within the infarct zone with healing.

This article has been cited by other articles:

				T. Lockie, E. Nagel, S. Redwood, and S. Plein Use of Cardiovascular Magnetic Resonance Imaging in Acute Coronary Syndromes Circulation, March 31, 2009; 119(12): 1671 - 1681. [Full Text] [PDF]

				J. W. Goldfarb, S. Arnold, and J. Han Recent Myocardial Infarction: Assessment with Unenhanced T1-weighted MR Imaging Radiology, October 1, 2007; 245(1): 245 - 250. [Abstract] [Full Text] [PDF]

				A. H. Aletras, G. S. Tilak, A. Natanzon, L.-Y. Hsu, F. M. Gonzalez, R. F. Hoyt Jr, and A. E. Arai Retrospective Determination of the Area at Risk for Reperfused Acute Myocardial Infarction With T2-Weighted Cardiac Magnetic Resonance Imaging: Histopathological and Displacement Encoding With Stimulated Echoes (DENSE) Functional Validations Circulation, April 18, 2006; 113(15): 1865 - 1870. [Abstract] [Full Text] [PDF]

				E. W. Hsu, R. Xue, A. Holmes, and J. R. Forder Delayed reduction of tissue water diffusion after myocardial ischemia Am J Physiol Heart Circ Physiol, August 1, 1998; 275(2): H697 - H702. [Abstract] [Full Text] [PDF]

				E. E. van der Wall, H. W. Vliegen, A. de Roos, and A. V.G. Bruschke Magnetic Resonance Imaging in Coronary Artery Disease Circulation, November 1, 1995; 92(9): 2723 - 2739. [Abstract] [Full Text]