Author + information
- Received April 14, 2000
- Revision received May 23, 2000
- Accepted July 12, 2000
- Published online November 15, 2000.
- David S Fieno, PhD∗,§,
- Raymond J Kim, MD, FACC∗,†,
- Enn-Ling Chen, PhD∗,
- Jon W Lomasney, MD∗,‡,
- Francis J Klocke, MD, MACC∗,†,§ and
- Robert M Judd, PhD∗,†,§,* ()
- ↵*Reprint requests and correspondence: Dr. Robert M. Judd, Feinberg Cardiovascular Research Institute, Northwestern University Medical School, 303 E Chicago Avenue, Tarry 12-723, Chicago, Illinois 60611-3008
We sought to determine the relationship of delayed hyperenhancement by contrast magnetic resonance imaging (MRI) to viable and nonviable myocardium within the region at risk throughout infarct healing.
The relationship of delayed MRI contrast enhancement patterns to injured but viable myocardium within the ischemic bed at risk has not been established.
We compared in vivo and ex vivo MRI contrast enhancement to histopathologic tissue sections encompassing the entire left ventricle in dogs (n = 24) subjected to infarction with (n = 12) and without (n = 12) reperfusion at 4 h, 1 day, 3 days, 10 days, 4 weeks and 8 weeks. In vivo MR imaging was performed 30 min after contrast injection.
The sizes and shapes of in vivo myocardial regions of elevated image intensity (828 ± 132% of remote) were the same as those observed ex vivo (241 slices, r = 0.99, bias = 0.05 ± 1.6% of left ventricle [LV]). Comparison of ex vivo MRI to triphenyltetrazolim chloride–stained sections demonstrated that the spatial extent of hyperenhancement was the same as the spatial extent of infarction at every stage of healing (510 slices, lowest r = 0.95, largest bias = 1.7 ± 2.9% of LV). Conversely, hyperenhanced regions were smaller than the ischemic bed at risk defined by fluorescent microparticles at every stage of healing (239 slices, 35 ± 24% of risk region, p < 0.001). Image intensities of viable myocardium within the risk region were the same as those of remote, normal myocardium (102 ± 9% of remote, p = NS).
Delayed contrast enhancement by MRI distinguishes between viable and nonviable regions within the myocardium at risk throughout infarct healing.
☆ This work was supported in part by grants NIH-NHLBI R29-HL53411 and R01-HL63268 (R.M.J.), and a Graduate Fellowship from the Whitaker Foundation (D.S.F.).
- Received April 14, 2000.
- Revision received May 23, 2000.
- Accepted July 12, 2000.
- American College of Cardiology