Myocardium at Risk After Acute Infarction in Humans on Cardiac Magnetic Resonance
Quantitative Assessment During Follow-Up and Validation With Single-Photon Emission Computed Tomography
Quantitative Assessment During Follow-Up and Validation With Single-Photon Emission Computed Tomography
Marcus Carlsson, MD, PhD*, Joey F.A. Ubachs, MD*, Erik Hedström, MD, PhD*, Einar Heiberg, PhD*, Stefan Jovinge, MD, PhD, Håkan Arheden, MD, PhD*,*
* Cardiac MR Group, Department of Clinical Physiology, Lund University Hospital, Lund, SwedenDepartment of Cardiology, Lund University Hospital, Lund, Sweden
Objectives: Our goal was to validate myocardium at risk on T2-weighted short tau inversion recovery (T2-STIR) cardiac magnetic resonance (CMR) over time, compared with that seen with perfusion single-photon emission computed tomography (SPECT) in patients with ST-segment elevation myocardial infarction, and to assess the amount of salvaged myocardium after 1 week.
Background: To assess reperfusion therapy, it is necessary to determine how much myocardium is salvaged by measuring the final infarct size in relation to the initial myocardium at risk of the left ventricle (LV).
Methods: Sixteen patients with first-time ST-segment elevation myocardial infarction received 99mTc tetrofosmin before primary percutaneous coronary intervention. SPECT was performed within 4 h and T2-STIR CMR within 1 day, 1 week, 6 weeks, and 6 months. At 1 week, patients were injected with a gadolinium-based contrast agent for quantification of infarct size.
Results: Myocardium at risk at occlusion on SPECT was 33 ± 10% of the LV. Myocardium at risk on T2-STIR did not differ from SPECT, at day 1 (29 ± 7%, p = 0.49) or week 1 (31 ± 6%, p = 0.16) but declined at week 6 (10 ± 12%, p = 0.0096 vs. 1 week) and month 6 (4 ± 11%, p = 0.0013 vs. 1 week). There was a correlation between myocardium at risk demonstrated by T2-STIR at week 1 and myocardium at risk by SPECT (r2 = 0.70, p < p =" 0.16).">
Conclusions: This study demonstrates that T2-STIR performed up to 1 week after reperfusion can accurately determine myocardium at risk as it was before opening of the occluded artery. CMR can also quantify salvaged myocardium as myocardium at risk minus final infarct size.
Key Words: myocardium at risk • T2-STIR • CMR • salvaged myocardium
Am Coll Cardiol Img, 2009; 2:569-576
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