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MRI relaxation fluctuations in acute reperfused hemorrhagic infarction
Author(s) -
Foltz W.D.,
Yang Y.,
Graham J.J.,
Detsky J.S.,
Wright G.A.,
Dick A.J.
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21079
Subject(s) - medicine , methemoglobin , edema , infarction , myocardial infarction , cardiology , hemoglobin , anesthesia , nuclear medicine
MRI evaluations of intramyocardial hemorrhage in acute infarction have relied on T 2 and T 2 *shortening only. We propose a more comprehensive evaluation of hemorrhagic infarction based on the concept that fluctuations in T 2 and T 1 relaxation in acute reperfused infarction will reflect transient edema and hemoglobin oxidative denaturation to uncompartmentalized methemoglobin. Anteroapical infarction was created via percutaneous balloon in young swine (22–25 kg, N = 12). T 2 , T 1 , diastolic wall thickness (DWT), and the Gd‐DTPA partition coefficient (λ) were measured on days 0, 2, and 7. DWT was elevated at 1 hr postreperfusion (128% ± 53%, P = 0.0001), and alleviated on days 2 and 7 (48% ± 10%, P = 0.008; 53% ± 24%, P = 0.003). T 2 and T 1 elevations were coincident with early edema (Δ T 2 = 55% ± 24%, P < 0.0001; Δ T 1 = 27% ± 18%, P < 0.04). T 2 and T 1 were nearly normal on day 2 (Δ T 2 = 8% ± 8%, P = 0.27; Δ T 1 = 0% ± 1%, P = 0.65). On day 7, T 2 increased while T 1 decreased (Δ T 2 = 27% ± 16%, P = 0.005; Δ T 1 = −14% ± 10%, P = 0.02). λ was elevated by >150% at all time points ( P ≤ 0.002). Histology verified hemorrhagic injury. T 1 and T 2 fluctuations are consistent with transient edema, as well as hemoglobin oxidative denaturation to decompartmentalized methemoglobin. This methodological development may broaden our understanding of hemorrhagic microvascular injury and improve its detection in clinical populations. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.