Perfusion MRI at rest in subacute and chronic myocardial infarct

Einar Hopp; Atle Bjørnerud; Ketil Lunde; Svein Solheim; Svend Aakhus; Harald Arnesen; Kolbjørn Forfang; Thor Edvardsen; Hans-Jørgen Smith

doi:10.1177/0284185113475605

Perfusion MRI at rest in subacute and chronic myocardial infarct

Acta Radiol. 2013 May;54(4):401-11. doi: 10.1177/0284185113475605. Epub 2013 Apr 30.

Authors

Einar Hopp¹, Atle Bjørnerud², Ketil Lunde³, Svein Solheim⁴, Svend Aakhus³, Harald Arnesen⁵, Kolbjørn Forfang³, Thor Edvardsen⁶, Hans-Jørgen Smith⁷

Affiliations

¹ Department of Radiology and Nuclear Medicine, Oslo University Hospital, Rikshospitalet Faculty of Medicine, University of Oslo, Oslo einar.hopp@oslo-universitetssykehus.no.
² The Intervention Centre, Oslo University Hospital, Rikshospitalet Department of Physics, University of Oslo.
³ Department of Cardiology, Oslo University Hospital, Rikshospitalet.
⁴ Department of Cardiology, Oslo University Hospital, Ullevål, Norway.
⁵ Faculty of Medicine, University of Oslo, Oslo Department of Cardiology, Oslo University Hospital, Ullevål, Norway.
⁶ Faculty of Medicine, University of Oslo, Oslo Department of Cardiology, Oslo University Hospital, Rikshospitalet.
⁷ Department of Radiology and Nuclear Medicine, Oslo University Hospital, Rikshospitalet Faculty of Medicine, University of Oslo, Oslo.

PMID: 23401603
DOI: 10.1177/0284185113475605

Abstract

Background: Perfusion magnetic resonance imaging (MRI) and delayed contrast-enhanced MRI (DE-MRI) serve as tools for tissue characterization.

Purpose: To assess and compare semi-quantitative parameters of myocardial infarct (MI) in the subacute and chronic phase, and to correlate these parameters with qualitative enhancement analysis.

Material and methods: Perfusion MRI at rest and DE-MRI were performed in 63 patients with anterior wall MI at 2-3 weeks after revascularization and repeated after 6 months. Descriptive enhancement parameters of contrast arrival time, initial upslope, enhancement at normal tissue peak (TTPn) and wash-out slope, and kinetic tissue parameters rBF, K (trans), k ep and v e were calculated. Subacute infarct tissue was compared to normal myocardium and chronic infarct tissue. Patients were stratified at baseline according to a qualitative grading of hypoenhancement based on first-pass enhancement and presence of microvascular obstruction (MO) at perfusion MRI and on persistent MO at DE-MRI. The qualitative grade was correlated to semi-quantitative perfusion MRI parameters.

Results: Initial upslope, enhancement at TTPn, rBF, and k ep were decreased and wash-out slope and v e were increased in infarct tissue (P < 0.001 for all analyses). Infarct tissue v e decreased from baseline to 6 months (P = 0.045). At baseline infarct tissue with persistent MO revealed decreased K (trans) and delayed contrast arrival, and more pronounced decrease of enhancement at TTPn, rBF and k ep compared to other enhancement groups (P < 0.008 for pairwise analyses).

Conclusion: Perfusion is decreased in subacute reperfused infarct tissue compared to normal tissue. K (trans) is not decreased, consistent with increased surface area of the vascular bed of the subacute infarct. Infarct tissue v e is increased, and decreases with scarring. The presence of persistent MO correlates to more pronounced perfusion reduction and results in delayed contrast arrival, indicating microvascular collateral circulation.

Keywords: Cardiac; MR imaging; MR perfusion; infarction.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Chronic Disease
Contrast Media
Female
Gadolinium DTPA
Humans
Image Enhancement / methods
Magnetic Resonance Angiography / methods*
Magnetic Resonance Imaging / methods
Male
Middle Aged
Myocardial Infarction / pathology*
Myocardial Infarction / surgery
Percutaneous Coronary Intervention
Stents

Substances

Contrast Media
Gadolinium DTPA