Cardiac MR assessment of microvascular obstruction

Abstract

Microvascular obstruction (MVO) is usually seen in a proportion of patients with acute myocardial infarction following reperfusion therapy of an occluded coronary artery. It is characterized by damage and dysfunction of the myocardial microvasculature with a no-reflow phenomenon within the infarct zone. While MVO may be demonstrated via a number of different imaging modalities, cardiac MR (CMR) enables accurate identification of MVO and also permits assessment of infarct extent and overall left ventricular function during the same imaging examination. We present a pictorial review of the characteristic appearances of MVO on CMR and highlight the importance of this imaging diagnosis for patient outcome following acute myocardial infarction.

Impact of microvascular obstruction on left ventricular local remodeling after reperfused myocardial infarction

“…The presence of MVO is increasingly recognized as a poor functional recovery indicator since it represents more severe myocardial as well as microvasculature damage . However, conflicting data exist with respect to the MVO presence and regional function recovery.…”

“…The presence of MVO is increasingly recognized as a poor functional recovery indicator since it represents more severe myocardial as well as microvasculature damage. 2,15 However, conflicting data exist with respect to the MVO presence and regional function recovery. Some studies 6,[26][27][28] showed no significant functional recovery in segments with MVO, which is contrary to the findings of Nijveldt et al 8 : wall thickening improved equally in segments with and without MVO in nontransmural segments (ie, DHE transmural extent <75%); but less improved in transmural segments (>75%) with MVO than in transmural segments without MVO, suggesting a complex interplay between DHE transmural extent and MVO presence.…”

“…As reviewed previously, while MVO may be diagnosed via a number of different imaging modalities, cardiac MRI provides the most comprehensive assessment of MVO. It represents a central “dark zone” within the hyperenhanced region on gadolinium‐enhanced MRI sequences.…”

“…Moreover, since we did not perform T 2 or T 2 * MR sequences, the effect of myocardial hemorrhage could not be addressed. Indeed, intramyocardial hemorrhage (IMH) is closely linked to MVO, and is increasingly recognized as a more severe form of MVO . One recent study showed that patients with IMH exhibited worse functional recovery and adverse LV remodeling than those with MVO alone.…”

An hs-TNT Second Peak Associated with High CRP at Day 2 Appears as Potential Biomarkers of Micro-Vascular Occlusion on Magnetic Resonance Imaging after Reperfused ST-Segment Elevation Myocardial Infarction

“…Cardiac magnetic resonance imaging (CMR) can quickly assess infarct size and is considered as the gold standard for MVO evaluation and quantification [4,7,8]. By the way, CMR provides ventricular function and volumes [9], but its availability remains a problem, urging for identification of alternative markers of bad outcomes, and several biomarkers have been evaluated to assess MVO [10][11][12][13].…”