microvascular obstruction
Also written as: MVO — Microvascular Obstruction
No-reflow phenomenon in capillary beds following reperfusion, appearing as dark zones within areas of late gadolinium enhancement on cardiac MRI.
Full Definition
Microvascular obstruction (MVO) represents areas of severely damaged microcirculation where contrast agent cannot penetrate despite successful epicardial artery recanalization. On cardiac MRI, MVO appears as persistent dark zones within areas of late gadolinium enhancement, indicating regions where contrast distribution is impaired. This phenomenon is associated with larger infarct size, worse left ventricular remodeling, and poorer clinical outcomes. MVO can be detected using first-pass perfusion imaging immediately after contrast injection or as persistent dark cores within enhanced regions on late gadolinium enhancement sequences. The presence and extent of MVO provide important prognostic information following acute myocardial infarction.
Usage
Usage note: Distinguish from hemorrhagic infarction; specify timing of detection relative to contrast injection.
In Context
- "Extensive microvascular obstruction was evident as dark cores within the inferior wall enhancement." — Post-infarction cardiac MRI report
- "The presence of MVO predicted adverse remodeling at six-month follow-up." — Clinical outcomes analysis