Two of the upcoming cases incorporate examples of myocardial parametric imaging (MPI)
MPI is a technique dependent on software which automatically colour-encodes quantification of myocardial blood flow (MBF) relative to the degree of perfusion
For example, normal MBF may be coloured green, whereas slightly reduced blood flow is yellow and severely reduced or absent MBF is red
- MPI has been used successfully to evaluate both myocardial ischaemia (Yu EH et al J Am Coll Cardiol 2004) and myocardial viability (Korosoglou G et al Heart 2006)
Clinical Case 1
Patient with previously undiagnosed anterior MI who comes for the first time to medical attention because of heart failure symptoms. Angiography shows 70% LAD stenosis, in the absence of ischaemic symptoms, and revascularisation will be performed only if tissue in the LAD territory is viable.
Clinical Case 2
There is increasing evidence now to suggest that individuals are less likely to respond to cardiac resynchronization therapy (CRT) if the LV lead is placed over an area of underlying scar tissue. As the posterolateral cardiac vein is frequently used, ensuring viability of these walls is of paramount importance.
Clinical Case 3
77 year old male: inferior MI age 41, 2° MI 1996 CABG for diffuse severe 3-vessel disease. Since then several admissions for heart failure and an ICD implanted for resuscitated VF. Recent angiography shows disease in the LIMA graft which may be amenable to percutaneous revascularization, if distal myocardial tissue is viable. MCE at rest is performed with SonoVue infusion (1cc/min)
Clinical Case 4
Patient with previous anterior MI in 1999 treated with primary PCI on the LAD but also left main and RCA disease diagnosed, which required CABG after few months.
Clinical Case 5
Patient with a first anterior MI in 2003 subacutely treated with PCI on the LAD but an occluded RCA was also found and left untreated. In Jan 2011 new anterior STEMI with primary PCI of the LAD (progression of disease): RCA still occluded but also Cx is now severely diseased.
- Preservation of myocardial viability requires an intact microcirculation, which can be detected by MCE
- Homogenous contrast uptake suggests intact capillaries & hence myocardial viability
- Absence of contrast uptake implies scar / non-viable tissue
- This can be used to plan revascularisation strategy in patients with coronary disease or, for example, to determine optimal site of LV lead placement in patients awaiting biventricular pacing
- Quantitative analysis of myocardial blood flow can help confirm the findings of qualitative interpretation