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Assessment of myocardial viability in persistent defects on thallium-201 SPECT after reinjection using gradient-echo
A J Morguet1, A Kögler, H A Schmitt
1Department of Cardiology and Pulmonology, Georg August University, Göttingen, Germany.
Insights
Mild to moderate persistent thallium-201 (TI-201) defects indicate viable heart tissue in coronary heart disease patients. Severe persistent defects, however, suggest nonviable myocardium lacking contractile function.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiac Imaging
Background:
- Coronary heart disease (CHD) often leads to myocardial dysfunction.
- Assessing myocardial viability is crucial for guiding revascularization strategies.
- Thallium-201 (TI-201) single-photon computed tomography (SPECT) is used to evaluate myocardial perfusion and viability.
Purpose of the Study:
- To assess myocardial viability in patients with CHD and persistent TI-201 defects.
- To correlate TI-201 uptake patterns with myocardial wall thickness and function.
- To determine the significance of persistent TI-201 defects for predicting myocardial recovery after revascularization.
Main Methods:
- Prospective study of 30 CHD patients with persistent TI-201 defects despite reinjection.
- Observer grading of TI-201 uptake in 7 left ventricular segments.
- Gradient-echo magnetic resonance imaging (MRI) to assess end-diastolic wall thickness and systolic wall thickening.
- Analysis of 120 myocardial segments based on TI-201 defect severity.
Main Results:
- Significant differences in wall thickness and systolic thickening were found only between segments with severe persistent defects and all other groups.
- Segments with mild and moderate persistent TI-201 defects showed preserved or improved systolic wall thickening after revascularization.
- Segments with severe persistent TI-201 defects demonstrated minimal systolic thickening and did not improve after revascularization.
Conclusions:
- Mild to moderate persistent TI-201 defects suggest the presence of viable myocardial tissue.
- Severe persistent TI-201 defects are indicative of nonviable myocardium with absent contractile function.
- TI-201 SPECT, particularly after reinjection, remains valuable in differentiating viable from nonviable myocardium in CHD.
Abstract:
This prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (+/-SD) was 11.5 +/- 2.7 mm and 5.8 +/- 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 +/- 3.4 mm and 3.7 +/- 3.1 mm in 31 with reversible lesions, 11.3 +/- 2.8 mm and 3.3 +/- 1.9 mm in 10 with mild persistent defects, 9.2 +/- 2.9 mm and 3.2 +/- 2.2 mm in 15 with moderate persistent defects, 5.8 +/- 1.7 mm and 1.3 +/- 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p < 0.0005) and systolic wall thickening (p < 0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.