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[Tl-201 single-photon emission computed tomography for clinical assessment of dilated cardiomyopathy]
Insights
Thallium-201 (Tl-201) SPECT imaging detects more myocardial perfusion defects in dilated cardiomyopathy (DCM) patients than planar imaging. This advanced technique correlates better with cardiac function and wall motion abnormalities, aiding DCM assessment.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Dilated cardiomyopathy (DCM) can present with myocardial perfusion defects.
- Thallium-201 (Tl-201) imaging is used to assess myocardial perfusion.
Purpose of the Study:
- To clarify the mechanism of Tl-201 perfusion defects in DCM.
- To compare Tl-201 planar imaging with Tl-201 single-photon emission computed tomography (ECT) in DCM patients.
- To assess the correlation between perfusion defects and cardiac function/wall motion.
Main Methods:
- Thirteen DCM patients underwent conventional planar and ECT Tl-201 imaging.
- Defect severity was visually assessed.
- Correlations were made with gated cardiac blood pool scans (ejection fraction) and 2D echocardiography (wall motion).
Main Results:
- ECT imaging detected perfusion defects in 100% of patients, compared to 85% with planar imaging.
- ECT showed significantly higher mean defect scores than planar imaging (p<0.025).
- ECT defect scores correlated negatively with ejection fraction (r=-0.64) and showed strong correlation with wall motion abnormalities.
Conclusions:
- Tl-201 ECT imaging is superior to planar imaging for detecting perfusion defects in DCM.
- Perfusion defects and wall motion abnormalities in DCM are likely related to myocardial fibrosis or scarring.
- Tl-201 myocardial scintigraphy, especially ECT, is valuable for clinical DCM assessment.
Abstract:
In some cases of dilated cardiomyopathy (DCM) perfusion defects are demonstrable by Tl-201 imaging at rest. This study clarified the mechanism by which the Tl scan can show myocardial perfusion defects in patients with DCM by means of Tl-201 single-photon emission computed tomography (ECT) utilizing a rotating gamma camera to assess three-dimensional T1 distribution in the myocardium. Thirteen patients with DCM were studied by conventional planar and ECT imaging, and the degree of defects was determined visually. Perfusion defects were observed in 11 of 13 cases (85%) by planar imaging and in all 13 (100%) by ECT imaging. The mean defect score was higher in ECT than in planar imaging (4.15 +/- 1.46 vs 2.23 +/- 1.46, p less than 0.025). A comparative study of defect scores and left ventricular ejection fractions (EF) using gated cardiac blood pool scans established a negative correlation on ECT imaging (r= -0.64), and no correlation on planar imaging (r= -0.38). There was no statistically significant correlation between perfusion defects on planar imaging and regional wall motion abnormalities as observed by two-dimensional echocardiography (2-DE). In contrast, most of the segments with severe defects (defect score greater than or equal to 2) on ECT images showed high grade wall motion abnormalities on 2-DE. Both perfusion defects and wall motion abnormalities in DCM may be closely related to the fibrosis or scar formation in the myocardium. These results indicated that T1-201 myocardial scintigraphy, especially ECT imaging, is of great value in the clinical assessment of patients with DCM.