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Reverse redistribution in Tl-201 stress-redistribution myocardial scintigraphy. Effect of rest reinjection
Insights
Thallium-201 reverse redistribution (RR) in chronic coronary artery disease (CAD) indicates significant coronary artery stenosis. Pattern A RR segments, particularly those with no reinjection enhancement, show reduced Tc-99m MIBI uptake, suggesting myocardial viability issues.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Thallium-201 (Tl-201) reverse redistribution (RR) is a complex imaging finding in chronic coronary artery disease (CAD).
- Understanding the clinical significance of Tl-201 RR patterns is crucial for accurate diagnosis and patient management.
Purpose of the Study:
- To clarify the clinical significance of Tl-201 reverse redistribution (RR) in patients with chronic coronary artery disease (CAD).
- To correlate Tl-201 RR patterns with coronary arteriography findings and myocardial viability assessed by Tc-99m MIBI scintigraphy and rest reinjection.
Main Methods:
- 33 patients with chronic CAD underwent stress-redistribution Tl-201 imaging with rest reinjection.
- Coronary arteriography and 2D-echocardiography were performed.
- Rest Tc-99m MIBI scintigraphy was performed in 27 patients; 495 segments were analyzed for Tl-201 and 405 for Tc-99m MIBI.
Main Results:
- Reverse redistribution (RR) was identified in 9% of segments. Pattern A RR (normal stress, reduced redistribution) was associated with a higher rate of coronary artery stenosis (80%) compared to normal segments (49%).
- Segments with Pattern A RR showed significantly lower Tc-99m MIBI uptake than normal segments.
- Tl-201 segments with Pattern A RR that did not enhance after reinjection (Re-) had significantly lower Tc-99m MIBI uptake compared to reinjection-enhanced (Re+) segments and normal segments.
Conclusions:
- Thallium-201 reverse redistribution, particularly Pattern A, is associated with significant coronary artery stenosis in chronic CAD.
- The lack of reinjection enhancement in Pattern A RR segments correlates with reduced myocardial perfusion, indicating potential myocardial viability concerns.
Abstract:
To clarify the clinical significance of Tl-201 reverse redistribution (RR), 33 patients with chronic coronary artery disease (CAD) underwent stress-redistribution Tl-201 cardiac imaging with rest reinjection, coronary arteriography, and 2D-echocardiography. Rest Tc-99m MIBI scintigraphy was also performed in 27 of the 33 patients. A total of 495 segments were analyzed for Tl-201 scintigraphy (405 for Tc-99m MIBI). Each segment was assigned to one of the major coronary artery territories. Two patterns of RR were identified; 1) pattern A (RR-A) showed normal Tl-201 uptake on stress images and lower than normal on redistribution images, and 2) pattern B (RR-B) showed lower than normal Tl-201 uptake on stress images with further decrease on redistribution images. The RR phenomenon was found in 46 (9% of the total) segments; 25 with RR-A and 21 with RR-B. Reverse redistribution pattern A segments had lower Tc-99m MIBI uptake (84 +/- 9% versus 92 +/- 10%, P < 0.0001) and a higher percentage of stenosed coronary arteries (80% versus 49%, P < 0.05) compared to normal segments (n = 204, 41% of the total). No difference in wall motion was observed between RR-A and normal segments. Of the 25 segments with RR-A, 14 showed enhanced Tl-201 uptake after reinjection (Re+) and 11 remained unchanged after reinjection (Re-). Segments that were Re- showed significantly (P < 0.05) lower Tc-99m MIBI uptake (79 +/- 9%) compared to Re+ segments (87 +/- 8%) and normal segments (92 +/- 10%).(ABSTRACT TRUNCATED AT 250 WORDS)