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Significance of increased lung thallium uptake during adenosine thallium-201 scintigraphy
S Nishimura1, J J Mahmarian, M S Verani
1Department of Internal Medicine, Baylor College of Medicine, Houston, Texas 77030.
Insights
Elevated lung thallium activity during adenosine scintigraphy indicates more severe coronary artery disease and myocardial hypoperfusion. This finding helps assess coronary artery disease severity and perfusion defects.
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Coronary artery disease (CAD) diagnosis often relies on myocardial perfusion imaging.
- Assessing the severity and extent of CAD is crucial for patient management.
Purpose of the Study:
- To investigate the relationship between lung 201Tl activity during adenosine scintigraphy and the presence/extent of CAD.
- To determine if lung activity provides supplementary information on CAD severity and myocardial hypoperfusion.
Main Methods:
- 132 subjects were studied: normal volunteers, patients with normal coronaries, single-vessel CAD, and multivessel CAD.
- Lung 201Tl activity was quantified relative to maximal myocardial activity using planar and tomographic imaging.
- Lung-to-heart ratios were compared across different patient groups and correlated with perfusion defects.
Main Results:
- A strong correlation existed between planar and tomographic lung-to-heart ratios (r=0.83).
- Planar lung-to-heart ratios were significantly higher in multivessel CAD patients compared to single-vessel CAD or normal subjects.
- Elevated lung thallium activity correlated with more hypoperfused segments, increased redistribution, and larger perfusion defects.
Conclusions:
- Lung activity during adenosine thallium scintigraphy is a valuable indicator of CAD severity.
- Quantifying lung thallium uptake offers supplementary information on the extent of myocardial hypoperfusion.
- This assessment can aid in evaluating the severity of coronary artery disease.
Abstract:
To determine the relationship of lung 201Tl activity during adenosine scintigraphy to the presence and extent of coronary artery disease, we investigated 132 subjects comprising 4 groups: 36 normal volunteers, 19 patients with angiographically normal coronaries, 29 patients with single-vessel (greater than 50% luminal stenosis) and 48 patients with multivessel coronary artery disease. Lung activity was quantified relative to maximal myocardial activity in both an early anterior planar image (pretomography) and the unprocessed tomographic image in the anterior projection. A good correlation was found for the lung-to-heart ratio assessed by planar and tomographic imaging (r = 0.83, p less than 0.0001), but the ratio was higher with planar imaging. The lung-to-heart ratio in the planar images was significantly higher in patients with multivessel disease compared to those with single-vessel disease (p less than 0.05) or volunteers and subjects with normal coronary arteries combined (p less than 0.001). A lung-to-heart ratio of greater than 0.45 in the planar images (upper 95% confidence limit for the normal subjects) was found in 6 (21%) single-vessel disease and 17 (35%) multivessel disease patients. Patients with elevated lung thallium activity during adenosine infusion had more hypoperfused myocardial segments (p = 0.007), more segments with redistribution (p = 0.04) and larger initial perfusion defect size (p = 0.04) than those with normal lung activity. Thus, evaluation of lung activity during adenosine thallium scintigraphy provides supplementary information regarding the severity of coronary artery disease and extent of myocardial hypoperfusion.