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Thallium-201 myocardial scintigraphy in coronary triple-vessel disease: an attempt to increase sensitivity using
M Singer1, J Müller-Brand, M E Pfisterer
1Department of Nuclear Medicine, University Hospital, Basel, Switzerland.
Insights
Quantitative analysis of thallium-201 exercise scintigraphy in triple vessel disease (TVD) shows potential for improved sensitivity. Lung uptake and myocardial quotients offer promising indicators for detecting ischemia in TVD patients.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Thallium-201 exercise scintigraphy is a key diagnostic tool for coronary artery disease.
- Triple vessel disease (TVD) presents diagnostic challenges, potentially impacting scintigraphy sensitivity.
- Visual assessment of myocardial scintigrams has limitations in detecting subtle perfusion defects.
Purpose of the Study:
- To enhance the sensitivity of thallium-201 exercise scintigraphy for detecting triple vessel disease (TVD).
- To evaluate quantitative criteria for identifying ischemia in TVD patients with initially non-diagnostic scintigrams.
Main Methods:
- Retrospective analysis of 179 TVD patients' myocardial scintigrams and cardiac catheterization data.
- Comparison of TVD patients (scar or no defect) with a normal coronary angiography control group.
- Quantitative assessment using myocardial and lung region of interest (ROI) quotients and stress lung uptake.
Main Results:
- Quantitative criteria showed a tendency to confirm hypotheses regarding exercise-induced ischemia and left ventricular dysfunction.
- Significant differences (P < 0.05) were observed in lung ROI quotients and some myocardial ROI quotients.
- No significant differences were found in exposure time quotients or absolute stress lung uptake; ranges could not be established due to value overlap.
Conclusions:
- Quantitative analysis of thallium-201 scintigraphy may improve TVD detection sensitivity.
- Lung uptake and specific myocardial quotients show potential for identifying ischemia in challenging cases.
- Further refinement is needed to establish reliable quantitative ranges for diagnostic certainty.
Abstract:
In order to increase the sensitivity of thallium-201 exercise scintigraphy in patients with triple vessel coronary disease (TVD), we first examined retrospectively myocardial scintigrams of 179 patients with TVD, as documented subsequently by cardiac catheterization. Ischemia had been diagnosed visually in 141 (79%), scar without ischemia in 25 (14%) and no apparent perfusion defect in 13 (7%) cases. The subset of TVD patients without scintigraphic ischemia (i.e. those with scar or no perfusion defect) was then compared to a control group with normal coronary angiography using four quantitative criteria: (1) in preset-count analog images, a quotient of the exposure times rest image/stress image; (2) in preset-time digital images, a quotient of counts/pixel in stress image/rest image using two different myocardial regions of interest (ROI); (3) a similar quotient using paracardial lung ROIs of three different sizes; (4) the absolute values of stress lung uptake. Quotients (1) and (2) were expected to be lower in TVD patients than in normal controls due to exercise-induced global ischemia, quotient (3) and value (4) were expected to be higher due to exercise-induced left ventricular dysfunction with increased lung uptake of thallium-201. All results showed a tendency to confirm these hypotheses; significant differences (P less than 0.05) between patients and controls were obtained in all lung quotients and in 3 of 12 myocardial quotients. No significant differences were observed in the exposure time quotients of preset-count images and in the stress lung uptake. Due to overlapping values, it was not possible to fix normal and pathological ranges of any quotient.(ABSTRACT TRUNCATED AT 250 WORDS)