ISSN:
1573-0743
Keywords:
lung-heart ratio
;
thallium-201 scintigraphy
;
myocardial ischemia
;
revascularisation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Uptake of thallium (Tl)-201 in the lungs has been proposed as a measure of left ventricular dysfunction. In this study we were interested in pursuing two goals: 1) to assess possible relationships between the post-exercise Tl-201 lung-heart (LH-) ratio determined from the anterior view during SPECT-acquisition, myocardial ischemia and the extent of coronary artery disease; and 2) to explore the effects of coronary revascularisation procedures on the LH-ratio. The study group consisted of 145 patients with early and late postexercise Tl-201 tomograms, including 32 PTCA-patients with pre- and post-PTCA studies and 20 patients who underwent coronary artery bypass surgery (CABG) with corresponding pre- and post-CABG studies. Ischemia was defined as evoked angina during the exercise test in combination with ≥1 mm horizontal or downsloping ST-depression on the ECG. The severity of coronary obstructions was assessed from coronary angiograms with a PC-based digital caliper technique; a stenosis was defined to be significant when its severity exceeded 50% diameter stenosis. The LH-ratio was defined by the ratio of the mean pulmonary counts and the mean myocardial counts assessed from corresponding regions of interest (ROI's) positioned over the left lung and the heart, respectively in the anterior view of a tomographic data acquisition procedure. Our results made clear that the LH-ratio was not significantly different between patients with and without ischemia during exercise, and between patients with single vs. multiple vessel disease. However, the interventions had a significant effect of the LH-ratio: LH-ratio mean ± s.d. Pre-intervention Post-intervention p-value PTCA 0.33 ± 0.10 0.28 ± 0.08 〈 0.01 CABG 0.34 ± 0.11 0.29 ± 0.07 〈 0.01 In conclusion, the lung-heart ratio assessed from post-exercise Tl-201 tomograms is poorly correlated with myocardial ischemia and is not useful for the diagnosis of multiple CAD. However, the LH-ratio may be a useful complementary measurement in the serial assessment of patients undergoing revascularisation procedure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02398896
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