Objectives. The objective of this study was to assess the clinical significance of reduced regional fluorine-18 (18F) fluorodeoxyglucose uptake with normal flow in patients with chronic coronary artery disease. Background. In patients with ischemic left ventricular dysfunction, 18F-fluorodeoxyglucose uptake may be reduced in some myocardial regions despite normal flow. The significance of this finding to unclear and has not been investigated systematically. Methods. Twenty-three patients with coronary artery disease and impaired ventricular function (mean ejection fraction (±1 SD) 28 ± 10%) underwent positron emission tomography with 18F-fluorodeoxyglucose and oxygen-15-labeled water at rest, exercise thallium-201 tomographic imaging with rest reinjection and gated magnetic resonance imaging to measure end-diastolic wall thickness and systolisc wall thickening. Results. Of 168 regions with normal flow (≥0.7 ml/g per min), 125 (74%) had normal 18F-fluorodeoxyglucose uptake (98 ± 10%), and the remaining 43 (26%) showed moderately reduced 18F-fluorodeoxyglucose uptake (69 ± 8%). Systolic wall thickening was absent at rest in 14% of regions with normal 18F-fluorodeoxyglucose uptake compared with 32% of regions with reduced 18F-fluorodeoxyglucose uptake (p < 0.01). Reversible thallium abnormalities were observed in 45 (36%) of 125 regions with normal 18F-fluorodeoxyglucose uptake compared with 27 (63%) of 43 regions with reduced 18F-fluorodeoxyglucose uptake (p < 0.01). This difference was accounted for by a higher proportion of partially reversible defects in regions with reduced 18F-fluorodeoxyglucose uptake compared with regions with normal 18F-fluorodeoxyglucose uptake (42% vs. 18%, respectively, p < 0.01). Conclusions. Thus, regions with moderately reduced 18F-fluorodeoxyglucose uptake with normal flow occur commonly in patients with ischemic left ventricular dysfunction. The majority of these regions show impaired systolic function at rest and exercise-induced thallium abnormalities that are only partially reversible. These observations suggest that such regions represent an admixture of fibrotic and reversibly ischemic myocardium.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine