title: Impaired exercise-related myocardial uptake of technetium-99m-tetrofosmin in relation to coronary narrowing and diabetic state: assessment with quantitative single photon emission computed tomography.
abstract: Despite the diagnostic efficacy of stress myocardial perfusion imaging, the correlation between the actual perfusion tracer activity and diseased state of a coronary artery has not been studied in detail. We estimated exercise-related perfusion augmentation in relation to disease states of a coronary artery in diabetic and non-diabetic patients by a newly developed quantitative technetium (Tc)-99m-tetrofosmin myocardial imaging technique. Tc-99m-tetrofosmin tomographic imaging with an exercise-rest protocol was performed in 26 stable coronary patients and in 8 age-matched controls. Percent increase (%IR) in myocardial count during symptom-limited submaximal exercise-stress was calculated in 16 non-infarcted polar map segments and in each coronary territory by a subtraction technique with corrections for physical decay and injected tracer doses, and the results were compared with those of angiographically quantified coronary diameter stenosis (%DS). Percent IR and peak heart rate during exercise showed a positive linear correlation both in coronary territories with significant stenosis (%DS > or = 75%) and in control or nonstenotic (%DS < 75%) territories. The regression line in stenotic regions was, however. significantly (p < 0.01) shifted downward compared to that in non-stenotic regions. Percent IR in stenotic regions showed a significant inverse correlation with %DS. Coronary stenosis of 75% or more was identified by a %IR cutoff value of 40% with 77% sensitivity, 70% specificity, and an accuracy of 72%. In coronary territories with a %DS of less than 75%, %IR in diabetic patients was significantly lower (46+/-15%) than that in nondiabetic patients (61+/-25%). Thus, blunted exercise-related augmentation of myocardial uptake of Tc-99m-tetrofosmin correlates with the severity of coronary narrowing and diabetic state.
authors.affiliation: Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Hokkaido, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sasao
authors.forename: T
authors.initials: T
authors.lastname: Nakata
authors.forename: K
authors.initials: K
authors.lastname: Tsuchihashi
authors.forename: T
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: N
authors.initials: N
authors.lastname: Nakaihara
authors.forename: A
authors.initials: A
authors.lastname: Doi
authors.forename: A
authors.initials: A
authors.lastname: Hashimoto
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: K
authors.initials: K
authors.lastname: Shimamoto
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D048909:Diabetes Complications; D015444:Exercise / Q000502:physiology*; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin