The usefulness of stress tests performed in the nuclear medicine department: mathematical methods to assess efficacy at various angiographic endpoints.
Stress myocardial perfusion scintigraphy (SMPS) may be used to amplify or supplant information available from stress electrocardiography (ECG) in directing the clinical management of patients, including the need for coronary angiography. The apparent usefulness of SMPS may depend on referral bias, the stress mode employed and the criterion for disease. We compared markers of ischaemia on quantitative planar SMPS with 201 Tl in 503 referred patients; stress was tailored to the individual patient to include exercise (n = 154), dipyridamole (n = 118) or a combination of the two (n = 231). Four angiographic criteria of increasing severity (A-D) were targeted. The fraction of the population receiving diagnostic benefit was calculated for reversible defects (RD) or lung uptake (LU) in comparison to concurrent ST depression; abnormal baseline tracings and fixed 201Tl defects were regarded as indeterminate. Decision tree induction, a computer-learning algorithm and logistic regression were also used to assess the contribution of 13 scintigraphic and other input variables. In comparison to ST depression, RD showed incremental value in 167 (33%) patients with criterion A, decreasing to 5% with criterion D; LU showed its greatest benefit (21%) with criterion D. Both scintigraphic markers were more useful with dipyrida-mole-based tests than with exercise alone. Decision trees induced at each criterion for disease showed the predominant contribution of scintigraphic results in comparison to clinical and ECG data. In conclusion, in a referred population with a frequent requirement for pharmacological stress, the clinical utility of scintigraphy can be determined by comparison of markers of ischaemia; the results will depend, however on the angiographic criterion for disease.
Hurwitz
G A
GA
Department of Diagnostic Radiology/Nuclear Medicine, University of Western Ontario, Canada.
Weingert
M E
ME
Silver
D L
DL
MacDonald
A C
AC
Finnie
K J
KJ
Powe
J E
JE
Dawdy
J A
JA
D000792:Angiography; D002637:Chest Pain; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging; D015588:Observer Variation; D012044:Regression Analysis; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D013794:Thallium Radioisotopes; D004176:Dipyridamole