title: Delayed redistribution in thallium 201 SPECT myocardial perfusion studies.
abstract: Stress 201Tl myocardial perfusion studies are useful in differentiating viable, reversibly ischemic from infarcted myocardium. A perfusion defect that shows redistribution 2 to 4 h after 201Tl injection is diagnostic of ischemia, while a fixed defect suggests infarction. However, occasional patients with a fixed defect at 4 h have redistribution at 24 h. This study evaluates the frequency and significance of this delayed redistribution with SPECT 201Tl. Patients with either no or incomplete redistribution at 4 h had repeat imaging 18 to 48 h later. Delayed redistribution was seen in 8/26 (31 percent). Four had incomplete and four had no redistribution at 4 h. Delayed redistribution with SPECT 201Tl is more common than generally appreciated, and we recommend delayed images in patients with fixed perfusion defects or incomplete redistribution at 4-h imaging, particularly in patients with previous infarctions for whom a revascularization procedure is being considered.
authors: Department of Radiology, Georgetown University Medical Center, Washington, D.C. 20007.
authors: H A
authors: HA
authors: Ziessman
authors: J W
authors: JW
authors: Keyes
authors: L M
authors: LM
authors: Fox
authors: C E
authors: CE
authors: Green
authors: S M
authors: SM
authors: Fox
mesh_terms: D000328:Adult; D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013794:Thallium Radioisotopes