title: The value of 24-hour images after rest thallium injection.
abstract: Rest (201) Tl imaging has been used for detecting viability, but the ideal timing for imaging after injection to maximally estimate viability is not well established. Thirty patients with fixed or incompletely reversible defects on 4 h redistribution SPECT imaging after thallium rest injection underwent 24 h imaging. Global redistribution was subjectively rated none, minimal or meaningful by two experienced observers. Fourteen patients had no meaningful redistribution at either 4 h or 24 h. Ten patients had meaningful redistribution at 4 h only. Six patients had no meaningful redistribution at 4 h but did at 24 h. Defect size was quantified using a 70% threshold. For the total group, defect size was smaller at 4 h compared to immediate imaging (38+/-18% vs 41+/-19%, P=0.06) and smaller still at 24 h (36+/-16% vs 38+/-18%, P=0.02). Later (24 h) redistribution images detected additional redistribution in 30% of the patients who did not have meaningful redistribution on early (4 h) images, and in 8% of the segments which were abnormal at 4 h. It is concluded that, in patients who have incompletely reversible defects on early redistribution imaging at 4 h, late redistribution imaging after 24 h will demonstrate additional redistribution in 30% of the patients.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Wagdy
authors.forename: T F
authors.initials: TF
authors.lastname: Christian
authors.forename: T D
authors.initials: TD
authors.lastname: Miller
authors.forename: R J
authors.initials: RJ
authors.lastname: Gibbons
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012146:Rest; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013793:Thallium / Q000493:pharmacokinetics*; D013997:Time Factors; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000378:metabolism
chemical_list: D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium