SUMMARY Thallium-201 myocardial perfusion scintigraphy was performed after exercise, 4 hours after exercise (redistribution) and after a separate rest injection in 87 patients undergoing coronary arteriography. Significant coronary lesions were present in 62 of the patients.
Interpretation of the rest and redistribution scintiscans was the same in 69 patients, 45 of whom had coronary artery disease (CAD). In 16 of the 17 patients with CAD and differing interpretations, defects were present on redistribution scintiscans but not on rest scintiscans; 11 of these patients had evidence of prior transmural myocardial infarction and the other five had an occluded coronary artery supplying the region of the defect.
Redistribution scintiscans were more sensitive than rest scintiscans for the detection of prior myocardial infarction (93% vs 54%; P < 0.01). The increased sensitivity was confined to the detection of prior inferior myocardial infarctions. In 36 of 38 patients with persistent perfusion defects on 4-hour redistribution scintiscans, either a prior infaretion or an occluded coronary vessel was present.
Exercise scintiscans were compared with rest scintiscans or with redistribution scintiscans for the detection of CAD. The sensitivity was not significantly different with either technique (90% and 89%, respectively), but both scintigraphic techniques were more sensitive than exercise electrocardiography (66%, P < 0.01).
These data demonstrate that redistribution thallium-201 scintiscans may be substituted for conventional rest scintiscans, resulting in reduced cost and radiation exposure to the patient.