RESUMO
Technetium-99m-teboroxime (BATO) and 99mTc-sestamibi (MIBI) may provide the opportunity for first-pass evaluation of left and right ventricular function at rest and exercise in conjunction with myocardial perfusion scintigraphy. This study examined the results of age- and gender-matched patients with clinically normal left ventricular function who underwent resting first-pass studies with BATO (n = 25), MIBI (n = 25) and DTPA (n = 25). There were no significant differences between the observed first-pass tracer kinetics or clinical results of MIBI and DTPA. However, there was significantly greater first-pass pulmonary uptake of BATO compared with either MIBI or DTPA. This resulted in five clinically important differences in the BATO FPRNA images: (1) greater background during the levophase of the tracer transit, (2) prolongation of the measured mean pulmonary transit time, (3) lower raw and final ejection fractions, (4) obscured left ventricular border definition resulting in larger geometrically derived left ventricular volumes and (5) poorer image detail and quality which compromised functional image and regional wall motion interpretation. This study suggests that further refinement of the first-pass methodology, particularly with regard to methods of background subtraction, is needed to obtain quality FPRNA results with BATO. However, for the purposes of left ventricular function analysis with FPRNA, MIBI and DTPA are interchangeable.
