Interference from duodeno-gastric reflux of 99Tcm radiopharmaceuticals in SPET myocardial perfusion imaging.

Single photon emission tomographic (SPET) myocardial perfusion imaging was performed on 76 patients using 99Tcm-sestamibi (99Tcm-MIBI). Retrospective analysis of the data showed good cardiac uptake and adequate hepatobiliary clearance. However, duodeno-gastric reflux of the activity excreted from the liver and gallbladder was seen in 34% of the studies. This reflux was considered to be severe in 16% of the studies, resulting in interference with the myocardial uptake and requiring three studies to be repeated. In an attempt to minimize interference from duodeno-gastric reflux, a further 86 patients (18 using 99Tcm-MIBI and 68 using 99Tcm-tetrofosmin) were imaged after lying on their right side for 20 min prior to imaging. Good cardiac uptake with adequate hepatobiliary clearance was again achieved. The incidence of duodeno-gastric reflux was significantly lower (P < 0.001), occurring in 22% of studies, while severe reflux occurred in 6% of studies with no studies being repeated. There was no significant difference in the incidence of reflux between the two agents. Duodeno-gastric reflux of 99Tcm-MIBI and 99Tcm-tetrofosmin is common and can result in significant interference with myocardial uptake. It is concluded that having patients lie on their right side for 20 min prior to imaging is a simple and effective method for significantly reducing the likelihood of such interference.