BackgroundWhen using 99mTc sestamibi for myocardial perfusion imaging, increased splanchnic activity creates a problem in the visual and quantitative interpretation of the inferior and infero-septal walls of the left ventricle. We sought to determine whether the administration of diluted lemon juice or full-fat milk would be effective in reducing interfering infra-cardiac activity and therefore result in an improvement in image quality. We compared the administration of full-fat milk and diluted lemon juice to a control group that had no intervention.MethodsThe study was carried out prospectively. All patients referred to our institution for myocardial perfusion imaging from November 2009 to May 2012 were invited to be enrolled in the study. A total of 630 patients were randomised into three groups. Group 0 (G0), 246 patients, were given diluted lemon juice, group 1 (G1), 313 patients, were given full-fat milk, and group 2 (G2), 71 patients, had no intervention (control group). A routine two-day protocol was used and the patients were given the same intervention on both days. Raw data of both the stress and rest images were visually assessed for the presence of infra-cardiac activity, and quantitative grading of the relative intensity of myocardial activity to infra-cardiac activity was determined. The physicians were blinded to the intervention received and the data were reviewed simultaneously.ResultsThe overall incidence of interfering infra-cardiac activity at stress was 84.1, 84.5 and 96.6% in G0, G1 and G2, respectively (p = 0.005). At rest it was 91.7, 90.1 and 100% in G0, G1 and G2, respectively (p = 0.0063). The visual and quantitative results favoured both milk and lemon juice in reducing the amount of interfering infra-cardiac activity versus no intervention.ConclusionThe administration of milk or lemon juice resulted in a significant decrease in the intensity of infra-cardiac activity compared to the control group. This reduction in intensity was even more significant in the milk group for patients assessed during rest myocardial perfusion imaging.