Efficacy of milk versus water to reduce interfering infracardiac activity in 99mTc-sestamibi myocardial perfusion scintigraphy

Objective Interference from infra-cardiac radionuclide activity prevents accurate interpretation of true myocardial perfusion. The study aim was to compare the efficacy of milk versus water in reducing infra-cardiac activity in myocardial perfusion scintigraphy. Methods We prospectively randomized 198 patients undergoing stress-rest Tc-99m-sestamibi SPECT with exercise or pharmacological stress to drink 300 ml of water or milk prior to imaging. A semi-quantitative grading of the relative intensity of infra-cardiac activity compared to the myocardial activity and a qualitative assessment of the effect on the overall interpretation was performed. Results For stress images, there was no infra-cardiac activity in 379%, less intense infra-cardiac activity in 40.8%, equal in 11.7% and greater than infra-cardiac activity in 9.7% with milk, compared with 20.0%, 49.5%, 20.0% and 10.5%, respectively, with water (P = 0.038). For rest images, there was also less intense infra-cardiac activity with milk compared to water (P = 0.014). However, no change in subsequent image interpretation was seen. Conclusion Administration of milk resulted in a significant decrease in the intensity of infra-cardiac activity compared to water. However, this did not translate into an improvement in image interpretation.