Can a Carbonated Lemon Drink Reduce Extracardiac Activity in Myocardial Perfusion Imaging?

Myocardial perfusion imaging (MPI) provides physiologic and functional information about the heart muscle and its blood flow. Extracardiac radioactivity can interfere with visualization of the inferior wall of the myocardium, leading to poor-quality images, difficulties in interpretation, and delays in routine practice. This study aimed to identify the efficiency of having the patient consume a carbonated lemon drink to minimize the extracardiac radioactivity of ^99mTc-sestamibi in comparison to ^99mTc-tetrofosmin during MPI. Methods: This was a retrospective study that recruited 158 patients with known or suspected coronary artery disease referred to undergo ^99mTc-sestamibi or ^99mTc-tetrofosmin rest/stress single-day MPI. The patients were divided into 2 groups of mixed sexes and different ages. The first group comprised 78 patients injected with ^99mTc-sestamibi, and the second group comprised 80 patients injected with ^99mTc-tetrofosmin. For both groups, the patients drank 30 mL of fresh lemon juice diluted with 150 mL of soda water, and then we gave the patients about 100 mL of straight soda water, before imaging for both the rest and the stress phases. Results: Generally, in both groups, the ^99mTc-tetrofosmin produced a good-quality image in comparison with the ^99mTc-sestamibi. The mean rank of the total score for ^99mTc-tetrofosmin (62.75) was less than that for ^99mTc-sestamibi (96.68), and this difference was highly statistically significant (P = 0.000). There were statistically significant differences in the ratios and mean ranks for both groups in favor of ^99mTc-tetrofosmin in patients having coronary artery disease. Conclusion: The use of a carbonated lemon drink minimizes extracardiac activity from both ^99mTc-labeled MPI radiopharmaceuticals. This finding was more statistically significant for ^99mTc-tetrofosmin MPI, providing better image quality and earlier imaging in both the rest and the stress phases because of faster hepatobiliary clearance.