Acceleration of hepatobiliary excretion by lemon juice on 99mTc-tetrofosmin cardiac SPECT.

Background: We sought to determine whether drinking lemon juice reduces extra-cardiac activity and improves image quality on (99m)Tc-tetrafosmin myocardial single photon emission computed tomography (SPECT).

Methods: Eighty male patients were enrolled in this study and divided into four groups with 20 patients in each group. Each patient received 259-333 MBq tetrofosmin. Ten minutes after injection no action was taken for group 1 (G1), patients in group 2 (G2) each drank 250 ml of water, patients in group 3 (G3) each drank 250 ml of whole milk, and patients in group 4 (G4) each drank 250 ml diluted lemon juice. Myocardial perfusion imaging without attenuation correction was performed after a 1 day rest-stress protocol. Both rest and stress images were aligned at corresponding slices for comparison. Interfering activity was determined visually on reconstructed images, and the heart-to-liver (H/L) ratios were calculated with planar images at 25-30 min and at 45-50 min.

Results: Interfering activity was seen in 80% of G1, 70% of G2, 60% of G3, and 35% of G4 (G4 vs. G1, P=0.006) on rest images, and in 70% of G1, 60% of G2, 55% of G3, and 30% of G4 (G4 vs. G1, P=0.014) on stress images at 25-30 min. It was also observed in 60% of G1, 50% of G2, 45% of G3, and 15% of G4 (G4 vs. G1, P=0.006) on rest images, and in 50% of G1, 45% of G2, 40% of G3, and 10% of G4 (G4 vs. G1, P=0.011) on stress images at 45-50 min. The mean H/L ratios of rest images were 0.47+/-0.13 for G1, 0.71+/-0.17 for G2, 0.65+/-0.12 for G3, and 0.93+/-0.23 for G4 at 25-30 min, and 0.63+/-0.14 for G1, 0.73+/-0.14 for G2, 0.85+/-0.25 for G3, and 1.15+/-0.25 for G4 at 45-50 min. On stress images, they were 0.49+/-0.11 for G1, 0.74+/-0.16 for G2, 0.69+/-0.11 for G3, and 0.98+/-0.22 for G4 at 25-30 min, and 0.66+/-0.15 for G1, 0.77+/-0.11 for G2, 0.89+/-0.26 for G3, and 1.21+/-0.19 for G4 at 45-50 min.

Conclusion: Drinking 250 ml of diluted lemon juice accelerates the transit of tetrofosmin through the liver parenchyma and improves image quality on (99m)Tc-tetrafosmin myocardial SPECT.