Effect of Proton Pump Inhibitors and H2 Antagonists on the Stomach Wall in 99mTc-Sestamibi Cardiac Imaging

Abstract

On the basis of previously unpublished observations, we hypothesized that prolonged use of proton pump inhibitors (PPIs) causes an increase in 99m Tc-sestamibi uptake in the stomach wall, manifested as curvilinear activity surrounding the photopenic fundus of the stomach cavity. We prospectively evaluated the frequency of stomach wall uptake in patients undergoing myocardial perfusion SPECT who were taking PPIs or H 2 antagonists. Methods: Patients (n 5 138) who were scheduled for single-day rest/stress 99m Tc-sestamibi SPECT were randomly selected. Poststress SPECT was performed 30 min after treadmill exercise or 45 min after dipyridamole infusion. The rest scan was obtained 45 min after tracer injection. All patients drank 473 mL of water 5-10 min after both the rest and the stress radiotracer injections. Patients were questioned regarding their use of PPIs and H 2 antagonists. The significant use of either was defined as more than 2 wk of continuous therapy before cardiac SPECT. Masked observers assessed poststress planar projection images in endless-loop cinematic format for the following 3 patterns: stomach cavity uptake, attributable to duodenogastric reflux of tracer; stomach wall uptake; and no stomach uptake. A 2-tailed x 2 test with Yates correction was used to calculate statistically significant associations among variables. Results: Only patients with observed patterns of stomach wall uptake (n 5 30) and no stomach wall uptake (n 5 91) were included. Patients with stomach cavity uptake (n 5 17) were excluded because the assessment of the adjacent stomach wall uptake was not possible. Of the patients included (n 5 121), 30 were men and 91 were women. Sixty-seven patients were older than 60 y; 26 patients were taking PPIs. Of the 95 patients not taking PPIs, 14 were taking H 2 antagonists. No patients were taking both medications. Stomach wall uptake was strongly associated with prolonged use of PPIs (x 2 5 51.9, P , 0.0001). No statistically significant association was noted among age, sex, or use of H 2 antagonists (P 5 NS). Conclusion: Prolonged PPI therapy, but not H 2 antagonist therapy, contributes to a significant increase in stomach wall activity, potentially resulting in Compton scatter or ramp filter artifacts affecting the inferior wall of the left ventricle. Stomach wall activity, unlike the stomach cavity activity, cannot be prevented by the ingestion of water before imaging. Therefore, it is important to elicit a history of prolonged PPI use to better anticipate the possibility of increased stomach wall activity, which can confound the image quality and interpretation.

The Effects of Mineral Water Drinking and Extra-abdominal Pressure in Elimination of Attenuation Artifacts on Myocardial Perfusion SPECT

“…Attenuation artifacts are a problem in the accurate evaluation of myocardial perfusion scintigraphy. The left anterior-lateral attenuation artifact depending on breast tissue in female and inferior walls attenuation artifact due to diaphragm in men can lead to false positive evaluation on myocardial perfusion SPECT [4][5][6][7][8][9][10][11][12][13][14][15].…”

The way to the heart is through the stomach; PPI’s, aspirin, and gastric radiotracer activity

“…Increased gastric wall radiotracer activity (GWA) on SPECT myocardial perfusion imaging studies (MPI), as opposed to the more common hepatobiliary activity and reflux of activity into the stomach, is not well studied and appears to be uncommon, but can interfere with image interpretation. [1][2][3][4][5][6] GWA can lead to false positive or false negative MPI results through overlap with the inferior left ventricle, amplified by the effect of Compton scatter and ramp filtering. The association of gastric wall activity and proton pump inhibitors has been described by several authors previously, although possible mechanisms have been untested, and selection bias has been considered possible.…”

“…The association of gastric wall activity and proton pump inhibitors has been described by several authors previously, although possible mechanisms have been untested, and selection bias has been considered possible. [1][2][3][4][5][6] While a great many patients referred for SPECT MPI testing take proton pump inhibitors, this interfering activity seems to occur in the minority of them, and it appears to be a clinical problem in fewer still. Nevertheless, the images of occasional patients might be affected severely.…”

Increased Gastric Activity on Myocardial Perfusion Imaging

“…The uptake mechanism of 99m Tc-tetrofosmin in gastric tissue is unknown. Some have suggested that 99m Tc-sestamibi localizes in the mitochondria of parietal cells and is excreted via the H 1 /K 1 /adenosine triphosphatase pump into the gastric lumen (5,6), and it has therefore been hypothesized that 99m Tc-tetrofosmin may localize in a similar manner (6).…”