Liquid Gastric Emptying Study is often Abnormal after Normal Gastric Solid Emptying – Institutional Experience in a VA Hospital

Introduction: Traditionally, nuclear medicine literature states that solid radionuclide gastric emptying studies are more sensitive than liquid studies for detection of gastroparesis. However, newer data (Ziessman et al, 2009) challenge this paradigm. Following a small pilot study, and consultation with the Gastroenterology Service, our department added reflex liquid gastric emptying in patients with normal solid gastric emptying results.

Methods: The standard solid meal used was as per the Tougas Protocol using 1 mCi Tc99m sulfur colloid. The standard liquid study used 1 mCi Tc99m Sulfur Colloid in 500 ml water, followed by dynamic (anterior/posterior) imaging for 30 minutes. Our department uses a t_1/2 cutoff of 19 minutes for diagnosis of borderline abnormal liquid emptying and 22 minutes for abnormal liquid emptying. Between June and November 2021, out of 43 patients evaluated with solid gastric emptying, 11 had abnormal results. The remaining 32 patients were referred for reflex liquid gastric emptying.

Results: Two patients declined additional testing. Out of the 30 patients tested using liquid gastric emptying the following a normal solid gastric test emptying, 12 (40%) had normal results (t_1/2 < 19 minutes), 4 (13%) had borderline abnormal results (19 min ≤ t_1/2 ≤ 23min) and 14 (47%) had abnormal study findings (t_1/2 > 22 min). In the 30 patients with normal solid gastric emptying referred for liquid emptying, liquid emptying had a median t_1/2 of 21.5 minutes. These results are similar to the pilot data, where the corresponding rates were 48% normal t_1/2, 19% borderline abnormal t_1/2, and 33% abnormal t_1/2.

Conclusions: In our patient population, liquid gastric emptying is frequently abnormal in patients who have normal solid studies. Evaluation of liquid emptying should be routinely performed in addition to solid studies, to fully assess gastric motility in patients with clinical suspicion of gastroparesis.