Direct comparison of solid-phase gastric emptying times assessed by means of a carbon isotope-labeled sodium acetate breath test and technetium Tc 99m albumin colloid radioscintigraphy in healthy cats

Objective—To directly compare solid-phase gastric emptying times assessed by means of a [13C]sodium acetate breath test ([13C]-SABT) and technetium Tc 99m albumin colloid radioscintigraphy (99mTc-ACR) in healthy cats. Animals—12 healthy cats. Procedure—After ingestion of a test meal containing 50 mg of [13C]sodium acetate and 250 MBq of 99mTc-albumin colloid, each cat underwent simultaneous [13C]-SABT and 99mTc-ACR on 2 consecutive days. Breath samples and scintigrams were acquired at 30, 60, 90, 120, 150, 180, 210, 240, 300, 360, 480, and 600 minutes after meal ingestion. Quartiles of gastric emptying (25%, 50%, and 75%) were calculated for breath test analysis by use of the area under the curve of the 13C:12C ratio. Quartiles of gastric emptying times were extrapolated from the scintigraphic findings by beans of nonlinear curve regression analysis. Results—Mean ± SD gastric half-emptying (50%) times obtained with [13C]-SABT and 99mTc-ACR, were 239 ± 28 minutes and 276 ± 59 minutes, respectively. A 2-way repeated-measures ANOVA revealed that mean gastric emptying times determined with [13C]-SABT and 99mTc-ACR differed significantly. For the stages of gastric emptying, Pearson correlation between the 2 methods was good at 25% (r = 0.655) and weak at 50% (r = 0.588) and 75% (r = 0.566)of gastric emptying. Conclusions and Clinical Relevance—Results indicated that the [13C]-SABT can be a valid alternative to 99mTc-ACR in healthy cats; it was easy to perform, was tolerated well by the cats, and had acceptable correlation to scintigraphic findings at gastric emptying of 25%, 50% and 75%. Studies in cats with delayed gastric emptying will be needed to verify the validity of the [13C]-SABT.