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- Title
COMPARISON BETWEEN GASTRIC SCINTIGRAPHY AND THE [<sup>13</sup>C]-ACETATE BREATH TEST WITH WAGNER–NELSON ANALYSIS IN HUMANS.
- Authors
Sanaka, Masaki; Urita, Yoshihisa; Sugimoto, Motonobu; Yamamoto, Takatsugu; Kuyama, Yasushi
- Abstract
1. The [13C]-acetate breath test (ABT) quantifies gastric emptying as the half [13CO2]-excretion time (T1/2b), but T1/2b differs from the scintigraphic half-emptying time (T1/2s). The aims of the present study were to accurately determine the half-emptying time by ABT with Wagner–Nelson analysis (T1/2WN), to compare T1/2WN with T1/2s and to validate the Wagner–Nelson strategy in ABT. 2. For a comparative study, eight volunteers simultaneously underwent ABT and scintigraphy. Anterior images were acquired and breath samples were collected every 15 min for 4.0 h after ingestion of a 200 kcal liquid meal labelled with 37 MBq [99mTc]-colloidal sulphur and 100 mg [13C]-acetate. For the validation experiment, another six volunteers underwent ABT, on two randomized occasions, using the 200 kcal liquid meal with 100 mg [13C]-acetate. On either of the two occasions, a gel-forming agent was stirred into the meal to intentionally delay gastric emptying by increasing meal viscosity. Breath samples were collected at regular 15 min intervals for 4 h post ingestion. 3. The Wagner–Nelson equation for ABT is F(t) = (Abreath(t) + C(t)/0.65)/Abreath(∞), where F(t) is a fractional dose of the [13C] label emptied, C(t) is the [13CO2] excretion (% dose/h), Abreath(t) is the area under the C(t) curve (% dose) and Abreath(∞) is the ultimate [13CO2] recovery in breath (% dose). The percentage gastric retention was estimated as 100 × (1 − F(t)). The time plots of scintigraphic activity and 100 × (1 − F(t)) were fitted to y(t) = 100 × e−K×t, K values were estimated mathematically for each plot by regression analysis and T1/2s and T1/2WN were calculated as (ln2)/K. The time versus pulmonary [13CO2] excretion plots were fitted to z(t) = m × k × β × e− kt(1 − e− k×t)β−1, where m, k and β are constants; T1/2b was calculated as –(ln(1 − 2−1/β)]/ k. 4. Values of T1/2WN were closer to T1/2s than T1/2b, although T1/2WN and T1/2b yielded significant under- and overestimation of T1/2s, respectively. The high viscosity meal significantly prolonged T1/2WN and T1/2b; T1/2WN could detect the delayed transit of the viscous meal more sensitively than T1/2b. 5. The Wagner–Nelson method improves the accuracy of the ABT.
- Subjects
BREATH tests; EXCRETION; GASTRIC acid; TOXICOLOGY of alcohol; REGRESSION analysis; ESTIMATION theory
- Publication
Clinical & Experimental Pharmacology & Physiology, 2006, Vol 33, Issue 12, p1239
- ISSN
0305-1870
- Publication type
Article
- DOI
10.1111/j.1440-1681.2006.04516.x