Siegel J A, Urbain J L, Adler L P, Charkes N D, Maurer A H, Krevsky B, Knight L C, Fisher R S, Malmud L S
Department of Diagnostic Imaging, Temple University Hospital, Philadelphia, PA 19140.
Gut. 1988 Jan;29(1):85-9. doi: 10.1136/gut.29.1.85.
The existence of a lag phase during the gastric emptying of solid foods is controversial. It has been hypothesised that among other early events, the stomach requires a period of time to process solid food to particles small enough to be handled as a liquid. At present no standardised curve fitting techniques exist for the characterisation and quantification of the lag phase or the emptying rate of solids and liquids. We have evaluated the ability of a modified power exponential function to define the emptying parameters of two different solid meals. Dual labelled meals were administered to 24 normal volunteers. The subjects received meals consisting of either Tc-99m in vivo labelled chicken liver or Tc-99m-egg, which have different densities, and In-111-DTPA in water. The emptying curves were biphasic in nature. For solids, this represented an initial delay in emptying or lag phase followed by an equilibrium emptying phase characterised by a constant rate of emptying. The curves were analysed using a modified power exponential function of the form y(t) = 1-(1-e-kt)beta, where y(t) is the fractional meal retention at time t, k is the gastric emptying rate in min-1, and beta is the extrapolated y-intercept from the terminal portion of the curve. The length of the lag phase and half-emptying time increased with solid food density (31 +/- 8 min and 77.6 +/- 11.2 min for egg and 62 +/- 16 min and 94.1 +/- 14.2 min for chicken liver, respectively). After the lag phase, both solids had similar emptying rates, and these rates were identical to those of the liquids. In vitro experiments indicated that the egg meal disintegrated much more rapidly than the chicken liver under mechanical agitation in gastric juice, lending further support to the hypothesis that the initial lag in emptying of solid food is due to the processing of food into particles small enough to pass the pylorus. We conclude that the modified power exponential model permits characterisation of the biphasic nature of gastric emptying allowing for quantification of the lag phase and the rate of emptying for both solids and liquids.
固体食物胃排空过程中存在延迟期这一现象存在争议。据推测，在其他早期事件中，胃需要一段时间将固体食物处理成足够小的颗粒，以便能像液体一样被处理。目前，尚无用于表征和量化延迟期或固体及液体排空率的标准化曲线拟合技术。我们评估了一种修正的幂指数函数定义两种不同固体餐排空参数的能力。给24名正常志愿者给予双标记餐。受试者分别接受由体内用Tc - 99m标记的鸡肝或Tc - 99m - 蛋（二者密度不同）以及水中的In - 111 - DTPA组成的餐食。排空曲线本质上是双相的。对于固体食物，这表现为排空的初始延迟或延迟期，随后是平衡排空期，其特征为恒定的排空速率。使用形式为y(t) = 1 - (1 - e^(-kt))^β的修正幂指数函数分析曲线，其中y(t)是时间t时餐食的残留分数，k是每分钟的胃排空率，β是从曲线末端部分外推得到的y轴截距。延迟期的长度和半排空时间随固体食物密度增加而增加（蛋分别为31±8分钟和77.6±11.2分钟，鸡肝分别为62±16分钟和94.1±14.2分钟）。在延迟期之后，两种固体食物的排空速率相似，且这些速率与液体的排空速率相同。体外实验表明，在胃液机械搅拌下，蛋餐比鸡肝分解得快得多，这进一步支持了固体食物排空初始延迟是由于食物被处理成足够小的颗粒以通过幽门这一假说。我们得出结论，修正的幂指数模型能够表征胃排空的双相性质，从而对延迟期以及固体和液体的排空速率进行量化。
