Ehrenpreis E D, Zaitman D
Department of Gastroenterology, Cleveland Clinic Florida, Ft. Lauderdale, 33309, USA.
Am J Gastroenterol. 1996 Apr;91(4):674-9.
The solid phase gastric emptying scan (GES) is used to confirm the clinical impression of abnormal gastric emptying. There is variability in the interpretation of GES. Determination of initial lag phase of the GES and the emptying half-time (t1/2) is generally performed by curve inspection and thus may suffer from lack of objectivity. The purpose of this study was to develop a physiological model for interpretation of the GES using nonlinear curve fitting. This model resulted in computer-generated best fits for lag time and t1/2, which were analyzed in a group of patients with suspected gastroparesis.
All gastric emptying scans performed at our institution over a 3.5-yr period were studied. Raw data from these studies were analyzed by nonlinear curve fitting. Using the equation: If (x < xo, plateau, plateau * exp( - K * (x - xo))) data were best fit to a function describing a lag followed by a log linear decay. This model generated four parameters; lag, K, t1/2, and T50%. Forty patients with less than 50% emptying at 1 h (group II) were compared with 31 patients with normal emptying (group I).
The nonlinear model resulted in better curve fitting (higher r2) in 59 of 71 studies (81%) when compared with a monoexponential decay after a lag of 0 min. Mean lag for patients in group I was 8.5 +/- 1.2 min and was 25.9 +/- 3.1 min in group II (p < 0.0005). Mean t1/2 was 31.7 +/- 1.8 min in group I and 69.7 +/- 5.0 min in group II (p < 0.007). By adding 2 SD to lag and t1/2 in group I, normal values for these parameters were 21.9 and 52.2 min, respectively. Eleven patients in group II had a prolonged lag alone, 13 had a prolonged t1/2, and 13 had prolongation of both parameters.
A new physiological model for the interpretation of GES is presented. Individual patients with delayed gastric emptying may have increased lag times, a decreased rate of antral emptying, or both abnormalities.
固相胃排空扫描（GES）用于证实胃排空异常的临床印象。GES的解读存在差异。GES初始延迟期和排空半衰期（t1/2）的测定通常通过曲线检查进行，因此可能缺乏客观性。本研究的目的是使用非线性曲线拟合开发一种用于解读GES的生理模型。该模型生成了计算机生成的滞后时间和t1/2的最佳拟合值，并在一组疑似胃轻瘫患者中进行了分析。
对我们机构在3.5年期间进行的所有胃排空扫描进行研究。这些研究的原始数据通过非线性曲线拟合进行分析。使用方程：如果（x < xo，平台期，平台期 * exp( - K * (x - xo))），数据最适合描述一个延迟后接着对数线性衰减的函数。该模型生成了四个参数；延迟、K、t1/2和T50%。将40例1小时排空率低于50%的患者（第二组）与31例排空正常的患者（第一组）进行比较。
与0分钟延迟后的单指数衰减相比，在71项研究中的59项（81%）中，非线性模型产生了更好的曲线拟合（更高的r2）。第一组患者的平均延迟为8.5 +/- 1.2分钟，第二组为25.9 +/- 3.1分钟（p < 0.0005）。第一组的平均t1/2为31.7 +/- 1.8分钟，第二组为69.7 +/- 5.0分钟（p < 0.007）。通过在第一组的延迟和t1/2上加上2个标准差，这些参数的正常值分别为21.9分钟和52.2分钟。第二组中有11例患者仅延迟延长，13例t1/2延长，13例两个参数均延长。
提出了一种用于解读GES的新生理模型。胃排空延迟的个体患者可能延迟时间增加、胃窦排空率降低或两者均异常。
