Gastric half emptying time (T_½) for 4‐h gastric emptying scintigraphy simplifies reporting but reduces detection of gastroparesis

Abstract

Background Gastric emptying scintigraphy (GES) reports percent retention at 1, 2, and 4 h. Time to empty half the meal (T½) could simplify GE reporting. Aims To compare the performance of GES T½ to 1‐, 2‐, and 4‐h retention. Methods GES studies were reviewed; results determined according to retention at 1, 2, and 4 h. T½ was determined using 3 methods: (1) GES curve fitting using 0, 0.5, 1, 2, 3, and 4 h data; (2) linear interpolation using 0, 0.5, 1, 2, 3, and 4 h data; and (3) linear interpolation using only 0, 1, 2, and 4 h data. Results Of 495 patients, 265 had normal GE, 4 rapid GE (<30% retention at 1 h), and 226 delayed GE: 17 delayed only at 2 h (>60% ret); 94 delayed only at 4 h (>10% ret); and 115 delayed at both 2 h and 4 h. Strong correlations were seen between each T½ method and 1, 2, 3, and 4 h %‐empty values: curve‐fit T½ (r = −0.851, −0.942, −0.864, −0.744), linear T½ using all imaging times (r = −0.848, −0.972, −0.878, −0.763), and linear T½ using standard imaging times (r = −0.853, −0.974, −0.868, −0.760). The 132 min cutoff for delayed GE captures 99.1% to 100% of delayed GE at both 2 h and 4 h, 76.5% to 94.1% delayed at 2 h only, but only 36.7% to 39.4% delayed at 4 h only; 3.5 to 11.3% of patients with normal GE miscategorized as delayed. Conclusions GES T½ correlates more strongly with retention at 2 h than at 4 h. T½ alone may misclassify patients, particularly those with late‐phase (4 h only) delays, reducing its utility for diagnosing gastroparesis.

Proximal and distal intragastric meal distribution during gastric emptying scintigraphy: Relationships to symptoms of gastroparesis

“…Some previous research studies suggest the traditional 10% retention cutoff at 4 h may be too low and diagnose some individuals that have borderline normal GE as delayed GE. 13 For this reason, additional analyses were performed using subsets of patients with delayed GE: >20% retention at 4 h and > 35% TGR at 4 h (severely delayed GE). 1,13 A chi-squared test was used to determine whether a statistically uneven distribution of patients with severely delayed GE at 4 h >10% existed between increased proximal distribution and increased distal distribution.…”

“…13 For this reason, additional analyses were performed using subsets of patients with delayed GE: >20% retention at 4 h and > 35% TGR at 4 h (severely delayed GE). 1,13 A chi-squared test was used to determine whether a statistically uneven distribution of patients with severely delayed GE at 4 h >10% existed between increased proximal distribution and increased distal distribution. Student's t-tests compared symptoms of the severely delayed proximal distribution group to symptoms of the severely delayed distal distribution group.…”

Comparison of gastric emptying T‐half estimates using linear interpolation based on two, four, or nine data points

“…It is recommended 1 to measure gastric emptying (GE) with a radioisotopically labeled solid meal at least at the following time points: immediately after ingestion of the meal (time 0 h) and hourly for the next 4 h. Software programs such as MIM (MIM Software Inc., version 7.14) permit the estimation of GE T-half (GE T 1/2 ) from hourly measurements. Linear interpolation of GE T 1/2 using measurements at 0, 0.5, 1, 2, 3, and 4 h, or 0, 1, 2, and 4 h demonstrated good correlations with power exponential curve measurements at 0, 1, 2, and 4 h. 2 Our aim was to compare the estimation of GE T 1/2 using linear interpolation of 2 (points above the 50% emptying mark), 4 (emptying at 0, 1, 2, and 4 h), or 8/9 time point measurements (at 0, 15, 30, and 45 min, and 1, 1.5, 2, 3, and 4 h) of intragastric content using MIM Analysis.…”

A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

“…Delayed gastric emptying from an outflow obstruction (19), gastroparesis (20), or ileus (21) can exacerbate gastroesophageal reflux (GER) and esophageal dysmotility (20,22,23). Methods such as gastric emptying scintigraphy (24,25), ultrasound (26,27), or wireless motility capsules (28,29) can be employed to assess gastrointestinal motility. However, an extensive review of gastrointestinal motility and its assessment is beyond the scope of this manuscript.…”