Measuring the long diameter of the esophageal hiatus using axial CT images

The absence of normative anatomical benchmarks often leads to suboptimal crural closure during anti-reflux surgery. The hiatal long diameter represents a favorable anatomical parameter for measurement. This study therefore aimed to: 1) Validate a straightforward method for measuring it using axial CT images; 2) Establish normative thresholds for this diameter in an asymptomatic population; and 3) Evaluate its predictive value for key gastroesophageal reflux disease (GERD) related parameters.

We prospectively enrolled asymptomatic volunteers and patients who underwent GERD-related evaluation. The long diameter was measured using axial CT images. The inter- and intra-rater agreement were assessed using intraclass correlation efficient (ICC). GERD-related parameters were analyzed for associations with the long diameter of hiatus.

We included 200 asymptomatic volunteers and 203 patients underwent GERD evaluation. The mean hiatal long diameter and 95th percentile in asymptomatic volunteers were 2.4 cm and 3.0 cm respectively. The inter- (ICC = 0.745) and intra-rater (ICC > 0.90) agreement was moderate and excellent respectively for asymptomatic volunteers, while they were both excellent in patients underwent GERD-related tests (all ICC > 0.95). The hiatal long diameter is moderately predictive of GERD-related parameters, with the area under the curve being 0.703, 0.670, 0,693, and 0.680 for acid exposure time ≥ 4%, acid exposure time > 6%, Demeester score＞14.7, and LA-B or higher grade of esophagitis respectively.

The axial CT-based method for measuring the hiatal long diameter is straightforward and reliable, yielding normative values of 2.4 cm (mean) and 3.0 cm (95th percentile) in asymptomatic volunteers. Furthermore, this anatomical parameter moderately predicts GERD-related parameters.