Purpose or Case Report: To retrospectively review the imaging planes performed, the number pyloric layers visible and the location of measurements taken, in infants with suspected (HPS).
Methods & Materials: 103 pyloric ultrasound studies referred for suspected HPS were included. One pediatric radiologist with 20 years of experience and one medical doctor reviewed the studies. For each individual study, it was recorded whether longitudinal or transverse views were performed, the layers that could be visualised. A schematic was developed to categorise the interfaces of the anatomic layers of the pylorus visualised and position of the internal measurement cursor. Categories for the anterior wall were: a deep aspect of the muscularis propria; b superficial aspect of the muscularis mucosa; c deep aspect of the muscularis mucosa; d superficial aspect of the mucosa interfacing with the muscularis mucosa from a mucosal fold; e deep aspect of the muscularis mucosa from a mucosal fold. Categories for the posterior wall were: 1 deep aspect of the muscularis propria; 2 superficial aspect of the muscularis mucosa; 3 deep aspect of the muscularis mucosa; 4 deep aspect of the mucosa interfacing with muscularis mucosa from a mucosal fold; 5 deep aspect of the muscularis mucosa from a mucosal fold. Descriptive analysis was made for the categorical variables using STATA 15 software.
Results: A total of 100 studies (97 patients) were reviewed. Studies recorded longitudinal (99%) and transverse (69%) views of the pylorus. For the longitudinal view, measurements included muscle thickness in 95%, length in 97% and 0% for the pyloric diameter. For the transverse view, measurements included muscle thickness in 16% and the diameter in 3%. Pyloric layer interfaces (as defined above) were visible as follows: a in 64%, b in 64%, c in 66%, d in 30% and e in 26%. The internal (deep) reference point of cursor placement for measuring the muscle wall thickness in the longitudinal view was as follows: a in 46%, b in 27%, c in 30%, d in 1% and e in 2% of the studies.
Conclusions: New US technology provides more detailed anatomy and this affects measurements for muscle wall thickness. Considering that a millimetre can make a measurement fall into the abnormal category resulting in surgical treatment such differences in practice must be highlighted and recommendations need to be clarified. We believe that the largely abandoned diameter measurement, in the transverse or longitudinal views, may offer a solution as it is not defined by any internal layers.