Reproducibility of the Measurement of the Right Portal Vein Diameter at the 30–33-Week Scan

Objective : This study aimed to evaluate the intra- and inter-operator reproducibility of right portal vein (RPV) assessment during routine third trimester ultrasound in small- and appropriate-for-age fetuses. Materials and methods: This prospective cross-sectional study was conducted at a single center. The study population comprised 67 pregnancies, including 28 (42%) small-for-gestational-age (SGA) fetuses and 39 (58%) appropriate-for-gestational-age (AGA) fetuses. Two blinded sonographers (expert and non-expert) independently evaluated the right portal vein as normal or collapsed via grid evaluation and then repeated two measurements, generating two different appropriate images. Results : Intra-observer agreements of RPV diameter measurement for the two operators were excellent, with interclass correlation coefficients .98 (95% CI, .97–.99) and .98 (95% CI, .95–.99) in the SGA group and .98 (95% CI, .97–.99) and .98 (95% CI, .96–.99) in the AGA group, respectively; P < .0001. Inter-observer agreement was good in the SGA group (.71 < ICC .79; P < .0001) and excellent in the AGA group (.86 < ICC .87; P < .0001). Inter-observer agreement on the criteria for collapsed RPV was substantial to perfect in both the SGA (.62 < K < .92) and AGA group (.61 < K < .94). Conclusions : We demonstrated excellent intra- and inter-observer reproducibility of RPV diameter measurement. Large prospective studies on screening for growth-restricted fetuses could be conducted without concern about the reproducibility of the right portal vein diameter measurement.