EP01.67: Increased depth is associated with significant reduced scan quality

This study aimed to evaluate the correlation between the depth and scan quality. In this single-centre retrospective cross-sectional study, 187 consecutive 18-weeks scans with 205 fetuses and 565 ultrasound images were included. Ultrasound examinations were performed by a single operator using a General Electric Medical Systems machine and an RM6C 2–7-MHz curved array transducer. The review of the consistent settings included a high-frequency harmonic mode, an acoustic power output of 96%, a high linear gain curve, a level of speckle resolution imaging of 3, and contrast resolution imaging CrossXBeam at a level of 2. To optimise the performance of ultrasound, the depth and sector width were minimised as much as possible, the focal zones were adjusted to the level of the target organ, and the magnification was maximal. Two independent and blinded sonographers scored the contrast and noise levels on a scale of 1 to 3 for two regions of interest, each corresponding to a small and a large anatomical structure, in the four-chamber, abdominal perimeter, and longitudinal spine views. Based on the two sonographers mean, the CNR was classified as poor (CNR < .75), fair (CNR: .75÷1.5), good (CNR: 1.5÷2.25) and excellent (CNR >2.25). Scans were deemed unsatisfactory if they had at least one poor CNR, and considered good if they had more than three CNRs rated as good or excellent, and acceptable otherwise. We found significant differences in depth in the poor, acceptable and excellent scan quality groups, with no differences in frame rate: 10.7, 10.1 and 9.6cm respectively, P = .004 for the abdominal perimeter view, 10.6, 10.5 and 9.5cm for the 4-chamber view, P = .008 and 10.4, 9.8 and 9.4, P = .009 for the longitudinal spine view. Increasing depth correlates with decreased image quality, highlighting the importance of selecting entry sites, such as the supraumbilical, suprapubic, and iliac fossa, which are known for their minimal abdominal adipose tissue content, thereby ensuring superior image quality.