EP01.57: Enhancing ultrasound image quality for fetal kidney assessment: a prospective study on influential factors

Ultrasound has been the primary imaging method in obstetrics for decades. However, ultrasound has some major limitations due to various factors influencing image quality including maternal body composition and fetal position. These limitations become noticeable especially in low impedance structures such as the fetal kidneys. Currently, studies investigating the specific impact of different factors on image quality are lacking. Therefore, this study aims to investigate potential contributing factors in prenatal ultrasound. This was a prospective study analysing ultrasound images of fetal kidneys in axial and coronal plane. Ultrasound was performed at 20+0 to 24+6 gestational weeks. All images were audited by a fetal medicine expert and graded based on predefined quality criteria including resolution, kidney visualisation, kidney position and anatomical information. Achieved scores were correlated to gestational age, maternal BMI, scanning duration, fatty-layer-thickness and probe-to-organ-distance. 44 pregnant women were included and had detailed fetal kidney assessment. Included patients had a mean fatty-layer-thickness of 19.23mm and a mean probe-to-organ-distance of 36.45mm. Both measurements, fatty-layer-thickness and probe-to-organ-distance showed negative correlation with the image quality score. However, only fatty-layer-thickness reached significance (p = 0.032). Interestingly, maternal BMI did not significantly correlate with image quality (p = 0.462). Scanning duration and gestational age did not show significant correlation with image quality scores as well (p = 0.834; p = 0.320). Fatty-layer-thickness of patients significantly influences ultrasound image quality. However, BMI has limited impact on image quality indicating the importance of individual bodyfat distribution. We, therefore, conclude that individual body composition plays an important role in ultrasound imaging and should be considered in future ultrasound device development.