Reliability of Renal Length Measurements Made With Ultrasound Compared With Measurements From Helical CT Multiplanar Reformat Images

OBJECTIVE. The purpose of this article is to determine the reliability of sonographic renal length measurements compared with measurements obtained from helical CT multiplanar reformat images and compared with standard renal growth curves.MATERIALS AND METHODS. A retrospective review was performed of 76 subjects who underwent both renal ultrasound and abdominal CT within 2 weeks of one another. Renal lengths were measured using oblique coronal reformat images of helically acquired CT data by two observers on two occasions. Intraobserver and interobserver error for these measurements were calculated. Ultrasound renal length measurements were compared with CT measurements. Measurement variation was compared with standard renal growth curves.RESULTS. The mean (± SD) of the absolute value of interobserver error of CT measurements was 0.9 ± 0.8 mm. Compared with CT, individual ultrasound measurements underestimated renal length by 1.5 ± 5.6 mm on average, with a 95% CI of –12.5 to 9.5 mm. When the maximum of t...