Multiplanar Reformations in the Measurement of Renal Length on CT: Is It Plain Which Plane to Use?

• Published in: American journal of roentgenology (1976) Vol. 205; no. 4; pp. 797 - 801
• Main Authors: Lisanti, Christopher J, Oettel, David J, Reiter, Michael J, Schwope, Ryan B
• Format: Journal Article
• Language: English
• Published: United States 01.10.2015
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Contrast Media; Female; Humans; Iohexol; Iopamidol; Kidney - diagnostic imaging; Male; Middle Aged; Radiographic Image Interpretation, Computer-Assisted - methods; Reference Standards; Retrospective Studies; Tomography, X-Ray Computed - methods; renal CT; renal size; multiplanar reformations; renal length
• ISSN: 0361-803X; 1546-3141
• DOI: 10.2214/AJR.14.14248

The objective of this study was to determine the accuracy of renal measurement on CT in multiple imaging planes. In this study, three board-certified radiologists retrospectively measured 110 kidneys on CT in 55 consecutive patients. Five measurement methods were used: axial, coronal single image, coronal multiimage, sagittal single image, and sagittal multiimage. The coronal database was sent to a postprocessing workstation, and each radiologist performed a maximum renal measurement using a best off-axis plane that was our reference standard. An ANOVA test with repeated measures and posthoc Bonferroni corrected t tests were performed. The mean differences (± standard error) compared with the reference standard method were as follows: axial, 7.7 ± 0.7 mm; coronal single image, 13.1 ± 1.4 mm; coronal multiimage, 6.4 ± 0.8 mm; sagittal single image, 6.4 ± 0.6 mm; and sagittal multiimage, 2.8 ± 0.3 mm. The reference standard measurement was larger (p < 0.001), whereas the coronal single-image measurement (p ≤ 0.006) was smaller than all other methods. The sagittal multiimage (p ≤ 0.005) was statistically significantly different from all other methods. There were no statistically significant differences among the axial, coronal multiimage, and sagittal single-image methods (p ≥ 0.088). The single-image coronal method is the least accurate, with an error of approximately 13 mm. The axial, multiimage coronal, and single-image sagittal methods underestimate renal size by approximately 6-8 mm. Multiimage sagittal is the most accurate method for measuring kidneys with an error of approximately 3 mm.