The Renal Resistive Index in Allografts: Is Sonographic Assessment Sufficiently Reproducible in a Routine Clinical Setting? – Reproducibility of the Renal Resistive Index

• Published in: RöFo : Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebende Verfahren Vol. 192; no. 6; pp. 561 - 566
• Main Authors: Theilig, Dorothea Cornelia, Münzfeld, Hanna, Auer, Timo Alexander, Feldhaus, Felix, Krüger, Anne, Dürr, Michael, Geisel, Dominik
• Format: Journal Article
• Language: English
• Published: Stuttgart · New York Georg Thieme Verlag KG 01.06.2020
• Subjects: Adult; Biomarkers; Carotid Intima-Media Thickness; Correlation of Data; Creatinine - blood; Equipment Design; Female; Glomerular Filtration Rate - physiology; Humans; Kidney Glomerulus - blood supply; Kidney Transplantation; Male; Middle Aged; Observer Variation; Prospective Studies; Reproducibility of Results; Spleen - blood supply; Ultrasonography, Doppler - instrumentation; Urogenital Tract; Vascular Resistance - physiology; renal resistive index; reproduciblity; Doppler sonography
• ISSN: 1438-9029; 1438-9010
• DOI: 10.1055/a-1086-5191

Abstract Purpose  To assess the reproducibility of the renal resistive index (RRI) in a routine clinical setting. Materials and Methods  22 patients with a kidney allograft and 19 physicians participated in our prospective study. Within 2 hours each patient was examined by 5 different physicians using 2 out of 3 different, randomly allocated ultrasound machines. Each investigator determined the hilar and parenchymal RRI of the allograft. The reproducibility and reproducibility limit of the RRI were assessed as well as Cronbach’s alpha and the intraclass correlation coefficient (ICC). The deviation of the RRI from the mean RRI over the 5 measurements was used as an indicator of reproducibility. The impact of the ultrasound machine, examiner’s level of experience, and kidney function impairment (GFR < 45 ml/min) was assessed with the Kruskal-Wallis test. The bivariate linear correlation of the minimal transplant distance from the body surface with the variance of the parenchymal RRI was analyzed. Results  A reproducibility of 0.045 with a reproducibility limit of 0.124 was found for the parenchymal RRI. The ICC between RRIs was good with 0.852 for the parenchymal RRI and 0.868 for the hilar RRI. The type of ultrasound machine used was found to have a significant impact on the deviation of the parenchymal RRI (Kruskal-Wallis-Test, p = 0.003). Variance in serial parenchymal RRI measurements correlated significantly with the depth of the kidney transplant (p = 0.001). Conclusion  While the RRI is generally sufficiently reproducible, the type of ultrasound machine used and the depth of the kidney transplant within the recipient’s body have a significant impact on reproducibility. Key Points:   The renal resistive index (RRI) in allografts is reproducible. The type of ultrasound machine has an impact on the measured RRI. RRI reproducibility decreases with the depth of the renal allograft in the recipient. Citation Format Theilig DC, Münzfeld H, Auer TA et al. The Renal Resistive Index in Allografts: Is Sonographic Assessment Sufficiently Reproducible in a Routine Clinical Setting?. Fortschr Röntgenstr 2020; 192: 561 – 566