Prospective evaluation of interobserver variability of the hydronephrosis index and the renal resistive index as sonographic examination methods for the evaluation of acute hydronephrosis

Abstract

Study Type – Diagnosis (reliability) Level of Evidence 2b What's known on the subject? and What does the study add? Conventional sonography is the standard imaging technique used in patients with acute renal colic. A decreasing hydronephrosis index (HI) is associated with an increase in obstructive uropathy. Obstructive uropathy leads to an increase in the renal resistive index (RRI). The present study shows that both the RRI and HI methods are easily practicable in patients presenting with stone‐related renal colic. The grade of hydronephrosis correlates positively with the HI but not with the RI. OBJECTIVE To confirm the reliability of assessements of the renal resistive index (RRI) and the hydronephrosis index (HI) comprising two sonographic techniques providing additional information in patients with acute renal colic. PATIENTS AND METHODS Sonographic measurement of hydronephrosis and assessment of common clinical criteria was performed in 22 consecutive patients presenting with unilateral stone‐related renal colic. RRI and HI were separately recorded by two investigators within a prospective study. Interobserver agreement and comparison of sonographic with computed tomography (CT) findings were assessed with the Cohen's kappa statistic (κ) for attributive ordinal characteristics and Spearman's rank correlation/rho (ρ) for attributive metric characteristics. RESULTS There was a significant correlation between HI and the sonographically‐evaluated grade of hydronephrosis, although not between RRI and the grade of hydronephrosis. For all procedures (RRI, HI, sonography and CT), significant differences between the symptomatic and the asymptomatic kidney were assessed. Interobserver agreement was excellent for the grade assessment of hydronephrosis by conventional sonography (κ= 0.82; P < 0.001), good to very good for HI (ρ= 0.60; P= 0.003) and acceptable to good for RRI (ρ= 0.49; P= 0.021). CONCLUSIONS The RRI and HI methods are both easily practicable as stageless examination methods in patients presenting with stone‐related renal colic, and both also reliably distinguish between obstruction and non‐obstruction. Exact thresholds for both methods must still be defined based on further successive studies. Additionally, changes of values under medical expulsive therapy and correlation with the functional status of the obstructed kidney remain to be examined.

Learning Curves in Emergency Ultrasound Education

“…10 Studies comparing cardiology fellows using portable US to cardiology faculty found comparable agreement to our study (j = 0.66 to 0.89). 11,12 Echocardiography studies involving internists or EPs demonstrate similar agreement (j = 0.79).…”

The effect of ureterorenoscopy and retrograde intrarenal surgery procedures on renovascular hemodynamics

“…Arcuate arterial blood flow measurements can be performed with CDUS to detect RI changes. It was shown that RI value was related to urinary obstruction; also intrarenal pressure and renal vascular resistance were related to filtration fraction and effective renal plasma flow [10][11]. Technical advances in the field of urinary stone surgery have improved the minimally invasive treatment option by reducing surgical trauma and increasing comfort [12].…”

Management of hydronephrosis after radical cystectomy and urinary diversion for bladder cancer: A single tertiary center experience

“…Hydronephrosis was evaluated using a five-point classification based on the criteria of the Society for Fetal Urology: grade 0 = no HDN; grade 1 = isolated distension of the renal pelvis; grade 2 = clear distension of the renal pelvis with the calyx neck recognizable; grade 3 = massive renal pelvic distension with ectasia of the neck of the calyx without reduction of the renal parenchyma; grade 4 = as grade 3 but with a reduction of the renal parenchyma. 16 Grade 2 or greater HDN was considered clinically significant HDN. The pathological stage was described according to the 2009 TNM classification of the Union for International Cancer Control.…”