Mean resistive index as a prognostic tool for hydronephrosis in patients with acute renal colic: a study in a tertiary care

Abstract

Background: Uretolithiasis is one of the most common cause of urinary tract obstruction which leads to the admission into the emergency ward. The detection of urolithiasis or acute renal colic is by the radiography, conventional ultrasonography (US) and intravenous urography (IVU). A colour Doppler USG measures this change as a resistive index (RI) of the arcuate arteries at the corticomedullary junction or the interlobar arteries.Methods: 84 patients between the ages 15-50 years, who were admitted to the Emergency department of our hospital with unilateral renal colic were included into our study. Detailed demographic data was collected from all the patients and they were all subjected to a thorough physical and clinical examination. Bladder ultrasound was taken along with color Doppler for all the patients at the time of admission for every 6 hours. Thus, an increased RI index signifies an obstruction without a dilatation.Results: Left flank pain was slightly more than the right flank pain, although this was not found to be significant. Most of the patients were presented with vomiting or nausea and dysuria was seen in 48 patients. there were 41 cases of hydronephrosis in total and all of them were positive for mean RI. The specificity with the mean resistive index with color Doppler was 90%, while the sensitivity was 100%. Around 95% of the prediction was accurate with mean resistive index, with more than 90% efficiency.Conclusions: The mean resistive index is a very good tool for the diagnosis of hydronephrosis, with a very high level of specificity and sensitivity.

Diagnostic Accuracy of Renal Artery Resistive Index in Diagnosing Obstructive Uropathy

“…Our results, mirroring prior research, underscored the diagnostic value of RI, especially at a cutoff value exceeding 0.7, for confirming obstructive uropathy in a significant fraction of cases based on RI and CT scan findings (23,24). Further substantiation comes from studies examining the mean resistive index in patients suffering from acute renal colic, predicting hydronephrosis with notable specificity and accuracy (18,25). Our investigation's sensitivity and specificity metrics for Doppler ultrasound in diagnosing obstructive uropathy-81.13% and 85.81%, respectively-corroborate these prior findings, employing CT scans as the gold standard.…”

“…Ultrasonography remains the primary diagnostic tool for the initial assessment of patients with acute abdomen symptoms, especially in pediatric cases, highlighting its critical role in diagnosing acute renal coli, a prevalent pathology within the acute abdomen spectrum. Interestingly, studies indicate that up to 30% of patients with acute renal coli exhibit no observable dilation, underscoring that the dilatation observed in the collecting system does not always correlate with obstructions in the downstream urinary tract, and can occasionally be confused with pseudo-aneurysms of the intra-renal arteries (17)(18)(19). In this context, Color Doppler Ultrasound (CDUS) becomes an essential diagnostic tool for vascular anomalies, with the measurement of the renal artery resistive index (RI) via Doppler ultrasonography playing a crucial role in delineating changes in renal blood flow.…”

Doppler Comparison of Resistive Index of Renal Artery in Obstructive and Non Obstructive Kidneys

“…Around 95% of prediction was accurate with increased resistive index. They concluded that mean a resistive index is a good tool for the diagnosis of hydronephrosis (Ravindernath & Reddy 2017). There is a significant difference in RI (resistive index) of the renal artery in obstructive and non-obstructive kidneys.…”