THE USEFULNESS OF INTER-RENAL RESISTIVE INDEX DIFFERENCE IN DIAGNOSING ACUTE UNILATERAL URETERIC OBSTRUCTION DUE TO CALCULUS
Keywords:Color Doppler ultrasonography, , ureteral calculi,, hydronephrosis
Objectives: To evaluate the usefulness of inter-renal resistive index difference in diagnosis of acute unilateral ureteric obstruction due to calculus.
Study design: Case Control Study
Place and Duration of Study: Study was conducted in Department of Radiology, Combined Military Hospital Lahore, from August 2005 to February 2006.
Subjects and Methods: Sixty patients were divided in two groups of 30 each group I, 30 patients with unilateral acute ureteric colic due to ureteric calculus; and group II, 30 patients having no symptoms and with a normal ultrasound (as controls).
Interlobar arteries were examined by Colour Doppler ultrasound in upper, mid and lower renal pole with a two to five millimetre sample volume to calculate average resistive index. Inter-renal resistive index difference (∆RI) was then calculated.
Results: Statistically significant difference was observed in the inter-renal resistive index difference (∆RI) measurements with mean value in the case group of 0.09 compared to 0.021 in controls. Average intrarenal resistive index measurement in the obstructed kidney was .69 compared to 0.58-0.59 in the control group.
Conclusion: Measurement of inter-renal resistive index difference in patients with ureteric colic improves diagnostic accuracy of ultrasound in distinguishing between obstructive and non-obstructive dilatation.