RIs were measured in intrarenal arteries in 66 kidneys of 33 examinees without renal impairment and in 42 kidneys of 21 patients with unilateral urinary obstruction. The mean RI in normal kidneys was 0.593 +/- 0.040. Patients with unilateral obstruction had a mean RI of 0.709 +/- 0.039 in obstructed kidneys and a mean RI of 0.591 +/- 0.033 in contralateral nonobstructed kidneys. Statistically significant differences have been noticed in the groups of normal versus obstructed kidneys (P < 0.001) and of obstructed versus contralateral nonobstructed kidneys (P < 0.001). The mean dRI was 0.118 +/- 0.034 in patients with unilateral obstruction, and it was 0.014 +/- 0.012 in examinees without renal impairment (P < 0.001). A comparison of RI values between the right and left kidneys in a patient with unilateral obstruction proved more useful than using a 0.7 RI cutoff value in a Doppler sonographic diagnosis of unilateral obstruction.

Doppler indexes reflect increased RVR in diabetic nephropathy and correlate with laboratory and clinical parameters, but RI and PI measurements offer no advantages over these parameters to predict disease progress or in patient care.

Doppler indices do reflect the increased RVR in patients with ADPKD and they correlate with renal function disturbance, with the development of systemic arterial hypertension, and with ultrasonographic abnormality of the kidney in these subjects.

Renal changes in diabetic patients are detectable by conventional ultrasound only in very advanced stages of the disease. Pathologic resistive indices, however, may be detected in the earlier stages. Resistive indices correlate with serum creatinine levels and creatinine clearance rates. However, it remains unclear as to whether a diagnostic or prognostic benefit can be expected as compared to standard laboratory examinations.