[Assessment of separate renal function with Doppler ultrasound measurement]

To evaluate measurement of separate renal function with Doppler ultrasound, renal blood flow velocity of interlobar and segmental arteries was examined with color Doppler echography.

Maximum blood flow velocity, minimum blood flow velocity, mean blood flow velocity, acceleration, resistive index, and pulsatility index were used as parameters of blood flow.

In 71 patients who had undergone unilateral nephrectomy (group 1), interlobar arterial minimal blood flow velocity correlated with creatinine clearance (r = 0.59) and 15 min. PSP value (r = 0.47). In 43 patients whose separate renal functions were different each other (group 2), the separate Ccr calculated from radioisotope renogram, correlated with interlobar arterial minimal blood flow velocity (r = 0.75). As far as unilateral renal blood flow velocity showed the same value, Ccr in group 1 was larger than in one kidney of group 2. This would be account for the fact that the volume of unilateral renal parenchyma which was measured by CT scan was larger in group 1 than in one kidney of group 2. In addition, the left to right ratio of Ccr was similar to that of interlobar arterial minimal blood flow velocity. Interlobar arterial minimal blood flow velocity has been decreasing along with aging in cases with normal kidneys.

Color Doppler echography is a useful technique for estimating separate renal function.