The indirect (distal) technique used sonographically to assess the intra-renal segmental areas including the right and left bipolar and middle pole regions bilaterally for the arcuates and the interlobar arteries. The resistive indices are normal and less than 0.70 bilaterally. Mean normal ranges in adults is <0.70 while in children at 4 years and below, >0.70 is considered normal¹.

Any presence of renal artery stenosis have been excluded directly as well (proximal approach) where the systolic velocities of the bilateral main renal arteries have been divided (as a ratio) with the systolic velocity of the proximal abdominal aorta in each side, to arrive at the renal aortic ratios (RARs) values bilaterally with the right being 0.70 while the left being 0.57. Normal range value is <3.5².

Occasionally in practice, overtly gaseous abdomen may result in poor visualization of the main renal arteries proximally at their osteal ends. In such situations, Systolic velocity values of the main renal arteries may still be sampled distally (preosteal ends) just before their entry into the renal parenchymas. In this case however, the velocities have been sampled at their osteal ends. The abdominal aorta systolic velocity may be sampled a few centimeters proximal to the superior mesenteric bifercation. Also to document are:

•  bilateral renal sizes.
• gross bilateral renal morphology (cortical- medullary differentiation and cortical thickness).
• bilateral renal color/power Doppler perfusion.
• exclusion of nephropathies such as; hydronephrosis, features of acute infective process, masses, calculi or chronic atrophy changes/disease.