The value of ultrasonic scanning in the differentiation of acute post-transplant renal failure.

In 43 renal transplant patients studied by ultrasonography there were 32 episodes of acute rejection and 17 of acute tubular necrosis. The size of the kidney increased in all cases. However, in 75 per cent of the patients with acute rejection the central echoes of the renal sinus increased conspicuously, while in 77 per cent of those with acute tubular necrosis the echogenicity of the central sinusal complex decreased. These findings may be expressions of different pathological lesions at the renal sinus level in patients with acute rejection and acute tubular necrosis, which would modify the acoustic interphase. Therefore, we have found panniculitis, vasculitis, thrombosis and inflammatory cellular infiltration of the urinary collecting systems to be significant in patients with acute rejection but not in those with acute tubular necrosis. Ultrasonography can be an adjuvant instrument for the sometimes difficult differential diagnosis between acute tubular necrosis and acute rejection immediately after transplantation, and also for the diagnosis of acute rejection whenever it appears.