Ultrasound in experimental and clinical renal vein thrombosis.

Static ultrasound was used to study five dogs with surgically produced unilateral renal vein thrombosis and eight patients with unilaterally occluded renal veins. In both clinical and experimental situations, renal vein thrombosis acutely led to decreased cortical echogenicity and nephromegaly. Between 10 days and three weeks, there was an increase in cortical echogenicity with preservation of corticomedullary definition; the late changes were decreased renal size, increased cortical echogenicity, and loss of corticomedullary definition. Histologic examination showed a significant deposition of collagen within the cortex and medulla of the dogs' kidneys during the late stage of the disease. Real time ultrasonography in two dogs and in one patient during acute renal vein thrombosis demonstrated absence of transmitted pulsations to the affected renal vein. Doppler ultrasound in one patient with proved renal vein thrombosis demonstrated absence of flow. The differential diagnosis and significance of the ultrasound findings are discussed.