Malignant microvasculature in abdominal tumors in children: detection with Doppler US.

Malignant tumors produce a network of microscopic, thin-walled vessels that invade the host and provide the blood supply essential for growth. This network, situated at the periphery of malignant tumors, gives rise to characteristic, high-velocity Doppler shifts at ultrasound (US) scanning and was sought in 54 children with abdominal masses. Characteristic high-frequency Doppler signals (greater than 2.5 kHz) were found in 27 of 35 malignant tumors. These signals disappeared during successful chemotherapy in three children with neuroblastoma in whom the signals had been documented initially. The signals were absent in three other children, who had undergone clinically successful therapy, and were present in two children with rapidly progressing tumors despite chemotherapy. In 14 children, none of the benign tumors showed high-frequency Doppler shifts. The search for malignant neovasculature with Doppler US scanning may provide insight into tumor behavior. The Doppler US examination, a noninvasive adjunct to routine US, may become useful at both the time of diagnosis of a mass and afterward to assess the effect of chemotherapy.