Doppler perfusion index and contrast-enhanced ultrasound in diagnosis of liver metastases from colorectal cancer

Objective To assess the value of the Doppler perfusion index(DPI) and contrast-enhanced ultrasound(CEUS) in the detection of liver metastases in patients with colorectal cancer(CRC).Methods DPI was measured in 15 patients with CRC metastases and 15 control subjects.Then 9 patients with 9 liver metastases underwent CEUS.The beginning time of enhancement,the time of peak enhancement and the beginning time of washout were recorded.Results DPI of patients with CRC liver metastases was significantly higher than that of control subjects(0.41±0.12 vs 0.20±0.06,P0.05).All 9 liver metastasis showed rapid washout of contrast agent during the portal venous phase,followed by complete washout during the parenchymal phase,and were differentiated as "fast wash-in and fast wash-out" contrast enhancement patter.Conlusion DPI is a sensitive technique in the detection of liver metastases from CRC.More liver metastasis would be detected by DPI combined with CEUS.