Background/aims: To assess the value of the Doppler perfusion index (DPI) and contrast agent for the detection of liver metastases in patients with colorectal cancer.
Methodology: DPI was measured in 18 patients with colorectal cancer liver metastases and 18 control subjects. Sixteen patients were underwent contrast-enhanced ultrasonography (CEUS).
Results: patients with liver metastases had significantly greater DPI than control group (0.39 +/- 0.10 vs. 0.19 +/- 0.07, p < 0.05). Sixteen liver metastasis lesions underwent a rapid wash-out of contrast agent during the portal venous phase followed by a complete wash-out of SonoVue during the sinusoidal phase and were differentiated as "fast-in and fast-out" contrast enhancement patter. Another 3 lesions which were not found by baseline ultrasonography were detected to be enhancement defects at sinusoidal phases by CEUS.
Conclusions: DPI is a sensitive index in detection of colorectal liver metastases; if used combined with contrast agent, much more occult liver metastasis would be detected by ultrasonography.