Ultrasound imaging of flow patterns in liver metastases from colorectal cancer

The ability of colour Doppler, power Doppler and echo-enhanced Doppler imaging to detect the blood flow in liver metastases from colorectal cancer was investigated. An evaluation was then made to determine whether the flow pattern could be used as an indication of disease elsewhere.

Forty-two patients with hepatic metastases from colorectal cancer were examined, 8 of whom had local recurrence of their colorectal cancer. Seventy-seven liver metastases were evaluated with colour Doppler and power Doppler, and the presence or absence of a Doppler signal in the halo or centre was noted. Forty-three of these metastases were further examined after contrast media echo-enhancement.

Signals from the peripheral halo were detected by colour Doppler imaging in 34% of the metastases, and in 77% by power Doppler (P < 0.001). Use of contrast media enhanced the power Doppler detection rate to 98% (P < 0.005). Central signals were detected by power Doppler in 12 patients, 8 (66%) of whom also had local recurrence. Thirty patients had neither local recurrence nor central signals, as detected by power Doppler (P < 0.001).

The results indicate that the halo in liver metastases corresponds to the vascular flow. There seems to be an association between metastases showing a central power Doppler flow and local tumour recurrence.