Detection of colorectal liver metastases: comparison of laparotomy, CT, US, and Doppler perfusion index and evaluation of postoperative follow-up results.

PURPOSE: To assess the value of the Doppler perfusion index (DPI = the ratio of hepatic arterial to total liver blood flow) as measured with duplex and color Doppler sonography (DCDS) in comparison with computed tomography (CT), conventional ultrasound (US), and laparotomy for the detection of liver metastases in patients with colorectal cancer.
MATERIALS AND METHODS: DCDS measurement of the DPI and CT, US, and laparotomy were performed in 161 consecutive colorectal cancer patients. Patients who underwent an apparently curative resection were followed up at 3-month intervals with US and at annual CT.
RESULTS: Fifty-six patients had histologically proved liver metastases at initial examination. Liver metastases were detected with DPI, CT, US, and laparotomy in 56, 45, 27, and 36 patients, respectively. After a 1-year follow-up, 23 patients had developed liver metastases, all of which were predicted on the basis of an abnormal DPI value.
CONCLUSION: Results suggest that DCDS measurement of the DPI is the most sensitive technique in detection of colorectal liver metastases. All studies should attempt to define normal liver on the basis of follow-up results rather than those of laparotomy.