Variability of three-dimensional high-frequency ultrasound measurements of small tumor volumes

The intraobserver variability in volume measurements of small (less than 2 mm³) tumors using three-dimensional high-frequency ultrasound has been assessed in two murine liver metastasis models. The maximum coefficient of variation was 10.7% for five B16F1 murine melanoma liver metastases and 18.2% for seven HT-29 human colon carcinoma liver metastases. The intraobserver variability was small compared to the tumor growth measured at two-day intervals in the rapidly progressing B16F1 model. However, the maximum measurement variability was comparable to the four-day growth rate in the slowly progressing HT-29 model.