Quantitative microbubble enhanced transrectal ultrasound as a tool for monitoring hormonal treatment of prostate carcinoma

Background. We quantified changes in Prostate carcinoma vascularity treated with anti-androgens using color Doppler and power transrectal ultrasound in combination with microbubble contrast agent Levovist(R). Methods. Thirty-six men with prostate carcinoma were studied at baseline and at intervals during treatment. At each attendance, Levovist(R) (10 ml, 300 mg/ml) was given as an iv bolus. Using quantitative analysis, we calculated the pre-enhancement scores, arrival time, time to peak, peak value, and area under the time-enhancement curve (AUC). These were compared to pre-treatment values and serial PSA measurements. Results. The pre-enhancement, peak value, and AUC each showed a marked response with reductions within one week. The average AUC declined to 68%+/-9% (mean+/-standard error) by week 1, 56%+/-9% by week 3, and 20%+/-4% by week 6. A strong correlation with changes in the mean PSA (r=0.95, P<0.001) was also measured. In four patients, Doppler indices did not fall with PSA: two patients with the most marked discrepancy relapsed at 6 months. Conclusion. The vascular enhancement declined with therapy, similar to PSA. Microbubble enhanced ultrasound can show early response to treatment.