Purpose: To compare areas of contrast material enhancement in the prostate at ultrasonography (US) with whole-mount radical prostatectomy specimens to determine if the use of contrast material improves the detection rate of prostate cancer.
Materials and methods: Transrectal US was performed in 12 subjects with cancer of the prostate prior to radical prostatectomy. Each gland was evaluated with conventional gray-scale and wide-band harmonic US at baseline and again during intravenous infusion of a microbubble contrast agent. Focal areas of contrast enhancement were identified prospectively in the transverse plane at the base, midgland, and apex of the prostate. US findings were then compared with whole-mount prostatectomy specimens. Baseline and contrast-enhanced findings were compared by using the Wilcoxon signed rank test.
Results: Thirty-one foci of prostate cancer were present at pathologic evaluation, with multiple foci of cancer in 11 of the 12 glands. Three of 10 inner-gland cancers and five of 21 outer-gland cancers were detected at baseline imaging. Diffuse inner-gland enhancement was identified in all subjects during contrast agent infusion. Contrast-enhanced imaging demonstrated an additional five cancer foci in the outer gland (P =.025), for an overall sensitivity of 42% (13 of 31 foci). Seven additional sites of focal contrast enhancement were identified. Five of these sites corresponded to foci of hyperplasia. Two sites were false-positive with no pathologic abnormality. Increased flow was not demonstrated posteriorly in the midline, even when a tumor was present.
Conclusion: Contrast-enhanced US of the prostate with Sonazoid can improve sensitivity for the detection of cancers in the outer gland, but it can also demonstrate focal enhancement in areas of benign hyperplasia.