Contrast‐enhanced ultrasonography of the prostate: various imaging findings that indicate prostate cancer

Study Type – Diagnostic (non‐consecutive case series) Level of Evidence 3b What’s known on the subject? and What does the study add? Contrast‐enhanced ultrasonography (CEUS) can visualize some prostate cancer lesions. Findings suggestive of cancer have been defined as rapid contrast enhancement; increased contrast enhancement. CEUS could be useful for targeted biopsy in patients with a PSA level <10 ng/mL. The CEUS findings suggestive of prostate cancer are more varied than previously reported. Low‐echogenicity areas containing abnormal blood vessels were also found to represent cancer. OBJECTIVES To perform transrectal ultrasonography (TRUS) with an ultrasonography (US) contrast agent to visualize prostate cancer. To explore the possibility of targeted biopsy by studying the findings obtained by different cancerous tissue imaging modalities and evaluating needle biopsies from prostate cancer using contrast‐enhanced ultrasonography (CEUS). PATIENTS AND METHODS In all, 41 patients undergoing prostate biopsy and 13 patients undergoing prostatectomy received i.v. injection of the US contrast agent (Sonazoid®). We evaluated pre‐contrast and contrast‐enhanced US images, and then compared ultrasonographic images and the pathological findings. RESULTS Cancer was significantly more frequent at the sites of targeted biopsy where CEUS findings suggested cancer (36.3%) than at sites of systematic biopsy (17.7%, odds ratio = 2.7, P = 0.0026). In cases with prostate‐specific antigen (PSA) level <10 ng/mL, in particular, prostate cancer was detected at a significantly higher rate by targeted biopsy than by systematic biopsy (27.3 vs 9.5%, odds ratio = 3.4, P = 0.013). Pathological examination found 26 tumours in prostatectomy specimens. The diameters of the 10 CEUS‐identified tumours were significantly greater than those of the 16 lesions missed by US (mean 18.7 vs 5.9 mm). CEUS findings suggestive of cancer varied widely: strong contrast enhancement, rapid contrast enhancement, vessels with abnormal perfusion and low contrast enhancement. CONCLUSIONS CEUS could be useful for targeted biopsy in patients with a PSA level <10 ng/mL. The CEUS findings suggestive of prostate cancer are more varied than previously reported. Detailed examination of CEUS images and application of the data to prostate biopsy could lead to more efficient diagnosis.