Contrast-enhanced transrectal sonography in evaluation of prostate cancer: correlation with B-mode, power Doppler US and morphological findings

Recently, contrast-enhanced ultrasonography (CEUS) has been increasingly tested for diagnostic of prostate cancer (PC).

Aim: To evaluate the sensitivity of B-mode, power Doppler (PD) and CEUS in PC detection and to correlate it with morphological prostatectomy findings.

Material and methods: 50 patients with biopsy proven PC were examined transrectally using B-mode, PD and CEUS (pulse-inversion mode, low mechanical index) shortly before prostatectomy. Number, size and location of suspicious malignant foci were assessed. Measurements in transverse plane were done. Hypoechoic lesion, contour bulging and microcalciffications in B-mode US were considered as signs of malignancy. Asymmetric regions of hypervascularity in PD and CEUS were assessed as potentially malignant. Number, size and location of PC foci in pathological specimens were estimated. Correlative data analysis was performed using paired t-test; correlation coefficients were calculated.

Results: 76 cancer foci were found morphologically; of them 26– <1cm, 25–1–3cm; 25– >3cm in diameter. 31 were pure peripheral gland lesions, 19 pure transitional zone (TZ), 26 mixed peripheral and TZ tumours. Using B mode US 48%, PD 48%, CEUS 59% of overall PC foci were detected. Size of tumour was assesed correctly using B mode in 27%, PD 32%, CEUS 51%. In the subgroup of small size (<1cm) PC foci lesions were detected using B-mode in 5%, PD 5%, CEUS 8%. In 1–3cm subgroup 68% of PC foci were detected using B-mode, 60%, PD, 90% CEUS. In subgroup of lesions >3cm detection rates using B-mode, PD and CEUS were 76%, 84%, 80%, respectively. Using B-mode, PD and CEUS pure peripheral gland tumours were detected in 58%, 54%, 61%; pure TZ lesions in 5%, 5% and 26%; mixed peripheral and TZ tumours in 69%, 73%, 80%.

Conclusions: Contrast-enhanced transrectal sonography improves sonographic detection of prostate cancer and allows more precise assesement of tumour size. The best cancer detection rate is in the 1–3cm size group. Majority of lesions under 1cm in size as well as those located in tranzitional zone are sonographically undetectable. The detection rate of peripheral and mixed peripheral-tranzitional zone prostate cancers is higher when contrast-enhanced ultrasonography has been used.