Differentiation of prostate cancer from benign lesions using strain index of transrectal real-time tissue elastography.

Objective: This study was to assess the diagnostic value of strain index (SI) for transrectal real-time tissue elastography (TRTE) on differentiating malignant from benign lesions in the prostate peripheral zone.

Methods: 83 patients suspected of having prostate cancer (PCa) underwent transrectal ultrasonography (TRUS) and TRTE examinations. The lesions in the prostate peripheral zone detected by TRTE were set as the regions of interest (ROI) for strain ratio (SR) measurement (SRA). The moderate texture tissues without lesion were set as the reference ROI for SR measurement (SRB). Then, SI (SRB/SRA) of total lesions (ASI) and local lesion (PSI) were calculated, and the diagnostic values of ASI and PSI on differentiating benign from malignant lesions were assessed respectively.

Results: The range of PSI was 2.23-67.21 (29.97 ± 15.58) in malignant tumors and 0. 4-43.6 (7.79 ± 8.75) in benign lesions (AUC=0.90), while the range of ASI was 2.84-47.9 (8.38 ± 12.20) in malignant tumors and 0.4 -2.79 (5.85 ± 7.29) in benign lesions (AUC=0.62). There was significant difference of PSI values between the benign and malignant lesions (P<0.01). At the cutoff value of 17.44, PSI yielded the highest sensitivity (74.5%) and specificity (83.3%) for discriminating PCa from benign lesions. The capability of PSI in the diagnosis of PCa improved with the increase of Gleason scores.

Conclusion: PSI is one of the elasticity parameters obtained easily by TRTE, it can provide more information in the differentiation of prostate peripheral zone lesions.