Diagnostic Value of Transrectal Shear Wave Elastography for Prostate Cancer Detection in Peripheral Zone: Comparison with Magnetic Resonance Imaging

Objective: To assess the diagnostic value of transrectal shear wave elastography (SWE) for detecting prostate cancer (PCa) in peripheral zone and compare it with magnetic resonance imaging (MRI). Materials and Methods: Two hundred twenty-one patients suspected of PCa were enrolled, in which 172 patients of them underwent both SWE and MRI. Elastic value was measured in the area prepared for systematic biopsy and suspicious lesion detected on B-mode or SWE, histopathological result was compared for each biopsy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were derived by obtaining optimal threshold from receiver operating characteristic (ROC) curve. The correlation between the stiffness of PCa and Gleason scores, prognostic grades, and percentage of cancer in biopsy were evaluated by Spearman rank correlation. Multivariate logistic regression analysis was performed to determine predictors for diagnosing PCa. The diagnostic capacity of MRI and SWE for detecting PCa and clinically significant PCa in the peripheral zone were assessed by comparing area under curve of ROC curve. Results: A value of 42 kPa was used as the cutoff for differentiating benign from malignant prostatic tissue; the sensitivity, specificity, PPV, NPV, and accuracy were 78.97%, 90.67%, 71.30%, 93.66% and 88.03%, respectively. Rank correlation analysis revealed that the stiffness of PCa had a correlation with Gleason score, prognostic grade, and percentage of cancer in biopsy. On multivariate analysis, the age, free prostate-specific antigen (PSA), PSA density, SWE, and MRI were independent predictors for diagnosing PCa. There was no statistical difference for diagnosing PCa between SWE and MRI (p = 0.259). However, for clinically significant PCa, the diagnostic capacity of SWE was a little higher than MRI (p = 0.013). Conclusions: SWE may provide additional information for PCa detection, which could increase the positive rate of PCa in targeted biopsy and reduce unnecessary biopsy. SWE is compatible with MRI for detecting PCa in the peripheral zone.