Shear wave elastography for detection of prostate cancer: a preliminary study.
OBJECTIVE
To assess the diagnostic value of shear wave elastography (SWE) for prostate cancer detection.


METHODS
In this retrospective study, 87 patients with the suspicion of prostate cancer (prostate-specific antigen > 4 ng/mL and abnormal digital rectal examination) underwent a protocol-based systematic 12-core biopsy followed by targeted biopsy at hypoechoic areas on grey-scale ultrasound. Prior to biopsy, SWE was performed by placing two circular 5 mm-sized regions of interest (ROIs) along the estimated biopsy tract in each sector and one ROI for hypoechoic lesions. SWE parameters, S (mean stiffness) and R (mean stiffness ratio), were calculated and compared regarding different histopathologic tissues and their accuracy for diagnosing prostate cancer was analyzed. SWE parameters were correlated with Gleason score and were compared between indolent (< 8) and aggressive (≥ 8) tissues in prostate cancer patients.


RESULTS
Prostate cancer was detected in 7.5% of 1058 cores in 29.9% of 87 patients. Seven (43.8%) of 16 hypoechoic lesions were confirmed as prostate cancer. SWE parameters were significantly different among the histopathologic entities (p < 0.001). Prostate cancer was stiffer than benign tissues (p ≤ 0.003). Sensitivity, specificity and receiver operating characteristic curve area for diagnosing cancer were 43%, 80.8%, and 0.599, respectively, for a cutoff of S > 43.9 kPa and 60.8%, 66.4%, and 0.653, respectively, for R > 3. Both, S and R showed a significant correlation with Gleason score (r ≥ 0.296, p ≤ 0.008) and were significantly different between indolent and aggressive prostate cancer (p ≤ 0.006).


CONCLUSIONS
Shear wave elastographic parameters are significantly different between prostate cancer and benign prostate tissue and correlate with Gleason score.
Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea.
Sungmin
S
Woo
Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea.
Sang Youn
SY
Kim
Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine and Kidney Research Institute, Seoul National University Medical Research Center, Seoul 110-744, Korea.
Jeong Yeon
JY
Cho
Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea. ; Institute of Radiation Medicine and Kidney Research Institute, Seoul National University Medical Research Center, Seoul 110-744, Korea.
Seung Hyup
SH
Kim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000379:methods
D017430:Prostate-Specific Antigen
Gleason score; Prostate cancer; Shear wave elastography; Ultrasonography; Young modulus