Echogenicity in transrectal ultrasound is determined by sound speed of prostate tissue components.
Typically, conventional transrectal ultrasound (TRUS) imaging of the cancer tissue is hypoechoic in echo texture. However, TRUS does not reliably distinguish between cancerous and non-cancerous tissue in the prostate. In the present study, sound speed of prostate needle biopsy specimens were measured by ultrasound speed microscope (USM) to construct a database for interpreting clinical TRUS images. Biopsy specimens were formalin-fixed and sectioned approximately 5 µm in thickness. They were mounted on glass slides without cover slips. The ultrasonic transducer with the central frequency of 120 MHz was mechanically scanned over the specimen to measure sound speed distribution. Echo intensity of TRUS images were qualitatively classified into three categories; hyperechoic, iso-echoic and hypoechoic areas. Sound speed was 1596.9 ± 28.2 m/s in hyperechoic, 1571.2 ± 35.8 m/s in iso-echoic and 1562.6 ± 35.1 m/s in hypoechoic area, respectively. However, echo intensity showed no significant relationship to malignancy of prostatic tissue. Echo intensity of TRUS is significantly affected with tissue components and USM findings would provide important information for interpretation of TRUS images.
Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579 Japan. ypoons1950@nifty.com
Hideki
H
Tanoue
Yoshihiro
Y
Hagiwara
Kazuto
K
Kobayashi
Yoshifumi
Y
Saijo
D000162:Acoustics; D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D001707:Biopsy, Needle; D006801:Humans; D008297:Male; D033401:Microscopy, Acoustic / Q000295:instrumentation / Q000379:methods; D011467:Prostate / Q000000981:diagnostic imaging* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012007:Rectum / Q000000981:diagnostic imaging; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods