title: Contrast-enhanced transrectal ultrasonography: measurement of prostate cancer tumor size and correlation with radical prostatectomy specimens.
abstract: OBJECTIVE
  To determine the accuracy of contrast-enhanced transrectal ultrasonography for tumor size measurements of hypoechoic prostate cancer foci located in the peripheral zone.
  
  
  METHODS
  A total of 55 men scheduled for radical prostatectomy, with biopsy-proven cancer in hypoechoic foci located in the peripheral zone, were consecutively enrolled in the present prospective study. Each patient underwent grayscale ultrasound and contrast-enhanced transrectal ultrasonography of the prostate according to a standardized protocol. The maximum tumor diameter on grayscale imaging and contrast-enhanced transrectal ultrasonography was compared with that determined using histopathology.
  
  
  RESULTS
  A mean underestimation was documented to be approximately 3.9 mm and 0.6 mm for grayscale and contrast-enhanced transrectal ultrasonography imaging, respectively. Grayscale and contrast-enhanced transrectal ultrasonography imaging underestimated measurements by 76.67% (46 of 60) and 48.33% (29 of 60), whereas overestimated measurements were 20% (12 of 60) and 26.67% (16 of 60), respectively. A strong correlation was observed between contrast-enhanced transrectal ultrasonography and histopathological measurements (r = 0.91, P < 0.0001). A weak linear correlation was found between grayscale and histopathological measurements (r = 0.59, P < 0.0001). Bland-Altman analysis results were in complete accordance with correlation analysis results. For cases with maximum histopathological tumor diameters ≤10 mm and >10 mm, 40% (6 of 15) and 86.67% (39 of 45) were index tumors, respectively (P < 0.0001).
  
  
  CONCLUSIONS
  Contrast-enhanced transrectal ultrasonography is significantly more accurate than conventional grayscale imaging for measuring prostate tumor size, especially for tumors with a diameter >10 mm, and it might have a role in preoperative assessment of prostatic index tumor sizes.
authors.affiliation: Department of Ultrasonography, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Ting Yue
authors.initials: TY
authors.lastname: Qi
authors.forename: Ya Qing
authors.initials: YQ
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.forename: Yun Kai
authors.initials: YK
authors.lastname: Zhu
authors.forename: Xiao Hong
authors.initials: XH
authors.lastname: Yao
authors.forename: Jun
authors.initials: J
authors.lastname: Qi
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013459:Sulfur Hexafluoride; D014463:Ultrasonography
chemical_list: D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride
keywords: contrast-enhanced ultrasonography; grayscale; prostate cancer; radical prostatectomy