title: Evaluation of Frequency Domain Analysis of a Multiwavelength Photoacoustic Signal for Differentiating Malignant From Benign and Normal Prostates: Ex Vivo Study With Human Prostates.
abstract: OBJECTIVE
  The purpose of this study was to investigate the feasibility of differentiating malignant prostate from benign prostatic hyperplasia (BPH) and normal prostate tissue by performing frequency domain analysis of photoacoustic images acquired at 2 different wavelengths.
  
  
  METHODS
  We performed multiwavelength photoacoustic imaging on freshly excised human prostate specimens taken from a total of 30 patients undergoing prostatectomy for biopsy-confirmed prostate cancer. Histologic slides marked by a genitourinary pathologist were used as ground truth to define regions of interest (ROIs) in the photoacoustic images. Primarily, 3 different prostate tissue categories, namely malignant, BPH, and normal, were considered, while a fourth category named nonmalignant was formed by combining the ROIs corresponding to BPH and normal tissue together. We extracted 3 spectral parameters, namely slope, midband fit, and intercept, from power spectra of the radiofrequency photoacoustic signals corresponding to the 3 primary tissue categories.
  
  
  RESULTS
  We analyzed data from 53 ROIs selected from the photoacoustic images of 30 patients. According to the histopathologic analysis, 19 ROIs were malignant, 8 were BPH, and 26 were normal. All the 3 spectral parameters and C-scan grayscale photoacoustic image pixel values were found to be significantly different (P < .01) between malignant and nonmalignant prostate as well as malignant and normal prostate.
  
  
  CONCLUSIONS
  Preliminary results of our ex vivo human prostate study suggest that spectral parameters obtained by performing frequency domain analysis of photoacoustic signals can be used to differentiate between malignant and nonmalignant prostate.
authors: Rochester Institute of Technology, Rochester, New York USA saugata.sinha@ece.vnit.ac.in.
authors: Saugata
authors: S
authors: Sinha
authors: Rochester Institute of Technology, Rochester, New York USA.
authors: Navalgund A
authors: NA
authors: Rao
authors: University of Rochester, Rochester, New York USA.
authors: Bhargava K
authors: BK
authors: Chinni
authors: University of Rochester, Rochester, New York USA.
authors: Vikram S
authors: VS
authors: Dogra
mesh_terms: D003937:Diagnosis, Differential; D005240:Feasibility Studies; D006801:Humans; D008297:Male; D061088:Photoacoustic Techniques / Q000379:methods*; D011467:Prostate / Q000000981:diagnostic imaging / Q000601:surgery; D011468:Prostatectomy; D011470:Prostatic Hyperplasia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods*
keywords: frequency domain analysis; genitourinary ultrasound; multiwavelength; photoacoustic imaging; power spectrum; prostate cancer