title: Transrectal electrical impedance tomography of the prostate: spatially coregistered pathological findings for prostate cancer detection.
abstract: OBJECTIVE
  Prostate cancer ranks as one of the most common malignancies and currently represents the second leading cancer-specific cause of death in men. The current use of single modality transrectal ultrasound (TRUS) for biopsy guidance has a limited sensitivity and specificity for accurately identifying cancerous lesions within the prostate. This study introduces a novel prostate cancer imaging method that combines TRUS with electrical impedance tomography (EIT) and reports on initial clinical findings based on in vivo measurements.
  
  
  METHODS
  The ultrasound system provides anatomic information, which guides EIT image reconstruction. EIT reconstructions are correlated with semiquantitative pathological findings. Thin plate spline warping transformations are employed to overlay electrical impedance images and pathological maps describing the spatial distribution of prostate cancer, with the latter used as reference for data analysis. Clinical data were recorded from a total of 50 men prior to them undergoing radical prostatectomy for prostate cancer treatment. Student's t-tests were employed to statistically examine the electrical property difference between cancerous tissue and benign tissue as defined through histological assessment of the excised gland.
  
  
  RESULTS
  Example EIT reconstructions are presented along with a statistical analysis comparing EIT and pathology. An average transformation error of 1.67% is found when 381 spatially coregistered pathological images are compared with their target EIT reconstructed counterparts. At EIT signal frequencies of 0.4, 3.2, and 25.6 kHz, paired-testing demonstrated that the conductivity of cancerous regions is significantly greater than that of benign regions ( p < 0.0304).
  
  
  CONCLUSIONS
  These preliminary clinical findings suggest the potential benefits electrical impedance measurements might have for prostate cancer detection.
authors.affiliation: Thayer School of Engineering at Dartmouth, 14 Engineering Drive, Hanover, New Hampshire 03755, USA. yuqingwan@gmail.com
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Wan
authors.forename: Andrea
authors.initials: A
authors.lastname: Borsic
authors.forename: John
authors.initials: J
authors.lastname: Heaney
authors.forename: John
authors.initials: J
authors.lastname: Seigne
authors.forename: Alan
authors.initials: A
authors.lastname: Schned
authors.forename: Michael
authors.initials: M
authors.lastname: Baker
authors.forename: Shaun
authors.initials: S
authors.lastname: Wason
authors.forename: Alex
authors.initials: A
authors.lastname: Hartov
authors.forename: Ryan
authors.initials: R
authors.lastname: Halter
mesh_terms: D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D010992:Plethysmography, Impedance / Q000379:methods*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014054:Tomography / Q000379:methods*