title: Magnetic resonance imaging is a complementary method to stereological measurement of testicular volume.
abstract: OBJECTIVE
  The objective of our research was to determine the accuracy and precision of the Cavalieri principle with images obtained from magnetic resonance imaging (MRI) in estimation of the actual testicular volume in humans.
  
  
  METHODS
  We performed volume measurements of 42 testes from 21 patients scheduled for bilateral orchiectomy for prostate cancer. We performed volume estimation measurements with ultrasonography (US), Prader's orchidometer (PrOM), and Cavalieri principle MRI (we used views in axial sagittal and planes) before orchiectomy. We measured actual testes volume with the fluid displacement technique after orchiectomy. Differences and correlations between estimated and actual volumes were evaluated. For all patients, we compared right and left testicular volumes independently with these measurements.
  
  
  RESULTS
  Mean +/- SD actual testicular volume and estimated testicular volumes with US, PrOM, and Cavalieri principle using MRI axial and sagittal images were 15.3 +/- 3.3 and 17.7 +/- 3.0 cm(3), 20.0 +/- 3.5 cm(3), and 16.0 +/- 3.7 and 16.0 +/- 3.6 cm(3), respectively. Estimated and measured volumes were not different from each other. US and PrOM measured volumes were correlated with the actual volume. However, r-values with Pearson correlation test for estimated volumes measured with the Cavalieri principle with MRI were higher than US and PrOM (r-values were 0.934 and 0.961 vs 0.919 and 0.757, respectively).
  
  
  CONCLUSIONS
  The results of this study demonstrate that testicular volume measurements with the Cavalieri principle using images obtained from MRI may be considered a complementary method to traditional techniques to estimate the actual testicular volume.
authors.affiliation: Department of Urology, Dumlupinar University Faculty of Medicine, Kutahya, Turkey. skabay@yahoo.com
authors.forename: Sahin
authors.initials: S
authors.lastname: Kabay
authors.forename: Mehmet
authors.initials: M
authors.lastname: Yucel
authors.forename: Hilmi
authors.initials: H
authors.lastname: Ozden
authors.forename: Faik
authors.initials: F
authors.lastname: Yaylak
authors.forename: Orhan
authors.initials: O
authors.lastname: Ozbek
authors.forename: Yakup
authors.initials: Y
authors.lastname: Gumusalan
mesh_terms: D000368:Aged; D015331:Cohort Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009919:Orchiectomy / Q000379:methods; D011336:Probability; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013737:Testis / Q000473:pathology*; D047368:Tumor Burden