title: Volume and landmark analysis: comparison of MRI measurements obtained with an endorectal coil and with a phased-array coil.
abstract: OBJECTIVE
  To compare prostate volumes and distances between anatomical landmarks on MRI images obtained with a phased-array coil (PAC) only and with a PAC and an endorectal coil (ERC).
  
  
  METHODS
  Informed consent was waived for this Health Insurance Portability and Accountability Act-compliant study. Fifty-nine men underwent PAC-MRI and ERC-MRI at 1.5 (n = 3) or 3 T (n = 56). On MRI images, two radiologists independently measured prostate volume and distances between the anterior rectal wall (ARW) and symphysis pubis at the level of the verumontanum; ARW and symphysis pubis at the level of the mid-symphysis pubis; and bladder neck and mid-symphysis pubis. Differences between measurements from PAC-MRI and ERC-MRI were assessed with the Wilcoxon RANK SUM test. Inter-reader agreement was assessed using the concordance correlation coefficient (CCC).
  
  
  RESULTS
  Differences in prostate volume between PAC-MRI and ERC-MRI [median: -0.75 mm(3) (p = 0.10) and median: -0.84 mm(3) (p = 0.06) for readers 1 and 2, respectively] were not significant. For readers 1 and 2, median differences between distances were as follows: -10.20 and -12.75 mm, respectively, ARW to symphysis pubis at the level of the verumontanum; -6.60 and -6.08 mm, respectively, ARW to symphysis pubis at the level of the mid-symphysis pubis; -3 and -3 mm respectively, bladder neck to mid-symphysis pubis. All differences in distance were significant for both readers (p ≤ 0.0005). Distances were larger on PAC-MRI (p ≤ 0.0005). Inter-reader agreement regarding prostate volume was almost perfect on PAC-MRI (CCC: 0.99; 95% CI: 0.98-1.00) and ERC-MRI (CCC: 0.99; 95% CI: 0.99-1.00); inter-reader agreement for distance measurements varied (CCCs: 0.54-0.86).
  
  
  CONCLUSIONS
  Measurements of distances between anatomical landmarks differed significantly between ERC-MRI and PAC-MRI, although prostate volume measurements did not.
authors.affiliation: Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA; Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. Electronic address: mazahery@mskcc.org.
authors.forename: Y
authors.initials: Y
authors.lastname: Mazaheri
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Afaq
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: S I
authors.initials: SI
authors.lastname: Jung
authors.affiliation: Department of Epidemiology & Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Goldman
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: H
authors.initials: H
authors.lastname: Aslan
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Zelefsky
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: O
authors.initials: O
authors.lastname: Akin
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: H
authors.initials: H
authors.lastname: Hricak
mesh_terms: D000368:Aged; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity