title: Magnetic Resonance Imaging Underestimation of Prostate Cancer Geometry: Use of Patient Specific Molds to Correlate Images with Whole Mount Pathology.
abstract: We evaluated the accuracy of magnetic resonance imaging in determining the size and shape of localized prostate cancer.
  
  
  
  The subjects were 114 men who underwent multiparametric magnetic resonance imaging before radical prostatectomy with patient specific mold processing of the specimen from 2013 to 2015. T2-weighted images were used to contour the prostate capsule and cancer suspicious regions of interest. The contours were used to design and print 3-dimensional custom molds, which permitted alignment of excised prostates with magnetic resonance imaging scans. Tumors were reconstructed in 3 dimensions from digitized whole mount sections. Tumors were then matched with regions of interest and the relative geometries were compared.
  
  
  
  Of the 222 tumors evident on whole mount sections 118 had been identified on magnetic resonance imaging. For the 118 regions of interest mean volume was 0.8 cc and the longest 3-dimensional diameter was 17 mm. However, for matched pathological tumors, of which most were Gleason score 3 + 4 or greater, mean volume was 2.5 cc and the longest 3-dimensional diameter was 28 mm. The median tumor had a 13.5 mm maximal extent beyond the magnetic resonance imaging contour and 80% of cancer volume from matched tumors was outside region of interest boundaries. Size estimation was most accurate in the axial plane and least accurate along the base-apex axis.
  
  
  
  Magnetic resonance imaging consistently underestimates the size and extent of prostate tumors. Prostate cancer foci had an average diameter 11 mm longer and a volume 3 times greater than T2-weighted magnetic resonance imaging segmentations. These results may have important implications for the assessment and treatment of prostate cancer.
authors.affiliation: Department of Bioengineering, University of California Los Angeles, Los Angeles, California.
authors.forename: Alan
authors.initials: A
authors.lastname: Priester
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California; Department of Bioengineering, University of California Los Angeles, Los Angeles, California.
authors.forename: Shyam
authors.initials: S
authors.lastname: Natarajan
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California.
authors.forename: Pooria
authors.initials: P
authors.lastname: Khoshnoodi
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Margolis
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Reiter
authors.affiliation: Department of Pathology, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Jiaoti
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Bioengineering, University of California Los Angeles, Los Angeles, California.
authors.forename: Warren
authors.initials: W
authors.lastname: Grundfest
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California. Electronic address: lmarks@mednet.ucla.edu.
authors.forename: Leonard S
authors.initials: LS
authors.lastname: Marks
mesh_terms: D000368:Aged; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D011467:Prostate / Q000473:pathology*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies
keywords: computer-assisted; diagnostic errors; image processing; magnetic resonance imaging; pathology; prostatic neoplasms; surgical