title: Novel three-dimensional imaging volumetry in autosomal dominant polycystic kidney disease: comparison with 2D volumetry.
abstract: BACKGROUND
  Autosomal dominant polycystic kidney disease (ADPKD) volumetry is an important marker for evaluating the progression of disease. Three-dimensional (3D) volumetry is generally more timesaving than 2D volumetry, but its reliability and accuracy are uncertain.
  
  
  METHODS
  Small and large phantoms simulating polycystic kidneys and 20 patients with ADPKD underwent magnetic resonance imaging (MRI) volumetry. We evaluated the total kidney volume (TKV) and total cyst volume (TCV) using a novel 3D volumetry program (XelisTM) and compared 3D volumetry data with the conventional 2D method (the reference volume values). After upload and threshold setting, the other organs surrounding the kidney were removed by picking and sculpting. The novel method involves drawing of the kidney or cyst and automatic measurement of kidney volume and cyst volume in 3D images.
  
  
  RESULTS
  The 3D volume estimation of the small and large phantoms differed from the actual values by 6.9% and -8.2%, respectively, for TKV and by 2.1% and 1.4% for TCV. In ADPKD patients, the intra-reader reliability of 3D volumetry was 30 ± 180 mL (1.3 ± 10.3%) and 25 ± 113 mL (1.2 ± 9.4%), respectively, for TKV and TCV. Correlation between 3D volumetry and 2D volumetry of TKV and TCV resulted in a high correlation coefficient and a regression slope approaching 1.00 (r = 0.97 - 0.98). The mean of the volume percentage differences for 3D vs. 2D for TKV : TCV were -6.0 ± 8.9% : 2.0 ± 11.8% in large ADPKD and -16.1 ± 10.4% : 13.2 ± 21.9% in small ADPKD.
  
  
  CONCLUSIONS
  Our study showed that 3D volumetry has reliability and accuracy compared with 2D volumetry in ADPKD. 3D volumetry is more accurate for TCV and large ADPKD.
authors.affiliation: Department of Internal Medicine, Kangbuk Samsung Hospital, Department of Radiology, Sungkyunkwan University School of Medicine, Department of Internal Medicine, Eulji General Hospital, and Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dongsuk
authors.initials: D
authors.lastname: Shin
authors.forename: Kyu-Beck
authors.initials: KB
authors.lastname: Lee
authors.forename: Young Youl
authors.initials: YY
authors.lastname: Hyun
authors.forename: Young Rae
authors.initials: YR
authors.lastname: Lee
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Hwang
authors.forename: Hayne Cho
authors.initials: HC
authors.lastname: Park
authors.forename: Curie
authors.initials: C
authors.lastname: Ahn
mesh_terms: D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007677:Kidney Function Tests; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D016891:Polycystic Kidney, Autosomal Dominant / Q000473:pathology*; D015203:Reproducibility of Results