title: Segmentation of individual renal cysts from MR images in patients with autosomal dominant polycystic kidney disease.
abstract: OBJECTIVE
  To evaluate the performance of a semi-automated method for the segmentation of individual renal cysts from magnetic resonance (MR) images in patients with autosomal dominant polycystic kidney disease (ADPKD).
  
  
  METHODS
  This semi-automated method was based on a morphologic watershed technique with shape-detection level set for segmentation of renal cysts from MR images. T2-weighted MR image sets of 40 kidneys were selected from 20 patients with mild to moderate renal cyst burden (kidney volume < 1500 ml) in the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP). The performance of the semi-automated method was assessed in terms of two reference metrics in each kidney: the total number of cysts measured by manual counting and the total volume of cysts measured with a region-based thresholding method. The proposed and reference measurements were compared using intraclass correlation coefficient (ICC) and Bland-Altman analysis.
  
  
  RESULTS
  Individual renal cysts were successfully segmented with the semi-automated method in all 20 cases. The total number of cysts in each kidney measured with the two methods correlated well (ICC, 0.99), with a very small relative bias (0.3% increase with the semi-automated method; limits of agreement, 15.2% reduction to 17.2% increase). The total volume of cysts measured using both methods also correlated well (ICC, 1.00), with a small relative bias of <10% (9.0% decrease in the semi-automated method; limits of agreement, 17.1% increase to 43.3% decrease).
  
  
  CONCLUSIONS
  This semi-automated method to segment individual renal cysts in ADPKD kidneys provides a quantitative indicator of severity in early and moderate stages of the disease.
authors.affiliation: Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. baek@upmc.edu
authors.forename: Kyungsoo
authors.initials: K
authors.lastname: Bae
authors.forename: Bumwoo
authors.initials: B
authors.lastname: Park
authors.forename: Hongliang
authors.initials: H
authors.lastname: Sun
authors.forename: Jinhong
authors.initials: J
authors.lastname: Wang
authors.forename: Cheng
authors.initials: C
authors.lastname: Tao
authors.forename: Arlene B
authors.initials: AB
authors.lastname: Chapman
authors.forename: Vicente E
authors.initials: VE
authors.lastname: Torres
authors.forename: Jared J
authors.initials: JJ
authors.lastname: Grantham
authors.forename: Michal
authors.initials: M
authors.lastname: Mrug
authors.forename: William M
authors.initials: WM
authors.lastname: Bennett
authors.forename: Michael F
authors.initials: MF
authors.lastname: Flessner
authors.forename: Doug P
authors.initials: DP
authors.lastname: Landsittel
authors.forename: Kyongtae T
authors.initials: KT
authors.lastname: Bae
mesh_terms: D000293:Adolescent; D000328:Adult; D057205:Automation, Laboratory; D018450:Disease Progression; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards; D007668:Kidney / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000592:standards; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D016891:Polycystic Kidney, Autosomal Dominant / Q000175:diagnosis* / Q000473:pathology; D011237:Predictive Value of Tests; D012016:Reference Values; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014481:United States; D055815:Young Adult