title: Fitting methods for intravoxel incoherent motion imaging of prostate cancer on region of interest level: Repeatability and gleason score prediction.
abstract: To evaluate different fitting methods for intravoxel incoherent motion (IVIM) imaging of prostate cancer in the terms of repeatability and Gleason score prediction.
  
  
  
  Eighty-one patients with histologically confirmed prostate cancer underwent two repeated 3 Tesla diffusion-weighted imaging (DWI) examinations performed using 14 b-values in the range of 0-500 s/mm2and diffusion time of 19.004 ms. Mean signal intensities of regions-of-interest were fitted using five different fitting methods for IVIM as well as monoexponential, kurtosis, and stretched exponential models. The fitting methods and models were evaluated in the terms of fitting quality [Akaike information criteria (AIC)], repeatability, and Gleason score prediction. Tumors were classified into three groups (3 + 3, 3 + 4, > 3 + 4). Machine learning algorithms were used to evaluate the performance of the combined use of the parameters. Simulation studies were performed to evaluate robustness of the fitting methods against noise.
  
  
  
  Monoexponential model was preferred over IVIM based on AIC. The "pseudodiffusion" parameters demonstrated low repeatability and clinical value. Median "pseudodiffusion" fraction values were below 8.00%. Combined use of the parameters did not outperform the monoexponential model.
  
  
  
  Monoexponential model demonstrated the highest repeatability and clinical values in the regions-of-interest based analysis of prostate cancer DWI, b-values in the range of 0-500 s/mm2. Magn Reson Med 77:1249-1264, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Turku PET Centre, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.
authors.forename: Harri
authors.initials: H
authors.lastname: Merisaari
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.|Department of Information Technology, University of Turku, Turku, Finland.
authors.forename: Parisa
authors.initials: P
authors.lastname: Movahedi
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.|Department of Information Technology, University of Turku, Turku, Finland.
authors.forename: Ileana M
authors.initials: IM
authors.lastname: Perez
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.|Department of Information Technology, University of Turku, Turku, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Toivonen
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.
authors.forename: Marko
authors.initials: M
authors.lastname: Pesola
authors.affiliation: Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Taimen
authors.affiliation: Department of Urology, Turku University Hospital, Turku, Finland.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Boström
authors.affiliation: Department of Information Technology, University of Turku, Turku, Finland.
authors.forename: Tapio
authors.initials: T
authors.lastname: Pahikkala
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.
authors.forename: Aida
authors.initials: A
authors.lastname: Kiviniemi
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.
authors.forename: Hannu J
authors.initials: HJ
authors.lastname: Aronen
authors.affiliation: Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Turku PET Centre, University of Turku, Turku, Finland.|Department of Information Technology, University of Turku, Turku, Finland.
authors.forename: Ivan
authors.initials: I
authors.lastname: Jambor
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D000069550:Machine Learning; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
keywords: diffusion weighted imaging; intraclass correlation coefficient Gleason score; prostate cancer; repeatability