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Mathematical models for diffusion‐weighted imaging of prostate cancer using b values up to 2000 s/mm 2 : Correlation with Gleason score and repeatability of region of interest analysis
Author(s) -
Toivonen Jussi,
Merisaari Harri,
Pesola Marko,
Taimen Pekka,
Boström Peter J.,
Pahikkala Tapio,
Aronen Hannu J.,
Jambor Ivan
Publication year - 2015
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25482
Subject(s) - repeatability , kurtosis , spearman's rank correlation coefficient , intraclass correlation , nuclear medicine , effective diffusion coefficient , receiver operating characteristic , prostate cancer , mathematics , correlation coefficient , correlation , diffusion mri , medicine , nuclear magnetic resonance , reproducibility , magnetic resonance imaging , statistics , radiology , cancer , physics , geometry
Purpose To evaluate four mathematical models for diffusion weighted imaging (DWI) of prostate cancer (PCa) in terms of PCa detection and characterization. Methods Fifty patients with histologically confirmed PCa underwent two repeated 3 Tesla DWI examinations using 12 equally distributed b values, the highest b value of 2000 s/mm 2 . Normalized mean signal intensities of regions‐of‐interest were fitted using monoexponential, kurtosis, stretched exponential, and biexponential models. Tumors were classified into low, intermediate, and high Gleason score groups. Areas under receiver operating characteristic curve (AUCs) were estimated to evaluate performance in PCa detection and Gleason score classifications. The fitted parameters were correlated with Gleason score groups by using the Spearman correlation coefficient (ρ). Coefficient of repeatability and intraclass correlation coefficient [specifically ICC(3,1)], were calculated to evaluate repeatability of the fitted parameters. Results The AUC and ρ values were similar between parameters of monoexponential, kurtosis, and stretched exponential (with the exception of the α parameter) models. The absolute ρ values for ADC m , ADC k , K, and ADC s were in the range from 0.31 to 0.53 ( P < 0.01). Parameters of the biexponential model demonstrated low repeatability. Conclusion In region‐of‐interest based analysis, the monoexponential model for DWI of PCa using b values up to 2000 s/mm 2 was sufficient for PCa detection and characterization. Magn Reson Med 74:1116–1124, 2015. © 2014 Wiley Periodicals, Inc.