Harri Merisaari1, Jussi Toivonen2, Marko Pesola3, Pekka Taimen4, Peter J Boström5, Tapio Pahikkala6, Hannu J Aronen7, Ivan Jambor8. 1. Department of Information Technology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland. 2. Department of Information Technology, University of Turku, Turku, Finland; Department of Diagnostic Radiology, University of Turku, Turku, Finland. 3. Department of Diagnostic Radiology, University of Turku, Turku, Finland. 4. Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland. 5. Department of Urology, Turku University Hospital, Turku, Finland. 6. Department of Information Technology, University of Turku, Turku, Finland. 7. Department of Diagnostic Radiology, University of Turku, Turku, Finland; Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland. 8. Department of Diagnostic Radiology, University of Turku, Turku, Finland. Electronic address: ivjamb@utu.fi.
Abstract
PURPOSE: To evaluate the effect of b-value distribution on the repeatability and Gleason score (GS) prediction of prostate cancer (PCa). METHODS: Fifty PCa patients underwent two repeated 3T diffusion-weighted imaging (DWI) examinations using 12 b values in the range from 0 to 2000s/mm(2) and diffusion time of 20.3ms. Mean signal intensities of regions of interest, placed in PCa using whole mount prostatectomy sections as the reference, were fitted using monoexponential, kurtosis, stretched exponential, and biexponential models. In total, 4083 different b-value combinations consisting of 2 to 12 b values were evaluated. Repeatability was assessed by intraclass correlation coefficient, ICC(3,1), and coefficient of repeatability (CoR). Areas under receiver operating characteristic curve (AUCs) for PCa characterization were estimated while the correlation of the fitted values with GS groups (3+3, 3+4, >3+4) was evaluated by using the Spearman correlation coefficient (ρ). RESULTS: The parameters of monoexponential, kurtosis, and stretched exponential models estimated using only 4-5, 5-7, 5-7 b values, respectively, had similar ICC(3,1), CoR, AUC, and ρ values as the parameters estimated using all 12 b values. Optimized b-value distributions demonstrated improved ICC(3,1) and CoR values but failed to improve AUC and ρ values. The parameters of biexponential model demonstrated the worst repeatability and diagnostic performance. CONCLUSION: B-value distribution influences mainly the repeatability of DWI-derived parameters rather than the diagnostic performance.
PURPOSE: To evaluate the effect of b-value distribution on the repeatability and Gleason score (GS) prediction of prostate cancer (PCa). METHODS: Fifty PCa patients underwent two repeated 3T diffusion-weighted imaging (DWI) examinations using 12 b values in the range from 0 to 2000s/mm(2) and diffusion time of 20.3ms. Mean signal intensities of regions of interest, placed in PCa using whole mount prostatectomy sections as the reference, were fitted using monoexponential, kurtosis, stretched exponential, and biexponential models. In total, 4083 different b-value combinations consisting of 2 to 12 b values were evaluated. Repeatability was assessed by intraclass correlation coefficient, ICC(3,1), and coefficient of repeatability (CoR). Areas under receiver operating characteristic curve (AUCs) for PCa characterization were estimated while the correlation of the fitted values with GS groups (3+3, 3+4, >3+4) was evaluated by using the Spearman correlation coefficient (ρ). RESULTS: The parameters of monoexponential, kurtosis, and stretched exponential models estimated using only 4-5, 5-7, 5-7 b values, respectively, had similar ICC(3,1), CoR, AUC, and ρ values as the parameters estimated using all 12 b values. Optimized b-value distributions demonstrated improved ICC(3,1) and CoR values but failed to improve AUC and ρ values. The parameters of biexponential model demonstrated the worst repeatability and diagnostic performance. CONCLUSION: B-value distribution influences mainly the repeatability of DWI-derived parameters rather than the diagnostic performance.
Authors: Ivan Jambor; Anna Kuisma; Esa Kähkönen; Jukka Kemppainen; Harri Merisaari; Olli Eskola; Jarmo Teuho; Ileana Montoya Perez; Marko Pesola; Hannu J Aronen; Peter J Boström; Pekka Taimen; Heikki Minn Journal: Eur J Nucl Med Mol Imaging Date: 2017-11-16 Impact factor: 9.236
Authors: Ileana Montoya Perez; Antti Airola; Peter J Boström; Ivan Jambor; Tapio Pahikkala Journal: Stat Methods Med Res Date: 2018-08-20 Impact factor: 3.021
Authors: Harri Merisaari; Pekka Taimen; Rakesh Shiradkar; Otto Ettala; Marko Pesola; Jani Saunavaara; Peter J Boström; Anant Madabhushi; Hannu J Aronen; Ivan Jambor Journal: Magn Reson Med Date: 2019-11-08 Impact factor: 4.668