Volume 74, Issue 4 pp. 1116-1124
Full Paper

Mathematical models for diffusion-weighted imaging of prostate cancer using b values up to 2000 s/mm2: Correlation with Gleason score and repeatability of region of interest analysis

Jussi Toivonen

Jussi Toivonen

Department of Diagnostic Radiology, University of Turku, Turku, Finland

Department of Information Technology, University of Turku, Turku, Finland

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Harri Merisaari

Harri Merisaari

Department of Information Technology, University of Turku, Turku, Finland

Turku PET Centre, University of Turku, Turku, Finland

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Marko Pesola

Marko Pesola

Department of Diagnostic Radiology, University of Turku, Turku, Finland

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Pekka Taimen

Pekka Taimen

Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland

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Peter J. Boström

Peter J. Boström

Department of Urology, Turku University Hospital, Turku, Finland

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Tapio Pahikkala

Tapio Pahikkala

Department of Information Technology, University of Turku, Turku, Finland

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Hannu J. Aronen

Hannu J. Aronen

Department of Diagnostic Radiology, University of Turku, Turku, Finland

Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland

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Ivan Jambor

Corresponding Author

Ivan Jambor

Department of Diagnostic Radiology, University of Turku, Turku, Finland

Correspondence to: Ivan Jambor, M.D., Department of Diagnostic Radiology, University of Turku, Kiinamyllynkatu 4–8, P.O. Box 52, FI-20521 Turku, Finland. E-mail: [email protected]Search for more papers by this author
First published: 20 October 2014
Citations: 51

Abstract

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/mm2. 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 ADCm, ADCk, K, and ADCs 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/mm2 was sufficient for PCa detection and characterization. Magn Reson Med 74:1116–1124, 2015. © 2014 Wiley Periodicals, Inc.

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