Radiomics and machine learning of multisequence multiparametric prostate MRI: Towards improved non-invasive prostate cancer characterization
: Jussi Toivonen, Ileana Montoya Perez, Parisa Movahedi, Harri Merisaari, Marko Pesola, Pekka Taimen, Peter J. Boström, Jonne Pohjankukka, Aida Kiviniemi, Tapio Pahikkala, Hannu J. Aronen, Ivan Jambor
Publisher: Public Library of Science
: 2019
PLoS ONE
PLoS ONE
: 14
: 7
: 1932-6203
: 1932-6203
DOI: https://doi.org/10.1371/journal.pone.0217702
: https://research.utu.fi/converis/portal/detail/Publication/42073491
Purpose
To
 develop and validate a classifier system for prediction of prostate 
cancer (PCa) Gleason score (GS) using radiomics and texture features of T2-weighted imaging (T2w), diffusion weighted imaging (DWI) acquired using high b values, and T2-mapping (T2).
Methods
T2w, DWI (12 b values, 0–2000 s/mm2), and T2
 data sets of 62 patients with histologically confirmed PCa were 
acquired at 3T using surface array coils. The DWI data sets were 
post-processed using monoexponential and kurtosis models, while T2w
 was standardized to a common scale. Local statistics and 8 different 
radiomics/texture descriptors were utilized at different configurations 
to extract a total of 7105 unique per-tumor features. Regularized 
logistic regression with implicit feature selection and leave pair out 
cross validation was used to discriminate tumors with 3+3 vs >3+3 GS.
Results
In
 total, 100 PCa lesions were analysed, of those 20 and 80 had GS of 3+3 
and >3+3, respectively. The best model performance was obtained by 
selecting the top 1% features of T2w, ADCm and K with ROC AUC of 0.88 (95% CI of 0.82–0.95). Features from T2
 mapping provided little added value. The most useful texture features 
were based on the gray-level co-occurrence matrix, Gabor transform, and 
Zernike moments.
Conclusion
Texture feature analysis of DWI, post-processed using monoexponential and kurtosis models, and T2w
 demonstrated good classification performance for GS of PCa. In 
multisequence setting, the optimal radiomics based texture extraction 
methods and parameters differed between different image types.

