The role of multi-parametric (mp)MRI in the diagnosis and treatment of prostate cancer has increased considerably. An alternative to visual inspection of mpMRI is the evaluation using histogram-based (first order statistics) parameters and textural features (second order statistics). The aims of the present work were to investigate the relationship between benign and malignant sub-volumes of the prostate and textures obtained from mpMR images. The performance of tumor prediction was investigated based on the combination of histogram-based and textural parameters. Subsequently, the relative importance of mpMR images was assessed and the benefit of additional imaging analyzed. Finally, sub-structures based on the PI-RADS classification were investigated as potential regions to automatically detect maligned lesions. Twenty-five patients who received mpMRI prior to radical prostatectomy were included in the study. The imaging protocol included T2, DWI, and DCE. Delineation of tumor regions was performed based on pathological information. First and second order statistics were derived from each structure and for all image modalities. The resulting data were processed with multivariate analysis, using PCA (principal component analysis) and OPLS-DA (orthogonal partial least squares discriminant analysis) for separation of malignant and healthy tissue. PCA showed a clear difference between tumor and healthy regions in the peripheral zone for all investigated images. The predictive ability of the OPLS-DA models increased for all image modalities when first and second order statistics were combined. The predictive value reached a plateau after adding ADC and T2, and did not increase further with the addition of other image information. The present study indicates a distinct difference in the signatures between malign and benign prostate tissue. This is an absolute prerequisite for automatic tumor segmentation, but only the first step in that direction. For the specific identified signature, DCE did not add complementary information to T2 and ADC maps.
Physics in medicine and biology. 2017 Aug 24 [Epub ahead of print]
Peter Kuess, Piotr Andrzejewski, David Nilsson, Petra Georg, Johannes Knoth, Martin Susani, Johan Trygg, Thomas H Helbich, Stephan H Polanec, Dietmar Georg, Tufve Nyholm
Radiation Oncology, Medical University of Vienna, AKH Vienna, Department of Radiooncology, Comprehensive Cancer Center Vienna Währingergürtel 18-20 1090 Wien - Austria, Vienna, 1090, AUSTRIA., Department of Radiation Oncology, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Vienna, AUSTRIA., Department of Chemistry, Umea Universitet, Umea, SWEDEN., EBG MedAustron GmbH, Wiener Neustadt, AUSTRIA., Radiation Oncology, Medical University of Vienna, Vienna, AUSTRIA., Clinical Institute of Pathology, Medical University of Vienna, Vienna, AUSTRIA., Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, AUSTRIA., Dept of Biomedical Imaging and Image-Guided Therapy, Medizinische Universitaet Wien, Vienna, AUSTRIA., Department of Radiation Oncology, Universitaet Wien, Wahringer Gurtel 18-20, 1090 Vienna, Vienna, AUSTRIA., Dept of Radiation Sciences - Radiation Physics, Umea University, S-901 87 Umea, Umeå, SWEDEN.