Radiomic features on MRI enable risk categorization of prostate cancer patients on active surveillance: Preliminary findings

Radiomic analysis is defined as computationally extracting features from radiographic images for quantitatively characterizing disease patterns. There has been recent interest in examining the use of MRI for identifying prostate cancer (PCa) aggressiveness in patients on active surveillance (AS).

To evaluate the performance of MRI-based radiomic features in identifying the presence or absence of clinically significant PCa in AS patients.

Retrospective.

MRI/TRUS (transperineal grid ultrasound) fusion-guided biopsy was performed for 56 PCa patients on AS who had undergone prebiopsy.

3T, T2-weighted (T2w) and diffusion-weighted (DW) MRI.

A pathologist histopathologically defined the presence of clinically significant disease. A radiologist manually delineated lesions on T2w-MRs. Then three radiologists assessed MRIs using PIRADS v2.0 guidelines. Tumors were categorized into four groups: MRI-negative-biopsy-negative (Group 1, N = 15), MRI-positive-biopsy-positive (Group 2, N = 16), MRI-negative-biopsy-positive (Group 3, N = 10), and MRI-positive-biopsy-negative (Group 4, N = 15). In all, 308 radiomic features (First-order statistics, Gabor, Laws Energy, and Haralick) were extracted from within the annotated lesions on T2w images and apparent diffusion coefficient (ADC) maps. The top 10 features associated with clinically significant tumors were identified using minimum-redundancy-maximum-relevance and used to construct three machine-learning models that were independently evaluated for their ability to identify the presence and absence of clinically significant disease.

Wilcoxon rank-sum tests with P < 0.05 considered statistically significant.

Seven T2w-based (First-order Statistics, Haralick, Laws, and Gabor) and three ADC-based radiomic features (Laws, Gradient and Sobel) exhibited statistically significant differences (P < 0.001) between malignant and normal regions in the training groups. The three constructed models yielded overall accuracy improvement of 33, 60, 80% and 30, 40, 60% for patients in testing groups, when compared to PIRADS v2.0 alone.

Radiomic features could help in identifying the presence and absence of clinically significant disease in AS patients when PIRADS v2.0 assessment on MRI contradicted pathology findings of MRI-TRUS prostate biopsies.

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Journal of magnetic resonance imaging : JMRI. 2018 Feb 22 [Epub ahead of print]

Ahmad Algohary, Satish Viswanath, Rakesh Shiradkar, Soumya Ghose, Shivani Pahwa, Daniel Moses, Ivan Jambor, Ronald Shnier, Maret Böhm, Anne-Maree Haynes, Phillip Brenner, Warick Delprado, James Thompson, Marley Pulbrock, Andrei S Purysko, Sadhna Verma, Lee Ponsky, Phillip Stricker, Anant Madabhushi

Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA., Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA., Garvan Institute of Medical Research, Sydney, Australia., Department of Diagnostic Radiology, University of Turku, Turku, Finland., Department of Urology, St. Vincent's Hospital, Sydney, Australia., Douglass Hanly Moir Pathology, Sydney, Australia., Section of Abdominal Imaging and Nuclear Radiology Department, Imaging Institute, Cleveland Clinic, Cleveland, OH, USA., Department of Radiology, College of Medicine, University of Cincinnati, Cincinnati, OH, USA., Department of Urology, Case Western Reserve University, Cleveland, Ohio, USA.