Supervised and unsupervised methods for prostate cancer segmentation with multispectral MRI

作者：Ozer Sedat^*; Langer Deanna L; Liu Xin; Haider Masoom A; van der Kwast Theodorus H; Evans Andrew J; Yang Yongyi; Wernick Miles N; Yetik Imam S

来源：Medical Physics, 2010, 37(4): 1873-1883.

DOI：10.1118/1.3359459

• biomedical MRI
• cancer
• image segmentation
• Markov processes
• medical image processing
• support vector machines
• unsupervised learning

Methods: The authors use multispectral MRI data from 20 patients with biopsy-confirmed prostate cancer patients, and the image set consists of parameters derived from T2, DWI, and DCE-MRI. The authors utilize large margin classifiers for prostate cancer segmentation and compare them to an unsupervised method the authors have previously developed. The authors also develop thresholding schemes to tune support vector machines (SVMs) and their probabilistic counterparts, relevance vector machines (RVMs), for an improved performance with respect to a selected criterion. Moreover, the authors apply a thresholding method to make the unsupervised fuzzy Markov random fields method fully automatic.
Results: The authors have developed a supervised machine learning method that performs better than the previously developed unsupervised method and, additionally, have found that there is no significant difference between the SVM and RVM segmentation results. The results also show that the proposed methods for threshold selection can be used to tune the automated segmentation methods to optimize results for certain criteria such as accuracy or sensitivity. The test results of the automated algorithms indicate that using multispectral MRI improves prostate cancer segmentation performance when compared to single MR images, a result similar to the human reader studies that were performed before.
Conclusions: The automated methods presented here can help diagnose and detect prostate cancer, and improve segmentation results. For that purpose, multispectral MRI provides better information about cancer and normal regions in the prostate when compared to methods that use single MRI techniques; thus, the different MRI measurements provide complementary information in the automated methods. Moreover, the use of supervised algorithms in such automated methods remain a good alternative to the use of unsupervised algorithms.

• 出版日期2010-4
• 单位河北医科大学