ABSTRACT
This paper deals with the adaptation, the tuning and the evaluation of the multiple organs Optimal Surface Detection (OSD) algorithm for the T2 MRI prostate segmentation. This algorithm is initialized by first surface approximations of the prostate (obtained after a model adjustment), the bladder (obtained automatically) and the rectum (interactive geometrical model). These three organs are then segmented together in a multiple organs OSD scheme which proposes a competition between the gray level characteristics and some topological and anatomical information of these three organs. This method has been evaluated on the MICCAI Grand Challenge: Prostate MR Image Segmentation (PROMISE) 2012 training dataset.
Subject(s)
Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Prostate/pathology , Rectum/pathology , Urinary Bladder/pathology , Algorithms , Humans , Male , Prostatic Neoplasms/pathologyABSTRACT
Prostate segmentation in 3-D transrectal ultrasound images is an important step in the definition of the intra-operative planning of high intensity focused ultrasound (HIFU) therapy. This paper presents two main approaches for the semi-automatic methods based on discrete dynamic contour and optimal surface detection. They operate in 3-D and require a minimal user interaction. They are considered both alone or sequentially combined, with and without postregularization, and applied on anisotropic and isotropic volumes. Their performance, using different metrics, has been evaluated on a set of 28 3-D images by comparison with two expert delineations. For the most efficient algorithm, the symmetric average surface distance was found to be 0.77 mm.
Subject(s)
High-Intensity Focused Ultrasound Ablation/methods , Image Interpretation, Computer-Assisted/methods , Pattern Recognition, Automated/methods , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/surgery , Surgery, Computer-Assisted/methods , Ultrasonography/methods , Algorithms , Humans , Image Enhancement/methods , Male , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Prostate segmentation in MRI may be difficult at the interface with the bladder where the contrast is poor. Coupled-models that segment simultaneously both organs with non-overlapping constraints offer a good solution. As a pre-segmentation of the structures of interest is required, we propose in this paper a fast deformable model to segment the bladder. The combination of inflation and internal forces, locally adapted according to the gray levels, allow to deform the mesh toward the boundaries while overcoming the leakage issues that can occur at weak edges. The algorithm, evaluated on 33 MRI volumes from 5 different devices, has shown good performance providing a smooth and accurate surface.
Subject(s)
Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Models, Anatomic , Models, Biological , Pattern Recognition, Automated/methods , Urinary Bladder/anatomy & histology , Algorithms , Computer Simulation , Humans , Image Enhancement/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A moment-based approach is proposed for texture analysis of medical images. The neighborhood of texture pixel is calculated by moments for texture feature extraction. After verified on Brodatz textures, the moment-based texture analysis method is applied on CT liver scan classification and prostate ultrasound segmentation. A support vector machine and a multi-channel active contour model are used in our application. The result shows that our method works well but still have some limitations.
Subject(s)
Diagnostic Imaging/methods , Image Interpretation, Computer-Assisted/methods , Humans , Liver/diagnostic imaging , Male , Prostate/diagnostic imaging , Tomography, X-Ray Computed , UltrasonographyABSTRACT
This letter describes a temperature-varying attenuation approach for preoperative planning of high intensity ultrasound interstitial targeted therapy. Such approach is mainly aimed at the treatment of primary liver cancer for which a precise lesion control must be achieved. It is shown through simulation that the shape and size of the resulting necrotic volume is significantly different from the one obtained when this tissue property is considered constant in time.
Subject(s)
Hyperthermia, Induced/instrumentation , Models, Theoretical , Ultrasonic Therapy/instrumentation , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/therapy , Liver Neoplasms/pathology , Liver Neoplasms/therapy , Necrosis , Temperature , TransducersABSTRACT
This paper describes a modeling method of the tissue temperature evolution over time in hyperthermia. More precisely, this approach is used to simulate the hepatocellular carcinoma curative treatment by a percutaneous high intensity ultrasound surgery. The tissue temperature evolution over time is classically described by Pennes' bioheat transfer equation which is generally solved by a finite difference method. In this paper we will present a method where the bioheat transfer equation can be algebraically solved after a Fourier transformation over the space coordinates. The implementation and boundary conditions of this method will be shown and compared with the finite difference method.
