segmentation region

good evening I want to select only the outer contour of medical image to be subsequently two regions: region interest and region non interest thank you

EDIT [30 May 2012, 10:26 BST - OK] Moved answer here which was not supposed to be an answer but at most a comment

thanks you I want to decompose an image such as ultrasound 2 region: the content of image and background thanks

[Stephen]

can you provide a link to a picture?

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers

[Image Analyst]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer